Apple flavonols and n-3 polyunsaturated fatty acid-rich fish oil lowers blood C-reactive protein in rats with hypercholesterolemia and acute inflammation.

Both quercetin glycosides and omega-3 polyunsaturated fatty acids (n-3 PUFA) are well established for their individual health benefits in ameliorating metabolic disease. However, their combined effects are not well documented. It was hypothesized that the beneficial properties of quercetin glycosides can be enhanced when provided in combination with n-3 PUFA. Therefore, the aim of the present study was to investigate the effects of apple flavonols (AF) and fish oil (FO), alone and in combination, on proinflammatory biomarkers and lipid profiles in rats fed a high-fat diet. Sixty male Wistar rats were randomly divided into 5 groups (n = 12) and fed a high-fat diet for 4 weeks. One of the 5 groups of rats was used as the high-fat control. The other 4 groups of rats were injected with lipopolysaccharide (LPS) (5 mg/kg body weight) intraperitoneally, 5 hours before euthanization. One of these 4 groups was used as the hypercholerolemic and inflammatory control (high-fat with lipopolysaccharide [HFL]), and the other 3 received AF (HFL + 25 mg/kg per day AF), FO (HFL + 1 g/kg per day FO), or the combination (HFL + AF + FO). Compared to the HFL group, the AF, FO, and AF + FO groups showed lower serum concentrations of interleukin-6 and C-reactive protein (CRP) levels. The AF, FO, and AF + FO also had lowered serum triacylglycerol and non-high-density lipoprotein cholesterol (HDL-C) concentrations, but higher HDL-C levels relative to the HFL group. An additive effect was observed on serum CRP in the AF + FO group as compared with the AF or FO groups. The results demonstrated that AF and FO inhibited the production of proinflammatory mediators and showed an improved efficacy to lower serum CRP when administered in combination, and they significantly improved blood lipid profiles in rats with diet-induced hyperlipidemia and LPS-induced acute inflammation.