Bioactive compounds and antimicrobial potential of the roots extract of Anogeissus leiocarpa, a chewing stick used for oral care in Benin Republic

Abstract

Chewing stick are still used in developing countries for oral hygiene in other to prevent oral diseases. But still, few is known about their phytochemical potential and antimicrobial activity. The present work was devoted to one of these plants used in the Republic of Benin, namely the root of Anogeissus leiocarpa. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods were used for the antioxidant activity of three crude extracts (aqueous, decoction and ethanolic). Antimicrobial activity of the crude extracts as well as three fractions namely the chloroform fraction, the ethyl acetate fraction and the butanol fraction was carried out by the diffusion method. High performance liquid chromatography (HPLC) analysis of the three fractions of A. leiocarpa was performed to identify the active fraction as well as bioactive compounds. The results show that the crude extracts exhibited a good ability to inhibit the DPPH radical and a good ability to reduce ferric Fe3+ ions to ferrous Fe2+ ion and this could be explained by their good content in phenolic compounds. The ethanolic extract of A. leiocarpa was the most active against all microorganisms used in this study. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) ranged from 0.195 to 12,500 mg/mL. The butanolic fraction was the most active with an inhibition diameter of 20.666 ± 0.577 and 22.333 ± 2.081 mm, respectively at the concentration of 50 and 100 mg/mL. HPLC analysis revealed the presence of phenolic acids such as chlorogenic, ferulic and gallic acids as well as tannins including tannic acid and ellagic acid and from these results, A. leiocarpa is a good plant candidate for the production of herbal toothpaste. Key words: Phenolic compound, antimicrobial, antioxidant, chewing stick, oral care.