INVITRO AND INVIVO ANTIMICROBIAL EFFECTS OF WRIGHTIA TINCTORIA (ROXB.) R. BR. AGAINST EPIZOOTIC ULCERATIVE SYNDROME IN CHANNA STRIATUS

摘要

Murrels are often affected by the dreadful disease Epizootic Ulcerative Syndrome (EUS) and the primary causative agent of EUS is the fungus Aphanomyces invadans and the opportunistic bacterial pathogen is Aeromonas hydrophila. The antibacterial activity and antifungal activity of W. tinctoria were studied against selected pathogens and invivo antibiotic effect in EUS affected striped murrel Channa striatus was also examined. The leaves of a medicinal herb namely Wrightia tinctoria (Roxb.) R. Br. was evaluated against five fish pathogens. Phytochemical screening of the leaves revealed the presence of steroids, reducing sugars, alkaloids, phenolic compounds, flavonoids, saponins and tannins . The TLC chromatogram of the extracts revealed several coloured bands. Antibacterial activities of the extracts were determined by the agar disc diffusion method. Chlortetracycline (5mcg/disc) was used as positive control for comparison of the inhibition zones. The extract showed efficient antibacterial activity against Aeromonas hydrophila with maximum zone of inhibition. The Minimum Inhibitory Concentration of the extract against the pathogens was determined. Growth of Aphanomyces invadans was inhibited by 85-90%. The herbal paste applied topically on the lesions showed a positive effect by controlling and curing the lesions. Thus, the active extract of W. tinctoria could be taken to the next step of bioassay guided purification to characterize the novel antimicrobial agents