Antimicrobial activity and Antioxidant Property of Osyris abyssinica

Osyris abyssinica (Syn Osyris quadripartite, Qeret in Amharic) belongs to Santalaceae family which is locally used to treat diarrhea, sexually transmitted diseases, anemia, cancer and wounds. The phytochemical constituents of the plant extracts were qualitatively assessed by the standard protocols. Methanol extract of root, stem bark and leaf of O. abyssinica contained terpenoid, flavonoid, tannin and phenolic compounds. Saponin was present in methanol extract of stem bark and root but not on the leaf. Alkaloid, tannin and phenol were also found in ethyl acetate extract of all plant parts. The antimicrobial activity of its ethyl acetate extracts of the root, stem bark and leaf was evaluated using disc diffusion method and showed an effect on the growth of S.aureus and S.typhimurium at a concentration of 100g/ml and 150g/ml but not on L. monocytogenes and C. albican at the same dose. Methanol extract of the root, stem bark and leaf has better effect on all tested microbial. The DPPH radical scavenging activity of the methanol extract of the root has a higher antioxidant capacity (IC50=102.9g/ml) than stem bark (IC50=168.57g/ml) and leaf (IC50=214.81g/ml), respectively. Ethyl acetate extract of the root has a higher antioxidant activity (IC50=340.5g/ml) than leaf (IC50=452.6g/ml) and stem bark (IC50=859.29g/ml), respectively. The observed antimicrobial and antioxidant activities of the methanol extract are, therefore, due to the presence of many secondary metabolites including phenolic compounds which have inhibitory effect on the test microbial and/or better hydrogen donating ability, respectively.