Antioxidant Effect In Vitro And Anti-Inflammatory Effect On TNBS Induced Mice Colitis Of Anthocyanins Dioscorea Alata L.

Non-toxic and less side effects have made the natural product became a hot topic. Purple tube of yam cultivated in the Agricultural Research Center of Hainan University was used in this assay, anthocyanins were extracted and purified, measured the content and structure of anthocyanins, and in vitro antioxidant capacity and the capacity of reducing colitis induced by TNBS in mice, all these effort was made to provide important basic information for research and development of anthocyanins in Hainan purple yam. The main findings are as follows:1.The research of content and structure of anthocyanins in Dioscorea alata LIn this experiment, acidified ethanol was used to extract anthocyanin in Hainan purple yam tuber and purified by AB-8 macroporous resin, extracts of lyophilized powder are purple. Determination by pH differential method, anthocyanin content of purple yam tubers was 3.32mg/g(fresh sample), the purity of freeze-dried samples of anthocyanin was 96.15%. Five different structure of anthocyanins were found by HPLC-DAD-MS/MS, namely cyanidin 3,5-diglucoside, cyanidin-3-diglucoside-5-celery glycosides, delphinidin-3-glucose-5-rutinoside, delphinidin-3-glucoside and delphinidin-3,5-diglucoside.2. The antioxidant capacity of DACN in vitroIn this test, vitamin C and vitamin E were used as a positive control, in vitro model of free radical were set to determine the antioxidant capacity of DACNs.The results showed:great antioxidant capacity were found in DACNs, which can effectively scavenge DPPH, OH- and chelate metal ions. DACN showed a dose-related antioxidant capacity, as the concentration was above 60?g/mL, reducing power, scavenging of O2- and T-AOC were higher than VC; The reducing power of DACN were higher than the same concentration of VE, concentrations above 60 ?g/mL, the scavenging of O2- and T-AOC were also higher than VE. To further study the influential factors on antioxidant capacity of DACNs, experimental design solution pH value of 4,5,6,7,8,9 to compare the effect of different pH on the antioxidant capacity of DACNs also the synergism effect of DACN and vitamin C or vitamin E. The results showed that:the antioxidant capacity of DACNs was significantly affected by pH value (p<0.05), the antioxidant capacity of DACNs were significantly lower in acidic environment compared with alkaline environment (p <0.05). Synergism were found in mixture of DACNs and vitamin C in free radical scavenging and chelating metal ions (CI<0.95),synergism was found in ratio of 60%: 40%(CI<0.9); however, synergism was only found in DACNs and vitamin E in scavenging OH- (CI<0.95),antagonism was found in scavenging DPPH and chelating metal iron (CI>1.05).3. Anti-inflammatory effect of DACNs in TNBS-induced colitis in miceIn this experiment, colitis model was established by rectal infusion of TNBS. After experimenting with different concentrations of DACNs as protection treatment, and 5-amino salicylic acid as positive control to relieve inflammation to determine the anti-inflammatory effect of DACNs. The results showed that:compared with TNBS group, mice received DACNs got lighter weight loss, significantly lower score in forming stool score, occult blood and DAI (p<0.05); mice received DACNs got better intestine surface, mucosal repaired faster, more distinct boundaries, mice received highest concentration of DACNs colonic got colonic surface state similarly to the control group, also goblet cell and colon muscle are more complete with the concentration increasing, colonic mucosa forms significantly improved in A80 group which had clearer boundary of mucous layer, no edema, and similar with control group; In addition, high concentration of DACNs also significantly improved the expression of ZO-1,Claudin-1,Occludin, Mucin-1 and Mucin-2 (p<0.05), which can improve the maintenance of the structural integrity of the colon, also high concentrations of DACNs (80mg/kg) and 5-ASA administered alone were without harmful effects (p> 0.05)in mice normal colon tissue; After rectal infusion of different concentrations of DACNs, MPO, IFN-y, TNF-a in serum were significantly decreased (p<0.05),which mice received 80mg/kg anthocyanin and 5-ASA got similar MPO, IFN-y, TNF-a level with normal group (p> 0.05), however 20mg/kg and 40mg/kg DACNs significantly reduced MPO and TNF-a (p<0.05), but still significantly higher than the control group (p<0.05), there was no significant difference of IFN-y level in comparison of 40mg/kg group and control group (p> 0.05), in addition,20mg/kg DACNs significantly inhibited mouse iNOS activity in serum (p<0.01), but still significantly higher than that of the control group (p= 0.002),40mg/kg,80mg/kg DACNs and 5-ASA significantly inhibited iNOS activity in serum (p<0.05), no significant differences compared with normal control group(p> 0.05). High concentrations of DACNs and 5-ASA had no significant effect (p>0.05) in normal mouse serum inflammatory factors. Description DACNs can effectively relieve inflammation in mouse models of colitis, a high concentration of DACNs has no adversely affecting in normal colon tissue of mice and has a fairly efficacy of 5-ASA.With the above data, we can see DACNs contained high antioxidant capacity and relieve inflammation mouse models of colitis, which has broad development prospect.