Search

The phytochemical investigation of Caralluma quadrangula aerial parts yielded six new pregnane glycosides, quadrangulosides A–F (1–6), in addition to nine known pregnane glycosides and three known flavone glycosides.

Chemical constituents of Raphanus sativus Linn. roots were extracted and tested for their toxicity against adults and second instar nymphs of A. gossypii under laboratory conditions. The most effective fraction against both adults and nymphs was methylene chloride fraction with LC50 values of 386.63 and 309.43 ppm, followed by ethyl acetate fraction with LC50 values of 394.9 and 334.37 ppm then petroleum ether fraction with LC50 values of 636.2 and 424.56 ppm, for adults and nymphs, respectively. Also, the volatile components of each fraction were qualitatively and quantitatively identified and characterized by GC/MS technique. Moreover, the impact of the sub-lethal concentrations of R. sativus roots extracts on transaminases and alkaline phosphatase of A. gossypii was studied. Great inhibition of all tested enzymes activity was observed. This suggested the high potency of R. sativus roots extracts as environmentally friendly alternatives of traditional insecticides. Chemical constituents of Raphanus sativus Linn. roots were extracted and tested for their toxicity against adults and second instar nymphs of A. gossypii under laboratory conditions. The most effective fraction against both adults and nymphs was methylene chloride fraction with LC50 values of 386.63 and 309.43 ppm, followed by ethyl acetate fraction with LC50 values of 394.9 and 334.37 ppm then petroleum ether fraction with LC50 values of 636.2 and 424.56 ppm, for adults and nymphs, respectively. Also, the volatile components of each fraction were qualitatively and quantitatively identified and characterized by GC/MS technique. Moreover, the impact of the sub-lethal concentrations of R. sativus roots extracts on transaminases and alkaline phosphatase of A. gossypii was studied. Great inhibition of all tested enzymes activity was observed. This suggested the high potency of R. sativus roots extracts as environmentally friendly alternatives of traditional insecticides.

Four isolates of Botryococcus braunii Kutzing were isolated from the Nile River in Egypt. The morphological examinations and results of 5.8S rRNA gene sequences confirmed that EG-Bb01 (JN580448.1), EG-Bb02 (JN580449.1), EG-Bb03 (JN580450.1) and EG-Bb04 (JN580451.1) are B. braunii. The isolates were cultivated in modified Chu 13 medium and incubated for 8 weeks at 25±1 °C under light intensity of 16 ± 3 μmol m−2 s−1 with 16:8 h light: dark cycle. The dry weight biomass ranged between 0.382 gl−1 and 0.628 gl−1 for the isolates EG-Bb03 and EG-Bb01. Also, the hydrocarbon production (% w/w) varied significantly (P ≤ 0.05) between 33% (EG-Bb03) and 53% (EG-Bb01). GC/MS analysis revealed marked qualitative and quantitative variations in hydrocarbon profile of B. braunii isolates. A total of 24 C16 C31 different compounds were identified. The hydrocarbon of the four isolates was mainly composed of aliphatic hydrocarbons with the odd carbon numbered C25 C31, indicating that these isolates are a typical race A of B. braunii. Isolate EG-Bb01 maintained the highest content of C25 C31 hydrocarbons of (36.44%). The hexahydrofarnesylacetone (C18H38O) ketone was detected in the four isolates with different proportions ranged between 0.216% (EG-Bb01) and 13.86% (EG-Bb04). Meanwhile, the alcohol hexacosanol C26H54O (31.52%) was only detected in the isolate EG-Bb03.

