Abstract
In our previous study, we showed the presence of liver lipid-lowering activity in the rat by Miyazaki-koimidori (KM), a traditional variety of bitter melon (Momordica charantia). Here, we studied the effect of novel varieties of M. charantia and ethanol/water extracts on rat liver lipid levels. First, we found that the liver lipid-lowering activity of Sadowara-sangou (S3), a main variety of bitter melon in Miyazaki was comparable to that of KM. Next, the effect of ethanol/water (100 : 0, 80 : 20, 60 : 40) extracts of S3 on liver lipid reduction was examined, and we found that the 60% ethanol extract was the most effective in lowering hepatic triglyceride levels. Finally, in addition to S3, 4 novel bitter melon cultivars (Miyazaki-N-ichigou, N1 ; Miyazaki-N-nigou, N2 ; Miyazaki-N-sangou, N3 ; Miyazaki-N-yongou, N4) were fed to rats and the serum and liver triglycerides were analyzed. Among the 5 varieties, N3 and N4 tended to exert the most potent hepatic triglyceride-lowering activity, suggesting a variety-dependent difference. In these experiments, diets containing either bitter melon or ethanol/water extract caused no adverse effects on food intake or growth of rats, and the effects on serum lipids were marginal.
The results of the present and previous studies clearly show that bitter melon exhibits a potent hepatic triglyceride-lowering activity.
