Phytochemical, Antioxidant and Antimicrobial Analyses of Pterocarpus mildbraedii Stem Extracts

Abstract

Phytochemical screening, antioxidant and antimicrobial activities of n-hexane, ethyl acetate and methanol extracts of Pterocarpus mildbraedii stem were studied in this research. Pterocarpus mildbraedii is used in folk medicine to treat fever, convulsions and respiratory disorders. The air-dried and milled plant materials were extracted with soxhlet apparatus at a temperature of 80 0C using n-hexane, ethyl acetate and methanol successively. The preliminary screening of the extracts was carried out using standard methods, and the free radical scavenging capacity using 2, 2 diphenyl-1-picryhydrazyl (DPPH) was determined to evaluate the antioxidant activity. Likewise, the antimicrobial screening was also carried out using the Broth dilution method. Phytochemical screening of the extracts (n-hexane, ethyl acetate and methanol) revealed the presence of alkaloids, tannins, flavonoids, steroids, terpenes and phenol. However, tannin was not found in the n-hexane extract, while saponin and cardiac glycoside were also absent in all the extracts. The extracts were concentration dependent on the DPPH free radicals scavenging. The IC50 values were 0.8546, 0.8953 and 0.9081 μg/mL for the methanol, n-hexane and ethyl acetate extracts respectively. The antimicrobial screening showed that the methanol extract was still active at a concentration of 12.5 mg/mL. The result of this study suggests that the stem of Pterocarpus mildbraedii may be a good source of antioxidants and antimicrobial agents. Hence, the research justifies the use of Pterocarpus mildbraedii in traditional medicines.