Essential Oil Composition and DNA Barcode and Identification of Aniba species (Lauraceae) Growing in the Amazon Region.

Lauraceae species are widely represented in the Amazon, presenting a significant essential oil yield, large chemical variability, various biological applications, and high economic potential. Its taxonomic classification is difficult due to the accentuated morphological uniformity, even among taxa from a different genus. For this reason, the present work aimed to find chemical and molecular markers to discriminate Aniba species collected in the Pará State (Brazil). The chemical composition of the essential oils from Aniba canelilla, A. parviflora, A. rosaeodora, and A. terminalis were grouped by multivariate statistical analysis. The major compounds were rich in benzenoids and terpenoids such as 1-nitro-2-phenylethane (88.34-70.85%), linalool (15.2-75.3%), α-phellandrene (36.0-51.8%), and ß-phellandrene (11.6-25.6%). DNA barcodes were developed using the internal transcribed spacer (ITS) nuclear region, and the matK, psbA-trnH, rbcL, and ycf1 plastid regions. The markers psbA-trnH and ITS showed the best discrimination for the species, and the phylogenic analysis in the three- (rbcL + matK + trnH - psbA and rbcL + matK + ITS) and four-locus (rbcL + matK + trnH - psbA + ITS) combination formed clades with groups strongly supported by the Bayesian inference (BI) (PP:1.00) and maximum likelihood (ML) (BS ≥ 97%). Therefore, based on statistical multivariate and phylogenetic analysis, the results showed a significant correlation between volatile chemical classes and genetic characteristics of Aniba species.

Secondary Metabolic Profile as a Tool for Distinction and Characterization of Cultivars of Black Pepper (Piper nigrum L.) Cultivated in Pará State, Brazil.

This study evaluated the chemical compositions of the leaves and fruits of eight black pepper cultivars cultivated in Pará State (Amazon, Brazil). Hydrodistillation and gas chromatography-mass spectrometry were employed to extract and analyze the volatile compounds, respectively. Sesquiterpene hydrocarbons were predominant (58.5-90.9%) in the cultivars "Cingapura", "Equador", "Guajarina", "Iaçará", and "Kottanadan", and "Bragantina", "Clonada", and "Uthirankota" displayed oxygenated sesquiterpenoids (50.6-75.0%). The multivariate statistical analysis applied using volatile composition grouped the samples into four groups: γ-Elemene, curzerene, and δ-elemene ("Equador"/"Guajarina", I); δ-elemene ("Iaçará"/"Kottanadan"/"Cingapura", II); elemol ("Clonada"/"Uthirankota", III) and α-muurolol, bicyclogermacrene, and cubebol ("Bragantina", IV). The major compounds in all fruit samples were monoterpene hydrocarbons such as α-pinene, ß-pinene, and limonene. Among the cultivar leaves, phenolics content (44.75-140.53 mg GAE·g-1 FW), the enzymatic activity of phenylalanine-ammonia lyase (20.19-57.22 µU·mL-1), and carotenoids (0.21-2.31 µg·mL-1) displayed significant variations. Due to black pepper's susceptibility to Fusarium infection, a molecular docking analysis was carried out on Fusarium protein targets using each cultivar's volatile components. F. oxysporum endoglucanase was identified as the preferential protein target of the compounds. These results can be used to identify chemical markers related to the susceptibility degree of black pepper cultivars to plant diseases prevalent in Pará State.

Potential inhibitors of the enzyme acetylcholinesterase and juvenile hormone with insecticidal activity: study of the binding mode via docking and molecular dynamics simulations.

Models validation in QSAR, pharmacophore, docking and others can ensure the accuracy and reliability of future predictions in design and selection of molecules with biological activity. In this study, pyriproxyfen was used as a pivot/template to search the database of the Maybridge Database for potential inhibitors of the enzymes acetylcholinesterase and juvenile hormone as well. The initial virtual screening based on the 3D shape resulted in 2000 molecules with Tanimoto index ranging from 0.58 to 0.88. A new reclassification was performed on the overlapping of positive and negative charges, which resulted in 100 molecules with Tanimoto's electrostatic score ranging from 0.627 to 0.87. Using parameters related to absorption, distribution, metabolism and excretion and the pivot molecule, the molecules selected in the previous stage were evaluated regarding these criteria, and 21 were then selected. The pharmacokinetic and toxicological properties were considered and for 12 molecules, the DEREK software not fired any alert of toxicity, which were thus considered satisfactory for prediction of biological activity using the Web server PASS. In the molecular docking with insect acetylcholinesterase, the Maybridge3_002654 molecule had binding affinity of -11.1 kcal/mol, whereas in human acetylcholinesterase, the Maybridge4_001571molecule show in silico affinity of -10.2 kcal/mol, and in the juvenile hormone, the molecule MCULE-8839595892 show in silico affinity value of -11.6 kcal/mol. Subsequent long-trajectory molecular dynamics studies indicated considerable stability of the novel molecules compared to the controls.AbbreviationsQSARquantitative structure-activity relationshipsPASSprediction of activity spectra for substancesCommunicated by Ramaswamy H. Sarma.

