Anti-microfilarial activity of methanolic extract of Vitex negundo and Aegle marmelos and their phytochemical analysis.

In the present study, methanolic extracts of roots of Vitex negundo L. and extracts of leaves of Vitex negundo L., Ricinus communis L. and Aegle marmelos Corr. were explored for possible antifilarial effect against Brugia malayi microfilariae. It was observed that among the herbal extracts, root extract of Vitex negundo L. and leaves extract of Aegle marmelos Corr. at 100 ng/ml concentration showed complete loss of motility of microfilariae after 48 hr of incubation. Thin layer chromatography of the extracts revealed the presence of alkaloids, saponin and flavonoids in the roots of Vitex negundo L. and coumarin in the leaves of Aegle marmelos Corr.

Norfloxacin induced resistance to fluoroquinolones & structurally unrelated antimicrobial agents in coagulase negative staphylococci.

Nine clinical isolates of coagulase negative staphylococci (CONS) susceptible to norfloxacin (MIC 1.8-2 micrograms/ml) were manipulated in vitro to induce norfloxacin resistance by means of serial passage in brain heart infusion broth containing increasing concentrations of norfloxacin. Exposure of CONS to norfloxacin resulted in 18 to 20 times increase in MIC of norfloxacin and change in in vitro susceptibility to ciprofloxacin, pefloxacin, ofloxacin, kanamycin, neomycin and tobramycin, indicating development of cross resistance to fluoroquinolones and aminoglycosides. These results show that exposure to increasing concentrations of norfloxacin can induce the development of resistance to various antimicrobial agents, suggesting its mutagenic role.