Wax apple (Syzygium samarangense) fruit extract ameliorates endothelial dysfunction and liver damage in high cholesterol diet-fed rats

Abstract

Background and aim

Wax apple fruit (Syzygium samarangense) is one of the most popular tropical fruit in Asia, and contains several essential nutrients. Therefore, this study explored the effects of the wax apple fruit extract on a high-cholesterol diet-induced vascular endothelial dysfunction and fatty liver in rats.

Experimental procedure

Male Sprague Dawley rats were fed a diet with 1.5% cholesterol (HCD) for 8 weeks, and were given wax apple fruit extract (50 and 100 mg/kg/day) orally for the last 4 weeks. After 8 weeks, blood sample, thoracic aorta, and liver were collected and processed for biochemical and histological analysis. Additionally, vascular endothelial function and the protein expression of oxidative stress markers in aortae were evaluated.

Results and conclusion

Wax apple reduced serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), but increased high-density lipoprotein cholesterol (HDL-C) levels. Furthermore, the liver levels of TG and TC were reduced in wax apple-treated hypercholesterolemic rats. Histological studies revealed that wax apple ameliorated HCD-induced morphologic changes of aortic and liver tissues of rats. In aortic tissues, the impaired endothelium-dependent responses to acetylcholine, the reduced nitric oxide (NO) contents, the elevated endothelin (ET)-1 contents, and the increased expression of NADPH oxidase subunit p47^phox and 4-hydroxynonenal in HCD-fed rats were reversed by wax apple treatment. These results suggest that oral administration of wax apple improves vascular dysfunction and damage in hypercholesterolemic rats possibly through increasing NO bioavailability, decreasing ET-1 levels and reducing oxidative stress. Furthermore, wax apple ameliorates the HCD-induced fatty liver in rats.