Search

The Aedes aegypti mosquito is a vector of important viral diseases in tropical countries, as Zika, Chikungunya and Dengue fever. The use of the chemical control of the insect life cycle is one of the most popular strategies used as prophylactic for the human population exposed. However, potential environmental and human toxicity, as well as the resistance phenomena acquired by the insects, are the main limitations for the available options. This scenario encourages the continuous search for more potent and less inconvenient chemical alternatives. In this paper, we report a potent in vitro larvicidal activity in Aedes aegypti found to a chalcone compound, previously mined by an exhaustive virtual screening by molecular docking calculations in an important protein for the larvae growth. The protein 3-hydroxykynurenine transaminase enzyme (PDB ID: 6MFB) was then combined with potential ligands provided by a homemade databank, containing secondary metabolites found in plants of the brazilian Caatinga biome. Structural rationalization of the compounds with high affinity pointed the chalcone class as most promising. Subsequent in vitro tests allowed the identification of a specific molecule with very high larvicidal potency (100% of lethality at 2.5 ppm). These results can be used in future and more refined studies, to propose a larvicidal formulation for direct application and the exploration of new compounds of this chemical class.

INTRODUCTION Kaurene diterpenes (KDs) constitute a chemical class often found in the genus Annona with interesting biological activities. To date, chromatographic tools have been mostly used to determine KDs. Quantitative nuclear magnetic resonance (qNMR) has distinguished itself in quantitative estimation of natural products and is an interesting choice to assess total KD contents. OBJECTIVE To establish a 1 H qNMR method for determining the total KD contents in extracts and fractions obtained from Annona vepretorum stems. METHODOLOGY Stems were extracted with hexane and methanol, resulting in the hexane extract (HEX-E) and the methanol extract (MeOH-E). The former was partitioned with the acid-base method to obtain the total alkaloid fraction (TA-F) and the neutral dichloromethane fraction (NDM-F). 1 H qNMR measurements were performed on 400 MHz with samples solubilized in deuterated dimethyl sulfoxide. Quantification was carried out using the signals at 4.71 and 4.78 ppm related to hydrogens of the exocyclic double bond of the basic skeleton of KDs and gallic acid as the standard reference. The selectivity, intra- and inter-day precision, reproducibility, limit of detection, limit of quantification, and robustness of the methodology were evaluated. RESULTS Using the newly developed method, the total KD contents (in μg/mg) were 653.80 ± 12.15 (HEX-E), 458.90 ± 25.94 (NDM-F), 375.60 ± 27.52 (TA-F), and 315.10 ± 19.20 (MeOH-E). For determining the most promising bioactive sample, the KD contents and the sample discriminations obtained by principal component analysis were correlated to the antibacterial activity. Such approach pointed out HEX-E as a potential source of KDs. CONCLUSION The developed method offers a fast and simple way of determining total KD contents.

Spondias tuberosa Arruda (Anacardiaceae) is an endemic tree in the Caatinga Brazilian Biome, known locally as "umbuzeiro" and used for various purposes, especially as food and folk medicine. In this study, it was realized for the first time, the extraction and characterization by gas chromatography-mass spectrometry (GC-MS) of the fixed oils of barks, leaves and stems of S. tuberosa. The constituents of the oils were identified by comparing the mass spectra obtained with those of the equipment database. The major component of fixed oil obtained from barks was the 3-n-Pentadecylphenol (44.91 %), in the leaves and stems was observed presence of the tetratetracontane (38.17 and 28.57%, respectively). Antioxidant activity was evaluated by using 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging and β-carotene-linoleic acid bleaching test. The fixed oil obtained from the leaves presented the best antioxidant activity (51.13%±11.8) in β-carotene-linoleic acid bleaching test. This study described for the first time identification and quantification of the components present in the fixed oils of the bark, leaves and stems of Spondias tuberosa. Key words: Natural products, fatty acids, gas chromatography-mass spectrometry (GC-MS), antioxidant.

