Antimicrobial property and antioxidant composition of crude extracts of Pueraria mirifica, Butea superba and Mucuna macrocarpa

Abstract

In this study, crude extracts of Pueraria mirifica, Butea superba and Mucuna macrocarpa were prepared using sequential extraction with three different solvents (hexane, ethyl acetate and methanol). The extracts obtained were then used to test for their antimicrobial activity by the disc diffusion method, which showed that, against a wide range of Gram-positive and Gram-negative bacteria, only the P. mirifica extract obtained with ethyl acetate exhibited antimicrobial activities. The minimum inhibitory concentration (MIC) of the extract was also determined with values between 15 and 50 mg/ml depending on the microbes tested. Thin layer chromatography (TLC) was subsequently used to separate the chemical constituents of the extract. When tested against B. cereus, there were only two bands which showed anti-B. cereus activity. Additionally, the crude extracts of P. mirifica, B. superba and M. macrocarpa were analysed for some antioxidant compounds using HPLC. Our results showed that all the extracts contained daidzin, genistin, daidzein and genistein, all of which were present in the highest amounts (0.045, 0.037, 0.049 and 0.060 % respectively) in the ethyl acetate extract of P. mirifica.

Keywords

• antimicrobial activity
• antioxidants
• Kwao Krua
• Butea superba
• Mucuna macrocarpa
• Pueraria mirifica