Avaliação da integridade de constituintes químicos de Echinodorus macrophyllus (chapéu-de-couro) tratada por irradiação gama

Abstract

The herbal drugs used in popular medicine show a high level of microbiological contamination (bacteria and fungi). Gamma irradiation has been an alternative to increase shelf life and reduce microbial contamination of herbal products. Echinodorus macrophyllus Mich. (Chapéu-de-couro) is very popularly used as diuretic, antiarrhythmic, antiinflammatory and antirheumatic. This work describes a study of the effect caused by gamma irradiation on its leaves. Leaf samples were subjected to different gamma irradiation energies and the respective polar extracts containing phenolic, alkaloidic and saponinic compounds were analyzed by High Performance Liquid Chromatography (HPLC), in order to compare their chemistry integrity. HPLC chromatograms of these extracts showed changes in concentration of their components, suggesting formation of radiolytic products. In the phenolic fraction two constituents were identified, the trans-ferulic acid and a flavone called 6-C-hexa-hydroxy-apigenin which is firstly described in the literature. The irradiated samples were submitted to successive extraction with hexane and ethanol. In addition, the extracts (HE and EE, respectively) were tested on the different strains of bacteria. The extracts EH and EE were active against Bacillus subitilis and Staphylococcus aureus, independently of the gamma irradiation energy of. However, a decrease of the EH antibacterial activity observed against S. aureus when gamma irradiation energy is increased. The opposite is observed for the EE, an increase of antimicrobial activity when the energy of the gamma irradiation is increased