Contribution to chemical study and biological activity of Eugenia dysenterica Mart. ex. DC. Berg (Myrtaceae)

Esta dissertação contribui para o estudo químico e de atividade biológica dos extratos aquoso e hexânico das folhas de Eugenia dysenterica Mart. ex. DC. Eugenia dysenterica, pertencente à familia Myrtaceae, é uma árvore nativa do Cerrado, conhecida popularmente como cagaita ou cagaiteira e que deve seu nome à propriedade laxativa do fruto. O estudo químico do extrato aquoso das folhas levou ao isolamento e identificação de dois flavonoides, quercetina e catequina. As estruturas foram estabelecidas por resonância magnética nuclear (RMN) de 1H (600 MHz) e de 13C (150 MHz), DEPT, espectroscopia de ultravioleta-visível (UV-VIS) e espectrometría de infravermelho (IV). Os dados espectroscópicos foram comparados com os dados da literatura. Embora os flavonoides tenham sido descritos nas folhas da planta é a primeira vez que são isolados a partir de folhas de cagaita. O estudo químico do extrato hexânico levou à identificação de quatro triterpenos pentacíclicos (α-amirina, β-amirina, neolupenol e gammacer-16-en-3β-ol), e α-tocoferol ou vitamina E. As estruturas destes compostos foram confirmadas por RMN de 1H e de 13C, espectrometria de IV, espectrometria de UV-VIS e CG-EM. Quanto à atividade biológica, foi avaliada a viabilidade de células de neuroblastoma humano (linhagem celular SH-SY5Y) quando expostas ao extrato aquoso. O extrato aquoso se mostrou citotóxico a concentrações acima de 7,8 μg/mL. Para o mesmo extrato, foi avaliada a capacidade de inibição da enzima acetilcolinesterase (AChE), mostrando uma atividade inibitoria baixa (CI50 = 155,20±2,09) quando comparado com o padrão fisostigmina (CI50 = 18,69±0,07 μg/mL). O extrato hexânico assim como suas frações não se mostraram ativos contra algumas espécies de fungos e bactérias pertencentes aos gêneros Candida e Staphylococcus, respectivamente. Este estudo se constitui no primeiro registro de triterpenos identificados nas folhas de E. dysenterica. _______________________________________________________________________________________________ ABSTRACTThe present dissertation contributes to chemical study and the biological activity of aqueous and hexane extracts of leaves of Eugenia dysenterica Mart. ex. DC. Eugenia dysenterica is a native tree which belongs to the Myrtaceae family that occurred in the Cerrado biome. The plant is popularly known as “cagaita” or “cagaiteira” and gets its name from the laxative property of the fruit. The chemical study of the aqueous extract led to the isolation and identification of two flavonoids, quercetin and catechin. The structures were established by 1H (600 MHz) and 13C (150 MHz) nuclear magnetic resonance (NMR), distortionless enhancement by polarization transfer (DEPT), ultraviolet–visible spectroscopy (UV-VIS) and infrared spectroscopy (IR). The spectroscopic data were compared with literature reports. Although these flavonoids have been described in the plant, this is the first report of the isolation from leaves of cagaita. The chemical study of the hexane extract leds to the identification of four triterpenes (α-amyrine, β-amyrine, neolupenol and gammacer-16-en-3β-ol) and α-tocopherol. The structures were established by 1H and 13C NMR, UV-VIS, IR and gas chromatography coupled with mass spectrometry (GC-MS). All data were submit to literature data comparison. Related to biological activity, it was evaluated the cell viability of the human neuroblastoma cells (cell line SH-SY5Y) when exposed to aqueous extract of cagaita, proving to be cytotoxic at concentrations higher than 7.8 μg/mL. The extract also was evaluated the capability of inhibit the enzyme acetylcholinesterase. Results showed a relatively low acetylcholinesterase inhibitory activity (IC50 155.20±2.09) compared to the standard physostigmine (IC50 18.69±0.07 μg/mL). The hexane extract, as well as their fractions, were not active against certain fungi and bacteria species belonging to the genus Candida and Staphylococcus respectively. As far as we know, this is the first report of triterpenes identified from leaves of E. dysenterica

Eugenia dysenterica Mart. Ex DC. (cagaita): planta brasileira com potencial terapêutico

