A Bioactive Polyphenolic Constituent in the Bark of Pterocarpus indicus, Willd. I. Isolation and Characterization

Abstract

A nondialyzable polyphenolic substance having antiplasmin activity was isolated from the bark of Pterocarpus indicus, Willd as a brownish powder. The results of ultracentrifuging, HPLC and TLC of its acetate indicated a narrow distribution of its molecular weight, i.e. its relative homogeneity. This observation, and the pattern seen in its ¹³C-NMR spectrum that indicated a difference of its constituent units from the known coniferous polyflavanols, suggested some uniqueness of this substance (called PI in this paper) in the polyflavanol group. Its large apparent molecular weight, which was calculated from the sedimentation data, also seems to support this suggestion.

The substance inhibited plasmin esterolytic activity at ED₅₀ = 2.5μg/ml, and also showed a carcinostatic effect on mice bearing ascites Ehrlich carcinoma at a dose of 2 mg/kg.