The objective of this work was to evaluate the phytochemical profile and bioactivity of extracts of Brazilian stinging (“cansanção”) nettle (Cnidoscolus urens) on cabbage caterpillar (Ascia monuste orseis). Mortality, larval stage duration, pupal viability and mass, percentage of deformed pupae, and feeding preference were evaluated. The constituent classes of the ethanolic extracts were also identified by analytical thin-layer chromatography (TLC). Ethanolic extracts of leaves and roots at 2% (m/v) and aqueous extract of roots at 20% (m/v) prolonged the larval phase of the insect. The ethanolic extract of leaves at 2% reduced pupal viability, and pupae from all treatments showed reduced masses and generated deformed adults. Except for the ethanolic extract of stem at 2% (m/v), all other extracts showed a deterrent effect on A. monuste orseis larvae. The phytochemical analysis of ethanolic extracts showed the major presence of phenolic compounds, naphthoquinones, anthraquinones, coumarins, anthracene derivatives, terpenes, and steroids, as well as tannins. Aqueous extracts at 20% concentration and ethanolic extracts at 2% of leaves, stems, and roots of cansanção nettle cause larval mortality and also reduce leaf consumption, pupal viability, and pupal mass of A. monuste orseis.

This study was carried out to assess the antibacterial, cytotoxic and antioxidant activities of extracts of Morus nigra L. HPLC was used to determine the fingerprint chromatogram of the crude ethanolic extract (Mn-EtOH). The antibacterial effect was assessed through the method of microdilution. The cytotoxicity was tested against human tumour cell lines using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The total phenolic and flavonoid contents were also assessed through the Folin-Ciocalteu and aluminum chloride methods, respectively. Antioxidant activities of the extracts were evaluated by using 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging and β-carotene-linoleic acid bleaching methods. The presence of phenolic compounds in Mn-EtOH was confirmed using HPLC. The extracts showed activity against most microorganisms tested. The extracts did not show any expressive antiproliferative effect in the assessment of cytotoxicity. The most significant total phenolic content was 153.00 ± 11.34 mg of gallic acid equivalent/g to the ethyl acetate extract (AcOEt). The total flavonoid content was 292.50 ± 70.34 mg of catechin equivalent/g to the AcOEt extract, which presented the best antioxidant activity (IC50 50.40 ± 1.16 μg/mL) for DPPH scavenging. We can conclude that this species shows strong antibacterial and antioxidant activities, as well as weak cytotoxic effects. Resumo Este estudo foi realizado para avaliar as atividades antibacteriana, citotóxica e antioxidante de extratos de Morus nigra L. HPLC foi utilizado para determinar o perfil de compostos fenólicos do extrato etanólico bruto (Mn-EtOH). O efeito antibacteriano foi avaliado através do método de microdiluição. A citotoxicidade foi testada contra linhagens celulares de tumores humanos utilizando o ensaio do brometo de 3-(4,5-dimetil-2-tiazolil)-2,5-difenil-2H-tetrazólio (MTT). O conteúdo total de compostos fenólicos e flavonoides também foi avaliado por meio dos métodos de Folin-Ciocalteu e cloreto de alumínio, respectivamente. A atividade antioxidante dos extratos foi avaliada por meio do sequestro do radical livre 2,2-difenil-1-picrilhidrazil (DPPH) e co-oxidação do sistema β-caroteno-ácido linoleico. A presença de compostos fenólicos em Mn-EtOH foi confirmada utilizando HPLC. Os extratos mostraram atividade contra a maioria dos microrganismos testados. Os extratos não mostraram qualquer efeito antiproliferativo expressivo na avaliação da citotoxicidade. O conteúdo fenólico total mais significativo foi de 153,00 ± 11,34 mg de equivalente de ácido gálico/g para o extrato acetato de etila (AcOEt). O conteúdo de flavonoides totais foi de 292,50 ± 70,34 mg de equivalente de catequina/g para o extrato AcOEt, que apresentou a melhor atividade antioxidante (IC50 50,40 ± 1,16 mg/mL) para o sequestro do DPPH. Podemos concluir que esta espécie apresenta forte atividade antibacteriana e antioxidante, bem como fraca atividade citotóxica.

