Research On Anti-aging Activity Of The Goji Berry Extracts And Mechanism Of Action

The main components of goji berry are polyphenols,carotenoids,polysaccharides,etc.It is known as the"super fruit"for its bioactivities such as anti-oxidation,anti-proliferation and anti-aging,which is the first choice of regimen for modern people.Previous studies regarding goii berry mainly focused on the extraction,determination and identification of functional substances,especially on the structural identification of Lycium barbarum polysaccharides.From another perspective,this article focused on the bioactivity of two kinds of goji berry,namely Lycium ruthenicum Murr.(LRM)and Lycium BarbarumL.(LB),using their crude extracts to conduct related investigations.High performance liquid chromatography was employed for phytochemical profiles and their content were determined and the ORAC and PSC were used for in vitro antioxidant determination.Human hepatocarcinoma cell HepG2 was used as a model to determine the intracellular antioxidant capacity using CAA method.Meanwhile,methylene blue staining method was applied to determine the anti-cancer activity of goji berry extracts with human breast cancer cell MDA as a model.In order to further explore its anti-proliferation mechanism,the cell cycle,cell apoptosis and related gene expression were determined.On this basis,a Caenorhabditis elegans aging model was established to evaluate the anti-aging activity of goji berry extracts by measuring multiple aging indicators,including lifespan,stress tolerance(ultraviolet radiation,heat stress,paraquat culture),lipofuscin,mobility and fecundity.Finally,molecular biological methods were used to explore the anti-aging mechanism of goji berry extracts based on gene expression and enzyme activity levels.This article summarized the function of goji berry and its positive effects on human health from the perspective of food nutrition,aiming to clarify the activity of natural products in goji berry and its medicinal value,and provide a theoretical basis for anti-aging and related dietary guidance.The main research results were as follows:(1)LRM and LB contained a large amount of biologically active substances,and their polyphenols were both mainly existed in free forms.Concretely,the total contents of polyphenols and flavonoids of LRM were higher than these of LB,while the contents of V_Eand carotene in LB were higher than these of LRM.HPLC results showed that there was a large difference between the components of the two goji berries.Overall,anthocyanin was determined to be the most abundant polyphenols in LRM,while the ascorbic acid and gallic acid were the main components of LB.The results of ORAC and PSC assays showed that both the two goji berry extracts exhibited strong antioxidant activity,but the antioxidant capacity of LRM was stronger than that of LB.Furthermore,CAA results also confirmed that the intracellular bioavailability of LRM was much higher compared to LB.(2)LRM and LB showed favorable activity against the proliferation of breast cancer cell.Specifically,LRM exerted better anti-proliferation effect,which could cause higher lethality to cancer cells at a lower concentration.The EC₅₀ of LRM and LB were 4.08±0.09 mg/mL and17.86±1.77 mg/mL,respectively.From the cell cycle and apoptosis results,LRM also showed a more significant difference in blocking more cells in the G1 phase and presenting a higher early apoptosis rate induction compared to the blank group.The results of qPCR experiment suggested that LRM and LB achieved their anti-proliferation effects by regulating the expression of genes such as p53,p21,CDK and Bax.(3)In the study of anti-aging,we found that both LRM and LB could significantly prolong the life expectancy of Caenorhabditis elegans(C.elegans).The treatment of high-dose LRM and LB increased the average lifespan of nematodes by 25.19%and 51.38%,respectively;It could also improve the stress ability of nematodes under heat shock,oxidative stress and UV irradiation.In addition,LRM and LB extracts significantly enhanced the activity of antioxidant enzymes(SOD and CAT)in C.elegans,while reduced the level of lipofuscin.In summary,goji berry extract possessed the ability of postponing the aging of C.elegans.(4)Further genetic studies demonstrated that the expression levels of key genes related to lifespan in nematodes,daf-16,sod-2,sod-3,sir-2.1 and hsp-16.2,were significantly up-regulated after supplementation with goji berry extract,and the level of age-1 was down-regulated.In addition,daf-16(mu86)?,sir-2.1(ok434)? and hsf-1(sy441)? mutants reversed the longevity effect brought by LRM or LB,which confirmed that these genes were required in increasing the lifespan mediated by goji berry.Therefore,we conclude that HSF-1 and SIR-2.1cooperate with the IIS signaling pathway in a daf-16-independent form to regulate the lifespan of nematodes.