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The present study aims to describe the chemical composition of essential oils from three Vietnamese Annonaceae species, Meiogyne virgata, M. vietnamica, and Orophea polycarpa, and their antimicrobial activity. Essential oils were extracted by hydro-distillation. From the GC-FID/MS (gas chromatography-flame ionization detection and mass spectrometry) analysis, the leaf essential oil of M. virgata was reported to contain the major compound germacrene D (42.48%). Spathulenol (24.51%), bicyclogermacrene (18.58%), β-selinene (11.14%), and germacrene D (8.20%) can be seen as the main compound in M. vietnamica leaf essential oil. α-Phellandrene (39.35%), bicyclogermacrene (13.07%), β-phellandrene (10.87%), and limonene (8.27%) represented O. polycarpa leaf essential oil. Essential oil of M. virgata leaves exhibited strong antimicrobial activity against the Gram (+) bacterium Bacillus subtilis ATCC 5230, the Gram (-) bacterium Escherichia coli ATCC 8739, and the fungus Aspergillus niger ATCC 9587 with the same MIC value of 16 μg/mL. The docking method showed that germacrene D has the ΔGbinding (binding affinity) values of –6.68, –5.265, and –5.602 kcal/mol with the proteins E. coli DNA gyrase, B. subtilis TasA, and A. niger PhyA, respectively. Alkyl and pi-alkyl interactions are the main contributors to the binding affinity between the studied proteins and ligands. Furthermore, germacrene D is predicted to have low toxicity and is not active against any of the considered organ targets. [ABSTRACT FROM AUTHOR]

Chemical compositions in the leaf essential oils of four Syzygium species were first identified by the GC-FID/MS analysis. Monoterpene hydrocarbons (39.6-51.1%), and sesquiterpene hydrocarbons (27.0-37.8%) were the main chemical classes in S. formosum and S. syzygioides leaf oils, whereas sesquiterpene hydrocarbons (83.0-83.8%) were predominant in S. Megacarpum and S. chantaranothaianum leaf essential oils. Bicyclogermacrene (9.1-37.0%) was the principal compounds in these essential oils. All the tested essential oils with the MIC values of 16-128 µg/mL were comparable to the positive control streptomycin against Gram-positive bacteria Staphylococcus aureus and Bacillus cereus, and Gram-negative bacterium Pseudomonas aeruginosa. The leaf essential oils of S. formosum, S. syzygioides, and S. chantaranothaianum with the MIC values of 16-128 µg/mL were comparable to the positive control cycloheximide against the yeast Candida albicans. Four samples also exhibited good larvicidal activity against the mosquito Aedes aegypti with the 24-h and 28-h LC50 values of 25-40 µg/mL [ABSTRACT FROM AUTHOR]

This article discusses the chemical composition and antimicrobial activity of the essential oils of a newly discovered species of the Piper genus found in Central Vietnam. The study identifies 43 compounds in the oils, with terpenoids being the predominant chemical class. The oils exhibit strong antimicrobial activity against three Gram-positive bacteria. The research contributes to the understanding of the chemical properties and potential uses of Piper species. [Extracted from the article]

This article provides information on the chemical compositions of essential oils from the leaves of two species of Camellia plants, Camellia pukhangensis and Camellia quephongensis. The essential oils of these plants contain various compounds, including alkanes, esters, and ketones. The article specifically focuses on the chemical compositions of the leaf oils of C. pukhangensis and C. quephongensis, identifying the main compounds present in each. The two species differ significantly in the number of phytochemical classes and the presence of specific compounds. The document also provides information on the collection and analysis methods used. [Extracted from the article]

The chemical constituents and antimicrobial activity of the essential oils isolated from the leaves of Machilus cicatricosa S.K. Lee and Machilus bonii Lecomte from Vietnam were studied and reported. The techniques of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS) were used to characterize the chemical constituents of the essential oil while the microdilution assay was used to evaluate the antimicrobial activity. The main constituents of the leaf oil of M. cicatricosa were α-pinene (20.6%), bicyclogermacrene (15.2%), linalool (14.9%), and β-pinene (8.4%). On the other hand (E)-β-ocimene (26.3%), bicyclogermacrene (23.6%) and (E)-nerolidol (9.1%) were the major constituents of M. bonii leaf essential oil. The studied essential oils displayed antimicrobial activity against Enterococcus faecalis ATCC 29212, and Staphylococcus aureus ATCC 25923, with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. In addition, essential oil from the leaf of M. bonii was the most active towards Bacillus cereus ATCC14579 with MIC value of 64.0 μg/mL, while M. cicatricosa showed stronger anti-candidal activity against Candida albicans ATCC 10231 with MIC value of 32.0 μg/mL. This is the first report on the chemical constituents and antimicrobial activity of the essential oils of M. cicatricosa and M. bonii. [ABSTRACT FROM AUTHOR]

The essential oils of five Vietnamese Syzygium species (Syzygium levinei, S. acuminatissimum, S. vestitum, S. cumini, and S. buxifolium) were first hydro-distilled and analyzed using GC-FID/MS (gas chromatography–flame ionization detection/mass spectrometry). Monoterpene hydrocarbons, sesquiterpene hydrocarbons, and oxygenated sesquiterpenoids were the main chemical classes in these oils. All these essential oils showed good–excellent antimicrobial activities against Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, and the yeast Candida albicans. S. levinei leaf essential oil, rich in bicyclogermacrene (25.3%), (E)-β-elemene (12.2%), (E)-caryophyllene (8.2%), and β-selinene (7.4%), as well as S. acuminatissimum fruit essential oil containing (E)-caryophyllene (14.2%), α-pinene (12.1%), caryophyllene oxide (10.9%), β-selinene (10.8%), α-selinene (8.0%), and α-humulene (5.7%), established the same MIC value of 8 µg/mL against E. faecalis and B. cereus, which were much better than the positive control streptomycin (MIC 128–256 µg/mL). The studied essential oils showed the potential to defend against mosquitoes since they caused the 24 and 48 h LC50 values of less than 50 µg/mL against the growth of Culex quinquefasciatus and Aedes aegypti larvae. Especially, S. buxifolium leaf essential oil strongly inhibited Ae. aegypti larvae with 24 and 48 h LC50 values of 6.73 and 6.73 µg/mL, respectively, and 24 and 48 h LC90 values of 13.37 and 10.83 µg/mL, respectively. These findings imply that Vietnamese Syzygium essential oils might have potential for use as supplemental antibacterial agents or as "green" alternatives for the control of mosquitoes. [ABSTRACT FROM AUTHOR]

The paper reports that the main constituent of essential oil from the leaves of Macclurodendron oligophlebia (Merr.) Hartl. growing in Vietnam was α-pinene (81.7%), while α-pinene (67.4%) and limonene (11.2%) were the major compounds in fruit essential oil. The composition of essential oils from the leaves and fruits of Melicope ptelefolia (Champ. ex Benth.) T.G. Hartley was characterized as germacrene D (34.0% and 31.1%, respectively), bicyclogermacrene (5.5% and 7.6%, respectively), d-elemene (9.9% and 9.0%, respectively) and α-pinene (6.5% and 9.8%, respectively). The fruit essential oil contains limonene (4.9%) and (E)-β-ocimene (8.1%). The fruit essential oils of M. oligophlebia and M. ptelefolia exhibited anti-candial activity towards Candida albicans ATCC 10231, with minimum inhibitory concentration (MIC) value of 8.0 μg/mL and 32.0 μg/mL, respectively. M. oligophlebia fruit oil also showed action against Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 14579, each with MIC value of 32.0 μg/mL. Also, M. oligophlebia leaf showed higher activity against Pseudomonas aeruginosa ATCC 27853 (MIC, 32.0 μg/mL). The other oil samples exhibited varying degrees of antimicrobial activity with MIC values of either 64.0 μg/mL or 128. 0 μg/mL. The leaf essential oil of M. oligophlebia displayed larvicidal activity against Aedes aegypti larvae with minimum lethal concentration (LC50) values of 16.71 μg/mL and 11.40 μg/mL, respectively at 24 h and 48 h. The fruit oil did not exhibit any larvicidal action. However, M. ptelefolia leaf and fruit showed activity at 24 h with LC50 values of 33.18 μg/mL and 35.06 μg/mL, respectively. [ABSTRACT FROM AUTHOR]

