The hypoglycemic activity of fenugreek may be associated with the galactomannan fiber and saponin components that reduce gastrointestinal glucose and cholesterol absorption, and increase bile acid excretion (14). Hypoglycemic activity is also attributed to the trigonelline, nicotinic acid, and coumarin fractions. 4-Hydroxyisoleucine, an amino acid constituent of fenugreek, potentiates insulin secretion in non-insulin-dependent diabetic (NIDD) rats when administered intraperitoneally (15).
In addition to lower fasting and postprandial glucose levels, fenugreek-treated diabetic rats have higher hemoglobin, GSH, and plasma antioxidant levels and lower glycosylated hemoglobin, plasma lipids, and TBARS levels than diabetic controls (4). Dietary fenugreek also normalizes the activities of glucose and lipid-metabolizing enzymes in diabetic rats (3).
Studies involving healthy mice and rats indicate that dietary fenugreek is associated with increased serum T4, liver GSH, glyoxalase I, and GST activities, and decreased T3 levels and T3/T4 ratio (17) (18) (19).
Fenugreek intake in humans was associated with an increase in molar insulin binding sites of erythrocytes, which may enhance glucose utilization (16).
In MCF-7 estrogen receptor-positive breast cancer cells, fenugreek extract induced cell cycle arrest as well as apoptosis (9).