Isolation of intestinal glucose uptake inhibitor from Punica granatum L.

摘要

Inhibition of intestinal glucose uptake is beneficial in reducing blood glucose level for diabetes. To search for an effective intestinal glucose uptake inhibitor from natural sources, 70 native edible plants, fruits and vegetables were screened using Caco-2 cells and fluorescent D-glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG). A compound that was able to inhibit glucose uptake (termed PG-1a) was isolated from a methanol extract of pomegranates. PG-1a appeared to be a phthalic acid-diisononyl ester-like compound with mol. wt. = 418. Inhibitory effect of PG-1a on intestinal glucose uptake was dose-dependent with 89% inhibition at 100 mug/ml. Also, intestinal glucose uptake inhibitory effect of PG-1a was 1.2-fold higher than phlorizin, a glucose uptake inhibitor. Results suggest that PG-1a may play a role in controlling dietary glucose absorption, and that PG-1a can effectively improve the diabetic condition with potential as an optional therapeutic and preventive agent.