Avaliação biológica in vitro de espécies vegetais da Caatinga: Bauhinia cheilantha e Lippia gracilis

Abstract

Medicinal plants have been growing in their social, cultural and economic importance in Brazil, which has the greatest biodiversity of the planet. Caatinga is the main ecosystem in the northeastern region and the only biome exclusively Brazilian. There is a great diversity of species popularly used for medicinal purposes in communities in the semiarid region of Alagoas. However, research proving their therapeutic efficacy is still insufficient. Ethanol extracts of two endemic species of the Caatinga, Bauhinia cheilantha (Bong.) Steud. and Lippia gracilis Schauer, known popularly as "mororó" and " alecrim-da-chapada", underwent in vitro assays to evaluate its antimicrobial and antioxidant potential, as well as identification of the class of its constituents through phytochemical screening. The bacterial strains Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Klebisiella pneumoniae, Pseudomonas aeruginosa and the fungal strain Candida albicans were used in the Agar diffusion method and broth microdilution, which determined the minimum inhibitory concentration (MIC) of extracts. For the evaluation of the scavenging capacity of antioxidants free radicals present in the extracts, the method of measuring the reduction of the synthetic radical 2,2- diphenyl - 1 - picryl - hidrazila (DPPH) was used. The results demonstrated the antioxidant potential of the leaves, stem bark and stem of B. cheilantha and antimicrobial potential of stem and aerial parts of the specie L. gracilis with MIC values comparatively lower than essential oils from other species of Lippia already studied. These findings can be attributed to the presence of flavonoids, tannins and steroids and flavonoids and terpenes, respectively, detected in phytochemical screening. Results support the popular use of B. cheilantha for the treatment of diabetes and L. gracilis for infectious processes, and provide direction for phytochemical studies to identify the constituents responsible for the verified biological activities.