Structure-activity relationship studies of chalcones as SRS-A receptor antagonists
He, K.Q.; Cheng, G.F.; Xi, F.D.; Guo, Z.R.; Zhu, X.Y.
Yao Xue Xue Bao 31(11): 878-880
1996
ISSN/ISBN: 0513-4870 PMID: 9863261 Document Number: 465037
A simple, reliable and highly sensitive bioassay with sensitized longitudinal strips of guinea pig ileum was used for screening the receptor antagonists of slow reacting substance of anaphylaxis (SRS-A). The SRS-A receptor antagonistic activities of 17 chalcones were studied. Most compounds in these chalcones were found to have SRS-A receptor antagonistic action at the concentration of 10-4 mol cntdot L-1. Among them, compounds 5, 13 and 17 were highly effective with IC-50 of 7.5 times 10-6, 7.5 times 10-6 and 6.8 times 10-5 mol cntdot L-1, respectively. Under the same conditions, the IC-50 of FPL 55712, a known leukotriene D-4 receptor antagonist, was shown to be 3 times 10-4 mol cntdot L-1. It would appear that compounds 5, 13 and 17 were 40, 40 and 4.4 times more potent, respectively, than FPL 55712. From analysis of structure-activity relationship of chalcones, these results suggest that the following factors may be important for an active antagonist of SRS-A receptors: (a) There is a system of pi, pi conjugation in the molecule; (b) The ester group in the B ring of chalcones is more favorable than the carboxyl group; (c) Antagonism for meta- or para-substituted derivatives of carboxyl or ester group in the B ring are more potent than ortho-substituted compounds; (d) The length of carbon chain of alkyl group in the A ring of chalcones is more effective for 1, 4 or 6 carbon atoms than for 10 or 14 carbon atoms.