No abstract

Metabolic syndrome (MS) is a cluster of metabolic disorders such as abdominal obesity, hypertension, glucose intolerance, dyslipidemia and hepatic steatosis that contribute to increased cardiovascular morbidity and mortality. There is an urgent need for strategies to prevent this emerging global epidemic. Recently, growing interest in discovering food functional nutrients for the prevention and treatment of MS has generated. In the present study, sea cucumber cerebrosides (SCC) and the main structural units, long-chain bases (LCB), were prepared from Acaudina molpadioides and then administered to high fat (HF) diet-induced obese C57BL/6J mice at a diet supplement dosage of 0.025% for 5 weeks to evaluate their effects on obesity-related metabolic disorders. SCC and LCB significantly decreased epididymal adipose tissue weights, lowered hepatic triacylglycerol levels, and reduced serum glucose, insulin levels and HOMA-IR index in mice. The activities of hepatic lipogenetic enzymes including FAS, ME and the mRNA levels of SREBP-1c and FAS were reduced by SCC and LCB treatment. However, SCC and LCB showed no effect on the hepatic lipolysis pathway. Besides, SCC and LCB also efficiently up-regulated the gene expression of SREBP-1c, FAS, ACC, ATGL and HSL, and down-regulated the gene expression of LPL and VLDL-r in the adipose tissue. These results demonstrated that SCC and LCB were efficacious in suppressing hepatic SREBP-1c mediated lipogenesis, inhibiting lipid uptake and increasing TG catabolism in the adipose tissue. The ameliorative degree and regulatory mechanisms of these two compounds were basically the same, suggesting that LCB are the key active structural units. Such findings would offer new insight into the application of SCC or LCB in the development of functional foods for preventing MS in humans.

No abstract

Antarctic krill (Euphausia superba) is one of the important bioresources in Antarctic waters, containing many bioactives (e.g., astaxanthin), which have a highly potential value for commercial exploitation. In this study, the effects of processing methods on the content, structural isomers, and composition of astaxanthins (free astaxanthin and astaxanthin esters) were studied. Three drying methods, comprising freeze-drying, microwave drying, and hot-air drying, were used. Free astaxanthin (Ast), astaxanthin monoesters (AM), and astaxanthin diesters (AD) in boiled krill (control) and dried krill were extracted and analyzed using high-resolution mass spectrometry with ultraviolet detection. After the three processes, total astaxanthin loss ranged from 8.6 to 64.9%, and the AM and AD contents ranged from 78.3 to 16.6 and 168.7 to 90.5 μg/g, respectively. Compared to other kinds of astaxanthin esters, astaxanthin esters, which linked to eicosapentaenoic acid and docosahexaenoic acid, as well as the Ast, were more easily degraded, and AM was more susceptible to degradation than AD. All-E-astaxanthin easily transformed to the 13Z-astaxanthin than to the 9Z-astaxanthin during the drying process, but the proportions of optical isomers changed due to drying by no more than 5%. The results suggested that freeze-drying, low-power microwave drying (≤1 kW), and low-temperature hot-air drying (≤60 °C) are optimal drying methods for ensuring the quality of krill products.