Antimicrobial and phytochemical screening of Oligochaeta ramose against different pathogenic microbes- An In vitro study

Biologically active compounds obtained from the medicinal plants are the effective chemotherapeutic agents and offering a broad spectrum of activity with greater emphasis on preventive action. The present study was aimed at evaluating the antimicrobial activities of crude methanolic extract of Oligochaeta ramose ( Asteraceae ) against pathogenic bacteria species of both G +ve strains ( Staphylococcus aureus, Bacillus pumilus, Streptococcus pneumoniae), G -ve strains, (Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae) and fungal species ( Candida albicans, Aspergillus niger ). In-vitro antimicrobial test was performed by disc diffusion method on nutrient agar and sabouraud dextrose agar for bacteria and fungi respectively, in order to analyze the percentage zone of inhibition and phytochemical screening was also performed. Methanolic extract showed significantly high inhibitory effect against G +ve strains, as compared to G -ve strains, whereas, no effect against C. albicans and A. niger. Modified agar well diffusion method was used to measure the minimum inhibitory concentration (MIC) and MIC values lies within the range of 75 to 150 ?g /ml for the G +ve while 300 to 600 ?g /ml for G-ve. Or.Cr was found to contain alkaloids, tannins, saponins, flavonoids and antraquinones and these agents may be responsible for antibacterial activity of this plant. Keywords : Oligochaeta ramose, Methanolic extract, Antimicrobial assay, Nutrient agar