Estudo fitoquímico pioneiro de Pavonia cancellata (L.) - Malvaceae

The use of plants to control of various diseases and pests is as old as the appearance of humanity. Nowadays, many medicinal plants and its preparations are studied in order to understand its action mechanism and isolation of active principles. Regarding the diversity of Brazilian flora we aimed to isolate and identify the chemical constituents of Pavonia cancellata (L.) through a pioneer phytochemical study. Pavonia cancellata (L.) belongs to Malvaceae family that has been known by the use of its species in folk medicine. The leaves of Pavonia cancellata (L.) popularly known as corda de viola or malva rasteira are used as a poultice to boils treatment. By using classical chromatographic techniques were isolated four chemical constituents from crude ethanol extract of the aerial parts of Pavonia cancellata ( L. ): a mixture of sitosterol (Pc-1a) and stigmasterol (Pc-1b), a mixture sitosterol-3-O-β-D-glucopyranoside (Pc- 2a) and stigmasterol-3-O-b-D-glucopyranoside (Pc-2b), 4 5-di-hyidroxy- 3,7- dimethoxiflavone (Pc-3) and kaempferol-3-O-b-D-(6 -E-p-coumaroyl) glucopyranoside (Pc-4). The structural identification of these compounds was performed using spectroscopic methods such as Infrared and 1H and 13C Nuclear Magnetic ResonanceCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESO emprego das plantas no controle de diversas doenças e pragas é tão antigo quanto o próprio aparecimento da humanidade. Nos tempos atuais, muitas espécies e preparados vegetais medicinais são estudados visando o entendimento de seu mecanismo de ação e isolamento dos princípios ativos. Dentro da diversidade de flora brasileira buscou-se, através de um estudo fitoquímico pioneiro, isolar e identificar constituintes químicos da espécie Pavonia cancellata (L.), pertencente à família Malvaceae que se destaca pelos relatos da utilização de suas espécies na medicina popular. As folhas da espécie Pavonia cancellata (L.) popularmente conhecida como corda de viola ou malva rasteira, são utilizada pela medicina na forma de cataplasma para combater furúnculos. Através de técnicas cromatográficas clássicas foram isolados do extrato etanólico bruto das partes aéreas de Pavonia cancellata (L.) quatro constituintes químicos: uma mistura de sitosterol (Pc-1a) e estigmasterol (Pc-1b); uma mistura sitosterol-3-O-Dglicopiranosídeo (Pc-2a) e estigmasterol-3-O-b-D-glicopiranosídeo (Pc-2b); 4 ,5- dihidroxi-3,7-dimetoxiflavona (Pc-3) e o canferol 3-O-β-D-(6 -E-p-coumaroil) glicosídeo (Pc-4). A identificação estrutural destas substâncias foi realizada utilizandose métodos espectroscópicos tais como Infravermelho e Ressonância Magnética Nuclear de 1H e 13C, com o auxílio das técnicas uni e bidimensionais

First Chemical Constituents from Cordia exaltata Lam and Antimicrobial Activity of Two Neolignans

The phytochemical study of Cordia exaltata Lam. (Boraginaceae) led to the isolation, through chromatographic techniques, of nineteen secondary metabolites: 8,8\u27dimethyl-3,4,3\u27,4\u27-dimethylenedioxy-7-oxo-2,7\u27cyclolignan (1), 8,8\u27-dimethyl-4,5-dimethoxy-3\u27,4\u27-methylenodioxy-7-oxo-2,7\u27cyclolignan (2), sitosterol (3a), stigmasterol (3b), sitosterol-3-O-β-d-glucopyranoside (4a), stigmasterol-3-O-β-d-glucopyranoside (4b), phaeophytin A (5), 132-hydroxyphaeophytin A (6), 173-ethoxypheophorbide A (7), 132-hydroxy-173-ethoxypheophorbide A (8), m-methoxy-p-hydroxybenzaldehyde (9), (E)-7-(3,4-dihydroxyphenyl)-7-propenoic acid (10), 1-benzopyran-2-one (11), 7-hydroxy-1-benzopyran-2-one (12), 2,5-bis-(3\u27,4\u27-methylenedioxiphenyl)-3,4-dimethyltetrahydrofuran (13), 3,4,5,3\u27,5\u27-pentamethoxy-1\u27-allyl-8.O.4\u27-neolignan (14), 3,5,7,3\u27,4\u27-pentahydroxyflavonol (15), 5,7-dihydroxy-4\u27-methoxyflavone (16), 5,8-dihydroxy-7,4’-dimethoxyflavone (17), kaempherol 3-O-β-d-glucosyl-6\u27\u27-α-L-ramnopyranoside (18) and kaempherol 3,7-di-O-α-l-ramnopyranoside (19). Their structures were identified by 1H and 13C-NMR using one and two-dimensional techniques. In addition, the antimicrobial activity of compounds 1, 2, 13 and 14 against bacteria and fungi are reported here for the first time