This paper reports the first study of the variation of the chemical composition and abundance of the essential oil of Croton heliotropiifolius, in four seasons, and the evaluation of its antibacterial activity. Essential oil obtained from leaves of C. heliotropiifolius were analyzed by GC/MS and evaluated against eight bacteria strains by broth microdilution method. The chemical constituents identified were the same in all samples, but with different proportions. The total percentages identified were 96.58% in summer, 92.08% in autumn, 98.44% in winter and 90.78% in spring. The majors constituents are β-caryophyllene, bicyclogermacrene, germacrene-D, limonene and 1,8-cineole. β-Caryophyllene was the major compound in all samples. The results of the antibacterial evaluations showed weak to moderate activity against the analyzed strains. In all analyzes was observed that essential oil sample collected in summer stands out from the others, displaying stronger activity against Gram-positive as Gram-negative bacteria. Keywords: β-Caryophyllene, Antibacterial activity, Essential oil, Seasonal variation

Alternanthera brasiliana is popularly known as "penicillin" and has been used as an anti-inflammatory and for wound healing in folk medicine, been the flavonoids the main chemical markers with pharmacological activity in this species. The objective of this work was to perform the pharmacognostic characterization of the powder of Alternanthera brasiliana, the optimization of the extraction of total flavonoids and the preparation of a gel with photoprotective effect from the addition of this extract enriched of flavonoids. The pharmacognostic characterization, the preparation of fluid enriched extract of flavonoids and quality control of the gel were carried out according to the Brazilian Pharmacopeia, and the evaluation of photoprotective activity was carried out according to the Mansur method. Regarding pharmacognostic characterization, some data are being published for the first time, such as acid insoluble ash (10.02 ± 0.22 %), sulfated ash (12.77 ± 0.01 %), extractable substances by ethanol (4.75 ± 0.07 %) and the foam index (0). In the optimization of extraction, the condition that provided the extract with the highest concentration of total flavonoids was Ab-EFE-3, with solvent hydration at low level, powder:solvent ratio at low level and magnetic stirring at high level. The highest total flavonoid content was 503.7 ± 14.01 mg of rutin equivalents/g. A gel was manipulated with Alternanthera brasiliana enriched flavonoid extract and had its quality control attested by the tests performed. The spectrophotometric SPF of the prepared gel was analyzed at the beginning (T0) and at the end (T12) of the stability study, presenting statistically different initial and final values. The final SPF-UVB of formulation was 21.33 ± 1.25 for the sample submitted to freezing/defrosting cycle, and 19.57 ± 0.74 for the sample maintained at room temperature.

