Pomelo peel dietary fiber ameliorates alterations in obesity-related features and gut microbiota dysbiosis in mice fed on a high-fat diet.

Pomelo peel has abundance of dietary fiber and various biological activities but is often discarded as waste. This study evaluated the biological activities of pomelo peel dietary fiber (PPDF) in preventing obesity and regulating intestinal microbiota in obese mouse model induced using a high-fat diet (HFD). As for the composition, the prepared PPDF contained 89.64% of total dietary fiber, 53.27% of insoluble dietary fiber, and 36.37% of soluble dietary fiber. PPDF treatment significantly reduced weight gain and fat accumulation in the liver and epididymal tissues of obese mice; significantly alleviated HFD-induced dyslipidemia; and restored the levels of triglycerides, low-density lipoprotein-cholesterol, and high-density lipoprotein--cholesterol to control levels, and the PPDF 5% dose restored total cholesterol to the control level. Furthermore, PPDF ameliorated HFD-induced gut microbiota dysbiosis by increasing intestinal microbial diversity, decreasing the Firmicutes/Bacteroidetes ratio, increasing beneficial bacteria (Bifidobacterium, Alloprevotella, and Lactobacillus), and decreasing harmful bacteria (Staphylococcus and Corynebacterium_1). This study provided a new idea to use PPDF as functional food to prevent obesity, alleviate dyslipidemia, or a potential probiotic to ameliorate gut microbiota dysbiosis.

Response surface methodology-optimized extraction of flavonoids from pomelo peels and isolation of naringin with antioxidant activities by Sephadex LH20 gel chromatography.

In this study, flavonoids were extracted from pomelo peels and naringin was isolated from the flavonoid extract. The effects of extraction parameters, namely, ethanol concentration, solid-to-liquid ratio, and extraction time, on the yield of flavonoids extracted from pomelo peels were analyzed according to the Box-Behnken design of response surface methodology. The experimental conditions for flavonoid extraction were optimized, and naringin was separated from the extracted flavonoids using Sephadex LH-20 column chromatography. Experimental results showed that the influence of factors on the extraction rate of flavonoids from pomelo peels was in the order of ethanol concentration > solid-to-liquid ratio > extraction time, and the optimal extraction parameters were 85% ethanol concentration, 1:20 solid-to-liquid ratio, and 4-h extraction time for extracting flavonoids from pomelo peels. Under these conditions, the yield of flavonoids was 6.07 ± 0.06 mg/g. After three times of extraction, the flavonoid extraction rate reached 96.55%, and the residual naringin in the pomelo peels was 0.017 mg/g, at which point the bitterness in the pomelo peels disappeared. Two components, namely, PF1 and PF2, were separated from the crude flavonoid of pomelo peels through Sephadex LH20 column chromatography. PF2 was identified as naringin by high-performance liquid chromatography tandem mass spectrometry, with a purity of 95.7 ± 0.23%. Both flavonoids and PF2 exhibited good in vitro radicals scavenging activities on DPPH, ABTS, superoxide anion and hydroxyl.

Abalone visceral peptides containing Cys and Tyr exhibit strong in vitro antioxidant activity and cytoprotective effects against oxidative damage.

The in vitro antioxidation and cytoprotection of abalone visceral peptides against oxidative damage were investigated. Results show that the DPPH· scavenging activities of the 16 chemically synthesized peptides were significantly and positively correlated with their reducing power. Their scavenging activities against ABTS·+ were positively correlated with their ability to inhibit linoleic acid oxidation. Only Cys containing peptides exhibited good DPPH· scavenging activity, while only Tyr containing peptides showed significant ABTS·+ scavenging activity. In the cytoprotection assay, all four representative peptides significantly increased the viability of H2O2-damaged LO2 cells and the activities of GSH-Px, CAT, and SOD, and all decreased MDA levels and LDH leakage, in which the Cys-containing peptides were more effective at increasing the activities of antioxidant enzymes, while the Tyr-containing peptides were more effective at decreasing MDA levels and LDH leakage. Abalone visceral peptides containing both Cys and Tyr exhibit strong in vitro and cellular antioxidation.

Characterization and Functionality of Cellulose from Pomelo Fruitlets by Different Extraction Methods.

