Abstract
A new phthalic acid ester has been isolated from the chloroform soluble fraction of Heliotropium strigosum and assigned the structure o-phthalic acid bis-(2-ethyl decyl)-ester 1. In addition, 4-hydroxybenzoic acid 2 and beta-sitosterole 3 have also been isolated. 4-Hydroxybenzoic acid 2 is reported for the first time from this species. The structures of these compounds were elucidated with the help of 1D and 2D NMR techniques and by comparison with the data reported in the literature. The new compound 1 indicated to be a competitive inhibitor of trypsin with the K (i) value of 12.1 mu m.