Study On Anti-aging Effect Of Different Tea Against UVB Induced Epidermal Cells

Aging is the phenomenon that the body's ability to adaptability to the environment is decreasing and it tends to die.It is characterized by degenerative changes in organs,tissues and cells of the body,resulting in reduced adaptability and resistance to the environment.According to different causes,aging includes physiological aging and pathological aging.Tea contains many kinds of active ingredients such as tea polyphenols,amino acids,alkaloids and water-soluble sugars.They have certain anti-aging effect.The research on the anti-aging effect of tea at home and abroad is mostly focused on tea polyphenols(especially EGCG),and the aging model of rats induced by D-galactose.The detection indices of these studies include only the antioxidant enzyme activity and the content of oxidation products,and less research on skin aging caused by ultraviolet radiation(the most common factor that causes human aging by external factors).In order to make a more comprehensive analysis of the anti aging effect of tea and to compare the anti aging effects of different tea types,the physicochemical composition of 7 kinds of tea extracts was detected,and the UVB induced aging model of epidermal cells was established.Then,the tea extract was used to intervene the model,and the related indicators of epidermal cell senescence were detected,and the anti-aging effects of different tea extracts were analyzed.The main results are as follows:(1)In this study,seven kinds of tea extracts were tested.The results showed that the content of tea polyphenols in the seven kinds of tea extracts was between 27.30%-45.80%,mainly EGC(6.16%-18.04%)and EGCG(3.61-16.45%).The content of free amino acids is between 4.89%-8.48%;The alkaloids are mainly caffeine,the content is between 4.01%-7.99%,the next is theobromine,the content is between 0.13%-0.77%,the content of theophylline is less,all the samples are less than 0.04%.The total content of water soluble sugar is between 8.25;25.72%.The highest content of tea polyphenols is the extract of white tea and green tea.The highest content of water soluble sugar is jasmine tea extract,and the highest content of alkaloid is black tea extract.(2)Based on the epidermal aging model induced by UVB,the anti-aging effect of seven kinds of tea extracts on UVB induced epidermal cells was studied.The cell morphology,survival rate,activity of intracellular antioxidant enzyme(GSH-Px,SOD,CAT),oxidation product(MDA)content and oxidation reaction(LDH),intracellular oxidation level(ROS),mitochondrial membrane potential change,cell apoptosis level,cell membrane function and senescence related protein mRNA expression were detected.The results showed that UVB irradiation showed aging characteristics of human epidermal cells,manifested as cell volume increasing,becoming round and vacuolization.The cell survival rate decreased by 36.93%.The activity of GSH-Px,SOD and CAT decreased by 321.75%,97.62%,140.12%,MDA content increased by 57.47%,LDH activity increased by 49.86%,ROS index increased 97.22%,Na~+,K~+-ATP enzyme activity decreased 109.58%,cell mitochondrial membrane potential index decreased by 1011.15%,cell early withering level increased by 85.93%,cell terminal apoptosis was85.93%.The level rose by 83.69%,The expression of Klotho protein mRNA decreased by 201.34%,Mfn2 protein mRNA expression decreased by 71.94%,Opa1 protein mRNA expression decreased by143.86%,Bcl-2 protein mRNA expression decreased 104.49%,Bax protein mRNA expression increased43.85%,Caspase-3 protein mRNA expression increased 52.187%.Among them,GSH-Px activity,Caspase-3 and Bcl-2 protein mRNA expression levels were significantly different from those in blank group at p<0.05 level,and the other indexes were significantly different at p<0.01 level.Using tea extract to treat cells can effectively inhibit the aging of epidermal cells induced by UVB irradiation.The effect of green tea extract and white tea extract in different samples was most obvious.The antiaging effect of tea extract increased with increasing concentration.(3)The effect of different tea extracts on the aging of epidermal cells induced by UVB may be related to maintaining the normal activity of intracellular enzymes,reducing the level of intracellular oxidation,protecting the normal structure and function of the cells,inhibiting the apoptosis and improving the expression of anti aging related protein mRNA in cell.Tea polyphenols may play a major role in the anti UVB epidermal cell aging effect of tea extracts,while the water soluble sugar,free amino acid content and the proportion of catechin components also play a role in the anti UVB epidermal cell aging effect of tea extracts.