IntroductionExcessive calorie intake and physical inactivity have dramatically increased nutrient overload-associated disease, becoming a global public health issue.Chimonanthus salicifoliusS. Y. Hu (CHI) is a homology plant of food and medicine in China and shows several health benefits.MethodsThis work investigated the antioxidant activity, the alleviating effects, and the mechanism of action on diabetes and hyperlipidemia ofCHIleaves.Results and discussionResults showed thatCHIleaves infusion displayedin vitroantioxidant activity measured by ABTS and ferric reducing antioxidant power methods. In wild-type Kunming mice,CHIleaves infusion consumption activated the hepatic antioxidant enzymes, including glutathione reductase, glutathioneS-transferase, glutathione peroxidase and thioredoxin reductase as well as thioredoxin reductase 1. In alloxan-induced type 1 diabetic mice,CHIleaves infusion ameliorated diabetic symptoms, including polyuria, polydipsia, polyphagia and hyperglycemia, in a dose-dependent and time-course manners. The mechanism involvedCHIleaves up-regulating renal water reabsorption associated protein – urine transporter A1–and promoting the trafficking of urine transporter A1 and aquaporin 2 to the apical plasma membrane. Despite this, in high-fat diet-induced hyperlipidemic golden hamsters,CHIleaves powder did not significantly effect on hyperlipidemia and body weight gain. This might be attributed toCHIleaves powder increasing the calorie intake. Interestingly, we found thatCHIleaves extract containing a lower dose of total flavonoid thanCHIleaves powder pronouncedly reduced the levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol in serum in golden hamsters fed a high-fat diet. Furthermore,CHIleaves extract elevated the diversity of gut microbiota and the abundance ofBifidobacteriumandRuminococcaceae_UCG-014.It also decreased the abundance ofLactobacillusat the genus level in golden hamsters fed a high-fat diet. Overall,CHIleaves benefit oxidative stress prevention and metabolic syndrome ameliorationin vivo.