Chemical profile of the twigs of Ozoroa obovata by HPLC-MS-ESI and antimicrobial activity

Abstract

In Mozambique, a large part of the population depends on plants for the treatment of various diseases. However, some of them have been little studied in relation to chemical and biological aspects. Among these species, Ozoroa obovata is widely used in traditional medicine in Mozambique. The factors that influence the use of medicinal plants in developing countries are mainly cultural habits, the inefficiency of the health system and the high cost of medicines. This work aimed to study the chemical composition and evaluate the antimicrobial activity of the twigs of O. obovata. Through the analysis by liquid chromatography coupled to mass spectrometry with electrospray ionization (HPLC-MS-ESI), it was possible to propose that in the ethanolic extract of the twigs, most of the constituents belong to the classes of phenolic acids and flavonoid. The phenolic compounds were represented by quinic, gallic and protocatechuic acids and five anacardic acids, whereas flavonoids were represented by mangiferin, taxifolin and quercetin mono and dihexoside. The extract was evaluated against bacteria in the oral cavity and showed moderate activity against Streptococcus mutans, S. mitis and Porphyromonas gingivalis (minimum inhibitory concentration-MIC 400 µg mL-1). In relation antifungal test, the extract showed activity against Candida albicans with MIC of 3000 µg mL-1. The biological results indicated that the twigs of O. obovata have bioactive metabolites with antimicrobial potential.