Research On The Mechanism Of Biochanin A Alleviating Oxidative Damage Induced By Urban Particular Matter

Urban fine particulate matter(UPM)can enter the body with respiratory tract to induce oxidative stress and inflammation,and exacerbation of lung diseases.The heavy metal ions and polycyclic aromatic hydrocarbons(PAHs)adsorbed by fine particles are the main substances that cause the oxidative stress reaction of the organism.Dietary isoflavones can effectively alleviate the damage of fine particles to biological tissue.Biochanin A,as a kind of chickpea isoflavones,has a high antioxidant activity,which potentially alleviates the effect of fine particles on organism damage.The mechanism of biochanin A in alleviating oxidative damage was studied by cell culture,western blotting and RT-PCR combined with KEGG Pathway system in this paper,in order to provide theoretical foundation and scientific basis for the further study of natural active substances.The analysis of urban fine particulate matter showed that it contained more heavy metal ions.It was confirmed by MTT experiment that UPM had dose-effect relationship with cytotoxicity.The antioxidative effects of daidzein,formononetin and biochanin A were evaluated by test of the scavenging capacity of DPPH free radicals,superoxide radicals and hydroxyl radicals.The results showed that biochanin A had stronger scavenging ability.In cell culture experiment,as a protective substance,biochanin A decreased the content and activity of several related indicators of oxidative stress,but increased the related indexes of antioxidant,indicating that it plays an important role in antioxidant.Cell model was made via UPM exposure after biochanin A treatment.The expression level of proteins in MEK5/ERK5/Nrf-2 signaling pathway was detected by western blotting.It was concluded that water-soluble extracts from UPM could activate MEK5/ERK5/Nrf-2 signaling pathway.Moreover,biochanin A can promote the signal transmission of this signal pathway.And the expression of HO-1,Nqo-1 and GPX in the downstream genes of Nrf-2 was measured by RT-PCR.It was found that the expression of downstream related genes was also increased when Nrf-2 was highly expressed.It was systematically verified that biochanin A promoted signal transduction in MEK5/ERK5/Nrf-2 signaling pathway,and biochanin A could alleviate the damage caused by water-soluble extracts of UPM.