Screening of Bactericidal Activity of Selected Plumbago Species Against Bacterial Pathogens

Abstract

The present study was undertaken to determine the antibacterial potential of Plumbago species viz., Plumbago zeylanica Linn., Plumbago auriculata Lam. and Plumbago rosea Linn. collected from various localities of South India. For the bio-efficacy studies six different extracts of Plumbago species with various concentrations viz., 20, 40, 60, 80 and 100µg/ml against Gram positive and Gram negative bacterial pathogens viz., Staphylococcus aureus (MTCC 737), Streptococcus pyogenes (MTCC 1928), Bacillus subtilis (MTCC 441), Klebsiella pneumoniae (MTCC 109), Morganella morganii (MTCC 662) and Pseudomonas aeruginosa (MTCC 1688) using well diffusion method. Among the eighteen different extracts of three different Plumbago species, highest frequency of antibacterial activity (54%) was recorded in P. rosea. The antibacterial activity of various extracts in different concentration of the selected Plumbago species are as follows: P. rosea (54%) > P. zeylanica (49%) > P. auriculata (40%). The ethanolic extract of all the Plumbago species revealed superior bactericidal activity compared to other tested extracts. The ethanolic extracts of P. zeylanica, P. auriculata and P. rosea showed 91%, 50% and 99% of activity against Gram positive pathogens and 66%, 26% and 89% of activity against Gram negative pathogens. The bioactive compound plumbagin and extract of aerial parts of Plumbago species show a wide spectrum of antibacterial activity. The compound shows promise as a new drug for various bacterial infectious diseases. Hence, this study offers a base of using Plumbago species as herbal alternative for the synthesis of antimicrobial agents.