In Vitro Anti Bacterial Potential of Different Extracts of Tagetes Erecta and Tagetes Patula

Abstract

The antimicrobial activity of cold aqueous, hot aqueous and methanol extracts of Tagetes erecta and Tagetes patula flowers was evaluated by agar well diffusion method against ten different pathogenic species of Gram-negative bacteria viz.,  Escherichia coli, Proteus vulgaris, Proteus mirabilis, Aeromonas sobria, Aeromonas hydrophila, Plesiomonas shigelloides, Salmonella enterica serotype Typhi, Salmonella enterica serotype Typhimurium, Salmonella enterica serotype Aboni and Salmonella enterica serotype Enteritidis, four different pathogenic species of Gram-positive bacteria such as Bacillus subtilis, Bacillus cereus, Bacillus circulans and Staphylococcus aureus. Methanol extract of Tagetes erecta at 40 mg/ml concentration was found to have better inhibitory activity when compared to cold and hot aqueous extracts, which were evident through the increased zones of inhibition against Gram-negative and Gram-positive bacteria. Methanol extract of Tagetes erecta showed highest inhibition zone of 26 mm against Aeromonas sorbia, Aeromonas hydrophila, Staphylococcus aureus (MTCC7405) and Staphylococcus aureus (clinical isolate), while lowest inhibition zone of 12 mm with Bacillus subtilis. Similarly, hot aqueous extracts of Tagetes patula had better activity as compare to cold aqueous extract and methanol extract at 40mg/ml concentration. It had highest and lowest zone of inhibition with Proteus vulgaris OX19 (30 mm) and Staphylococcus aureus (clinical iolate) (13 mm) respectively. Minimal inhibitory concentrations (MICs) were between concentrations of 20 - 160 mg/ml with aqueous or methanol extracts of Tagetes erecta and Tagetes patula flowers for most of the tested bacteria. Results of antimicrobial activity of extracts indicate that they possess potential broad spectrum antibacterial activity.

Keywords: Tagetes flower extracts, antibacterial activity