The mechanism underlying the hypocholesterolaemic activity of aqueous celery extract, its butanol and aqueous fractions in genetically hypercholesterolaemic RICO rats

Drinking aqueous celery extract for 8 weeks caused a significant reduction in serum total cholesterol (TC) level in growing genetically hypercholester olaemic (RICO) rats. In addition, administration of butanol fraction (Fbu) and aqueous fraction (Faq) of celery extract for 7 days by intraperitoneal (i.p.) infusion effectively decreased the serum TC and high-density lipopro tein cholesterol (HDL-C) levels of adult RICO rats. The 8-week study showed that oral intake of celery extract could enhance the C-14-cholesterol/ met abolites excretion. The liver and small intestinal sterol synthesis were no t affected. Also, long term drinking of aqueous celery extract did not lead to any undesirable side effects on liver functions. The Fbu and Faq lowere d serum TC level mainly through increased bile acid excretion but not by mo dulating the activity of the rate-limiting enzyme for cholesterol biosynthe sis, HMG-CoA reductase. Hence, the mechanism elucidated supports that sugge sted by the 8-week study. A preliminary chemical characterisation of Fbu an d Faq fractions by thin layer chromatography (TLC) showed the presence of s ugars and amino acids. There is a possibility that polar compounds with sug ar or amino acid side chains(s) could contribute to the hypocholesterolaemi c action of celery extract.