Estudo fitoquímico e atividade biológica de Bocageopsis pleiosperma Maas (Annonaceae)

Abstract

The present work describes the phytochemical and biological studies of Bocageopsis pleiosperma Maas, a specie with restricted distribution to the Amazon Region. The plant material (leaves, twigs and bark) was collected in the Adolpho Ducke Forest Reserve and submitted to hydrodistillation to obtain the essential oils and acid-base treatment to getting the alkaloidal fractions. In the study of the essential oils from leaves, twigs and bark it was identified 51 compounds, being β-bisabolene observed as major compound. The analysis by n ESI-IT-MS of alkaloidal fractions in analytical scale showed several ions of m/z pair. These ions had their fragmentation patterns studied. Also through analysis n by ESI-IT-MS it was possible to identified the alkaloidal fraction of the leaves as a promising source for the isolation of new compounds in the genus Bocageopsis. From the fractionation alkaloidal fraction of the leaves of B. pleiosperma obtained in preparative scale, it was isolated and characterized by nuclear magnetic resonance and unidimensional methods (NMR 1D/2D) and mass spectrometry (MS), alkaloids of aporphine type, proaporphine, oxoaporphine, benzyltetrahydroisoquinoline and β-carboline. Among these were isolated nornuciferine alkaloids, isoboldine, asimilobine and tetrahydroharmine and obtained as a mixture of two and three compounds, the reticulin and laurotetanine alkaloids; anonaine and liriodenine; estefarine, isoboldine and N- methyllaurotetanine. All alkaloids are being described for the first time in the Bocageopsis genus, being tetrahydroharmine alkaloid described for the first time in Magnoliales order. The essential oils showed low antimicrobial activity against C. albicans and P. aeruginosa.