[Bioactivity-guided isolation of anti-angiotensin converting enzyme constituents from Trichosanthis Pericarpium]

To isolate the anti-angiotensin converting enzyme (ACE) constituents from Trichosanthis Pericarpium based on bioactivity-guided separation. Trichosanthis Pericarpium was extracted with boiling water and precipitated by ethanol, then its supernatant was collected and dialyzed. The retentate of the fractions above 1 000 was lyophilized to obtain GLP, which was then successively separated by DEAE Sepharose fast flow anion-exchange and Superdex-75 gel permeation chromatographic steps to achieve GLP-1-1. A combination of HPGPC, monosaccharide compositions determination and ACE inhibitory activity studies was performed to investigate the structure and bioactivity. The results showed that an anti-angiotensin converting enzyme oligosaccharide, GLP-1-1, was obtained from Trichosanthis Pericarpium based on activity tracking, whose average molecular weight was estimated to 1 367; mainly composed of arabinose, mannose, and glucose at a ratio of 0.2∶4.3∶10.0. GLP-1-1 showed potent anti-angiotensin converting enzyme effect with the IC₅₀of (113.4±8.6) mg•L⁻¹. In this study, an oligosaccharide with anti-angiotensin converting enzyme effect was isolated from Trichosanthis Pericarpium, which could lay the foundation for the substance basis study of Trichosanthis Pericarpium.