Study On Extraction Optimization,Antioxidant And Antitumor Activity Of Polysaccharide From Ficus Carica Leaves

Fig（Ficus carica L.）is a medicinal and edible homologous plant in the Ficus moraceae.Its roots,stems,leaves and fruits are rich in active substances,mainly coumarin compounds,flavonoids,benzaldehyde,and polysaccharides.These active substances have become a hotspot in fig research in recent years.Among them,polysaccharides,as one kind of the active substances in figs,are rich in fig fruits and leaves,and they have antioxidant activities,can improve immunity,and enhance anti-tumor ability.However,there are still relatively few studies on fig leaf polysaccharides compared with fruits,and the comparisons between varieties and months are still relatively scarce.Therefore,in order to better develop and utilize the leaves of figs and give full play to the value of figs,using fig leaves of‘Brunswick’,‘Bojihong’and‘Masui Dauphine’from July to November as materials,this paper optimized the extraction conditions of polysaccharides from fig leaves.Under these conditions,the extraction rates of crude polysaccharides between varieties were compared.At the same time,the purification conditions were optimized,and the physical and chemical properties of the purified polysaccharide and the in vitro antioxidant activity were further studied.Furthermore,its in vitro anti-tumor mechanism was investigated and revealed.So as to provide a new theoretical basis for the development and utilization of fig leaves polysaccharides in the future.The main results are as follows:1.The optimum extraction conditions and purification technology of polysaccharides from fig leaves were studied.the results showed that:The extraction rate of polysaccharides was the highest at a ratio of 1:15 and water temperature of 80℃for 8 h,which was 6.97%.Under these conditions,the extraction rate of crude polysaccharides of different varieties and months was compared.In August,the yield of crude polysaccharides from the leaves of’Bojihong’was the highest,reaching 8.18%,while that of’Brunswick’and’Masui Dauphine’was the highest in September,which was 7.42%and 7.00%,respectively.The extraction rate of polysaccharides from leaves of all varieties was the lowest in July.The combination of AB-8 macroporous resin and Sevage reagent for the purification of polysaccharides could efficiently achieve the purpose of deproteinization and depigmentation.2.A comparative study of the physical and chemical properties and in vitro antioxidant activity of polysaccharides from different sources showed that:the purified fig leaves polysaccharide solution had no reducing sugar,protein,nucleic acid and other impurities.The total amount of purified polysaccharides averaged 84.86%,of which the total sugar content of’Masui Dauphine’was the highest,at 89.05%;on the other hand,the average content of uronic acid and sulfuric acid groups in’Brunswick’was the highest.They were28.44%and 5.01%respectively.Detecting the composition of functional groups by infrared spectroscopy showed that the structure of functional groups among all polysaccharides was consistent.However,the composition of monosaccharides and the molar ratio of monosaccharides were affected by variety and month.The main monosaccharide components are rhamnose,arabinose,glucose,galactose,and mannose,Xylose was detected only in the leaves of’Bojihong’in July.In the study of in vitro antioxidant activity,the ability of leaf polysaccharides to reduce Fe Cl₃ was the highest in’Brunswick’,followed by’Masui Dauphine’,and’Bojihong’was the lowest.In terms of months,the reducing power of the leaf polysaccharides of’Brunswick’was the highest in October,’Bojihong’was the highest in November,and’Masui Dauphine’was the highest in September.In terms of the ability to scavenge DPPH free radicals,there is no significant difference between the scavenge ability of’Masui Dauphine’and’Brunswick’,which is significantly higher than that of‘Bojihong’.From the leaf picking months,the scavenging activity of polysaccharides from leaves of’Brunswick’,’Masui Dauphine’and’Bojihong’was the highest in October,September and July,respectively.3.In order to further understand the effect of fig leaf polysaccharides on the growth of tumor cells,the gastric cancer cell SGC-7901 was used as the material to carry out research.The results showed that:Leaf polysaccharides（2 mg/m L）of different varieties and picking months had different inhibitory effects on the proliferation of gastric cancer cells SGC-7901.Among them,’Brunswick’September leaf polysaccharides（2 mg/m L）The inhibition rate was the highest,reaching 46.67%,and the inhibition of cell proliferation was dose-dependent.The morphological results showed that the morphology of the treated cells changed from a spindle shape to a round shape,and apoptotic bodies appeared.In addition,Cycle detection showed that different concentrations of polysaccharides had a significant blocking effect on the cycle of cancer cells,and the percentage of S phase cells increased.The content of reactive oxygen and the rate of apoptosis species also increased.When the concentration reached 4 mg/m L,the cell apoptosis rate reached 32.45%.After polysaccharide solution treatment,the expression of Bax and p53 genes in the cells increased at the m RNA level,while the expression of Bcl-2,Cyclins and CDKs decreased at the m RNA level.