Extraction And Biological Activities Of Total Polysaccharides From Petals Of Crocus Sativus L.

Metabolic Syndrome is a cluster of clinical syndromes based on the common pathological physiology of insulin resistance.It is the result of a combination of genetic and environmental factors.It is characterized by a combination of several kinds of metabolic disorders,including central obesity,diabetes,hypertension,dyslipidemia and so on.With the development of social economy and changes of lifestyle,the incidence of MS increased year by year.The incidence of cardiovascular disease and diabetes triggered by MS is rising.Due to the etiology of metabolic syndrome involves the complex interaction between genetic,metabolic,and environmental factors,the single-entity pharmaceuticals has certain limitations.Recently,drug trials have focused on herbal medicines.There are many botanicals that might provide safe,natural,and cost-effective alternatives to synthetic drugs.Saffron,a kind of rare medicinal herbs with obvious bioactivities,is the dry stigma ofCrocus sativus L.The petals of Croeus sativus L.is a by-product in the pharmaceutical industry.It is abundant in polysaccharides and other active ingredients,which may have potential use in exploitation and utilization.In order to achieve sustainable development and depth use of petals,we investigated the extraction technology of polysaccharides from petals of Crocus sativus L.in this study.Then we evaluated the antioxidant and anti-inflammatory activities of polysaccharides in vitro.Furthermore high-fat diet fed mice were used to evaluate the hypolipidemic effect of polysaccharides and its mechanisms.L9(33)orthogonal experiment was designed to optimize the extraction conditions of total polysaccharides from petals of Crocus sativus L(PPC).The results showed that the maximum yield rate and the purity of PPC reached to 11.54%and 61.80%respectively under conditions of the ratio of sample to water.The temperature for extraction was 100℃ and the time for extraction was 3 hours.Next,antioxidant and anti-inflammatory activities of PPC were also identified in vitro.The results showed that the scavenging effect of PPC on DPPH and ·OH free radical were significantly increased.Scavenging rate of PPC on DPPH and ·OH were 41.68%at the concentration of 32 mg/mL;and 63.01%at the concentration of 16 mg/mL,respectively.LPS-induced RAW 264.7 macrophages were used as in vitro model for the research of anti-inflammatory activity.The results showed that PPC at concentrations of 25-100 μg/mL coxuld significantly inhibit the mRNA expression of TNF-α,IL-6 and IL-lp in a dose-dependent manner.In vivo acute toxicity test indicated that the toxicity of PPC was actual non-toxic.Normal mice were used to investigate the effects of PPC on lipid metabolism.Oral administration with PPC(200,400 and 800 mg/kg)for 2 w reduced serum TC level compared with normal control group.However,PPC didn’t affect body weight,food intake,water intake,organ weights and serum TG level in normal mice.We then took further investigations into the effects of PPC on lipid metabolism and its mechanisms using the high-fat diet(HFD)fed mouse model.The results showed that HFD caused a significant increase in fat pad weights,serum TC level and AI whereas a marked decrease in serum LDL-C level.These results indicated that long term feeding of HFD induced hyperlipidemia.In addition,the level of hepatic TC was significantly increased in HFD treated group,suggesting that HFD caused the storage of TC in the liver.Oral administration with PPC at dose of 200 mg/kg for 12 w significantly reduced the levels of serum TC,TG,LDL-C,LDL-C/TC and AI.PPC at dose of 800 mg/kg significantly reduced the level of serum TG.In conclusion,PPC can significantly reduce the level of serum lipid profiles,and effectively prevent dyslipidemia induced by long term feeding of high fat diet.HE staining of liver tissue showed that the lipid droplet in PPC200 group significantly reduced when compared with HFD group,which indicated that PPC could relieve fatty liver disease caused by high fat diet.HE staining of epididymal adipose tissue indicated that HFD caused adipose cell enlarged obviously.Howerer,the sizes of adipocytes were considerably decreased in each group treated with PPC compared with those in the HFD group.The immunohistochemical images of adipose tissue stained by F4/80 indicated that PPC can reduce the infiltration of macrophages into the adipose tissue of HFD-fed mice.To better understand the molecular mechanism of PPC,the expression of several genes and protein that involved in lipid metabolism in liver and adipose tissue were detected.Compared with high-fat diet control group,the PPARa mRNA expressions in adipose tissue were upregulated by PPC(400 and 800 mg/kg)treatment,and p38MAPK protein expression was increased by 800 mg/kg PPC.Taken together,PPC ameliorated lipids metabolic disorder may be partly through activating PPARa expression and p38MAPK signal pathway.