Chemical characterisation of the constituents of Eugenia protenta McVaugh and leishmanicidal activity of dimethylxanthoxylin.

The chemical study of Eugenia protenta McVaugh extracts performed by classical and high-performance liquid chromatography techniques and spectral methods has led to the identification of known triterpenoids, flavonoids and an acetophenone derivative (dimethylxanthoxylin). The effect of dimethylxanthoxylin on Leishmania (Leishmania) amazonensis was evaluated against the promastigotes forms after 96 h of treatment. Dimethylxanthoxylin reduced 57 and 59% of the promastigotes growth when treated with 50 and 100 µg/mL solutions, respectively (IC50 117.35 µg/mL or 52.3 µM). Cytotoxicity experiments using MTT assays showed that this substance did not promote cell death after 24 h of treatment. Dimethylxanthoxylin was active on the promastigotes and could be a promising agent for treating leishmaniasis.

Leishmanicidal Activity of (+)-Phyllanthidine and the Phytochemical Profile of Margaritaria nobilis (Phyllanthaceae).

The effects of the Securinega alkaloid (+)-phyllanthidine on Leishmania (L.) amazonensis and the first chemical investigation of Margaritaria nobilis L.f. (Phyllanthaceae) are described. Treating the parasites with this alkaloid caused a dose-dependent reduction in promastigote growth of 67.68% (IC50 82.37 µg/mL or 353 µM) and in amastigote growth of 83.96% (IC50 49.11 µg/mL or 210 µM), together with ultrastructural alterations in the promastigotes. No cytotoxic effect was detected in mammalian cells (CC50 1727.48 µg/mL or CC50 5268 µM). Classical chromatographic techniques and spectral methods led to the isolation and identification of betulinic acid, kaempferol, corilagin, gallic acid and its methyl ester, besides (+)-phyllanthidine from M. nobilis leaves and stems. Margaritaria nobilis is another source of the small group of Securinega alkaloids, together with other Phyllanthaceae (Euphorbiaceae s.l.) species. The low toxicity to macrophages and the effects against promastigotes and amastigotes are suggestive that (+)-phyllanthidine could be a promising antileishmanial agent for treating cutaneous leishmaniasis.

Chemical composition, antitumor activity, and toxicity of essential oil from the leaves of Lippia microphylla.

The chemical composition, antitumor activity and toxicity of the essential oil from Lippia microphylla leaves (OEL) were investigated. The major constituents were thymol (46.5%), carvacrol (31.7%), p-cymene (9%), and γ-terpinene (2.9%). To evaluate the toxicity of OEL in non-tumor cells, the hemolytic assay with Swiss mice erythrocytes was performed. The concentration producing 50% hemolysis (HC50) was 300 µg/mL. Sarcoma 180 tumor growth was inhibited in vivo 38% at 50 mg/kg, and 60% at 100 mg/kg, whereas 5-FU at 50 mg/kg caused 86% inhibition. OEL displays moderate gastrointestinal and hematological toxicity along with causing some alteration in liver function and morphology. However, the changes were considered reversible and negligible in comparison to the effects of several anticancer drugs. In summary, OEL displays in vivo antitumor activity and a moderate toxicity, which suggests further pharmacological study.

Acetylcholinesterase inhibitory activity and molecular docking study of 1-nitro-2-phenylethane, the main constituent of Aniba canelilla essential oil.

The odoriferous principle of Aniba canelilla (H.B.K.) Mez is due 1-nitro-2-phenylethane, the main constituent of its essential oil and also responsible for the plant's cinnamon scent. This nitroderivative was previously reported by their antioxidant, antinociception, cardiovascular, and vasorelaxant properties, and now it was tested as the inhibitor of acetylcholinesterase using bioautography on TLC plates. The oil and a purified fraction containing 1-nitro-2-phenylethane were analyzed by GC and GC-MS. The percentage content of 1-nitro-2-phenylethane in the oil and after fractionation was 70.2% and 98.0%, respectively. The results showed that the oil and 1-nitro-2-phenylethane are strong acetylcholinesterase inhibitors with the detection limit of 0.01 ng, equivalent to physostigmine used as the positive control. A molecular docking study was used to determine the position and conformation of the 1-nitro-2-phenylethane inhibitor in the receptor-binding pocket of the acetylcholinesterase enzyme. The nitrogroup of 1-nitro-2-phenylethane was positioned near of the catalytic serine residue of acetylcholinesterase, forming strong hydrogen bond with its hydroxyl group. Therefore, the electronegative character of 1-nitro-2-phenylethane may explain the interaction that occurs with the catalytic serine residue and its significant inhibitory activity of acetylcholinesterase.

Molluscicidal and leishmanicidal activity of the leaf essential oil of Syzygium cumini (L.) SKEELS from Brazil.

