Immunomodulatory, analgesic and antipyretic effects of violacein isolated from Chromobacterium violaceum

Violacein was isolated from Chromobacterium violaceum, a soil Gram negative bacterium collected from the forest water body soil sample of Kolli Hills; Tamil Nadu, India. In the present study the immunomodulatory, analgesic and antipyretic activities of violacein were investigated in wistar rats and mice. Analgesic effect was evaluated by acetic acid- induced writhing, formalin induced paw licking and hotplate tests. Immunomodulatory effect was investigated by using ovalbumin- induced active paw anaphylaxis and sheep red blood cells (SRBC)-induced DTH tests. Antipyretic activity was evaluated by yeast- induced hyperpyrexia in rats. The anti- oedema effect was compared with indomethacin. Violacein inhibited 42.9% of ovalbumin- induced edema. Further we found that violacein (40 mg/kg b.w.) reduced the edema induced by sheep red blood cells. Violacein also produced significant (p<0.05) analgesic activity in acetic acid induced writhing response, formalin induced paw licking response and hot plate analysis. Treatment with violacein showed a significant (p<0.05) dose-dependent reduction in pyrexia in rats. The results suggest that violacein possesses potent immunomodulatory, analgesic and antipyretic activities.