However, monoterpene hydrocarbons (34.7%), oxygenated monoterpenes (4.7%), sesquiterpene hydrocarbons (49.8%), oxygenated sesquiterpenes (7.7%), and nonterpenes (1.4%) were the classes of compounds identified in the stem essential oil of I S. henryi i subsp I . hoatii i . However, the compositions of essential oils from other I Schisandra i plants have been described - essential oil from the berries of I S. chinensis i are comprised of I i I cis i -bergamotene (10.7%), selina-4,11-diene (5.2%), and I i -cadinol (5.1%), while the ylangene (10.1%), I i -himachalene (9.4%) and I di i I epi i I i -cedrene (8.9%) were found in the seed oil. The identities of these terpenes differ from species to species - for example, I i -ylangene, I cis i I i -bergamotene and I di i I epi i I i -cedrene, the major compounds of I S. chinesis i [[2]], were conspicuously absent in I S. henryi i subsp I . hoatii i essential oils. However, the fruit essential oil of I S. chinensis i isolated by simultaneous distillation extraction (SDE) showed good antibacterial activity against both Gram-positive ( I S. epidermidis i , I S. aureus i , I B. subtilis i ) and Gram-negative ( I E. coli i , I P. aeruginosa i , I Proteus vulgaris i ) bacteria [[3]]. [Extracted from the article]

Zingiber is a genus of medicinal plants containing a rich resource of essential oils. The current study aims to describe chemical analysis and antimicrobial assay for two Zingiber species Zingiber eberhardtii Gagnep. and Z. skornickovae N.S. Lý. The rhizome oils, which were obtained by hydro-distillation using a Clevenger apparatus, were analyzed by GC-MS (gas chromatography-mass spectrometry). Extraction of Z. eberhardtii rhizome gave a yellow oil with 41 identified compounds (96.3%), in which linalool (34.9%) and 1,8-cineole (12.7%) were the principal compounds. The yellow oil of Z. skornickovae rhizome included 53 identified compounds (97.8%), with β-pinene (25.0%), (E)-caryophyllene (8.8%), and α-pinene (7.9%) as the major agents. By broth dilution method, both oils moderately controlled the growth of Gram (+) bacteria Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 25923 with the same MIC (minimum inhibitory concentration) value of 128 μg/mL. In particular, Z. skornickovae rhizome oil showed the best antimicrobial activity against yeast Saccharomyces cerevisiae ATCC 4098 with a MIC value of 64 μg/mL. The obtained results are promising information for future research. [ABSTRACT FROM AUTHOR]

Syzygium plants are known as sources of biologically active substances. The essential oils constituents and antimicrobial activity of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam are being reported. Essential oils were obtained by hydrodistillation of the leaves of S. petelotii and S. syzygioides collected from Pù Hoạt Nature Reserve, Vietnam. The constituents of the essential oils were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated by microdilution broth susceptibility assay. The results indicate that γ-guaiene (24.1%), β-caryphyllene (9.3%), α-pinene (7.8%), and β-pinene (6.1%) were the major compounds of S. petelotii. The main constituents of S. syzygioides were caryophyllene oxide (14.8%), α-pinene (10.6%), β-pinene (6.6%) and spathulenol (6.4%). The essential oil of S. petelotii showed pronounced antimicrobial activity against Pseudomonas aeruginosa ATCC27853 and Enterococcus faecalis ATCC299212, with minimum inhibitory concentration (MIC) values of 16.0 μg/mL and 64.0 μg/mL, respectively. The essential oil of S. syzygioides only displayed activity towards Pseudomonas aeruginosa ATCC27853 with MIC value of 32.0 μg/mL. Both essential oils exhibited antimicrobial activity towards Bacillus cereus ATCC14579 (MIC value, 128.0 μg/mL), and anti-candidal action against Candida albicans ATCC10231 with MIC value of 64.0 μg/mL. The chemical compositions and antimicrobial activity of essential oils of S. petelotii and S. syzygioides are being reported for the first time. [ABSTRACT FROM AUTHOR]

In this study, the antimicrobial activity and constituents of essential oils from the leaves of Cinnamomum auricolor Kosterm. and C. petelotii Kosterm collected from Pù Hoạt Natural Reserve (Hạnh Dịch Commune, Quế Phong District), Vietnam were reported. The essential oils obtained by separate hydrodistillation were analyzed by means of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS). The antimicrobial activities were evaluated by microbroth dilution susceptibility assay. The main constituents of C. auricolor comprised of oxygenated sesquiterpenes mainly caryophyllene oxide (26.0%), spathulenol (11.1%), and (E)-nerolidol (10.7%). However, oxygen-containing monoterpenes were the main compounds identified in S. petelotii and they are linalool (34.3%), 1,8-cineole (20.8%) and terpinene-4-ol (9.9%). The essential oil of C. auricolor displayed prominent antimicrobial activity towards Bacillus cereus ATCC14579 and Staphylococcus aureus ATCC25923 with minimum inhibitory concentration (MIC) value of 16.0 μg/mL. In addition, the essential oil of C. auricolor also exhibited antimicrobial activity against Enterococcus faecalis ATCC29212, and anti-candidal activity towards Candida albicans ATCC10231 with MIC value of 32.0 μg/mL. The leaf essential oil of C. petelotii only exhibited activity towards S. aureus and C. albicans with MIC value of 64.0 μg/mL. The chemical constituents and antimicrobial activity of both essential oils are being reported for the first time. [ABSTRACT FROM AUTHOR]

Lindera chunii Merr. is an important member of the Lauraceae family of plants which are known for their medicinal values. In this research article, the chemical constituents and antimicrobial activity of essential oils from the leaves of L. chunii grown in Vietnam were reported. The essential oil was obtained by hydrodistillation of the leaves of L. chunii while the constituents were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated using a microdilution broth susceptibility assay. The constituents occurring in higher amounts in the leaf essential oil of L. chunii were mainly the monoterpene hydrocarbons comprising terpinolene (13.0%), α-pinene (8.0%), β-pinene (7.6%), camphene (7.3%), β-phellandrene (7.1%) and myrcene (5.0%). The leaf essential oil of L. chunii inhibited the growth of Enterococcus faecalis ATCC29212, Staphylococcus aureus ATCC25923 and Salmonella enterica ATCC13076, each with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. The corresponding median lethal concentration (IC50) values were 19.45 μg/mL, 20.45 μg/mL and 18.78 μg/mL, respectively. The essential oil also displayed anti-candidal activity towards Candida albicans ATCC10231 with MIC value of 64.0 μg/mL, and IC50 value of 23.12 μg/mL. The antimicrobial activity of L. chunii essential oil was reported for the first time as a confirmation of the traditional uses of the plant in the treatment of microbial infections. Furthermore, the paper discusses the chemotaxonomy of Lindera oil samples. [ABSTRACT FROM AUTHOR]

