| Current marine fish resources are undergoing problems such as research insufficiency and low utilization rate In addition,fish skin and other byproducts in the fishery are largely discarded and wasted,causing 60%biomass loss and environmental pollution.Thus we attached great significance to accelerate relevant developmental and practical researches.Shark skin byproducts are rich in collagen peptides that have been shown to be up to 92%of dry weight.White-spotted bamboo sharks(Chiloscyllium plagiosum)are widely distributed,numerous,and of fast reproduction of shallow sea sharks,thus,in this study we take them as research material to extract the fish skin compound peptides called SCP(Skin Compound Peptides from Chiloscyllium plagiosum)for the hope of exploiting shark skin resources application.Fresh shark skin was obtained,followed by a series of procedures including fat removal,enzymatic hydrolysis and freeze-drying to obtain SCP freeze-dried powder.The components were measured,in which the total protein content was as high as 94.219±0.751%,while the fat content was only 0.365±0.007%.Among amino acids,the contents of glycine,proline and hydroxyproline were high,while that of cysteine was very low,showing that the amino acid composition presented characteristic of collagen peptides.SCP were rich in elements,among which calcium content was up to 1.45g/kg,while heavy metal elements were lower than the national standard.It was composed of peptides with moleculars less than 1000 Da and could be ingested by the body quickly.Physical and chemical property tests of SCP showed that the UV full wavelength absorption spectrum of SCP represented the characteristic of peptides,and SCP rapidly became sticky after moisture absorption,had strong moisture retention capability and easily inactivated by heat.The biological activities of SCP were detected in several aspects:1)in terms of cell activity,it was uncovered that SCP promoted the cell activity(the best group up to 186.6±12.97%),proliferation(the best up to 4.5 times)and migration ability of human immortalized keratinocytes(HaCAT),had no effect on cell cycle and protein expression,and could reduce mitochondrial membrane potential;2)in terms of antioxidant activity,SCP was found to reduce endogenous ROS content in HaCAT cells(the lowest group down to 49.1%)and protect cells from exogenous H2O2 damage(the best group up to 119%on cell viability);3)in terms of bone-strengthening effect:after ingesting the SCP to a dose of 15 g/kg in C57BL/6 mice,the efficacy were measured by weighing the tibia,scanning electron microscopy and HE staining,and results showed that SCP significantly increased bone weight,promoted osteogenesis activity,improved bone mineral density,enhanced marrow abundance and reduced its lipogenesis;4)in terms of anti-inflammatory activity,SCP was found to promote the activity of macrophage RAW 264.7 and significantly inhibit liver and kidney inflammation induced by LPS in mice.After subacute toxicity test on mice,SCP was found to have no toxic and side effects in mice body weight,viscera coefficient,viscera morphology and viscera microstructure,verifying that SCP was non-toxic.This study showed that SCP had great practical value in development of protein nutrition supplements,wound healing drugs,bone-strengthening functional food and anti-aging cosmeceuticals,providing a research basis and development ideas for the utilization of shark skin byproduct. |
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