Lucienir Pains Duarte

Bio: Lucienir Pains Duarte is an academic researcher from Universidade Federal de Minas Gerais. The author has contributed to research in topics: Celastraceae & Maytenus. The author has an hindex of 15, co-authored 102 publications receiving 905 citations.

Two epimeric friedelane triterpenes isolated from Maytenus truncata Reiss : 1H and 13C chemical shift assignments.

Abstract: An NMR study of 3α‐ and 3β‐friedelinol is described. In addition to conventional 1D NMR methods, 2D shift‐correlated NMR experiments HMQC [(1J(C,H)], HMBC [nJ(C,H); n=2 and 3] and 2D 1H,1H‐NOESY were used for 1H and 13C chemical shift assignments of these triterpenes. Copyright © 2000 John Wiley & Sons, Ltd.

New triterpenes from Maytenus robusta: structural elucidation based on NMR experimental data and theoretical calculations.

Abstract: Leaves of Maytenus robusta (Celastraceae) were subjected to phytochemical investigation mainly directed at the isolation of pentacyclic triterpenes. The compounds friedelin (1), β-friedelinol (2), 3-oxo-21β-H-hop-22(29)-ene (7), 3,4-seco-friedelan-3,11β-olide (8), 3β-hydroxy-21β-H-hop-22(29)-ene (9), 3,4-seco-21β-H-hop-22(29)-en-3-oic acid (10), 3,4-seco-friedelan-3-oic acid (11), and sitosterol were identified in the hexane extract of M. robusta leaves. Compounds 8 and 9 are described herein for the first time. The structure and stereochemistry of both compounds were experimentally established by IR, HRLC-MS, and 1D (1H, 13C, and DEPT 135) and 2D (HSQC, HMBC and COSY) NMR data and supported by correlations with carbon chemical shifts calculated using the DFT method (BLYP/6-31G* level). Compounds 7 and 10 are also described for the first time, and their chemical structures were established by comparison with NMR data of similar structures described in the literature and correlations with BLYP/6-31G* calculated carbon chemical shifts. Compound 9, a mixture of 11 and sitosterol, and 3β,11β-dihydroxyfriedelane (4) were evaluated by the Ellman’s method and all these compounds showed acethylcholinesterase inhibitory properties.

Constituintes químicos voláteis de especiarias ricas em eugenol

Abstract: Utilizando a tecnica de hidrodestilacao, usando um adaptador Clevenger, foram extraidos oleos essenciais das especies Pimenta dioica (folhas e frutos) e Syzygium aromaticum (botoes florais, talos e folhas) A composicao quimica dos oleos foi determinada atraves da analise CG-EM Os teores de oleos essenciais variaram de 0,97 a 1,41% e 2,30 a 15,40% nas especies Pimenta dioica e Syzygium aromaticum, respectivamente O componente majoritario presente nessas especies foi o eugenol, variando de 72,87 a 90,41% Syzygium aromaticum forneceu maior teor de oleo essencial rico em eugenol Em quantidades menores foram tambem encontrados chavicol e? β-cariofileno

Evaluation of the bactericidal and trypanocidal activities of triterpenes isolated from the leaves, stems, and flowers of Lychnophora pinaster

Abstract: The phytochemical investigation on the aereal parts of Lychnophora pinaster Mart, Asteraceae, was carried to isolation of triterpenes 3-O-Acetyl-lupeol (1), 3-O-acetyl-pseudotaraxasterol (2), and 3-O-acetyl-α-amyrin (3) were isolated from hexanic extract and 4,4-dimethyl-cholesta-22,24-dien-5-ol (4), α-amyrin (5), and lupeol (6) were isolated from hexanic/dichlorometanic extract of the leaves Compounds Δ7-bauerenyl acetate (7), friedelin (8), stigmasterol (9), and sitosterol (10) were isolated from the hexanic/dichlorometanic extract of the stems The steroids 9 and 10 were also isolated from the hexanic/dichlorometanic extract of the flowers Triterpenes 1, 3, 4, and 7 are described for the first time in the genus Lychnophora The apolar fractions of the leaf and stem extracts and some isolated triterpenes showed low trypanocidal activity Moreover, apolar fractions of the leaf and stem extracts and 5 showed antibacterial action against Staphylococcus aureus