From hydro-distillation and GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry) analysis, chemical compositions in essential oils of two Vietnamese Piper plants Piper pendulispicum C. DC. and P. hymenophyllum Miq. were identified. Essential oils of P. pendulispicum leaf and stem are highlighted with the predominant amount of sesquiterpene hydrocarbons (73.21-78.06%), in which bicyclogermacrene (12.17-12.54%) and β-caryophyllene (12.10-14.51%) were the principal compounds. Monoterpene hydrocarbons (87.44%) are the main chemical class of P. hymenophyllum leaf oil, in which α-pinene (52.92%) and β-pinene (26.65%) are the principal compounds. These obtained essential oils with the MIC (minimum inhibitory concentration) values of 16-128 μg/mL are better than the positive control streptomycin ((MIC 128-256 μg/mL) in antimicrobial assay against three Gram-positive bacteria Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 14579. P. pendulispicum essential oils (MIC 16-32 μg/mL) are also comparable to the other standard cycloheximide (MIC 32 μg/mL) against the yeast Candida albicans ATCC 10231. In general, P. pendulispicum essential oil is better than P. hymenophyllum leaf oil for antimicrobial treatment. [ABSTRACT FROM AUTHOR]

The essential oil from the leaf oil of I L. annamensis i displayed promising antibacterial activity against I Enterococcus faecalis i ATCC299212 and I Staphylococcus aureus i ATCC25923, and anti-candidal action towards I Candida albicans i ATCC10231, with a minimum inhibitory concentration (MIC) value of 32.0 g/mL (Table 2). In our previous communications, the chemical compositions and antimicrobial activity of essential oils from I L. glauca i [[2]] and I L. rufa i [[3]] were reported. The leaves of I L. annamensis i afforded essential oil dominated by sesquiterpene hydrocarbons (76.1%) and monoterpene hydrocarbons (14.9%). [Extracted from the article]

In this study, the leaves of Syzygium szemaoense Merrill & L.M. Perry and Syzygium corticosum (Lour.) Merr. & L.M. Perry was screened for their essential oils constituents and antimicrobial activities. The main constituent of S. szemaoense was cis-β-elemene (68.0%), while β-caryophyllene (54.0%) was the most abundant constituent of the essential oil of S. corticosum. Both essential oils displayed moderate antimicrobial activity against Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 25923 with minimum inhibitory concentration (MIC) value of 128.0 µg/mL, as well as anti-candidal action towards Candida albicans ATCC 10231 with MIC value of 64.0 µg/mL. The essential oil of S. corticosum showed antimicrobial activity towards Bacillus cereus ATCC 14579 with MIC value of 128.0 µg/mL. The chemical compositions and antimicrobial activities of both S. szemaoense and S. corticosum are being reported for the first time. The essential oils of S. szemaoense and S. corticosum may be considered for further investigation for antimicrobial uses. [ABSTRACT FROM AUTHOR]

The current study describes chemical compositions and antimicrobial activity of essential oils from the rhizome of two Vietnamese ginger plants Newmania orthostachys N.S. Lý & Škorničk. and Newmania serpens N.S. Lý & Škorničk. 49 compounds (98.4%) were identified in N. orthostachys rhizome oil, whereas 54 compounds (93.4%) were identified in N. serpens rhizome oil. N. orthostachys rhizome essential oil was dominated by monoterpene hydrocarbons (74.2%), in which β-pinene (35.7%), α-pinene (13.4%), sabinene (8.0%), camphene (6.7%), and limonene (5.1%) were characteristic compounds. Monoterpene hydrocarbons (33.5%) and sesquiterpene hydrocarbons (44.1%) represented N. serpens rhizome essential oil, as well as β-pinene (18.5%), bicyclogermacrene (12.4%), β-selinene (8.2%) were the principal compounds. In an antimicrobial assay against three tested Gram-positive bacteria Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 14579, both two essential oils showed the minimum inhibitory concentration (MIC) values of 16-64 µg/mL lower than those of positive control Streptomycin (MIC 128-256 µg/ml). These two essential oils with the MIC values of 8-16 µg/mL are also better than the positive control cycloheximide (MIC 32 µg/mL) against the yeast Candida albicans ATCC 10231. [ABSTRACT FROM AUTHOR]

The compositional pattern of I M. cochinchinensis i was similar to that of I M. obovatifolia i [[10]] and I M. philippinensis i [[12]] owing to high contents of monoterpene and sesquiterpene hydrocarbons. The chemical constituents of essential oils from I Machilus i species of Vietnamese origin such as I M. velutina i [[3]], I M. grandifolia i [[4]], I M. balansae i [[4]], and I M. japonica i [[5]] have been reported. Monoterpene hydrocarbons were the main compounds in I M. velutina i [[3]] and I M. japonica i [[5]], whereas sesquiterpene hydrocarbons were found in I M. grandifolia i [[4]]. I M. zuihoensis i [[7]], I M. pseudolongifolia i [[8]], I M. mushaensis i [[9]], I M. obovatifolia i [[10]], and I M. kusanoi i [[11]] also showed moderate action toward the organisms mentioned. [Extracted from the article]

The overuse of antibiotics has led to the sharp increase of antibiotic‐resistant bacteria that can consequently transmit and cause hard‐to‐cure human diseases. To deal with this problem, nano drug delivery systems have been widely researched. This report focuses on developing an Alginate/Chitosan‐based nanosystem that carried simultaneously Doxycycline (DOX), Florfenicol (FLO), and silver nanoparticles (AgNPs). The optimal Alginate/Chitosan ratio of 3 : 2 (w/w) created the most stable nanocarrier system. The fabricated DOX‐FLO@AgNPs had a spherical shape with a small size of about 20 nm and could release slowly DOX and FLO at pH of 7.4 and 5.0. In vitro drug release kinetics of DOX and FLO from DOX‐FLO@AgNPs fitted best to the Weibull or Higuchi model by the mechanism of the Fickian or non‐Fickian diffusion. The nanosystem of DOX‐FLO@AgNPs had much lower IC50 of 0.012±0.001 and 0.08±0.005 μg/mL against E.coli and B.subtilis, respectively, than the conventional form. The FIC50 value of smaller than 0.5 μg/mL for 5 out of 6 tested bacteria also indicated the synergistic effect of each component in this antibiotic combination. Moreover, the cytotoxicity assay confirmed the viability of 96.4±2.3 % for vero cell line that exposured to the treatment dose. Therefore, these findings strongly suggest that the DOX‐FLO@AgNPs formulation is promising for combined antibiotic drug delivery and silver nanoparticles, and will be worth investigating for further in vivo potential. [ABSTRACT FROM AUTHOR]

Thus, the essential oil of I V. solanifolia i should be considered a promising antimicrobial agent because the essential oil displayed activity at MIC < 50 g/mL. To our knowledge, this is the first report on the antimicrobial activity of the essential oil of I V. solanifolia i , and the results in this study are comparable with data on the antimicrobial potential of other I Vernonia i essential oils reported in the literature. In addition, the leaf essential oil of I V. patula i displayed antimicrobial activity toward I Enterococcus faecalis i ATCC299212 with a minimum inhibitory concentration (MIC) value of 8.67 g/mL and anticandidal property against I Candida albicans i ATCC10231 with a MIC value of 15.99 g/mL [[7]]. The main constituents of I V. patula i leaf oil from Vietnam were I i -caryophyllene, caryophyllene oxide, I i -copaene, and I i -humulene [[7]], whereas the leaf oil of I V. amygdalina i contained caryophyllene oxide and I i -caryophyllene [[8]]. [Extracted from the article]

