A comparative study of Kigelia pinnata fruit extracts in terms of antimutagenic potential and antimicrobial efficacy against antibiotic-resistant microbial strains

In recent years, antibiotic-resistant microbes have become a serious concern which needs proper attention either to solve the problem or to find out the solution to treat it. In this study, antibiotic resistant strains of Pseudomonas, Enterococcus, and Escherichia coli (E. coli) were used to assess the antimicrobial potential of Kigelia pinnata fruit extract. Further, antimutagenic potential of Kigelia pinnata fruit extract was also assessed by Ames assay using Salmonella typhimurium strain TA 98 and TA 100. In antimicrobial assay, only chloroform, ethanol and hexane extract was found to produce clear zone diameter between 1.08 +/- 0.1 to 2.1 +/- 0.2 mm. Results of minimum inhibitory concentration revealed the effectiveness of chloroform extract on Pseudomonas, Enterococcus and E.coli at 1.8 mg/mL concentration. However, better antimicrobial activity was found with ethanol extracts at 2.1x10(-2) mg/mL concentration revealing the effectiveness of the low dose of ethanol in killing the antimicrobial resistant strains. In the time-kill test method, chloroform extract of K. pinnata was found to be most effective in reducing 98-99% test microbial population at both dilutions in 30 min. Antimutagenicity test showed the equal potential of chloroform and ethanol extracted Kigelia fruit sample in reducing the number of revertants. Kigelia fruit extract (1000 mu L) dose can reduce the mutagens at 5 mu g/plate level but not at 10 mu g/plate dose level. Further research will open the new scope in the field of development of herbal antimicrobials and antimutagenic compound for treating antibiotic-resistant microbes and cancer.