Análises fitoquímica e farmacognóstica da raiz de Cochlospermum regium (Mart. et Schr.) Pilger, Cochlospermaceae

Abstract

Esta pesquisa se comprometeu a pesquisar os aspectos fitoquimicos e farmacognosticos da raiz de Cochlospermum regium (Mart. et Schr.) visando adquirir informacoes auxiliares para sua padronizacao como materia-prima vegetal para producao de fitoterapicos. Para analise fitoquimica foi realizado o fracionamento do extrato hidroalcoolico associado com a atividade antimicrobiana e, para o estudo farmacognostico foram realizados ensaios para caracterizacao morfoanatomica e fisico-quimica seguindo metodo farmacopeico. O extrato hidroalcoolico e suas fracoes, particularmente a fracao acetato de etila, apresentaram efeito antimicrobiano frente a Staphylococcus aureus e Pseudomonas aeruginosa e ausencia de atividade sobre Escherichia coli, Enterococcus faecalis e Klebsiella pneumoniae. O fracionamento quimico forneceu cinco derivados fenolicos [acido elagico, acido galico, diidrokaempferol-3-O-β-glicopiranosideo e diidrokaempferol-3-O-β-(6´´-galoil)-glicopiranosideo] e dois triacilbenzenos conhecidos como cochlosperminas A e B. Com excecao do diidrokaempferol e seu glicosideo, e a primeira vez que as substancias isoladas sao reportadas nesta especie e o registro do diidrokaempferol-3-O-β-(6´´-galoil)-glicopiranosideo e inedito na literatura. A presenca dos acidos fenolicos ratifica a acao antimicrobiana observada no extrato hidroalcoolico e fracoes mais polares de C. regium, alem de dar sustentacao ao uso tradicional da raiz para o tratamento de infeccoes. O estudo farmacognostico caracterizou a raiz de C. regium em crescimento secundario com regiao cortical menos desenvolvida, presenca de graos de amido, drusas, polifenois e bolsas oleosas. O po da droga forneceu media granulometrica de 0,285 mm, densidade aparente de 0,40 g/mL, densidade por compactacao de 0,62 g/mL, teores de umidade, cinzas totais e cinzas insoluveis em acido de 8,2, 3,1 e 0,08%, respectivamente. O fingerprint foi determinado por CCD e CLAE-DAD empregando o acido elagico, o acido galico e o diidrokaempferol-3-O-β-glicopiranosideo como marcadores. A quantificacao destas duas ultimas substancias indicou teor medio de 1,8 e 27,9 mg/g, respectivamente, sem haver variacao sazonal entre as amostras coletadas bimestralmente durante o ano de 2008. ______________________________________________________________________________________ ABSTRACT

The purpose of this study was to investigate the phytochemical and pharmacognostic features of the roots of Cochlospermum regium (Mart. et Schr.) Pilger in order to acquire ancillary information to support its standardization as a raw material for the production of phytotherapic preparations. Phytochemical analysis was based on the fractionation of its hydroalcoholic extract exhibiting antimicrobial activity. The pharmacognostic investigation involved morphoanatomical and physicochemical characterization using pharmacopea methods. The hydroalcoholic extract and its fractions, particularly the ethyl acetate fraction, had antimicrobial effect on Staphylococcus aureus and Pseudomonas aeruginosa, but not on Escherichia coli, Enterococcus faecalis, or Klebsiella pneumoniae. Phytochemical investigation of the hydroalcoholic extract supplied five phenolic derivatives [ellagic acid, gallic acid, dihydrokaempferol, dihydrokaempferol-3-O-β-glucopyranoside and dihydrokaempferol-3-O-β-(6´´-galloyl)-glucopyranoside dihydrokaempferol] and two triacyl benzenes known as cochlospermines A and B. Excluding dihydrokaempferol and its glycoside, the compounds described are being isolated from this species for the first time. Dihydrokaempferol-3-O-β-(6´´-galloyl)-β-glucopyranoside was unpublished. The presence of phenolic acids corroborates the antimicrobial activity observed in the hydroalcoholic extract and the polar fractions extracted from roots. It also corroborates traditional usage of the roots for the treatment of infections. The pharmacognostic study revealed secondary growth roots to have a less developed cortical region, with the presence of starch grains, druses, polyphenols, and oil pockets. The powdered drug had average particle size of 0.285 mm, bulk density of 0.40 g/mL, compaction density of 0.62 g/mL, and humidity, total ash content, and acid-insoluble ash contents of 8.2%, 3.1%, and 0.08%, respectively. Fingerprint was determined by TLC and HPLC-DAD (gradient mode) using gallic acid, ellagic acid, and diidrokaempferol-3-O-β-glucopyranoside as markers. Quantification of the last two compounds revealed average contents of 27.9 and 1.8 mg/g, respectively. No significant seasonal variability was observed for the species during 2008.