The main constituents of I A. calcicola i leaf essential oil were I i -pinene (14.4%), I i -cadinene (9.7%), I i -caryophyllene (7.7%), I i -cadinol (7.0%), and 9 I epi i -( I E i )-caryophyllene (5.1%), whereas I i -cadinol (19.1%), I i -pinene (15.3%), I i -cadinene (10.1%), and I epi i I i -muurolol (9.4%) were found in the rhizome essential oil. It could be seen that terpene compounds predominate in the essential oils, as was previously reported for other I Alpinia i oil samples grown in Vietnam, such as I A. napoensis i [[2], [4]], I A. menghaiensis i [[3]], I A. maclurei i [[3]], I A. globosa i [[5]], and I A. tonkinensis i [[5]]. Moreover, terpenes were also the predominant compounds of other I Alpinia i essential oils reported from other parts of the world, which include I A. kwangsiensis i [[15]] and I A. zerumbet i [[16]]. For example, the yields of the hydrodistilled essential oils of I A. napoensis i leaves, stems, and roots were 0.21%, 0.17%, and 0.25% respectively [[2]], whereas I A. napoensis i rhizome gave oil in a yield of 0.26% [[4]]. [Extracted from the article]

The present paper reports for the first time the chemical composition and antimicrobial activity of essential oil from the leaves of Phoebe macrocarpa C. Y. Wu. The yield of the essential oil was 0.28% (w/w). The essential oil features monoterpene hydrocarbons (3.3%), oxygenated monoterpenes (2.8%), sesquiterpene hydrocarbons (31.9%) and oxygenated sesquiterpenes (46.0%). The major compounds of the essential oil were β-caryophyllene (16.6%) and spathulenol (12.6%). The essential oil showed moderate antimicrobial activity towards Enterococcus faecalis ATCC299212 with minimum inhibitory concentration (MIC) value of 128 µg/mL, Staphylococcus aureus ATCC25923 (MIC 256 µg/mL) and Bacillus cereus ATCC14579 (MIC 1280 µg/mL). The essential oil did not display anti-candidal activity. [ABSTRACT FROM AUTHOR]

The compositions and antimicrobial activity of essential oils from the leaves and rhizomes of Zingiber magang N.S. Lý & Škornièk sp. nov. and Zingiber tamii N.S. Lý & Škornièk. sp. nov. from Vietnam were reported. The essential oils from Z. magang were obtained in yields of 0.12 % (leaf) and 0.18 % (rhizome), while Z. tamii afforded essential oils with yields of 0.15 % and 0.20 %, respectively, for the leaf and rhizome. The leaf essential oil of Z. magang consists of β-pinene (12.3 %) and (E)-nerolidol (10.3 %), while α-selinene (10.5 %), caryophyllene oxide (9.7 %), and neo-intermedeol (7.5 %) were found in the rhizome essential oil. However, the compositions of essential oils from the leaf and rhizome of Z. tamii comprised mainly of β-pinene (53.8 % and 55.4 %), and sabinene (12.3 % and 12.5 %), respectively. The rhizome essential oil of Z. magang displayed promising antimicrobial activity against Enterococcus faecalis ATCC 299212 and Staphylococcus aureus ATCC 25923 with the Minimum inhibitory concentration (MIC) values of 9.99 μg/mL and 9.67 μg/mL, respectively. In addition, essential oil from the leaf of Z. tamii was the most active against Escherichia coli ATCC 25922 (MIC 44.38 μg/mL) and Candida albicans ATCC 10231 (MIC, 45.62 μg/mL). This is the first report on the chemical compositions and antimicrobial activity of essential oils of Z. magang and Z. tamii. [ABSTRACT FROM AUTHOR]

Essential oils from the rhizomes of Boesenbergia quangngaiensis N.S. Lý were obtained by hydrodistillation and the chemical components were determined by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS). In addition, the microdilution broth assay was used to test the antimicrobial activity of essential oils. The yield of the B. quangngaiensis rhizome essential oils was 0.16 % (w/w). The major components identified from the rhizome essential oil of B. quangngaiensis were cis-β-elemene (18.4 %), zerumbone (11.4 %) and myrtenyl acetate (10.6 %). The antimicrobial activity test indicated that B. quangngaiensis rhizome essential oil displayed good activity against Pseudomonas aeruginosa ATCC 27853 with a Minimum inhibitory concentration (MIC) value of 7.68 μg/mL and IC50 value of 16.0 μg/mL. Also, the essential oil inhibited the growth of other tested bacteria and yeast, except Escherichia coli ATCC 25922 and Salmonella enterica ATCC 13076, with MIC value of about 30 μg/mL. The chemical components and antimicrobial activity of the B. quangngaiensis rhizome essential oil were reported for the first time. [ABSTRACT FROM AUTHOR]

Camellia pleurocarpa (Gagnep.) Sealy, a species of yellow camellia indigenous to Vietnam, was investigated for its essential oil properties in this study. Hydrodistillation of its leaves yielded a complex mixture rich in sesquiterpenes and diterpenes. Chemical analysis identified 50 constituents, with notable compounds including spathulenol (13.26%), phytol (9.94%), and α-selinene (5.34%). The essential oil exhibited significant antimicrobial activity against three Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus; one Gram-negative bacterium Pseudomonas aeruginosa; and one yeast Candida albicans, with minimum inhibitory concentration (MIC) values ranging from 16 to 32 μg/mL and half-maximal inhibitory concentration (IC50) values ranging from 7.26 to 16.23 μg/mL. Furthermore, it demonstrated larvicidal potential against Aedes aegypti and Culex quinquefasciatus mosquitoes, with LC50 values ranging from 13.49 to 28.95 μg/mL and LC90 values ranging from 28.29 to 53.24 μg/mL. These findings underscore the promising antimicrobial and mosquito larvicidal properties of C. pleurocarpa essential oil, suggesting its potential as a natural alternative in combating microbial infections and controlling mosquito-borne diseases. This study represents the first comprehensive report on the chemical compositions and bioactivities of C. pleurocarpa essential oil. [ABSTRACT FROM AUTHOR]

In the present communication, the composition and antimicrobial activity of essential oil from the leaves of Acorus macrospadiceus (Yam.) F. N. Wei & Y. K. Li from Vietnam were reported. The yield of the essential oil was 0.25 % (w/w). The main constituents of the essential oil were β-caryophyllene (31.1 %), α-selinene (12.6 %), α-asarone (12.0 %) and α-humulene (8.0 %). The essential oil displayed anti-candidal activity against Candida albicans ATCC 10231 with a minimum inhibitory concentration (MIC) value of 8.67 μg/ mL. In addition, the essential oil exhibited a broad spectrum of antimicrobial activity against the other tested microorganisms with MIC in the range 17.33 μg/mL (Enterococcus faecalis ATCC 299212) to 100.33 μg/mL (Escherichia coli ATCC 25922). The antimicrobial activities of A. macrospadiceus are being reported for the first time. [ABSTRACT FROM AUTHOR]