Detection of the antiviral activity of epicatechin isolated from Salacia crassifolia (Celastraceae) against Mayaro virus based on protein C homology modelling and virtual screening

Abstract: Mayaro fever, caused by Mayaro virus (MAYV) is a sub-lethal disease with symptoms that are easily confused with those of dengue fever, except for polyarthralgia, which may culminate in physical incapacitation. Recently, outbreaks of MAYV have been documented in metropolitan areas, and to date, there is no therapy or vaccine available. Moreover, there is no information regarding the three-dimensional structure of the viral proteins of MAYV, which is important in the search for antivirals. In this work, we constructed a three-dimensional model of protein C of MAYV by homology modelling, and this was employed in a manner similar to that of receptors in virtual screening studies to evaluate 590 molecules as prospective antiviral agents. In vitro bioassays were utilized to confirm the potential antiviral activity of the flavonoid epicatechin isolated from Salacia crassifolia (Celastraceae). The virtual screening showed that six flavonoids were promising ligands for protein C. The bioassays showed potent antiviral action of epicatechin, which protected the cells from almost all of the effects of viral infection. An effective concentration (EC50) of 0.247 μmol/mL was observed with a selectivity index (SI) of 7. The cytotoxicity assay showed that epicatechin has low toxicity, with a 50% cytotoxic concentration (CC50) greater than 1.723 µmol/mL. Epicatechin was found to be twice as potent as the reference antiviral ribavirin. Furthermore, a replication kinetics assay showed a strong inhibitory effect of epicatechin on MAYV growth, with a reduction of at least four logs in virus production. Our results indicate that epicatechin is a promising candidate for further testing as an antiviral agent against Mayaro virus and other alphaviruses.

Clove (Syzygium aromaticum): a precious spice.

Abstract: Clove (Syzygium aromaticum) is one of the most valuable spices that has been used for centuries as food preservative and for many medicinal purposes. Clove is native of Indonesia but nowadays is cultured in several parts of the world including Brazil in the state of Bahia. This plant represents one of the richest source of phenolic compounds such as eugenol, eugenol acetate and gallic acid and posses great potential for pharmaceutical, cosmetic, food and agricultural applications. This review includes the main studies reporting the biological activities of clove and eugenol. The antioxidant and antimicrobial activity of clove is higher than many fruits, vegetables and other spices and should deserve special attention. A new application of clove as larvicidal agent is an interesting strategy to combat dengue which is a serious health problem in Brazil and other tropical countries. Pharmacokinetics and toxicological studies were also mentioned. The different studies reviewed in this work confirm the traditional use of clove as food preservative and medicinal plant standing out the importance of this plant for different applications.

Biological Activities of Essential Oils: From Plant Chemoecology to Traditional Healing Systems

Abstract: Essential oils are complex mixtures of hydrocarbons and their oxygenated derivatives arising from two different isoprenoid pathways. Essential oils are produced by glandular trichomes and other secretory structures, specialized secretory tissues mainly diffused onto the surface of plant organs, particularly flowers and leaves, thus exerting a pivotal ecological role in plant. In addition, essential oils have been used, since ancient times, in many different traditional healing systems all over the world, because of their biological activities. Many preclinical studies have documented antimicrobial, antioxidant, anti-inflammatory and anticancer activities of essential oils in a number of cell and animal models, also elucidating their mechanism of action and pharmacological targets, though the paucity of in human studies limits the potential of essential oils as effective and safe phytotherapeutic agents. More well-designed clinical trials are needed in order to ascertain the real efficacy and safety of these plant products.

Screening Methods in Pharmacology.

Abstract: neurochemical subtleties. Lengthy discussion is published verbatim and in general enhances the value of the papers. A major justification of the duplicate publication usually involved in printing symposia proceedings is the orientation provided in the field by bringing together related work, not merely in juxtaposition, but under evaluative discussion by leading investigators within and across disciplines. In this case comment was incisive and much remains cogent.