Slow Acting Protein Extract from Fruit Pulp of Momordica charantia with Insulin Secretagogue and Insulinomimetic Activities

• Published in: Biological & pharmaceutical bulletin 2006, Vol.29(6), pp.1126-1131
• Main Authors: Yibchok-anun, Sirintorn, Adisakwattana, Sirichai, Yao, Cheng Yu, Sangvanich, Polkit, Roengsumran, Sophon, Hsu, Walter Haw
• Format: Article
• Language: English
• Subjects: 3T3-L1 Cells; Adipocytes - drug effects; Adipocytes - metabolism; Animals; antihyperglycemia; Blood Glucose - analysis; Cell Culture Techniques; Diabetes Mellitus, Experimental - blood; Diabetes Mellitus, Experimental - drug therapy; Fruit - chemistry; Glucagon - metabolism; Glucose - metabolism; Hypoglycemic Agents - isolation & purification; Hypoglycemic Agents - pharmacology; Hypoglycemic Agents - therapeutic use; Insulin - blood; Insulin - metabolism; insulin secretagogue; Insulin Secretion; insulinomimetic; Male; Mice; Momordica charantia; Momordica charantia - chemistry; Monocytes - drug effects; Monocytes - metabolism; Pancreas - drug effects; Pancreas - metabolism; pancreatic perfusion; Perfusion; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plant Proteins - isolation & purification; Plant Proteins - pharmacology; Plant Proteins - therapeutic use; protein extract; Rats; Rats, Wistar; Streptozocin
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.29.1126

The protein from Thai bitter gourd (Momordica charantia) fruit pulp was extracted and studied for its hypoglycemic effect. Subcutaneous administration of the protein extract (5, 10 mg/kg) significantly and markedly decreased plasma glucose concentrations in both normal and streptozotocin-induced diabetic rats in a dose-dependent manner. The onset of the protein extract-induced antihyperglycemia/hypoglycemia was observed at 4 and 6 h in diabetic and normal rats, respectively. This protein extract also raised plasma insulin concentrations by 2 fold 4 h following subcutaneous administration. In perfused rat pancreas, the protein extract (10 μg/ml) increased insulin secretion, but not glucagon secretion. The increase in insulin secretion was apparent within 5 min of administration and was persistent during 30 min of administration. Furthermore, the protein extract enhanced glucose uptake into C2C12 myocytes and 3T3-L1 adipocytes. Time course experiments performed in rat adipocytes revealed that M. charantia protein extract significantly increased glucose uptake after 4 and 6 h of incubation. Thus, the M. charantia protein extract, a slow acting chemical, exerted both insulin secretagogue and insulinomimetic activities to lower blood glucose concentrations in vivo.