Antispasmodic effects of curcuminoids on isolated guinea-pig ileum and rat uterus.

Curcuminoids, a yellow constituent isolated from Curcuma longa Linn. rhizomes was studied for its antispasmodic activity in isolated guinea-pig ileum and rat uterus. Curcuminoids at the concentration of 12 microg/ml significantly inhibited the ileum pre-contracted with acetylcholine (ACh) 5 x 10(-7) M and histamine 5 x 10(-7) M. (Force of contraction was 62.84 +/- 4.66% and 75.60 +/- 4.66% respectively) and the effects were prominently observed when the concentration of curcuminoids was increased to 36 microg/ml. (Force of contraction was 44.93 +/- 4.33% and 42.79 +/- 1.98%). In potassium depolarizing Tyrode solution, curcuminoids 4 microg/ml and 20 microg/ml reduced the contraction induced by calcium chloride (CaCl2) 1.8 mM. (The contraction was 63.31 +/- 1.80% and 36.87 +/- 3.25%). In rat uterus smooth muscle preparation, curcuminoids 8 microg/ml and 16 microg/ml significantly reduced force and frequency of contraction induced by oxytocin 1 x 10(-2) IU/ml. Curcuminoids 8 microg/ml produced 54.68 +/- 3.34 per cent force of contraction and 79.09 +/- 2.29 per cent frequency of contraction. Curcuminoids 16 microg/ml caused more relaxation of rat uterus smooth muscle. (Force of contraction was 43.38 +/- 3.56%, frequency of contraction was 49.96 +/- 5.20%). Curcuminoids 8 and 16 microg/ml significantly reduced force of contraction induced by KCl 50 mM. (Force of contraction was 54.10 +/- 4.92% and 36.60 +/- 2.99%). The results obtained from this study concluded that curcuminoids produced a smooth muscle, relaxation effect on isolated guinea-pig ileum and rat uterus by receptor-dependent and independent mechanism.