Antibacterial activity of Ilex Paraguariensis (Yerba Mate) after sub-fractionation with different solvents

Abstract

Infectious diseases account for one-third of all deaths in the world. About 50,000 people die each day because of infectious diseases as estimated by the World Health Organization (Chanda & Rakholiya, 2011). Antibacterial resistance is a worldwide concern, and plant extracts have been investigated extensively to study their antibacterial activity against several bacterial strains. Yerba Mate is a plant known to have several bioactive compounds that are beneficial to the human health. Its leaves and stems were extracted with acetone: water (1:1) and subfractionated with hexane, chloroform, ethyl acetate and water. The minimum inhibitory concentration (MIC) values against S. aureus ranged from 1.56 to 3.12 mg/ml for the chloroform fraction and from 1.56 to 3.12 mg/ml for the ethyl acetate fraction. The MIC values of the water fraction ranged from 0.78 to 3.12 mg/ml against S. aureus and from 1.56 mg/ml to 3.12 mg/ml against Salmonella species. The aqueous fraction was treated with different enzymes to mimic the in vivo digestion. The MIC values of the digested fraction against several Staphylococcus aureus strains were comparable to the undigested ones. Furthermore, the water fraction was run on High Performance Liquid Chromatography (HPLC) and different fractions were collected. HPLC fraction 3 gave the highest antibacterial activity against different strains of S. aureus with MIC of 0.19 to 1.56 µg/ml. Further work should be done in order to identify the bioactive fraction and to determine its mechanism of action.