The chemical composition and biological potential of the essential oil extracted from Syzygium cumini leaves collected in Brazil were examined. GC/MS Analyses revealed a high abundance of monoterpenes (87.12%) in the oil. Eleven compounds were identified, with the major components being α-pinene (31.85%), (Z)-ß-ocimene (28.98%), and (E)-ß-ocimene (11.71%). To evaluate the molluscicidal effect of the oil, it was tested against Biomphalaria glabrata and the LC50 obtained was 90 mg/l. The essential oil also showed significant activity against Leishmania amazonensis, with an IC50 value equal to 60 mg/l. In addition, to evaluate its toxicity towards a non-target organism, the essential oil was tested against Artemia salina and showed a LC50 of 175 mg/l. Thus, the essential oil of S. cumini showed promising activity as a molluscicidal and leishmanicidal agent and might be valuable in combating neglected tropical diseases such as schistosomiasis and leishmaniasis. Further research is being conducted with regard to the purification and isolation of the most active essential-oil compounds.

Ricinine and other constituents of Aparisthmium cordatum (Euphorbiaceae).

The chemical study of Aparisthmium cordatum (Euphorbiaceae) led to the isolation of tannins, together with the alkaloid ricinine and other common compounds. The composition of A. cordatum is similar to most of the Alchornea species, from the same subtribe, except for the occurrence of ricinine. This study rectifies the first investigations published for A. cordatum that were conducted with Croton palanostigma.

Constituintes químicos e avaliação preliminar in vivo da atividade antimalárica de Ouratea nitida Aubl (Ochnaceae) / Chemical constituents and in vivo preliminary evaluation of antimalarial activity of Ouratea nitida Aubl. (Ochnaceae)

O presente trabalho descreve o isolamento de triterpenos (ácido 3,4-seco-friedelan-3-óico, friedelina e b-amirina) e outros compostos (éster etílico do ácido p-hidroxibenzóico e tetracosano), bem como a avaliação preliminar in vivo da atividade antimalárica de extratos das folhas de Ouratea nitida Aubl. Análise qualitativa através de CG-EM de uma fração apolar do extrato em hexano também foi efetuada. Ésteres metílicos e etílicos dos ácidos laúrico, mirístico, palmítico, esteárico e oléico, metílicos dos ácidos pentadecanóico, heptadecanóico, araquidônico, behênico e lignocérico e o etílico do ácido linoléico foram os componentes majoritários; enquanto que o estearato de n-butila, o tetracosano e a 6,10,14-trimetil-2-pentadecanona foram os minoritários. Os compostos isolados foram identificados com base na análise dos dados espectrais (IV, EM e RMN, incluindo DEPT) e estão sendo descritos pela primeira vez nesta espécie.

This work describes the isolation of triterpenes (3,4-seco-friedelan-3-oic acid, friedelin, and b-amyrin) and other compounds (p-hydroxybenzoic acid ethyl ester and tetracosane) as well as a preliminary evaluation of in vivo antimalarial activity of the extracts from the leaves of Ouratea nitida Aubl. Qualitative analysis by GC-MS of an apolar fraction from the hexane extract was also carried out. Methyl and ethyl esters of lauric, myristic, palmitic, stearic and oleic acids, methyl ester of pentadecanoic, heptadecanoic, arachidonic, beenic and lignoceric acids, and ethyl ester of linoleic acid were found to be the main constituents while n-butyl stearate, tetracosane and 6,10,14-trimetthyl-2-pentadecanone were the minor. All isolated compounds were identified on basis of the spectral data (IR, MS and NMR, including DEPT) and are being described for the first time in this specie.

Seasonal variation in the essential oil of Pilocarpus microphyllus Stapf.

The essential oils of the leaves and fine stems of Pilocarpus microphyllus, collected on iron mineralized soil of the Serra de Caraj s, Southeast of Par State, Brazil, during the rainy and dry seasons, were obtained by hydrodistillation and analyzed by GC-MS. The main identified compounds were 2-tridecanone, beta-caryophyllene, 2-pentadecanone, caryophyllene oxide and germacrene D. Their percentage contents varied with the season, the greater values having been detected mainly in the rainy season. For 2-tridecanone and beta-caryophyllene the higher values were observed in the fine stem oils for the former, and in the leaf oils for the latter. For 2-pentadecanone, caryophyllene oxide and germacrene D they were also in the leaf oils. In general, the leaf oils were very distinguishable from those of fine stem oils, even in the same specimen.

Seasonal variation in the essential oil of Pilocarpus microphyllus Stapf

The essential oils of the leaves and fine stems of Pilocarpus microphyllus, collected on iron mineralized soil of the Serra de Carajás, Southeast of Pará State, Brazil, during the rainy and dry seasons, were obtained by hydrodistillation and analyzed by GC-MS. The main identified compounds were 2-tridecanone, beta-caryophyllene, 2-pentadecanone, caryophyllene oxide and germacrene D. Their percentage contents varied with the season, the greater values having been detected mainly in the rainy season. For 2-tridecanone and beta-caryophyllene the higher values were observed in the fine stem oils for the former, and in the leaf oils for the latter. For 2-pentadecanone, caryophyllene oxide and germacrene D they were also in the leaf oils. In general, the leaf oils were very distinguishable from those of fine stem oils, even in the same specimen