The effects of royal jelly and tocotrienol-rich fraction on impaired glycemic control and inflammation through irisin in obese rats

The effects of royal jelly (RJ) and tocotrienol-rich fraction (TRF) on obesity-induced glucose intolerance and inflammation were assessed in the current study. Regarding irisin as an important adipomyokine that attenuates obesity-induced disorders, we evaluated whether RJ and TRF could exert their metabolism regulatory effects through irisin. Obese rats were fed a high-fat diet (HFD) with or without supplementation of RJ, TRF, or both, for 8 weeks. At the end of the intervention, weight, irisin, glycemic, and inflammatory indices were measured. The weight of the rats did not remarkably reduce in any of the groups. Glucose homeostasis and inflammation were improved when we added RJ and TRF to HFD. RJ elevated irisin concentration, but the effect of TRF on irisin was not noticeable. Our results indicated that, despite the lack of significant weight loss, RJ and TRF promoted healthy obesity. This improvement was mediated by irisin in RJ consuming rats. Practical applications: Obesity is a public health concern associated with several chronic disorders. The beneficial effects of irisin on obesity-related disorders are well-established. It is the first study assessing the effect of RJ and TRF as functional foods, with pharmacological and nutritional activities on obesity complications, through irisin mediation. Our study demonstrated that RJ exerts its metabolic regulatory effects by irisin as a mediator. Our investigation makes a remarkable contribution to the literature, because it suggests a new mechanism for the anti-obesity properties of RJ and TRF.