Study On The Protective Effect Of Isoorientin In Corn Silk On Benzo(?)pyrene-induced Liver Injury And Preparation Of Chewable Tablets

Isoorientin(ISO)is one of the most important flavonoid-like compounds in the corn silk,accounting for 2%in the dry weight of the corn stigma,which is the key factor to generate resistance to plant diseases and insect pests.It has reported that ISO possesses the abilities to prevent liver damage as well as antioxidant,anti-inflammatory,and anti-nociceptive activities.Besides,ISO could also effectively inhibit human liver cancer cell proliferation,nerve cell toxicity,abdomen pain in rats and flu viruses to spread.However,the effects of ISO on hepatotoxicity induced by BaP remain unknown.Benzo(a)pyrene(BaP)is a kind of polycyclic aromatic hydrocarbons,and ubiquitously produces in the food processing,such as frying,smoking,grilling and roasting.Meanwhile,BaP possesses a highly active carcinogenicity,immunotoxicity and reproductive toxicity and so on.Apoptosis,autophagy and pyroptosis are three types of the programmed cell death.However,it remains unclear whether ISO can prevent the apoptotic,autophagic and pyroptotic injury caused by BaP.Therefore,ISO from corn silk was seen as the study subject in this study.And the objective of this study is to investigate the protective effect of ISO on cell growth which exposed in BaP.In addition,to increase the economic added value of corn,the chewable tablets of corn silk was developed,which possesses hepatoprotective effect.Main results for this study are as follows:1.ISO had obvious decreased the effect of BaP on the cell proliferation in HL-7702 cells.MTT and trypan blue dyeing test results showed that ISO could effectively increase the number of HL-7702 cells,enhance cell viability,and finally inhibit BaP-induced cells death.2.ISO had remarkably weakened the effect on BaP-induced apoptotic cell death in HL-7702 cells.AO-EB,DCFH-DA,JC-1 staining assays and WB test indicated that ISO is able to relieve the BaP-caused apoptotic cell death which characterized by decreasing the number of apoptotic cells,reducing ROS release and mitochondrial membrane potential level,up-regulating the protein expression of Bcl-2 and down-regulating the overexpression of Bax,Cyto-C,Cleaved-Caspase-3 and PARP in HL-7702 cells.3.ISO had significantly passivated the effect on BaP-induced autophagic cell death in HL-7702 cells.AO,MDC staining assays and WB test indicated that ISO was able to relieve the BaP-caused autophagic cell death by the means of decreasing the autophagic vacuole numbers,down-regulating the overexpression of LC3-? and Beclin-1 in HL-7702 cells.4.ISO had markedly prevented the effect on BaP-induced pyroptotic cell death in HL-7702 cells.The relative electrical conductivity,LDH and NO release level,and WB tests showed that ISO was able to relieve the BaP-caused pyroptotic cell death through decreasing the relative electrical conductivity,LDH and NO release,reducing the protein expression of Cleaved-Caspase-1 and iNOS,and the subsequent inflammatory cytokines release(Cox-2,IL-1?,IL-18).5.Based on the research of the protective effect of ISO on liver injury induced by BaP,the hepatoprotective chewable tablets of corn silk was developed,its optimum technology parameter(contents ratio)were corn stigma:microcrystalline cellulose:5%PVP:aspartame:citric acid:magnesium stearate = 45:20:10:22.5:0.9:1.This research relatively systematically explored that the protective effect of ISO on food injurant BaP-induced apoptotic,autophagic and pyroptotic death in HL-7702 cells.Simultaneously,the hepatoprotective chewable tablets of corn silk were developed based on above the research,in order to fully excavate the nutrition and health values of ISO from corn silk.Moreover,it is of great importance to further research corn stigma and its other bioactive substances.