O Brasil possui uma das maiores diversidades florísticas do mundo, com vários biomas de características diversas. Esses biomas são uma rica fonte de espécies vegetais utilizadas pelos habitantes locais como alimento e/ou para fins medicinais. Em 2006 foi publicada a Politica Nacional de Plantas Medicinais e Fitoterápicos (PNPMF) que estabeleceu diretrizes de atuação do Governo Federal na área, com o objetivo de fomentar o desenvolvimento industrial e tecnológico e estimular o uso sustentável da biodiversidade nacional. O Programa Nacional de Plantas Medicinais e Fitoterápicos, por sua vez, estabeleceu as ações dos diversos parceiros, para garantir o acesso, o desenvolvimento tecnológio e o uso de plantas medicinais e fitoterápicos de forma segura, eficaz e com qualidade. Eugenia dysenterica Mart ex DC é uma espécie brasileira encontrada no bioma Cerrado e utilizada como alimento e para fins medicinais. Assim, no sentido de contribuir para a PNPMF, foi elaborada uma monografia mostrando os avanços nos estudos sobre essa espécie, potencialmente útil para no desenvolvimento de fitoterápico genuinamente nacional

Chemical profile and biological activity of Crinum americanum L. (Amaryllidaceae)

Two different alkaloid-guided extraction approaches were used to obtain extracts and fractions of leaves and bulbs from Crinum americanum L. (Amaryllidaceae). Samples were analyzed by gas chromatography-mass spectrometry (GC-MS) and acetylcholinesterase (AChE) inhibition activity, and evaluated for antioxidant capacity and cytotoxicity in human neuroblastoma cells (SH-SY5Y). Crinine (1), 1,2-didehydrocrinan-3-one (2), flexinine (3), lycorine (4), 1-O-acetyl-lycorine (5), caranine (6), acetyl-caranine (7), 11,12-didehydro-anhydrolycorine (8), hippadine (9), crinamine (10), 6-oxo-isocrinamine (11), macronine (12), and epipowelline (13) were identified in different extracts and fractions. Additionally, four steroids were identified: stigmasterol (14), beta-sitosterol (15), cycloartenol acetate (16), and cycloeucalenol acetate (17). Lycorine and crinine were isolated, and their structures were confirmed by nuclear magnetic resonance (NMR) spectroscopy. All extracts and fractions inhibited AChE activity, but with IC50 values ranging from 1–290 µg/mL. One fraction (L_EE2) from the ethanol extract of C. americanum leaves achieved the highest AChE inhibitory activity (IC50 = 1.21 µg/mL), when compared to other extracts or fractions. The extracts did not exhibit significant antioxidant activity. After 24 h of treatment, ethanol extracts of leaves and bulbs showed cytotoxic effects on SH-SY5Y cells in a dose-dependent manner from 25 µg/mL. In this study, we highlighted that, after organic extraction, the remaining plant material still presented secondary metabolites, which is interesting for a better understanding of the chemical composition of C. americanum. To the best of our knowledge, this is the first report of in vitro AChE inhibition and cytotoxicity in SH-SY5Y cells using extracts and fractions from C. americanum. Furthermore, among the 17 compounds, ten were identified for the first time in this species

Influence of in vitro micropropagation on lycorine biosynthesis and anticholinesterase activity in Hippeastrum goianum

Hippeastrum goianum (Ravenna) Meerow, Amaryllidaceae, is an endemic species from the Cerrado, Brazil; there are only few studies about its chemistry or biological activity. This study aimed to investigate the occurrence of lycorine in extracts from in vitro H. goianum plantlets, as well as evaluate a possible inhibition of acetylcholinesterase. The ethanol extract of plantlets produced by in vitro seed germination and micropropagation of bulblets was obtained from seedlings from in vitro germination, while the ethanol extract micropropagtion of bulblets was obtained from a subculture of those seedlings. The presence of lycorine was detected in only in the micropropagation of bulblets. The micropropagation of bulblets was more active than the plantlets produced by in vitro seed germination, with an IC50 of 114.8 ± 0.95 µg/ml and IC50 386.00 ± 0.97 µg/ml, respectively. These results showed that both in vitro germination and micropropagation of H. goianum can lead to the biosynthesis of lycorine. Moreover, the micropropagation led to improved anticholinesterase activity