Dr. Jiming Ye of the Shanghai Institute of Materia Medica said the researchers used 1 ton of the fruit to extract four bioactive components and found all four appear to activate the enzyme AMPK, which regulates fuel metabolism and aids in glucose uptake.
The findings, published online in Chemistry & Biology, liken the action of the four compounds to that of exercise which also activates AMPK. Drugs are also used to activate AMPK, but these may have side effects.
"The advantage of bitter melon is that there are no known side effects," Ye said in a statement. "Practitioners of Chinese medicine have used it for hundreds of years to good effect."
Exercise activates AMPK in muscle, which in turn mediates the movement of glucose transporters to the cell surface -- the major reason that exercise is recommended for those with type 2 diabetes.
"We can now understand at a molecular level why bitter melon works as a treatment for diabetes," David James of the Garvan Institute of Medical Research in Sydney said in a statement.