Pesquisa de bioativos e avaliação da atividade antimicrobiana de extratos hidroetanólicos de Cola acuminata

Abstract

Plants with therapeutic properties have been used as medicines for a long time. The research of active principles from natural compounds, which may act as antimicrobials presents itself as a valuable option to synthetic drugs, mainly as a result of progressive mechanisms of bacterial resistance. Cola acuminata, known as cola nut, is a plant that produces fruit whose seeds are used as food and for treatment of gastrointestinal diseases, cardiac, respiratory and neurological disorders. However, your antimicrobial activity has been little studied. In this work, we evaluated the antimicrobial activity of hidroetanólicos extracts from stem, leaf and seed of Cola acuminata, by agar diffusion tests. Minimum inhibitory concentration and minimum microbicide concentration was determined on Gram-positive bacteria, Gram-negative bacteria, yeast and Mycobacterium tuberculosis, held in the laboratory of Microbiology of the UNIFAL-MG. The extracts of Cola acuminata were active on Bacillus cereus, Kocuria rizophila, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Candida albicans, Saccharomyces cerevisae and Mycobacterium tuberculosis. The minimum inhibitory concentration ranged from 0.78 to 25 mg/mL. Extracts tests revealed the presence of tannins, catechins, terpens, flavonoids, alkaloids and gallic acid in different concentrations. The CC50 for culture of BHK-21 showed less cytotoxic to the fresh leaf extract. Hydroethanolics extracts of Cola acuminata presented promising antimicrobial activity, especially in relation to Gram-positive bacteria, Mycobacterium tuberculosis and the yeast Candida albicans and Saccharomyces cerevisae species. The dry extract of the stem showed selectivity index greater than 1, demonstrating better profile between antimicrobial activity and cell toxicity.