The herb, Elettariopsis triloba (Gagnep.) Loes. (syn. Amomum trilobum Gagnep. or Elettariopsis trilobum (Gagnep.), has been used ethnomedically for the treatment of rabies, inflammation and amelioration of microbial infections. We report herein the chemical constituents and antimicrobial activity of the rhizome essential oil of E. triloba from north-central Vietnam. The technique of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS) was used to analyze the oil sample while the microdilution assay was employed to determine the antimicrobial efficacy. Monoterpene compounds including camphene (23.2 %), fenchyl acetate (12.7 %), bornyl acetate (10.6 %), α-pinene (5.7 %) and limonene (5.1 %) were the main constituents of the rhizome essential oil. The essential oil displayed antimicrobial activity only towards Gram-positive bacteria of Enterococcus faecalis ATCC 299212, Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 14579 with minimum inhibitory concentration (MIC) values of 16.0 μg/mL, 256 μg/mL and 32.0 μg/mL, respectively. The oil also inhibited the growth of the yeast, Candida albicans ATCC 10231, with a MIC value of 16.0 μg/mL. The chemical constituents and antimicrobial activity of essential oil from E. triolba were being reported for the first time and validation of the ethnomedicinal usage of the plant. [ABSTRACT FROM AUTHOR]

Amomum velutinum X.E.Ye, Škornièk. & N.H.Xia (local name: Sa nhân lông hung) has been used in ethnomedicine for the amelioration of fever, rheumatism and microbial infections among others. In this study, the chemical constituents and antimicrobial activity of essential oils from the leaf, pseudo-stem and rhizome of A. velutinum were described. The study includes hydrodistillation of essential oils from the plant parts, instrumental analysis of the essential oils by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS) and the determination of the antimicrobial activity of the essential oils by the microdilution broth susceptibility assay. The essential oils were obtained in yields of 0.18 %, 0.11 and 0.21 % (v/w,±0.01) respectively for the leaf, pseudo-stem and rhizomes. β-Pinene (43.5 %-46.3 %) and α-pinene (5.2 %-8.1 %) were the main constituents of the essential oils. The leaf oil contained a significant quantity of myrtenyl acetate (10.5 %) and thymol (6.8 %), while β-caryophyllene (14.0 %), cis-β-elemene (9.8 %) and α-pinene (5.2 %) were found in the pseudo-stem oil in sizeable amount. The essential oils inhibited the growth of gram-positive bacteria namely Enterococcus faecalis ATCC299212 with minimum inhibitory concentration value (MIC) of 3.98-25. 56 μg/mL), Staphylococcus aureus ATCC25923 (MIC 32.87-100.56 μg/mL), Bacillus cereus ATCC14579 (MIC19. 78-20.45 μg/mL) and a strain of yeast, Candida albicans ATCC10231 (MIC 20.56-55.67 μg/mL). This was the first report on the chemical compositions and antimicrobial activity of essential oils from A. velutinum. The results are an indication of the potential of A. velutinum essential oils as a source of antimicrobial agents. [ABSTRACT FROM AUTHOR]

The rhizome essential oil of Curcuma sahuynhensis from Quang Ngãi Province, Vietnam, was obtained by hydrodistillation and analyzed by gas chromatographic techniques. The major components in the essential oil were β-pinene (52.7 %), β-caryophyllene (11.1 %), α-pinene (8.6 %), caryophyllene oxide (6.5 %), and (Z)-β-farnesene (5.9 %). The rhizome essential oil was screened for antimicrobial activity and showed good activity against the Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, and the pathogenic yeast Candida albicans with minimum inhibitory concentrations of 64 μg/mL against each of the microorganisms. This study represents the first phytochemical analysis and bioactivity screening of C. sahuynhensis. [ABSTRACT FROM AUTHOR]

Essential oil hydrodistilled from the rhizomes of Alpinia naopensis H.G. Dong & G.J. Xu was characterised by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity was evaluated by microdilution broth susceptibility assay while the larvicidal efficacy on Aedes albopictus and Culex quinquefasciatus was determined by the World Health Organization protocol. The main constituents of the essential oil were 1,8-cineole (18.2 %), γ-terpinene (12.5 %), terpinene-4-ol (9.6 %), β-pinene (9.2 %) and fenchyl acetate (7.7 %). From the antimicrobial study, the essential oil showed activity towards six of the eight tested microorganisms with MIC < 50.0 μg/mL. At concentration 100 μg/mL, the essential oil exhibited 100 % mortality towards Ae. albopictus and Cx. quinquefasciatus under 24 h and 48 h. The oil displayed larvicidal activity against Ae. albopictus with median lethal concentrations (LC50) values of 56.39 μg/mL (24 h) and 53.85 μg/mL (48 h), as well LC50 values of 46.67 μg/mL (24 h) and 38.29 μg/mL (48 h) towards Cx. quinquefasciatus. [ABSTRACT FROM AUTHOR]

This paper reports the chemical constituents and the antimicrobial activity of essential oils hydrodisitlled from the leaves of Alpinia globosa Hour (syn. Amomum globosum Lour.) and Alpinia tonkinensis Gagnep. The essential oils were analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) techniques. The minimum inhibitory concentration (MIC) values were measured by the microdilution broth susceptibility assay. The absolute yields of the essential oils were 0.16 % (v/w, ± 0.01) and 0.21 % (v/w, ± 0.02), respectively for A. globosa and A. tonkinensis, calculated on a dry weight basis. The major constituents of A. biglobosa were β-pinene (12.1 %), α-gurjunene (10.5 %) and (Z)-13-docosenamide (9.0 %). The compounds occurring in higher amount in A. tonkinensis includes β-pinene (33.5 %), (E)-β-ocimene (9.6 %), γ-terpinene (9.2 %) and α-pinene (8.4 %). The essential oil of A. tonkinensis inhibited the growth of Saccharomyces cerevisiae (ATCC 16404) with MIC value of 25.0 μg/mL. In addition, both essential oils displayed antimicrobial activity against Escherichia coli (ATCC 25922), Staphylococcus aureus subsp. aureus (ATCC 11632) and Fusarium oxysporum (ATCC 48112) with MIC value of 50.0 μg/mL. The chemical constituents and antimicrobial activity of the studied essential oils were being reported for the first time. [ABSTRACT FROM AUTHOR]

Abstract Commercial carbon felt (CF) substrates have been modified with iron-rich MFI zeolite nanoseeds prepared by a solvothermal microwave-assisted synthesis method. The as-prepared material (MFI@CF) was characterized by TGA, XRD, SEM, and used as both cathode and catalyst in heterogeneous electro-Fenton (EF) process for the abatement of a biorefractory model dye pollutant, Acid Orange 7 (AO7). The complete degradation of 200 mL AO7 (0.1 mM) was achieved after 40 min contact with the modified material instead of more than 120 min with the pristine one. The proposed catalytic system exhibited an attractive activity with the total organic carbon (TOC) removal reaching 26.6% after 8 h at pH 6.5. The present results prove a promising efficiency of iron-rich MFI@CF material for a "green" EF treatment of water pollutants, avoiding the use of any non-recyclable soluble Fe2+ salt classically required as EF catalyst. Graphical abstract Image 1 Highlights • Novel electrode active for heterogeneous electro-Fenton process was developed. • Iron-rich MFI zeolites exhibit both high adsorption and electrochemical activity. • High efficiency of the system for biorefractory compounds degradation was assessed. [ABSTRACT FROM AUTHOR]

A new method utilizing fluorescent ratiometry is proposed for detecting putrescine and spermidine. The method involves the use of a fluorescent probe comprising a 2D halide perovskite synthesized from octadecylamine-iodine and PbI2via a grinding-sonicating technique, along with a Eu3+-complex. Upon excitation at 290 nm, the probe fluoresces at two distinguishable wavelengths. The addition of putrescine and spermidine significantly decreases the emission of the 2D halide perovskite at 496 nm, while the emission of the Eu3+-complex at 618 nm remains stable. The color changes of the probe depend on the concentration of putrescine and spermidine, and the assay offers linearity over a wide concentration range (30–4000 ng mL−1), a low detection limit (4 ng mL−1 for putrescine, and 7 ng mL−1 for spermidine), and a quick response time. Furthermore, a portable device based on a smartphone can be used to record the color change of the paper test strip using the prepared fluorescent materials. The fluorescence quenching mechanism of the probe is explained as dynamic quenching. [ABSTRACT FROM AUTHOR]

