Borrelidin, an antibiotic isolated from Streptomyces californicus, is a potential drug candidate due to its recently reported antiangiogenic activity and other biological activities. Keeping in view the scope of the antibiotic, some biological studies were performed to know the effect of borrelidin on isolated frog heart at different concentrations (10, 30 & 100 μg / ml). Boreelidin resulted in considerable drop in heart beat, corresponding decreased cardiac output and finally cardiac arrest was noticed at 100μg/ml dose. Influence of borrelidin on peripheral blood vasculature was also tested and found to cause peripheral vasoconstriction at higher concentration, resulting in the reduction of the flow rate. Further, borrelidin could not show any effect on the motility of intestinal smooth muscle of guinea pig ileum.
