This project was designed to evaluate the antibacterial efficacy of hexane, chloroform, ethanol and aqueous extracts of Opuntia dillenii Haw. stems against common poultry pathogens. Pathogens used were Staphylococcus aureus, Escherichia coli, Salmonella, Clostridium perfringens type A and Haemophilus species.
This study was conducted to assess antibacterial and cytotoxic activity of O. dillenii Hexane, chloroform, ethanol and water extracts were prepared and antibacterial activity was evaluated by agar well diffusion method in which zones of inhibition were measured. Minimum inhibitory concentration (MIC) of plant extracts was evaluated by micro broth dilution method. The extracts which showed the antimicrobial activity were evaluated for cytotoxicity by using MTT assay on Vero cell line. Cell culture media was prepared and cell lines were propagated, monolayer was formed. Monolayer was exposed to plant extract dilutions. After 24-48 hours, MTT dye was introduced and cell survival percentage was calculated.
O. dillenii stems extracts inhibited the growth of both Gram negative and Gram positive bacteria. Chloroform and ethanol extracts of O. dillenii showed significant antibacterial activity against all the pathogens studied as compared to hexane and aqueous extracts. Hexane extract showed maximum zone of inhibition against Haemophilus species (13mm), for chloroform extract maximum zone of inhibition was obtained for C. perfringens (25.6mm), for ethanol extract maximum zone of inhibition was obtained for C. perfringens (23.0mm) and for aqueous extract maximum zone of inhibition was obtained for C. perfringens (23.0mm). Minimum inhibitory concentration for chloroform extract was lowest for all the tested strains. For S. aureus, C. perfringens type A and S. enterica MIC was 1250μg/mL. For E. coli and
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Haemophilus species MIC was 2083.3 and 2916μg/mL, respectively. The extracts were further investigated to test cytotoxic effect on Vero cell line using MTT assay. Only ethanol extract was observed to be cytotoxic.
Statistical analysis was conducted with Statistic Package for Social Sciences (SPSS for windows version 16, SPSS inc, Chicago, IL, USA). The results of antibacterial activity and MTT assay were evaluated for significance of difference using analysis of variance (ANOV). The homogeneity of groups was verified by Duncan’s test at an alpha level equal to 5%.
Chloroform extract of O. dillenii stems possess antibacterial activity and can be used to design traditional medicines for the development of therapeutic agent which will be more safe, effective and economical.