Estudo fitoquímico e bioatividade dos extratos e frações de Minquartia guianensis (olacaceae)

Abstract

The aim of this study was to isolate the chemical compounds of Minquartia guianensis (Olacaceae) and evaluate the leaf and branch extracts as antifungal and antibacterial agents. There were performed two collections of this species, the first in April and the second in July at Reserva Ducke, Manaus, AM. After drying and milling, the plant materials were extracted with dichloromethane (DCM), methanol (MeOH) and water (H2O). The DCM and MeOH extracts were submitted to thin layer chromatography analisys in order to identify chemical classes. The phytochemical study of DCM extract from leaves provided three triterpenes lupen-3-one (1), taraxerone (2), oleanolic acid (3) and polyacetylene minquartinoic acid (4). The DCM extract from branches yielded one triterpene, 3-β-methoxy-lup-20-(29)-ene (5). The extracts were evaluated against some bacteria and the best results were found to MeOH extract from leaves and branches from first collection against Edwarsiella tarda (MIC of 62.5 μg/mL) and the minquartinoic acid isolated from leaves against Aeromonas hydrophila (MIC of 45.5 μg/mL and MBC > 91 μg/mL). Some fractions were assayed against Cryptococcus gattii by the bioautography assay and several showed activity. One of the active fractions was fractionated and the polyacetylene, minquartinoic acid was isolated, which suggests than it can be the responsible for the activity. This is the first report of the substances taraxerone, oleanolic acid and 3-β-methoxy-lup-20-(29)-ene in Olacaceae and A. hydrophila and C. gattii activity of M. guianensis extracts.