Considering the therapeutic potential of medicinal plants as alternatives to antibiotic therapy, the research aims to evaluate the antimicrobial activity of Commiphora leptophloeos against isolates of Staphylococcus spp. from the milk of ruminants with subclinical mastitis. For this, the crude ethanolic extract from the bark and leaves of Commiphora leptophloeos was prepared, with these being chemically characterized by HPLC-DAD-MS and by MALDI-TOF. The extracts were then evaluated as to their antimicrobial effects against 60 isolates of Staphylococcus spp. through the broth microdilution technique to determine the minimum bactericidal concentration. In addition, the extracts were evaluated as to their ability to interfere with biofilm formation and with the already established biofilm. Although all tested extracts showed antimicrobial action, lower MBC values were recorded for the bark extract in the concentration 781.2 µg/mL (25/60). The extracts of the bark and leaves were able to interfere with the initial stages of biofilm formation, but there was no interference of the extract on the established biofilm. There was a high sensitivity of Staphylococcus spp. isolates from subclinical mastitis cases in ruminants when subjected to the extracts from bark and leaves of Commiphora leptophloeos, as well as regarding the ability of extracts to interfere in biofilm formation, indicating their potential in the use for ruminant mastitis therapy. Resumo Considerando o potencial terapêutico de plantas medicinais como alternativas à antibioticoterapia, a pesquisa visa avaliar a atividade antimicrobiana de Commiphora leptophloeos contra isolados de Staphylococcus spp. de leite de ruminante com mastite subclínica. Para isso, foi elaborado o extrato etanólico bruto da casca e folhas de Commiphora leptophloeos, sendo as mesmas caracterizadas quimicamente por HPLC-DAD-MS e por MALDI-TOF. Os extratos foram então avaliados quanto aos seus efeitos antimicrobianos contra 60 isolados de Staphylococcus spp pela técnica de microdiluição em caldo para determinação da concentração bactericida mínima. Além disso, os extratos foram avaliados quanto à sua capacidade de interferir na formação do biofilme e com o biofilme já consolidado. Apesar de todos os extratos testados terem apresentado ação antimicrobiana, valores menores de CBM foram registrados para o extrato da casca na concentração 781,2 µg/mL (25/60). Os extratos da casca e das folhas foram capazes de interferir nos estágios iniciais da formação do biofilme, mas não ocorreu interferência do extrato no biofilme consolidado. Houve alta sensibilidade do isolados testados quando submetidos a extratos de folhas e casca de Commiphora leptophloeos, bem como a capacidade de extratos interferirem na formação de biofilme, indicando seu potencial uso na terapia de mastite de ruminantes.

Kaurene diterpenes (KDs) constitute a chemical class often found in the genus Annona with interesting biological activities. To date, chromatographic tools have been mostly used to determine KDs. Quantitative nuclear magnetic resonance (qNMR) has distinguished itself in quantitative estimation of natural products and is an interesting choice to assess total KD contents.To establish aStems were extracted with hexane and methanol, resulting in the hexane extract (HEX-E) and the methanol extract (MeOH-E). The former was partitioned with the acid-base method to obtain the total alkaloid fraction (TA-F) and the neutral dichloromethane fraction (NDM-F).Using the newly developed method, the total KD contents (in μg/mg) were 653.80 ± 12.15 (HEX-E), 458.90 ± 25.94 (NDM-F), 375.60 ± 27.52 (TA-F), and 315.10 ± 19.20 (MeOH-E). For determining the most promising bioactive sample, the KD contents and the sample discriminations obtained by principal component analysis were correlated to the antibacterial activity. Such approach pointed out HEX-E as a potential source of KDs.The developed method offers a fast and simple way of determining total KD contents.

Lonchocarpus araripensis Benth. is largely distributed in the northeast region of Brazil. It is popularly known as ‘sucupira’. Recent studies have shown that some species of Lonchocarpus have interesting pharmacological activities. In this study, we evaluated the antinociceptive effect of a flavone isolated from L. araripensis. The chemical examination resulted in the isolation of 3,6-dimethoxy-6″,6″-dimethyl-(7,8,2″,3″)-chromeneflavone (DDF). The structure of the compound was established by spectral analysis. Antinociceptive activity of DDF was evaluated by measuring nociception by acetic acid, formalin and hot plate tests. The rota rod test was used to evaluate motor coordination. The results demonstrated that DDF was able to prevent acetic-acid-writhing-induced nociception (p

The antioxidant and photoprotective activities of dried extracts from the leaves of Encholirium spectabile were investigated. It was also evaluated the total phenolic and flavonoid contents by the Folin–Ciocalteu and aluminum chloride methods, respectively. Antioxidant activities of the extracts were evaluated by using of 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging and β-carotene–linoleic acid bleaching and compared with ascorbic acid, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) used as reference compounds. The photoprotective effect was evaluated by the spectrophotometric method. The most significant total phenolic and flavonoid contents was of 188.50 ± 27.50 mg of gallic acid equivalent/g and 129.70 ± 4.59 mg of catechin equivalent/g, respectively, for chloroform fraction (Es-CHCl3). The Es-CHCl3 also presented the best antioxidant activity (IC50 25.35 ± 4.35 μg/ml) for DPPH scavenging. The ethanol extract (Es-EtOH), Es-CHCl3 and the fraction ethyl acetate (Es-AcOEt) showed characteristic absorption bands in regions UVB and UVA in a concentration-dependent manner. Es-CHCl3 presented the highest sun protection factor SPF (8.89 ± 2.11). It shows the possibility to use this extract as sunscreen in pharmaceutical preparations.

