Background/Aims: Heart disease is the second leading cause of death in Japan, and antioxidants are known to reduce such risk. Boysenberry is said to contain more polyphenols than any other common berries and to be a potential antioxidant with the main polyphenol being ellagic acid. In this study, we report the effective antioxidant action of boysenberry and on the effect of ellagic acid on cholesterol metabolism.
Methods: First, we assay the total polyphenol content using the Folin-Denis method and the antioxidant activity using DPPH free radical and ABTS assay by the difference in color with the reagent. Next, to investigate the effect of ellagic acid on cholesterol metabolism, HepG2 human hepatoma cells were cultured medium in containing ellagic acid. After 24 h of treatment ellagic acid, we analyzed ABCG5 mRNA expression by RT-real-time PCR.
Results: We found that in comparison to raspberry, boysenberry has twice as much polyphenols as and is twice antioxidant. The main polyphenol, ellagic acid accounts for 15% -20% of antioxidant activity. Expression of ABCG5 which is a factor about cholesterol excretion, increased with increase in ellagic acid concentration compared to control medium having no ellagic acid.
Conclusions: In future, we would like to identify the most potent antioxidant polyphenolic type and to investigate the role of ABCG5 in chlosterol excretion on small intestine. Our results suggest that ellagic acid influenced cholesterol metabolism and its bioactivity does not depend on antioxidantion.
Funding Source: N/A