Study On The Probiotic Activity And Intestinal Immune Enhancement Activity Of Black Rice Anthocyanins And Their Acylated Compounds

With the rapid development of economy and the demand for healthy food is higher and higher.Anthocyanins not only could be used as natural pigments but also have the important effects on anti-tumor,anti-aging,anti-inflammatory and so on.In this paper,cyanidin-3-O-glucoside(C3G)extracted from black rice was acylated with lauric acid to produce acylated product(L-C3G).The anti-digestibility,prebiotic activity and immune activity of C3 G and L-C3 G were studied.(1)The anti-digestion of C3 G and L-C3 G was measured by simulating the gastrointestinal environment of human body.The model of in vitro digestion is divided into two stages: four hour gastric juice digestion and four hour intestinal digestion.The anthocyanins was analyzed quantitatively by p H-difference method,and the dynamic retention rate of C3 G and L-C3 G in gastrointestinal tract was obtained.The retention rate of L-C3 G was 82.29% after 4 hours of gastric digestion model,while that of C3 G after 4 hours gastric digestion model was 75.94%.In the simulated intestinal digestion model,C3 G was digested completely after 2.5 hours,and L-C3 G was completely digested after 4 hours.Obviously,the anti-digestion ability of C3 G after acylation was improved obviously.(2)The prebiotic activity of C3 G and L-C3 G were studied.The prebiotic activities of C3 G and L-C3 G were analyzed by measuring their growth.The results of prebiotic test showed that L-C3 G could promote the proliferation of Bifidobacterium infantis,Bifidobacterium adolescentis,Lactobacillus thermophilus and Lactobacillus acidophilus as a potential prebiotic.At the same time,the antibacterial effects of C3 G and L-C3 G were measured by inhibition zone test.The results showed that C3 G and L-C3 G could effectively inhibit the growth of Shigella dysentery,Yersinia enterocolitica,Salmonella enteritidis and Salmonella typhi.(3)The effects of C3 G and L-C3 G on human intestinal flora was studied.The effects of C3 G and L-C3 G on the proliferation of intestinal flora were evaluated by measuring the relative colony number,p H value,growth rate and short chain fatty acids(SCFA)in the metabolic process.The metabolites of C3 G and L-C3 G were analyzed by gas chromatography-mass spectrometry(GC-MS).Fourteen metabolites including propionic acid,phenyllactic acid and lauric acid were detected,and the possible metabolic pathways of C3 G and L-C3 G through intestinal flora were inferred.The results showed that C3 G and L-C3 G did not change the diversity of intestinal flora,but increased the content of probiotics such as Lactobacillus,reduced the content of harmful bacteria such as Shigella,and played a role in regulating the structure of intestinal flora.The results provide a theoretical basis for L-C3 G as a new intestinal health care product.(3)The effects of C3 G and L-C3 G on the immune activity in mice.The animal feeding experiment was conducted on 28 days.The body weight,organ index,blood serum biochemical test,p H of intestinal content,intestinal tissue morphology,immune cell activity,intestinal digestive enzyme activity(protease,amylase,fatty enzyme)and microbial diversity of intestinal tract were established in Kunming mice after taking C3 G and L-C3 G acylated product.The immune indexes of C3 G and L-C3 G were established The activity of epidemic was evaluated.C3 G and L-C3 G had no significant effect on the body weight,organ index,blood serum biochemical index and histopathological examination(P < 0.05).The activities of trypsin and amylase in the intestine of mice were significantly increased,and the activity of lipase was significantly reduced.The p H of intestinal content was slightly lower than that of the control group.This acidic intestinal environment is beneficial to the growth of beneficial bacteria and inhibit the growth of harmful bacteria.C3 G and L-C3 G could improve the height of intestinal villi,the depth of crypt and the number of immune cells(T cells,mast cells,goblet cells),which can improve the immunity of mice.