Hierarchical three-dimensional (3D) porous architecture Fe II Fe III layered double hydroxide (LDH) multiwall was grown on carbon-felt (CF) substrate via solvothermal process. The as-deposited Fe II Fe III LDH/CF cathode was composed of highly oriented and well crystallized interconnected nanowalls with high electrical conductivity and excellent catalytic activity over a wide pH range (pH 3–9) for heterogeneous electro-Fenton (HEF) degradation of antibiotic sulfamethoxazole (SMT) in aqueous medium. Mineralization efficiencies (in terms of TOC removal) of ∼97%, 93% and 90% was achieved at pH 3, 6 and 9 respectively for Fe II Fe III cathode during HEF treatment of 0.2 mM SMT solution at applied current density of 7.5 mA cm −2 using Ti 4 O 7 anode. Comparative electro-Fenton (EF-Fe 2+ ) with 0.2 mM Fe 2+ or electrooxidation with H 2 O 2 production (EO-H 2 O 2 ) studies using raw CF cathode at similar experimental conditions showed relatively lower mineralization with highest TOC removal efficiency of 77% and 64% obtained at pH 3 for EF-Fe 2+ and EO-H 2 O 2 respectively. Oxidative degradation of SMT in HEF system was by (i) Ti 4 O 7 ( OH) generated at anode surface at all pH studied, (ii) surface catalyzed process and (iii) contribution from homogeneous catalyzed process at pH 3 due to leached iron ions. The prepared Fe II Fe III LDH/CF exhibited excellent catalytic stability with good reusability up to 10 cycles of 4 h treatment at pH 6. Initial SMT solution showed relatively high toxicity but total detoxification of the solution was attained after 8 h of treatment by HEF with Fe II Fe III LDH/CF cathode. HEF with Fe II Fe III LDH/CF cathode is an exciting technique for remediation of organic contaminated wastewater. [ABSTRACT FROM AUTHOR]

In the title compound, C15H14IN3O2·CH3OH, two aromatic rings are linked by an N-substituted hydrazide function. The dihedral angle between the aromatic rings is 10.53 (8)°. The stereochemistry about the imine function is E. The methanol molecule forms an O-H...O hydrogen bond to the hydrazide O atom. In the crystal, chains of molecules running along the c-axis direction are formed by O-H...O hydrogen bonds. Adjacent chains are linked through N-H...O hydrogen bonds and π-π stacking interactions. The intermolecular interactions in the crystal packing were investigated using Hirshfeld surface analysis, which indicated that the most significant contacts are H...H (38.2%), followed by C...H/H...C (20.6%), O...H/H...O (11.1%) and I...H/H...I (9.7%). [ABSTRACT FROM AUTHOR]

Carbonaceous materials are abundantly used for electrochemical applications and especially for energy and environmental purposes. In this review, the carbon felt (CF) based-electrodes are discussed in a holistic manner. First of all, the study centers on the issues relevant to pristine CF materials such as manufacturing method and specific properties. The various methods and equations used to identify physical values of CF material are supplied. As main part of the review, the different modification methods for CF electrodes are described. The novel properties of fabricated materials are characterized by physical as well as electrochemical techniques. The strengths of each method are presented in the comparison with raw CF electrodes. The energy applications of CF based-electrodes are figured out in various fields such as vanadium redox flow batteries (VRFB), microbial fuel cells (MFCs), biofuel cells (BFCs), capacitors, solar cells and lithium ion batteries. For environmental applications, we focus our study on the wastewater treatment containing biorefractory pollutants by electro-Fenton (EF) process. The degradation result by EF technology using CF materials is impressive when most of toxic contaminants are mineralized to non-toxic compounds at the end of the electrolysis. To decrease the cost treatment and upgrade the treatment efficiency, the EF system has been improved by using modified electrodes or new catalyst sources. The CF materials are also investigated to apply in bio-fuel cell-Fenton in which electrons were produced from fuel cell (FC) towards zero-energy depollution. Finally, the sketches about EF pilot open new gates for application of CF materials in industrial areas. [ABSTRACT FROM AUTHOR]

Study and development of drug delivery nanosystem for cancer treatment are attracting great attention in recent years. In this work, we studied the role of folic acid as a targeting factor on magnetic nanoparticle Fe 3 O 4 based curcumin loading nanosystem. Characteristics of the nanosystems were investigated by Fourier transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and vibrating sample magnetometer (VSM), while targeting role of folic was accessed in vivo on tumor bearing mice. The results showed that folate attached Fe 3 O 4 based curcumin loading nanosystem has very small size and exhibits better targeting effect compared to the counterpart without folate. In addition, magnetic induction heating of this nanosystem evidenced its potential for cancer hyperthermia. [ABSTRACT FROM AUTHOR]

The in vivo imaging of the drug distribution during cancer treatment plays an important role in helping physicians and pharmacists to monitor the progress of treatment and improve the effectiveness of therapy. Our goal in this work was to prepare a multifunctional nano drug delivery system that not only co‐loaded iron oxide nanoparticles (Fe3O4 NPs) and Doxorubicin (Dox) but also attached the near‐infrared fluorescent agent Cyanine 5.5 based on poly(lactide)‐tocopheryl polyethylene glycol 1000 succinate (PLA‐TPGS) copolymer. Cyanine 5.5 was attached to the surface Fe3O4 NPs via the NH−CO chemical bond, followed by co‐loading of Dox onto the PLA‐TPGS copolymer by the emulsion solvent evaporation method. The structural, morphological, dimensional, stability, and optical‐magnetic properties of the as‐synthesized nanosystem were fully characterized. From the drug‐released study, the prolonged release of Dox accelerated with increasing acidic conditions (at pH 5.0 and 6.5), while a slow release was observed at pH 7.4. Through the MTT assay, the nanosystem had cellular toxicity against Hep−G2 and HeLa cell lines with low IC50 values of 0.42 and 0.78 μg.mL−1 in terms of Dox concentration, respectively. At a magnetic field of 7 T, this nanosystem also exhibited a high r2/r1 ratio of 164.5 and a strong contrast magnetic resonance (MR) image in the liver. In vivo biodistribution studies revealed that the highest fluorescence intensity achived in the liver after 6 h, and the nanosystem was eliminated from the body after at least 24 h. Collectively, these results demonstrated that the PLA‐TPGS‐Fe3O4‐Cyanine 5.5‐Dox nanosystem is a good candidate for simultaneously increasing contrast for MR and near‐infrared fluorescence imaging. [ABSTRACT FROM AUTHOR]

Diarylether (DE) is a privileged structure found in both natural products and synthetic compounds including small molecule drugs. We present the synthesis of a series of 13 new DE‐amino acid conjugates which were screened for cancer cells antiproliferation activity. Structure‐activity relationship suggests ester and phenyl groups in DE‐Phe‐OEt 4 c are important for the activity. Compound 4 c inhibited strongly MCF‐7 3D tumor sphere formation and have favourable calculated physical chemical properties according to Lipinski's rule of 5. Docking study suggests estrogen receptor and/ or 3a‐HSD type 3 protein could be the target(s) for anticancer activity of this class of compounds. [ABSTRACT FROM AUTHOR]