Specimens of Leonotis nepetiflolia were obtained from cultivated and wild environments to verify their influences in chemical composition. Phytochemical analyses were conducted for the ethyl acetate phase obtained by partitioning the crude ethanol extract from the cultivated leaves of L. nepetifolia. In doing so, flavonoid 3',4',5-trimethoxy-6,7-dihidroxyflavone (cirsiliol), a chemotaxonomic marker of the family Lamiaceae, was isolated. The results reveal that all phases and extracts tested exhibited weak to moderate antimicrobial activity against the strains of bacteria tested. The evaluation of in vitrocytotoxic and antitumor activity showed that the ethyl acetate phases obtained from both wild and cultivated leaves exhibit high potential cytotoxic and antitumor (> 78.0% of inhibition) activity. The major component of these phases was identified by high-performance liquid chromatography-diode array detector and nuclear magnetic resonance analyses using both 1D and 2D methods. The results further indicate that the flavonoid cirsiliol is the agent responsible for the activity observed in these phases.

The phytochemical screening, antioxidant and photoprotective activities of dried extracts from the leaves of Neoglaziovia variegata were investigated. It was also evaluated the total phenolic and flavonoid contents by the Folin-Ciocalteu and aluminum chloride methods, respectively. Antioxidant activities of the extracts were evaluated by using of 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging and β-carotene-linoleic acid bleaching and compared with ascorbic acid, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) used as reference compounds. The photoprotective effect was evaluated by the spectrophotometric method. Preliminary analysis demonstrated that the extracts were found to be positive for the presence of anthracene derivatives, flavonoids, tannins, mono and diterpenes, naphthoquinones, coumarins, triterpenoids and steroids. The most significant total phenolic and flavonoid contents was of 608.50 ± 14.74 mg of gallic acid equivalent/g and 272.50 ± 9.25 mg of catechin equivalent/g, respectively, for ethyl acetate fraction (Nv-AcOEt). The Nv-AcOEt also presented the best antioxidant activity (IC50 3.51 ± 0.18 μg/ml) for DPPH scavenging. The chloroform fraction (Nv-CHCl3) and Nv-AcOEt showed characteristic absorption bands in regions UVB and UVA in a concentration-dependent manner. Nv-AcOEt presented the highest sun protection factor SPF (27. 68 ± 4.03). It shows the possibility to use this extract as sunscreen in pharmaceutical preparations.

Purpose: To investigate the phytochemistry and cytotoxic activity of stem bark extracts from Anaxagorea dolichocarpa and Duguetia chrysocarpa - two species of the Annonaceae family. Methods: The crude ethanol bark extracts (EtOH) of the plants were obtained by maceration. The crude extracts were suspended in a mixture of methanol (MeOH) and water (H2O) (proportion 3:7 v/v) and partitioned with hexane, chloroform (CHCl3) and ethyl acetate (AcOEt) in ascending order of polarity to obtain the respective fractions. The extracts were evaluated on thin layer chromatography (TLC) plates of silica gel to highlight the main groups of secondary metabolites. Cytotoxicity was tested against human tumor cell lines - OVCAR-8 (ovarian), SF-295 (brain) and HCT-116 (colon) - using 3(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Results: The screening results demonstrated that all the extracts were positive for the presence of flavonoids and tannins. The presence of alkaloids also was detected in some extracts. The hexane extract of A. dolichocarpa showed the strongest cytotoxicity against HCT-116 with cell growth inhibition of 89.02 %. Conclusion: The findings demonstrate for the first time the cytotoxic activity of the extracts of A. dolichocarpa and D. chrysocarpa, thus providing some evidence that plants of the Annonaceae family are a source of active secondary metabolites with cytotoxic activity.