Evaluation of Antibacterial Activities of Medicinal Plants

Abstract

Plant and plant products are used as medicine from the beginning of human civilization. This study compares the antibacterial activity of crude hexane, ethylacetate and methanol extracts of nine different medicinal plants used in traditional Nepalese medicine, tested against 10 species of bacteria: Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 20063), Klebsiella oxytoca, Proteus mirabilis (ATCC 49132), Proteus vulgaris, Pseudomonas aeruginosa (ATCC 27853), Salmonella typhi, Salmonella paratyphi and Shigella dysenteriae by agar well diffusion method. The selected parts of these medicinal plants namely Acorus calamus (Rhizome), Aegle marmelos (Fruit), Asparagus racemosus (Tuberous root), Mimosa pudica (Root), Terminalia bellirica (Fruit), Terminalia chebula (Fruit), Tinospora cordifolia (Stem), Woodfordia fruticosa (Flower) and Holarrhena antidysenterica (Seed) were taken for study.The result showed that out of nine tested plants, four plant extracts (44%) showed activity against at least five or more tested bacteria and five plant extracts (56%) were active against three or less than three bacteria. None of the tested plant extracts was active against all the tested bacteria. A. racemosus was the least effective against bacterial species. S. aureus was the most susceptible bacteria being sensitive to 18 extracts from 9 medicinal plants. P. vulgaris was the most resistant bacteria being resistant to all selective plants. The MBC value ranges from 3.12 mg/ml to >50 mg/ml. Lowest MBC was shown by ethylacetate extract of T. bellirica against E. coli and ethylacetate extract of W. fruticosa against S. dysenteriae. Largest ZOI (31 mm) was produced by ethylacetate extract of T. bellirica.

Nepal Journal of Science and Technology Vol. 13, No. 2 (2012) 209-214

DOI: http://dx.doi.org/10.3126/njst.v13i2.7738