Rhamnus prinoides - A Basotho Medicinal Plant with Antioxidant and Antimicrobial Potential

Manoharan Karuppiah Pillai; Sibusisiwe Magama; Lehlohonolo Isaac Santi

Manoharan Karuppiah Pillai Department of Chemistry and Chemical Technology, Faculty of Science and Technology, National University of Lesotho, Roma Campus, P.O. Roma 180, Kingdom of Lesotho.
Sibusisiwe Magama Department of Biology, Faculty of Science and Technology, National University of Lesotho, Roma Campus, P.O. Roma 180, Kingdom of Lesotho.
Lehlohonolo Isaac Santi Department of Chemistry and Chemical Technology, Faculty of Science and Technology, National University of Lesotho, Roma Campus, P.O. Roma 180, Kingdom of Lesotho.

Keywords: Rhamnus prinoides, Rhamnaceae, radical scavenging assay, antibacterial activity, IC50 values, MIC values, hexane extracts, ethyl acetate extracts, chloroform extracts, methanolic extracts

Abstract

Rhamnus prinoides finds therapeutic applications in traditional medicine in Southern Africa, which include treating pulmonary tuberculosis (TB), pneumonia, gonorrhoea, muscular rheumatism, cleaning the blood, bladder and kidneys. Hexane, chloroform, ethyl acetate and methanolic extracts from leaves and stem-bark of R. prinoides have been evaluated for their antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The percentage values of radical of scavenging activity of these extracts have been found to be in the range of 03.330.89 to 59.552.27% at various concentrations. The IC₅₀ values of these extracts have been determined to be in the range of 710.50 to >3000 g mL^-1. The positive control, ascorbic acid, showed an IC₅₀ value of <200 g mL^-1. Additionally, all these extracts have also been evaluated for their inhibitory effect against six bacterial isolates viz. Escherichia coli (wild), Escherichia coli (H0157), Staphylococcus aureus, Listeria monocytogens, Pseudomonas spp. and Serratia marcescens and two fungal isolates viz. Penicillium digitatum and Candida albicans. The zones of inhibition have been found to be in the range of 8.83.0 to 15.81.4 mm diameter against bacterial isolates and 10.31.8 to 14.32.5 mm diameter against fungal isolates. The minimum inhibitory concentrations (MICs) of these extracts have been found to be in the range of <31.25 to > 1000 g/mL. Further studies on this plant will be useful to commercialize products from this plant.