Estudo fitoquímico de Condalia buxifolia Reissek: isolamento, determinação estrutural, atividade antimicrobiana, determinação da configuração absoluta e modificações estruturais do alcaloide Condalina-A

Abstract

This work describes the phytochemical study of the species Condalia buxifolia Reissek belonging to Rhamnaceae family, the study of ratio structure/antimicrobial activity and confirmation of the absolute configuration of Condalina-A alkaloid (1). Of the bark of roots From the bark of roots of Condalia buxifolia were isolated: the cyclopeptide alkaloid Condalina-A (1), the phytosteroid -sitosterol (5), the anthraquinone Emodin (29), the oleic (30) and behenic (31) fatty acids and a phthalate (32). For study of the ratio structure/activity of functional groups of Condalina-A were obtained four derivatives: Dihydroconaline-A (33), Dimetildihydrocondaline-A (34), Hydrochloride (35) and Hydroiodide of Condaline-A (36). By X-ray diffraction of alkaloid as hydroiodide salt was possible to confirm the absolute configuration of the chiral centers of Condalina-A and determine the dihedral angle of the hydrogens H-3 and H-4. Additionally, the antimicrobial activity of the extracts, fractions, isolated compounds and derivatives Condalina-A were analyzed by microdilution in plates method, front five grampositive, six gram-negative bacteria and seven fungi. It was observed in this analysis that the tested extracts and fractions showed good results especially against bacteria Bacillus cereus, Bacillus subtilis, Morganella morganii, and Pseudomonas aeruginosa and fungi Candida krusei Cryptococcus gatti, Cryptococcus neoformans and Sacaromyces cerevisiae. In the study of ratio structure/antimicrobial activity has been observed that for Condalina-A and derivatives, the double bond of the NHCH3 group and N+H2CH3 are important for antibacterial activity front Enterococcus. As for antifungal activity the group N+H2CH3 and the absence of the double bond are importante for activity against Candida krusei.