| Cellular metabolism is a necessary energy conversion procession in mitochondria for living organisms.In this procession reactive oxygen species?ROS?are produced,which included superoxide anion radical?O2-?,hydrogen peroxide?H2O2?,and hydroxyl radical?·OH?.However,when these ROS are in excess,The biomolecules including protein,lipid,and nucleic acids can be damaged by the oxidative stress process which could lead to a variety of agerelated degenerative diseases,such as cancer,Alzheimer's disease,and Parkinson's disease.Lactic acid bacteria?LAB?regarded as probiotic bacteria.Previous study demonstrate that some LAB have strong antioxidant activities and can be served as new potential antioxidants.The ocean is rich in LAB resources that have not been developed.Some marine lactic acid bacteria can effectively solve the problem.In this paper,marine lactic acid bacteria strains were isolated and explored their antioxidant activity.Furthermore,the HT-29 cells were used to simulate human intestinal,to ability of reducing H2O2-induced oxidative damage in HT-29 cells of marine lactic acid bacteria strains.First,29 marine lactic acid bacteria strains were screened through spread-plate method,gram stain and catalase test.13 of them processed DPPH free radical scavenging activity.Strain Y3,Y4,Y16,Y41,Y42,Y44 with significantly better DPPH free radical scavenging activity than other strains,for respectively is 42.97±2.68%?37.65±4.79%?43.18±6.03%?29.57±2.04%?32.73±1.43%?33.45±7.43%?P<0.05?.The six strains were identified as Lactobacillus casei?Y3,Y4,Y16?,Lactobacillus plantarum subsp.Plantarum?Y41?,other two were Lactobacillus plantarum?Y42,Y44?by using 16 S r RNA gene sequencing.Then the 6 LAB strains were explored their axtioxidant activity through intact cells and intracellular cell-free extract.6 LAB strains could resistant 0.5 m M hydrogen peroxide,Strain Y44 could resistant 1 m M hydrogen peroxide.Strain Y44's intact cells and intracellular cellfree extract had hydroxyl free radicals scavenging activity for respectively is 67.09±7.83%,71.40±1.99%.Strain Y3,Y4,Y16,Y44's intact cells and intracellular cell-free extract and Y42's intracellular cell-free extract had better superoxide anions scavenging activity.The 6 LAB strains had lower reducing power than LGG.The intracellular cell-free extract of 6 LAB strains had lower DPPH free radical scavenging activity intact cells'.Strain Y4,Y42,Y44 showed higher SOD activity for respectively is 19.62±0.65 U/mg prot,17.14±1.29 U/mg prot,16.37±1.84 U/mg prot.Strain Y3 showed the highest GSH-Px activity,which is 35.92±8.04 U/mg prot.Strain Y3,Y44 showed higher antioxidant activity in 6 LAB strains in this research.When L.casei Y3 and L.plantarum Y44 were testing protective effect of H2O2-induced oxidative stress in HT-29 cells.L.casei Y3 and L.plantarum Y44 could significantly increased the cell viability from 50.06%±1.68 to 68.76% and 85.89%?P<0.05?,significantly increased SOD activity of HT-29 cells from 2.41±0.07 U/mgprot to 4.46±0.18 and 7.24±0.30U/mgprot?P<0.05?,significantly increased GSH-Px activity of HT-29 cells from 11.37±0.35U/mgprot to 13.05±0.79 and 17.92±1.56U/mgprot?P<0.05?.And they could significantly decreased MDA content of HT-29 cells from 3.43±0.43nmol/mgprot to 1.49 ± 0.36 and 1.18 ±0.19nmol/mgprot?P<0.05?.In addition,L.casei Y3 and L.plantarum Y44 could reduced the E.coli-induced IL-8 content in HT-29 cells from 63.33pg/m L to 38.41±4.72 and 36.53±5.51pg/m L?P<0.05?.Therefore,Lactobacillus casei Y3 and Lactobacillus plantarum Y44 may have potential vablue of probiotic. |
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