[Active constituents in compound whole grain and its regulation on bile acids metabolism].

OBJECTIVE

To analyze and compare the contents of dietary fiber, resistant starch, flavonoid and total saponins in the compound whole grain, to observe the effects of compound whole grain on the excretion of bile acid and its regulation mechanisms.

METHODS

The contents of dietary fiber, resistant starch, flavonoid and saponins in compound whole grain were determined according to the national standard methods and other methods in literatures. Forty-four SPF grade SD rats were allocated randomly into four groups: the negative control group, hyperlipemia model group, rice-flour group and compound whole grain group, and each group was provided with corresponding diet for 8 consecutive weeks. The excrements of rats were collected at the beginning and the ending of the experiment by using metabolic cages. The expression of CYP7A1 mRNA and LXRalphamRNA were also observed.

RESULTS

The composition of compound whole grain was dietary fiber 15.3g, resistant starch 9.03g, flavonoid 0.45g and saponins 0.24g per 100g. The excretion of bile acid was increased significantly (P < 0.05), and the expression of CYP7A1 mRNA and LXRalphamRNA was significantly higher in the compound whole grain group than the other three groups (P < 0.05).

CONCLUSION

Compound whole grain is rich in DF, RS, flavonoid and saponins than common flour and rice. The expression of rate-limiting enzyme CYP7A1 mRNA in the classical pathway of bile acid synthesis and its upstream acceptor LXRalpha mRNA could be up-regulated by compound whole grain, thus effectively increasing bile acid excretions, and improving the disorders of lipid metabolism.