INHIBITORY ACTIVITIES OF ALKALOID FROM COCCINIA GRANDIS AGAINST ALDOSE REDUCTASE AND GENERATION OF ADVANCED GLYCATION ENDPRODUCTS

The aim of the present study was to evaluate the anti-diabetic complications of Coccinia grandis leaf extract. Anti-diabetic complications activities were evaluated via rat lens aldose reductase (RLAR), human recombinant aldose reductase (HRAR), and advanced glycation endproducts (AGE) assays. Among the different solventsoluble fractions obtained from the methanolic extract, the dichloromethane (CH2Cl2) fraction was found to exhibited potent inhibitory activities against RLAR, HRAR and AGE with IC50 values of 8.26 ± 0.10, 10.20 ± 0.13 and 28.18 ± 0.06 µg/mL, respectively. Silica gel column chromatography of the CH2Cl2 fraction yielded a alkaloid, 1-tert-butyl-5,6,7-trimethoxyisoquinolene, based on the comparison with reported 1H- and 13C-NMR spectroscopic data. 1-tert-butyl-5,6,7-trimethoxyisoquinolene showed potential inhibitory activity against RLAR, HRAR and AGE with the respective IC50 values of 3.26 ± 0.11, 5.40 ± 0.25, and 18.54 ± 0.55 µM, respectively. Our results clearly indicate the potential RLAR, HRAR and AGE formation inhibitory activities of C. grandis as well as its isolated constituents, which could be further explored to develop therapeutic modalities for the treatment of diabetes and related complications. Keywords: C. grandis; Diabetic complications; Aldose reductase; Advanced glycation end products.