Contribuição ao estudo químico e biológico do gênero Bocageopsis (Annonaceae) da Região Amazônica

Abstract

The Annonaceae family is known for its species possess a varied amount of compounds and their economic importance. The substances that stand out are the alkaloids, terpenes and acetogenins, since they are relevant for the biological and pharmacological activities reported in the literature. Although many genus have been phytochemically explorereds, there are some with less studies such as Bocageopsis that consists of four species (B. mattogrossensis, B. canescens, B. multiflora and B. pleiosperma), all restricted to tropical South America and eastern of the Andes Cordillera. Recent phytochemical approaches carried out with B. multiflora and B. pleiosperma essential oils - EOs and B. pleiosperma alkaloid fractions have demonstrated the chemical potential of this genus. The present work presents the phytochemical and biological data of three species of the genus Bocageopsis (B. canescens, B. multiflora and B. pleiosperma) commonly found in the Amazon Region. Different parts of the plants were submitted to hydrodistillation, acid-base treatment and infusion to obtain the substances and later they were submitted to integrative approaches such as environmental ionization mass spectrometry (LS-MS), chromatographic techniques hyphenated to mass spectrometry (GC-MS, HPLC-MS and HPLC-MS/MS) and 1D and 2D NMR. GC-MS analysis of the EOs of the three species, allowed the identification of 63 constituents, besides revealing the exclusive presence of sesquiterpenes and their derivatives and absence of monoterpenes. The antimicrobial essays of the EOs revealed bacteriological activity of the EOs of the fine branches and thick branches of B. multiflora, and of the leaves of B. canescens and B. pleiosperma against the strains of Staphylococcus aureus, Serratia marcens and Mycobacterium smegmatis, in addition to fungicidal activity of EOs from leaves of B. canescens and thin branches and thick branches of B. multiflora against the pathogen Candida albicans. The integrative approaches of alkaloid fractions of leaves and thin branches of B. canescens and the thick branches of B. multiflora the alowed identification tentatively of five alkaloids (anonaine, stepharine, isoboldine, asimilobine and norushinsunin). The chromatographic fractionation of the leaves of B. canescens resulted in the isolation of two alkaloids isomers of the class of simple isoquinolines, salsolina and isosalsolina, besides the alkaloids liriodenina, atherolina, nornuciferina and laurotetanina. Fractionation of the alkaloid fraction of the thick branches of B. multiflora resulted in the isolation of the alkaloids salsolina, isosalsolin, pronuciferine and N-formyl-stepharine. The fractionation of the aqueous extract of the leaves of B. canescens allowed the obtention of the flavonoids kaempferol-3,7-O-α-L-dirhamnoside (kaempferitrine) and the novel flavonoid kaempferol-3-O-[α-L-rhamnopyranosyl-(1→2)-β-L-rhamnopyranosyl]-7-O-α-L-rhamnopyranoside, uncommun in Annonaceae family, named canescentine. All the substances identified and isolated are unpublished in the species studied, being the alkaloids norushinsunine, atheroline, pronuciferine and N-formyl-stepharine inedits in the genus Bocageopsis. The alkaloids salsolina and isosalsolina were published for the first time in the order Magnoliales. Therefore, our phytochemical and biological results for the genus Bocageopsis reinforce the importance of the genus for the Annonaceae family.