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Crocodiles are cultured in large numbers in Asia and other places in order to protect wild resources and meet the needs of human life. In this study, crocodile (Crocodylus siamensis) meat proteins were extracted and hydrolyzed into peptides, their antioxidant peptides were isolated and purified by silica gel chromatography and identified by LC/MS. Crocodile meat proteins were optimally extracted with water and hydrolyzed by papain based on the degree of hydrolysis and antioxidant activity. The hydrolysates were fractionated by ultrafiltration into 3 kDa, 3–30 kDa, and ≥ 30 kDa fractions. The 3 kDa fraction showed most antioxidant activity of the hydrolysates. Its active peptides were separated by silica gel column chromatography and purified by silica gel TLC, based on TLC bio-autographic assays of the activity. Four highly active peptides were identified by LC/MS as SSLTIQFVEGQFVDSYDPTIENTFTK, VPPHIY, VAPEEHPVLLTEAPLNPK, and RNGLPGPIGPAG. The identified peptides were synthesized and showed 50% free radical scavenging activities at 1.0 mg/mL, equal or higher to ascorbic acid at 0.5 mg/mL, in both DPPH and ABTS assays. The results indicated that the 3 kDa hydrolyzed peptides of crocodile meat had high antioxidant activity and the active peptides can be effectively separated and purified by silica gel column chromatography and TLC. [ABSTRACT FROM AUTHOR]

Background: Hepatitis B virus-associated acute-on-chronic liver failure (HBV-ACLF) is an important type of liver failure in Asia. There is a direct relationship between HBV-ACLF and gastrointestinal barrier function. However, the nutritional status of HBV-ACLF patients has been poorly studied., Aim: To investigate the nutritional risk and nutritional status of HBV-ACLF patients and evaluated the impact of nutritional support on the gastrointestinal barrier and 28-d mortality., Methods: Nutritional risk screening assessment and gastrointestinal barrier biomarkers of patients with HBV-ACLF ( n = 234) and patients in the compensatory period of liver cirrhosis (the control group) ( n = 234) were compared during the period between 2016 and 2018. Changes were analyzed after nutritional support in HBV-ACLF patients. Valuable biomarkers have been explored to predict 28-d death. The 28-d survival between HBV-ACLF patients with nutritional support ( n = 234) or no nutritional support (2014-2016) ( n = 207) was compared., Results: The nutritional risk of the HBV-ACLF patients was significantly higher than that of the control group. The nutritional intake of the patients with HBV-ACLF was lower than that of the control group. The decrease in skeletal muscle and fat content and the deficiency of fat intake were more obvious ( P < 0.001). The coccus-bacillus ratio, secretory immunoglobulin A, and serum D-lactate were significantly increased in HBV-ACLF patients. The survival group had a lower nutritional risk, lower D-lactate, and cytokine levels (endotoxin, tumor necrosis factor alpha, interleukin-10, and interleukin-1). Interleukin-10 may be a potential predictor of death in HBV-ACLF patients. The 28-d survival of the nutritional support group was better than that of the non-nutritional support group ( P = 0.016)., Conclusion: Patients with HBV-ACLF have insufficient nutritional intake and high nutritional risk, and their intestinal barrier function is impaired. Individualized and dynamic nutritional support is associated with a better prognosis of 28-d mortality in HBV-ACLF patients., Competing Interests: Conflict-of-interest statement: No conflicts of interest, financial or otherwise, are declared by the authors., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)