Study On Extraction,antioxidant And Anticancer Activity Of Flavonoids From Fig Leaves

Fig（Ficus carica L.）belongs to the temperate deciduous fruit tree of Ficus moraceae,its roots,stems,leaves and fruits have medicinal values.Flavonoids are secondary metabolites of plants.They are known for their antioxidant,anti-aging,and anti-cancer effects,and their content in fig leaves is considerable.However,the current research on the flavonoids in fig leaves is limited,and there is a lack of systematic research on the flavonoids in fig leaves in different growth stages,which makes the fig leaves unable to be utilized to the greatest extent.In addition,the predecessors had few studies on the anticancer activity of fig leaves,and the literature on the structure of the anticancer activity of fig leaves flavonoids is still blank,which greatly hindered the pharmacological application of fig leaves.Therefore,this experiment used the mature leaves of‘Brunswick’,‘Bojihong’,and‘Masui Dauphine’from July to November as materials,and started with the extraction and purification of flavonoids from the leaves,and studied the figs of different varieties in different months.We investigated the accumulation of leaf flavonoids and the pattern of their antioxidant activities,and then explored their anti-tumor activities and screened the active ingredients,laying a solid foundation for the further development and utilization of fig leaves.The main results are as follows:1.We obtained the optimal extraction process of fig leaf flavonoids by using ultrasonic method through response surface test design:The volume fraction of ethanol is 80%,the ratio of substance to liquid is 1:49（g/m L）,the extraction time is 40 min,the extraction temperature is 70°C,and the predicted extraction rate of flavonoids could reach 39.74 mg/g.The actual extraction rate is 39.37 mg/g which is pretty close to the predicated results,indicating that the test conditions are feasible.Under these conditions,there are significant differences among the extraction rates of flavonoids from fig leaves of different varieties.Among them,‘Brunswick’is the highest,‘Masui Dauphine’is the second,and‘Bojihong’is the lowest;there are also significant differences between different months,of which,‘Brunswick’and‘Masui Dauphine’are the highest in October,and‘Bojihong’is the highest in August.These results provide a theoretical basis for the extraction of flavonoids from fig leaves and the harvest and utilization of the varieties.2.The method of macroporous resin static adsorption analysis was used to purify the flavonoids in fig leaves,and the optimal purification conditions obtained by the factor method are:concentration of 0.12 mg/m L,40 m L of crude fig flavonoids solution of p H 5 for adsorption for 10 h,70%ethanol solution as eluent,calculate the required eluent volume according to the ratio of 1:20 g/m L（saturated macroporous resin:elution volume）.The flavonoids from fig leaves were purified by the above method,and the mass fraction of the purified flavonoids increased from 28.4%to 59.3%.The results of Fe Cl₃ reducibility and DPPH clearance rate test are basically the same.The antioxidant activity of‘Brunswick’is the highest,followed by‘Masui Dauphine’,and‘Bojihong’is the lowest.In terms of growth stages,‘Brunswick’has the highest antioxidant activity in September,the worst in August,and‘Masui Dauphine’shows the highest in October in,while the antioxidant activity of‘Bojihong’is the highest in June and the worst in August.The content of flavonoids in fig leaves in different months of the same species showed a positive correlation with their ability to reduce Fe³⁺.These results provide a theoretical basis for the development and utilization of figs,and at the same time provide a basis for the research on the anti-cancer effect of fig leaf flavonoids.3.The inhibitory rates of flavonoids in fig leaves of different varieties and different months on cancer cells are different,of which‘Brunswick’leaf flavonoids in August showed the strongest anti-cancer effect and had the best inhibitory effect on gastric cancer cells SGC-7901.Both have a concentration effect.Under the treatment of the flavonoid solution,the cell morphology changed from a spindle to a round shape,and the cell density and adhesion decreased.Fig leaf flavonoids induce apoptosis of cancer cells,which block cell division in S phase and significantly reduce the level of cell mitochondrial membrane potential.Meanwhile the expressions of pro-apoptotic genes Bax and p53 and cell cycle regulating gene E1F2 were up-regulated,whilst that of the anti-apoptotic gene Bcl-2 and the cell cycle-related genes Cyclin D1 and CDKs were down-regulated.LC-MS/MS technology and related analysis show that fig leaves contain a variety of flavonoids,among which narcissus,isoorientin,morin and others can be candidates for anticancer activity.The results of this study provide a theoretical basis for the development and utilization of fig leaf flavonoids as anti-cancer medicines.