The antidiabetic potential of bitter melon is well established in normal, streptozocin-or alloxan-induced diabetic animals and in genetic models of diabetes (Ahmed et al 2004, Bailey etal 1985, Day et al 1990, Jayasooriya etal 2000, Karetal 2003, Miura et al 2001, 2004, Reyes et al 2005, Sarkar et al 1996, Shibb et al 1993). All parts of the plant (fruit pulp, seeds, leaves and whole plant) have shown activity.
A systematic study comparing the hypoglycaemic activity of three extracts in vivo found that the methanolic extract of dried whole fruits and seeds reduced blood glucose by 49% at the end of the first week, which became 39% by week 5; the aqueous extract of fresh, unripe, whole fruits reduced fasting blood glucose by 50%, which was consistent until the study ended, and the chloroform extract of dried whole fruits and seeds showed almost no hypoglycaemic activity (Virdi et al 2003).
These observations have special significance when one considers that the whole bitter gourd is cooked in water and consumed in many cultures, particularly in India.
The hypoglycaemic activity is attributed to a mixture of steroidal saponins known as charantins, insulin-like peptides and alkaloids that are concentrated in the fruit (Grover & Yadav 2004).
Based on studies with animal models, it appears that Momordica charantia increases the renewal of beta-cells in the pancreas, or may permit the recovery of partially destroyed beta-cells (Ahmed et al 1998), and stimulates pancreatic insulin secretion (Welihinda et al 1982). It also improves peripheral glucose uptake (Welihinda & Karunanayake 1986). A study with streptozocin-induced diabetic animals found that bitter melon juice normalises the structural abnormalities of peripheral nerves, regulates glucose uptake into thejejunum membrane brush border vesicles and stimulates glucose uptake into skeletal muscle cells (Ahmed et al 2004).
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...