Myrtus nivellei is a plant traditionally used to treat diseases including infection of microbial origin. Several M. nivellei Batt. & Trab. extracts (dichloromethane, methanol and ethanol/water) were screened for their activity against 36 microorganisms, including strains resistant to antibiotics. These extracts inhibited on average 15 bacteria strains with minimum inhibition concentrations (MICs) ranging from 0.07 to 1.20 mg/mL. Bioassay guided fractionation was carried out with bioautography on TLC plates using four pathogenic bacteria strains, and following chromatographies (CPC and HPLC) led to the isolation of two novel enol ether nor-cadinane sesquiterpenes from the dichloromethane extract. The major compound (1) showed a strong antibacterial activity. Minimal inhibition concentration and minimal bactericidal concentration (MBC) values were determined against four bacteria: Acinetobacter baumanii, Stenotrophomonas maltophilia, Yersinia pseudotuberculosis and Staphylococcus lugdunensis. The best activity was observed against Acinetobacter baumanii with a MIC value of 9.7 μg/mL. This novel compound was also very active against a Staphylococcus aureus strain resistant to amoxicillin (MIC 19.5 μg/mL). In addition, compound 1 showed a very high antioxidant activity with both DPPH and metal chelate methods.

Chemical investigation of the whole Fagonia schimperi C. Presl plant yielded a new triterpene saponin, namely 3-O-β- xylopyranosyl-(1→2)-α-L-arabinopyranosyl-27-hydroxyoleanolic acid 28-O-β-glucopyranoside (1), along with five known natural products 2–6. Structures of the isolated compounds were elucidated by intensive spectroscopic methods including Electrospray Ionisation-Mass Spectrometry (ESI-MS) and 1D and 2D-NMR, which matched the literature data. Fagonia schimperi crude saponin fraction, ethyl acetate (EtOAc) fraction, and the new compound (1) were investigated for their biological activities as antibacterial, antioxidant, and cytotoxicity. EtOAc fraction and compound (1) were the most potent agents, wherein they displayed potent antibacterial activity against both Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Additionally, the EtOAc fraction displayed potent antiproliferative activity against hepatocellular carcinoma and mammary gland with IC50 values of 7.38 ± 0.4 and 4.89 ± 0.3 μg/ml, respectively. Furthermore, compound 1 showed a significant cytotoxic activity against the two cell lines with IC50 values of 19.20 ± 1.4 and 8.18 ± 0.9, μg/ml, respectively. This comes in agreement with the antioxidant activity that was assessed by 2,2,1-diphenyl-1-picrylhydrazyl and SOD-like activity methods in the following order: EtOAc fraction > compound 1 > crude saponin fraction.

During the screening programme for antibiotic produced by actinomycetes, an antibiotic was isolated from the fermentation broth of Streptomyces anulatus NEAE-94. The ethyl acetate extract of S. anulatus NEAE-94 showed high biological activity against Staphylococcus aureus NRRL B-313, multidrug-resistant S. aureus and Bacillus subtilis NRRL B-543. Thin-layer chromatography of the ethyl acetate extract showed one yellowish orange spot with an Rf value of 0.83. The structural elucidation of the isolated compounds was carried out using ultraviolet–visible mass spectrometry (MS), Fourier transform-infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR) and gas chromatography–mass spectrometry (GC–MS) analyses. Characterization of the ethyl acetate extract revealed the presence of 22 compounds, including an unsaturated fatty acid, saturated fatty acids, fatty acid esters, alkanes, alkenes and a triterpene. The antimicrobial efficacy of S. anulatus NEAE-94 might be due to the synergistic effects of the identified compounds.

Marine natural products (MNPs) continue to be in the spotlight in the global drug discovery endeavor. Currently, more than 30,000 structurally diverse secondary metabolites from marine sources have been isolated, making MNPs a profound, renewable source to investigate novel drug compounds. Marine sponges of the genus Suberea (family: Aplysinellidae) are recognized as producers of bromotyrosine derivatives, which are considered distinct chemotaxonomic markers for the marine sponges belonging to the order Verongida. This class of compounds exhibits structural diversity, ranging from simple monomeric molecules to more complex molecular scaffolds, displaying a myriad of biological and pharmacological potentialities. In this review, a comprehensive literature survey covering the period of 1998⁻2018, focusing on the chemistry and biological/pharmacological activities of marine natural products from marine sponges of the genus Suberea, with special attention to the biogenesis of the different skeletons of halogenated compounds, is presented.

