The effects of bitter melon (Momordica charantia) extracts on serum and liver lipid parameters in hamsters fed cholesterol-free and cholesterol-enriched diets.

The hypolipidemic effect of dietary methanol fraction (BMMF) extracted from bitter melon (Koimidori variety), at the levels of 0.5% and 1.0%, was examined in male golden Syrian hamsters fed diets supplemented with and without cholesterol. The feeding of BMMF at 0.5% and 1.0% levels in the diets for 4 wk tended to reduce food intake and growth, although there was no difference in food efficiency (weight gain/food intake). An effect of dietary BMMF on serum triglyceride was not seen in hamsters fed diets free of cholesterol, while hypertriglyceridemia induced by dietary cholesterol was significantly lowered in a dose-dependent manner in those fed diets containing the BMMF Serum total cholesterol concentration also tended to decrease in a dose-dependent manner following feeding of increasing amounts of BMMF in the presence and absence of cholesterol in the diet. The effects of dietary BMMF on liver triglyceride and total cholesterol levels were marginal, although dietary cholesterol caused a marked accumulation of these lipid molecules in the liver. These results suggest that the BMMF contains some components that could ameliorate lipid disorders such as hyperlipidemia.

The effects of bitter melon (Momordica charantia) on serum and liver triglyceride levels in rats.

Effects of three different varieties (Koimidori, Powerful-Reishi, and Hyakunari) of bitter melon (Momordica charantia) and those of methanol fraction extract of Koimidori variety on serum and liver triglycerides were studied in rats. Feeding of diets containing either bitter melon or various fractions isolated by organic solvents caused no adverse effects on food intake or growth of rats. When the effect of three different varieties of bitter melon was compared, the Koimidori variety was found to be the most effective in lowering hepatic triglyceride levels as compared to the other two varieties, suggesting a variety-dependent difference in their activity. Furthermore, the active component(s) responsible for the liver triglyceride lowering activity of Koimidori variety was assumed to be concentrated in the methanol fraction, but not in other fractions such as the n-hexane, the acetone, or the residual fraction. The triglyceride lowering activity was furthermore confirmed by the dose-dependent reduction of hepatic triglyceride, resulting the lowest level in rats fed 3.0% supplementation. In these experiments, the effects on serum lipids were marginal. The results of the present and previous studies clearly show that bitter melon, especially Koimidori variety, exhibits a potent liver triglyceride-lowering activity.