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

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 p47phox 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.

Protective effect of wax apple (Syzygium samarangense (Blume) Merr. & L.M. Perry) against streptozotocin-induced pancreatic ß-cell damage in diabetic rats.

The purpose of this study was to investigate the protective properties and mechanisms of wax apple (Syzygium samarangense (Blume)) against streptozotocin (STZ)-induced pancreatic ß-cell apoptosis in diabetic rats. Diabetes was induced by STZ (65 mg/kg; i.p.) injection and wax apple (100 mg/kg) was orally administered to diabetic rats for a period of 30 days. During this time, fasting blood glucose (FBG) and body weight were measured weekly. At the end of the experiment, serum insulin, HOMA-B, and pancreatic insulin expression were assessed. The expression of apoptosis-related proteins along with the nitrotyrosine level, antioxidant activities, and pro-inflammatory cytokine TNF-α in the pancreas were also determined. STZ-induced diabetic rats exhibited an increase in FBG, and a decrease in body weight, serum and pancreatic insulin, as well as HOMA-B. Pancreatic apoptosis was noted in diabetic rats and indicated by enhancing the expression of cleaved caspase-3 and Bax proteins and downregulating the expression of Bcl-2 and Bcl-xl proteins. The activities of antioxidant CAT and SOD in the pancreas of the diabetic rats was also reduced. Importantly, wax apple treatment resulted in a significant reduction of FBG and increased body weight in diabetic rats. Wax apple also improved pancreatic ß-cell function, this was clearly evidenced by increased HOMA-B and pancreatic and serum insulin levels in diabetic rats. Moreover, pancreatic ß-cell apoptosis was alleviated with significantly down-regulated cleaved caspase-3 and Bax protein expression, and upregulated Bcl-2 and Bcl-xl protein expression in wax apple treated diabetic rats. These were related to the induction of CAT and SOD activities, and reduction of nitrotyrosine and TNF-α levels in wax apple administration. Overall, these results provide evidence that wax apple protects against STZ-induced pancreatic ß-apoptosis and dysfunction in diabetic rats, possibly through inhibiting oxidative stress and pro-inflammatory cytokine, and activating anti-apoptotic proteins.

Lactulose production from milk concentration permeate using calcium carbonate-based catalysts.

Milk concentration permeate (MCP), a low-value by-product of ultrafiltration plants and calcium carbonate-based catalysts were used for lactulose production. The results obtained show the effectiveness of oyster shell powder and limestone for lactose isomerisation as a replacement for egg shell powder. With the reaction conditions of 12mg/ml catalyst loading, reflux time of 120min at 96°C, a maximum yield of 18-21% lactulose was achievable at a cost of <50% of original lactose degradation (measured by HPLC). De-proteination of MCP by acidification prior to isomerisation helped lactulose formation in the earlier stages, but did not significantly increase the yield. The resulting lactulose MCP (40°B) incorporated at the rate of 3-4% was effective in enhancing the growth rate and acid production of Lactobacillus acidophilus (LA-5) in probiotic products.