Pyrroloquinoline and guanidine-derived alkaloids present distinct groups of marine secondary metabolites with structural diversity that displayed potentialities in biological research. A considerable number of these molecular architectures had been recorded from marine sponges belonging to different marine genera, including Batzella, Crambe, Monanchora, Clathria, Ptilocaulis and New Caledonian starfishes Fromia monilis and Celerina heffernani. In this review, we aim to comprehensively cover the chemodiversity and the bioactivities landmarks centered around the chemical constituents exclusively isolated from these three marine genera including Batzella, Crambe and Monanchora over the period 1981–2017, paying a special attention to the polycyclic guanidinic compounds and their proposed biomimetic landmarks. It is concluded that these marine sponge genera represent a rich source of novel compounds with potential applications for cancer and other therapeutic areas.

Four previously undescribed sucrose diester of aryldihydronaphthalene-type lignans, named echiumins A-D, were isolated from the butanol fraction of Echium angustifolium Mill, in addition to a known compound, trigonotin A, which is reported for the first time from the title plant. The structures of isolated compounds were elucidated using spectroscopic methods such as HRESIMS and 1D and 2D NMR spectroscopy. The isolated compounds displayed strong to weak antitumor activity against HepG2 and MCF7 cancer cell lines, with echiumins A and D showed the most potent activity.

This study involves the development and characterization of a series of sodium alginate-based pH-responsive hydrogel microspheres encapsulating poly( d , l -lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). The effect of the drying technique (air- or freeze-drying) on the size of the developed particles was determined. Swelling characteristics at different pH values, in vitro biodegradation and moisture contents of both air-dried and freeze-dried hydrogel particles were investigated. The effect of drying method on the morphology of the particles was also studied using SEM and AFM. Then, the developed alginate-PLGA particles were evaluated as potential carriers, through a new approach, to improve the dissolution, bioavailability and oral sustained release of silymarin, as a model of hydrophobic natural therapeutics. The used silymarin was isolated from the seeds of some native milk thistle (Silybum marianum) ecotypes of delta Egypt and was characterized with the aid of several analytical techniques including; 1H NMR, UV and FTIR. The obtained data showed a considerable effect of the alginate content and the drying method onto the characteristics of the prepared particles. Also, the results demonstrated that the developed alginate-based hydrogel microparticles encapsulating silymarin-loaded PLGA NPs can be used as biodegradable carriers that can confer sustained oral release of silymarin in addition to enhancing its overall dissolution and oral bioavailability.

This review presents the phytochemical constituents of the genus Plectranthus reported up to 1999. Only a tetrameric derivative of caffeic acid was isolated from P. japonicus, but a group of long-chain alkylphenols, of possible taxonomic significance in the genus, was also isolated. As a genus of the subfamily Nepetoideae, Plectranthus is free from iridoid glycosides and rich in essential oil (i.e. > 0.5% volatile oil on a dry weight basis). Diterpenoids are the more common secondary metabolites in Plectranthus. The majority of them are highly modified abietanoids. This seems to be similar to the pattern of diterpenoids observed for Salvia, but no clerodane diterpenoids were found in Plectranthus.

Separation of the extract of the tubers of Scirpus holoschoenus L. (familyCyperaceae), a species easily confused with Juncus plants, afforded 2-prenyl-3,5,4'-trimethoxystilbene, 2-prenyl-3-hydroxy-5,4'-dimethoxystilbene, 2-prenyl-3,4'-dihydroxy-5-methoxy-stilbene and 3,5,4'-trimethoxystilbene, in addition to a new acetophenonederivative. The isolated compounds were identified on the basis of spectral measurements. Keywords: Scirpus holoschoenus , Cyperaceae, stilbene, prenylstilbenes, acetophenonederivative. _________________________________________________________________________________________________ _____________ Introduction Scirpus holoschoenus L. (family Cyperaceae) is a rare, salty-marsh, perennial, ca. 1 meter highgrass-like herb. Morphologically, it could be easily confused with Juncus (rush; family Juncaceae)because it is devoid of the characteristic solid three-angled stem of Scirpus [1], having instead a hollowcylindrical stem.From the phytochemical point of view

