Anti-aging Mechanism Of Flavonoids Extract From Lycium Barbarum Leaves On T98G Cells And Preparation Of Effervescent Tablets

Aging is a major risk factor for memory impairment,and abnormal accumulation of senescent cells in the brain is closely related to neurodegeneration and cognitive impairment.Lycium barbarum leaves are widely used as medicinal vegetables and functional tea in China.The content of flavonoids in Lycium barbarum leaves is much higher than that of Lycium barbarum leaves.Although flavonoids have been proved to have antioxidant,anti-depression and other biological functions,there are few studies on the anti-aging mechanism of lycium barbarum leaves and the development of related health products.This study aims to evaluate the anti-aging effect of LBLF on the aging model of T98G induced by H2O2 from LBLF,and preliminarily explore its mechanism.Based on the results of previous studies,effervescent tablets of LBLF were prepared in order to provide theoretical guidance for high value utilization and practical production of Lycium barbarum leaves.The main research contents and results are as follows:(1)Study on the mechanism of anti-aging effect of LBLF on T98G cells induced by H2O2.Cell survival rate,SA-β-gal staining,ROS levels,MDA levels and antioxidant related substances(SOD,CAT,GSH)contents were determined.The expression of age-related proteins and genes was detected by Western Blot and RT-qPCR.The results showed that the cell senescence model could be established by treating 250 μM H2O2 for 8 h.The safe concentration of LBLF and its positive control MET was 20-60 μg/mL.Compared with model group,LBLF and MET preprotection increased cell survival rate,decreased SA-β-gal positive rate,decreased ROS fluorescence intensity,MDA content and LDH activity,and increased antioxidant capacity.The expressions of age-related proteins Keap1,p21 and p53 were up-regulated,while the expressions of Nrf2 and HO-1 were down-regulated.Keap1 gene was significantly down-regulated,while Nrf2 and HO-1 genes were significantly up-regulated.Therefore,both LBLF and MET have a certain protective effect on T98G cells,and LBLF has a better protective effect at the same concentration.It is speculated that LBLF and MET may play a role in delaying senescence of H2O2-induced T98G senescent cells by activating Keap1/Nrf2/HO-1 signaling pathway.(2)Study on formulation optimization and antioxidant activity of LBLF effervescent tablets.To optimize the formulation of effervescent tablets of LBLF,add several excipients,use single factor,climbing slope and response surface methods,and evaluate its quality and antioxidant capacity.According to the experimental results,the best formula of LBLF effervescent tablets was as follows:LBLF 6%,polyvinylpyrrolidone 1%,maltodextrin 25%,magnesium stearate 1.5%,stevia 0.9%,starch 9%,microcrystalline cellulose 1.5%,disintegrator 55.1%,citrate-sodium bicarbonate ratio 1:0.6.The average weight of LBLF effervescent tablets was(408±11)mg,the hardness was(46.7±0.51)N,the disintegration time was(217.8±2.07)s,the foaming capacity was(5.01 ±0.49)mL,the pH value was(4.80±0.004).Flavonoid content(47.93±0.05)mg/g.The IC50 of flavonoids effervescent tablets for DPPH radical,ABTS cationic radical and hydroxyl radical were 0.77,2.01 and 1.10 mg/mL,respectively.When the mass concentration was 5 mg/mL,the iron reduction capacity of LBLF effervescent tablets was 28.85%of Vc.The technology of LBLF effervescent tablets is stable and feasible,and has good antioxidant activity.