Pomelo fruitlets have the potential for extracting cellulose. This study aimed to investigate characterization and functionality of cellulose extracted from pomelo fruitlets by different extraction methods. Cellulose extracted by acidic-alkaline hydrogen peroxide hydrolysis (CAA), alkaline hydrogen peroxide hydrolysis (CA), and ultrasonic assisted alkaline hydrogen peroxide hydrolysis (CUA) were prepared from pomelo fruitlets. The results showed that cellulose CUA had higher yield and purity with higher crystallinity and smaller particle size than those of CAA or CA (p < 0.05). Specifically, the yield of CUA was 82.75% higher than that of CAA, and purity was increased by 26.42%. Additionally, water- and oil-holding capacities of CUA were superior to those of CAA or CA, increasing by 13-23% and 10-18%, respectively. The improvement of water- and oil-holding capacities were highly related to its smaller particle size with increased surface area. The results suggested that ultrasonic assisted alkaline hydrogen peroxide hydrolysis is a promising and efficient method to prepare high-purity cellulose from pomelo fruitlets, and this cellulose is expected to be a food stabilizer and pharmaceutical additive.

Preparation and antioxidant activities of polysaccharides obtained from abalone viscera by combination of enzymolysis and multiple separation methods.

Abalone viscera were byproducts of the abalone processing and usually discarded as wastes. In this study, we tried to obtain functional polysaccharides from abalone viscera by a combination of enzymatic hydrolysis, membrane separation, anion exchange chromatography, and gel filtration techniques. Abalone viscera underwent successive hydrolyzation with alcalase and flavourzyme. Each enzymolysis was followed by deproteinization via membrane separation. The final yield of crude abalone viscera polysaccharide (CAVP) was 19.72%; the polysaccharide content of CAVP was 51.75%. Furthermore, three fractions of polysaccharides (AVP1, AVP2, and AVP3) were isolated from the CAVP by anion exchange chromatography and gel filtration. The molecular weights of each AVP were 14.99 kDa, 58.48 kDa, and 39.63 kDa, with a carbohydrate content of 62.75, 23.09, and 44.67%, respectively. These AVPs showed excellent antioxidant activities in vitro. Our results provide a scientific basis for the further utilization of polysaccharides from abalone viscera. PRACTICAL APPLICATION: This study demonstrated an eco-friendly approach for industrial production of high purity animal-derived polysaccharides without any environmental pollution caused by the viscera waste of abalone and promoting the comprehensive utilization of abalone resources.

Trimetazidine ameliorates myocardial ischemia-reperfusion injury.

Aim of this study was to investigate the effects of trimetazidine attenuating the myocardial ischemia-reperfusion injury to myocardium in rats and the underlying mechanisms. A model of myocardial ischemia reperfusion was established via ligating the left anterior descending coronary artery in 30 rats, and then they were randomly assigned to model group (n=10), low dose group (n=10) and high dose group (n=10). Moreover, additional 10 rats were collected and allocated to sham operation group, which was served as control group. Then, rats in the low dose group and high dose group were given trimetazidine with the dose of 10mg/kg and 30mg/kg respectively by intragastric administration, while rats in the control group and model group were given the equivalent volume saline. The dose was given once a day for consecutive 4 weeks in all rats. Echocardiography was applied to evaluate cardiac function, including left ventricular end-systolic dimension (LVESD), left ventricular end diastolic dimension (LVEDD) and left ventricular ejection fraction (LVEF). Next, myocardial tissue was collected, and Bax and Bcl-2 mRNA and the protein levels in the four groups were detected by RT-PCR and Western blot respectively. The level of malonaldehyde (MDA) and super oxide dismutase (SOD) activity in rat myocaridum in each group were detected by colorimetric methods, while the variables of apoptosis were measured by TUNEL methods. In comparison with the control group, LVEDD, LVEDS of rats increased significantly, LVEF decreased obviously, as well as Bax level, MDA level and the apoptotic variables in myocardial tissue increased (P<0.05), but Bcl-2 level and SOD activity decreased significantly in low dose, high dose and model group (P<0.05). Compared with model group, LVEDD, LVEDS of rats decreased obviously, LVEF increased significantly, as well as Bax level, MDA level and the apoptotic variables in myocardial tissue decreased (P<0.05), but Bcl-2 level and SOD activity increased significantly in low dose group, high dose group (P<0.05). The regulatory role of trimetazidine on above indicators of rats was in a dose-dependent manner. Trimetazidine can ameliorate rat myocardium following ischemia-reperfusion injury by effectively attenuating the injury from myocardial cell apoptosis; meanwhile, it can resist cell apoptosis through regulating Bax and bcl-2 expression, which exhibits guiding significance for the treatment of myocardial ischemia and reperfusion.