The volatile constituents of Artemesia monosperma Del. from Riyadh area, Saudi Arabia, using GC/MS are described. Twenty- five compounds, mainly sesquiterpenes, have been identified. The chemical findings ascertained that A. monosperma exhibits ecological variability in its chemical composition. A. monosperma was investigated previously for flavonoids (3-6) , acetylenes (2,3,7) , p-hydroxyacetophenone derivatives (3,7-10) , coumarins (9) , p-coumaric acid de- rivatives (3) , tetrahydrofuran-type terpenoids derived from davanone (11) , in addi- tion to cycloartenol, β-sitosterol and stigmasterol (11) . Comparing the chemical constituents of aerial parts of two specimens of A. monosperma, collected from Saint Katherine, South Sinai, Egypt (11) , and from Western Desert, Egypt( 3) , using the same method of processing, revealed that they are completely different. In this article, we have investigated the chemical constituents of the aerial parts of a third specimen of A. monosperma, collected from Riyadh area, Saudi Arabia. The results confirm the variability in the chemical constituents of A. monosperma according to locality accessions.

Separation of the extract of Maerua oblongifolia afforded, in addition to known compounds, three lupane triterpenoids; one of them is new natural product, which was identified, by one and two dimensional NMR, MS and IR spectra, as lup-20(29)-en-3β,30-diol.

5-Benzoylethyl barbituric acid derivatives 2a-c were prepared as useful precursors for the synthesis of pyrimidine fused heterocycles. Their behaviour as 1,5-diketocompounds towards aniline derivatives afforded the pyrimidoquinoline derivatives 6a-e. On the other hand, fusion of o -substituted anilines with 1,3-dimethyl barbituric acid derivatives 8a,b gave the corresponding benzazoles 10a-e. Furthermore, the reaction of 1,3-dimethyl barbituric acid (1) with catechol/K3|Fe(CN)6| or β-ketoester (19)/SiCl4 gave the benzofuro adduct 13a and the diphenylphenyl barbituric acid derivative 18, respectively.

Two new pregnane glycoside diesters, 1 and 2, in addition to two triterpenoids, 3 and 4, and two sterols, 5 and 6 were isolated and identified from Caralluma russeliana (family Asclepiadaceae). The new pregnane glycosides, 14β-benzoyloxy-15β-isovaleroyloxy-16α-hydroxypregn-20-on-3-O-[β-D-3-O-methyl-6-deoxyoleandrosopyranosyl-(1 → 4)-β-D-cymaropyranosyl-(1 → 4)-β-D-cymaropyranoside] (1) and 14β-isovaleroyloxy-15β-benzoyloxy-16α-hydroxypregn-20-on-3-O-[β-D-3-O-methyl-6-deoxyoleandrosopyranosyl-(1 → 4)-β-D-cymaropyranosyl-(1 → 4)-β-D-cymaropyranoside] (2), are different from those isolated previously from the same species in the sugar moiety, in being diester, in being 20-one and in being 5,6 saturated by hydrogen. The isolated compounds were identified on the basis of spectral data.

Balanites aegyptiaca (L.) Delile (Zygophyllaceae) is a tropical tree that has many folk uses in various countries. The bark extract is used for the control of the fresh water snails that act as intermediary host of Schistosoma.Study the molluscicidal activity and chemical constituents of seed oil and seed glycosides of B. aegyptiaca against Monacha cartusiana and determine the structure-activity relationship.Two bioassay methods (residual film application and the leaf dipping technique) were used to evaluate the toxicity effect of the seed oil and glycosides, in concentrations of 1.000, 0.500, 0.250 and 0.125%. The seed oil was analysed by GC/MS. Acid hydrolysis and chromatographic separation were used to study the seed saponins.The bioassay of B. aegyptiaca against the land snail, M. cartusiana, indicated the activity of the seed oil and the high activity of the seed saponins. The seed glycosides gave 30.0, 53.3, 73.0 and 73.3% mortality for concentrations of 0.125, 0.250, 0.500 and 1.00%, respectively. The LC(50) values were 0.335 and 0.256%, respectively. The seed oil was analysed by GC/MS. Acid hydrolysis of the seed saponins gave a mixture of diosgenin, yamogenin and 3,5-spirostadiene.To study the structure-activity relationship, a triterpenoidal saponin and a triterpenoidal saponins rich extract (of Zygophyllum coccenum) were proven to be inactive. Thus, the activity is associated with the steroidal, not triterpenoidal saponins. Moreover, a spirostane aglycone without sugar moiety, was found to be inactive and attained the activity by glycosidation.

