Comparative effects of black pigmented and non-pigmented brown rice on hypolipidemic activity and their mechanisms of action in high fat diet-induced hamsters

Brown rice consumption is known to have numerous therapeutic benefits. This study aimed to examine the bioactive components of black-pigmented (BRW) and non-pigmented (TK9W) brown rice and their comparative effects on hypolipidemic activity in high-fat diet (HFD)-induced hamsters. The results showed that besides total flavonoids and dietary fibers, BRW displayed higher total phenol and anthocyanin contents than TK9W. At 100 mg/kg/BW, although both BRW and TK9W significantly decreased the levels of serum and hepatic total cholesterols (TC) and triglycerides (TG), and increased the levels of serum high-density lipoprotein cholesterol (HDL-C) and fecal TC in HFD-induced hamsters, BRW was more effective than TK9W in lowering serum low-density lipoprotein cholesterol (LDL-C) and hepatic TG. BRW and TK9W also effectively down-regulated fatty acid synthase and PPARγ, and up-regulated lipoprotein lipase and PPARα expression in liver tissues at this dose level. This study demonstrates that, although BRW appears to have better hypolipidemic activity than TK9W, brown rice of different pigmentation effectively decreased the levels of serum and hepatic TG and TC, increased the serum HDL-C and fecal TC, as well as modulated the lipid metabolism-related protein expression in liver tissues.