Background: Leaves, flowers and young shoots of yellow Camellia species are often used as a substitute for green tea in Vietnam. Yellow Camellia species contain high levels of polyphenol compounds, and have shown activities such as antioxidant, anticancer, and cytotoxic. Objectives: We qualitatively screened phytochemicals, quantified total polyphenols of 70% ethanol (EtOH) extracts of leaves, young shoots, and flowers of Camellia vuquangensis and Camellia hatinhensis in Ha Tinh Province, Vietnam. Furthermore, these extracts have been evaluated for lipid peroxidation inhibitory activities at the in vivo level in the BALB/c mouse model, and in vitro cytotoxic activities. Materials and Methods: Chemical methods and thin-layer chromatographic (TLC) analysis were used for the qualitative screening of phytochemicals. High-performance liquid chromatography (HPLC) was used to determine total polyphenols. Cell survival was determined through optical density (OD) measured when the protein composition of the cells was stained with sulforhodamine B (SRB). Inhibition of lipid peroxidation was evaluated by determining the content of malondialdehyde (MDA), which is a product of membrane lipid peroxidation. Results: The total polyphenol contents of all parts of the two species were comparable to that of green tea with values between 319.3 and 342.6 mg gallic acid equivalents (GAE/g) dry weight. Extracts of leaves, flowers of C. vuquangensis and C. hatinhensis showed strong lipid peroxidation inhibitory activities (IC50: 7.92–17.45 µg/mL) and moderate cytotoxic activities against cell lines HepG2, A549, MCF7, SK-Mel-2, HT-29, and AGS (IC50: 34.73–80.58 µg/mL). Conclusion: These two tea species may be considered as herbal teas with various health benefits. [ABSTRACT FROM AUTHOR]

The Aicda gene encodes activation-induced cytidine deaminase (AID). Aicda is strongly transcribed in activated B cells to diversify immunoglobulin genes, but expressed at low levels in various other cells in response to physiological or pathological stimuli. AID’s mutagenic nature has been shown to be involved in tumor development. Here, we used a transgenic strategy with bacterial artificial chromosomes (BACs) to examine the in vivo functions of Aicda regulatory elements, which cluster in two regions: in the first intron (region 2), and approximately 8-kb upstream of the transcription start site (region 4). Deleting either of these regions completely abolished the expression of Aicda-BAC reporters, demonstrating these elements’ critical roles. Furthermore, we found that selectively deleting two C/EBP-binding sites in region 4 inactivated the enhancer activity of the region despite the presence of intact NF-κB-, STAT6- and Smad-binding sites. On the other hand, selectively deleting E2F- and c-Myb-binding sites in region 2 increased the frequency of germinal-center B cells in which the Aicda promoter was active, indicating that E2F and c-Myb act as silencers in vivo. Interestingly, the silencer deletion did not cause ectopic activation of the Aicda promoter, indicating that Aicda activation requires enhancer-specific stimulation. In summary, precise regulation of the Aicda promoter appears to depend on a coordinated balance of activities between enhancer and silencer elements. [ABSTRACT FROM AUTHOR]

The major compounds of the essential oil of I T. odorum i were I i -pinene (20.4%), I i -caryophyllene (6.4%), and -humulene (5.6%). The essential oils of I M. hypolampra i were dominated by I i -pinene (36.5 and 41.3%), I i -pinene (23.7 and 24.4%), and germacrene D (14.6 and 5.8%) [[14]]. On the other hand, monoterpene hydrocarbons (5.6%), monoterpene oxygenated (3.9%), sesquiterpene hydrocarbons (61.4%), oxygenated sesquiterpenes (10.4%), and nonterpenes (2.0%) constitute the bulk of the essential oil of I M. chevalieri i . Compounds such as I i -pinene and I i -pinene have previously shown antimicrobial activity against broad-spectrum microorganisms [[15]]. [Extracted from the article]

The essential oils from the leaves and rhizomes of I M. cristatissima i displayed moderate antimicrobial activity (Table 2). The obtained essential oils were light-yellow coloured and the yields were 0.16% (leaf) and 0.25% (rhizome), which is consistent with values reported previously for the majority of the I Amomum i essential oils from Vietnam - for example, essential oils from the leaf and rhizome I A. cinnamomeum i were obtained in yields of 0.12 and 0.19%, respectively [[1]], while the leaves and stems of I A. rubidum i afforded essential oils in yields of 0.22 and 0.15%, respectively [[2]]. It is well noted that terpene compounds predominate in the essential oils, and this has been previously reported for other I Amomum i essential oil samples grown in Vietnam [[1]]. [Extracted from the article]

This article describes the major gem materials of Vietnam, together with their new finds and recent production. The gemological properties and chemical composition of ruby, sapphire, spinel, tourmaline, garnet, and peridot from the most important Vietnamese sources are updated. Other gems such as aquamarine, green orthoclase, topaz, zircon, quartz, and pearls are briefly discussed. Commercially significant deposits of ruby, blue and fancy sapphire, and spinel are located in two northern provinces: Yen Bai (Luc Yen and Yen Binh Districts) and Nghe An (Quy Chau and Quy Hop Districts). Large volumes of blue, green, and yellow sapphire come from the Central Highlands provinces of Dak Lak and Lam Dong, as well as the southern provinces of Dong Nai and Binh Thuan. Of secondary commercial importance are the tourmaline and garnet from Yen Bai and the peridot and zircon from the Central Highlands. [ABSTRACT FROM AUTHOR]

Abstract: This article addresses a dearth in the literature on condominium apartment CIDs in transition economies, focusing on change in grassroots urban governance both at the apartment building level and the neighborhood. The authors attempt to explain why apartment building CIDs, a long established phenomenon in many developed and developing countries, is emerging for the first time in Vietnam. The authors use a relational perspective, emphasizing the evolutionary and contextual factors determining the realization of Webster’s characterization of homeowner associations as ‘collective consumption clubs’, which manages micro attributes at a specific residential scale. The paper argues that the development and spread of condominium apartment CIDs in Vietnam resulted from the major policy shifts of housing privatization and democratization at the grassroots. These broad policy changes are important constitutive elements for institutional functionality of condominium CIDs to become viable and effective. Further, they describe how the private collective (i.e. homeowner association) in charge of apartment building management co-exists and complements neighborhood governance under the local government, creating differentiated grassroots governance, which is a radical shift from a pure state administration at both the neighborhood and apartment building levels, dominant during the pre-Doi Moi era. These issues are illuminated and analyzed through the use of both qualitative and quantitative primary data and review of public documents, and empirically described through the use of a case study of a condominium apartment CID in Ho Chi Minh City. [Copyright &y& Elsevier]

[Display omitted] • The CdTe nanoparticles were succesfully synthesized by co-precipitate. • CdTe@βCD nanoparticles were fabricated by a sonication technique. • A novel aspartic chiral assay is suggested. • The available mechanism of the assay is proposed. • The proposed aspartic chiral assay exhibited as a simple and rapid sensing method. Based on the quenching effect of fluorescence intensity of CdTe nanoparticles coated β-cyclodextrin, a novel aspartic chiral assay is suggested. The CdTe nanoparticles were synthesized by co-precipitate and then modified with β-cyclodextrin through a sonication technique to get CdTe@βCD nanoparticles. To characterize CdTe@βCD, FT-IR spectra, fluorescence spectroscopy, and transmission electron microscope were applied. The coupling of host–guest interaction of β-cyclodextrin and aspartic and the fluorescence quenching effect resulted in high selectivity on aspartic of CdTe@βCD sensor. The quenching process was described by the Stern–Volmer equation. The available mechanism of the assay is proposed. Under optimal conditions, the limit of detection of the assay for D-aspartic form was calculated to be 19 ng/mL. The proposed aspartic chiral assay exhibited as a simple and rapid sensing method. [ABSTRACT FROM AUTHOR]