The extract of Schoenus nigricans afforded, in addition to a known stilbene and a known prenylflavanone, four new stilbenes and two new prenylflavanones. The structures were elucidated on the basis of spectral data.

Convolvulus hystrix Vahl. (family Convolvulaceae) is a common wild plant growing in the kingdom of Saudi Arabia. It is used in traditional medicine. Our study resulted in the isolation and structural elucidation of ten natural products from which a stilbene carboxylic acid was isolated for the first time as a new natural product. The isolated products are mainly shikimates in addition to two sterols; beta -sitosterol and stigmasterol, as well as one triterpenoid, oleanolic acid. The shikimate products are vanillin, vanillic acid, syringic acid, ferulic acid, isoferulic acid, isoscopoletin and the new stilbene derivative. The structures were elucidated on the basis of spectral data from 400 MHz H-1 NMR, MS, IR and UV. The biogenesis of the new stilbene is discussed.

Chromatographic separation of the extract of the aerial parts of Dodonaea viscosa L. (family Sapindaceae) afforded beta -sitosterol, stigmasterol, the flavone acacetin-7-methyl ether, the flavonol-3-methyl ethers 4,5,7-triliydroxy-3,6-dimethoxy-flavone and penduletin, as well as a new clerodane diterpenoid which was identified by spectral means as 15,16-epoxy-5,9-diepicleroda-3,13(16),14-trien-20,19-olide.

Chromatographic separation of an ethanolic extract of rhizomes of Asphodelus tenuifolius Cav. (Asphodelaceae) yielded in addition to β-sitosterol, stigmasterol and two anthraquinone derivatives, 1,8-dimethoxynaphthalene as well as two new naphthalene derivatives. The new compounds were identified as 2-acetyl-8-methoxy-3-methyl-1-naphthol and 2-acetyl-1,8-dimethoxy-3-methylnaphthalene. The separated compounds were identified on the basis of IR, MS, 1 H and 13 C NMR data.

The aerial parts of Francoeuria crispa gave, in addition to known sesquiterpene lactones, two new ones. From the polar parts a large amount of two diterpene glycosides derived from ent-kauren-19-oic acid were obtained.

An extract of the aerial parts of Cleome africana afforded in addition to known compounds two triterpenes of the dammarane type. The structures were elucidated using high field NMR spectroscopy.

A new sesquiterpene ether, named dactyloxene D, has been isolated from Laurencia obtusa . The structure was identified by spectroscopic methods and stereochemistry was established by NOE difference spectroscopy.

Reichardia tingitana var. orientalis afforded, in addition to lupeol, taraxasterol, and the corresponding acetates, three sesquiterpene lactones of the guaianolide type including a new glucoside. The structures were elucidated by spectral methods.

Artemisia monosperma afforded four flavonoids, two acetylenes, eight p -hydroxyacetophenone derivatives and three p -coumaric acid derivatives, two of them being new. The structures were elucidated by spectral methods. The flavonoids present are naringenin 7-methyl ether, eriodictyol 7-methyl ether, quercetin 3,7-dimethyl ether and quercetin 7,3′-dimethyl ether.

A reinvestigation of the aerial parts of Pyrethrum santolinoides afforded, in addition to known compounds, four new sesquiterpene lactones, three germacranolides and an eudesmanolide. The structures were elucidated by high field 1H NMR techniques.

Achillea fragrantissima afforded, in addition to several known glaucolides, five new compounds whose structures were elucidated by high field 1 H NMR spectroscopy.