The paper reports the chemical compositions and antimicrobial activity of essential oils from Blumea lacera (Burm. f.) DC., Tridax procumbens (L.) L., and Ageratum houstonianum Mill., of Asteraceae family grown in Vietnam. The essential oils were isolated by hydrodisitllation and analysed by GC and GC/MS. The Minimum inhibitory concentration (MIC) and Median inhibitory concentration (IC50) values were measured by the microdilution broth susceptibility assay. The main compounds of B. lacera were germacrene D (25.5%), 2,5-dimethoxy-p-cymene (20.6%), β-caryophyllene (17.9%), thymol methyl ether (6.3%). T. procumbens afforded essential oil whose major constituent was β-pinene (13.4%), while germacrene D (21.3%), α-pinene (19.0%), and β-caryophyllene (8.9%) constitute the bulk of A. houstenianum essential oil. The leaf essential oils of A. houstenianum collected in August (MIC, 8.0 μg/mL) and B. lacera (MIC, 16.0 μg/mL) were the most active against Enterococcus faecalis ATCC 29212, with corresponding IC50 values of 4.00 μg/mL and 5.67 μg/mL, respectively. The essential oil of T. procumbens exhibited the most potent activity towards Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 14579, with MIC value of 32.0 μg/mL and IC50 values of 12.45 μg/mL and 7.89 μg/mL, respectively. Also, both A. houstenianum essential oils collected in August and April displayed antibacterial action against Pseudomonas aeruginosa ATCC 27853 with MIC values of of 64.0 μg/mL (IC50, 21.45 μg/mL) and 32.0 μg/mL and (IC50, 15.22 μg/mL). Both B. lacera and T. procumbens showed anti-candidal property with MIC value of 16.0 μg/mL, as well as IC50 values of 5.69 μg/mL and 8.66 μg/mL, respectively. [ABSTRACT FROM AUTHOR]

Mosquitoes, in addition to being a biting nuisance, are vectors of several pathogenic viruses and parasites. As a continuation of our work identifying abundant and/or invasive plant species in Vietnam for use as ecologically friendly pesticidal agents, we obtained the essential oils of Blumea lacera, Blumea sinuata, Emilia sonchifolia, Parthenium hysterophorus, and Sphaeranthus africanus; analyzed the essential oils using gas chromatographic techniques; and screened the essential oils for mosquito larvicidal activity against Aedes aegypti and Aedes albopictus. The most active larvicidal essential oils were B. sinuata, which was rich in thymohydroquinone dimethyl ether (29.4%), (E)-β-caryophyllene (19.7%), α-pinene (8.8%), germacrene D (7.8%), and α-humulene (4.3%), (24-h LC50 23.4 and 29.1 μg/mL) on Ae. aegypti and Ae. albopictus, respectively, and Emilia sonchifolia, dominated by 1-undecene (41.9%) and germacrene D (11.0%), (24-h LC50 30.1 and 29.6 μg/mL) on the two mosquito species. The essential oils of P. hysterophorus and S. africanus were also active against mosquito larvae. Notably, B. sinuata, P. hysterophorus, and S. africanus essential oils were not toxic to the non-target water bug, Diplonychus rusticus. However, E. sonchifolia essential oil showed insecticidal activity (24-h LC50 48.1 μg/mL) on D. rusticus. Based on these results, B. sinuata, P. hysterophorus, and S. africanus essential oils appear promising for further investigations. [ABSTRACT FROM AUTHOR]

The empirical heat capacities of some hot-rotating A ∼ 200 nuclei (184Re, 200Tl, 211Po, and 212At) have been investigated by combining the angular-momentum dependent back-shifted Fermi gas (BSFG) model of nuclear level density (NLD) with the experimental NLD data extracted from the neutron-evaporation spectra at the average total angular momentum ⟨ J ⟩ = 12 ℏ. The parameters of the BSFG are obtained by fitting its NLD to the corresponding measured data using an advanced package of program modeling (CPM) provided by Python feature of IBM decision optimization CPLEX. The results obtained show that the shell correction plays an important role in the formation of empirical S -shaped heat capacity, which serves as a fingerprint for the pairing phase transition in finite nuclear systems. The 184Re nucleus, which is deformed and has small shell correction, exhibits a weaker S -shaped heat capacity than the remaining three spherical 200Tl, 211Po, and 212At nuclei that have large shell effects. This result contrasts with that recently predicted by the microscopic exact pairing plus independent-particle model at finite temperature (EP + IPM), in which the S -shaped heat capacity was predicted in 184Re only. This discrepancy between the heat capacities obtained within the BSFG and EP + IPM models suggests that an NLD model capable of well describing the experimental data while also having intrinsic and as complete as possible physical interpretations is still required in order to provide the exact description of nuclear thermodynamic quantities. In addition, more experimental NLD data in other mass and higher energy regions are also demanded. [ABSTRACT FROM AUTHOR]

We compare piezoelectric phonon scattering mechanism with optical phonon one in both Gallium arsenide (GaAs) and Gallium nitride (GaN) materials of a quantum well through the their contribution to the magneto-optical transition linewidths (MOTLWs). Applying the projection-operator and the profile methods to compute the magneto-optical conductivity tensor (MOCT), magneto-optical absorption power (MOAP), and MOTLWs. Numerical calculation results show that the MOTLWs increase as the temperatures and the magnetic fields increase, but decrease as the electron density and the well width increase for both GaN and GaAs materials. In particular, the MOTLWs due to piezoelectric phonons vary sharper and have larger value than they do due to optical phonons in both GaN and GaAs materials, and the MOTLWs of GaN are larger than those of GaAs for both piezoelectric and optical phonon scattering mechanisms. As small enough quantum-well-width, the piezoelectric phonon modes play an important role and they should be considered in studying the magneto optical transition properties in low-dimensional electron systems. • Influence of piezoelectric phonons on the magneto-optical transition linewidths (MOTLWs) in GaN and GaAs is studied. • MOTLWs are affected strongly by temperature, magnetic field, electron density, and well width. • MOTLWs for piezoelectric phonon are compared with those for optical phonon in both GaN and GaAs. • MOTLWs of GaN are compared with those of GaAs for both piezoelectric and optical phonons. • Influence of piezoelectric phonon on the MOTLWs is considerable and cannot be neglected. [ABSTRACT FROM AUTHOR]

In this study, we investigated the cyclotron–interface phonon resonance line-width in GaAs/AlAs asymmetric semiparabolic quantum wells when electrons are scattered by symmetric (antisymmetric) interface optical phonons. The operator projection and profile methods were employed to calculate the expressions for the absorption power and the full width at half maximum (FWHM), respectively. We found that the electron–interface phonon interactions by the antisymmetric modes are weaker than those by the symmetric modes under all phonon emission and absorption cases. In addition, the FWHM is more dominant for interface phonon absorption compared with that for interface phonon emission. The interface optical phonon modes at the resonance peak with a lower-photon frequency are much more important for electron–interface optical phonon scattering than those at the resonance peak with a higher-photon frequency. Our results are consistent with previously reported experimental data. • Cyclotron–interface phonon resonance line-width in asymmetric semiparabolic QWs. • Electron–interface phonon (EIP) interaction weaker in antisymmetric modes. • EIP interaction more dominant for phonon absorption than phonon emissions. • EIP interaction dependent on frequency of semiparabolic confinement potential. • Contribution of interface optical phonons significant at low photon frequencies. [ABSTRACT FROM AUTHOR]