Effect Of In Vitro Digestion On Active Components In Red Respberry And The Protection Of Intestinal Cells Damage

Red raspberry has been demonstrated to be a kind of natural antioxidant for scavenging reactive oxygen species (ROS) with the benefits ascribed to the active ingredients, such as polyphenolic, flavonoids, anthocyanins, SOD and so on. In vitro experiment generally ignored active composition changes after gastrointestinal digestion and absorption, in order to evaluate the potential function of the raspberry plant chemicals in human body, the changes of the active ingredients in red raspberry were researched in this paper. Relevant amounts of acrylamide (AA) have been identified in heat-treated carbohydrate-rich foods such as fried and baked food. Extensive in vivo and in vitro studies have revealed that AA could induce neurotoxic, genotoxic, carcinogenic effects. It will cause oxidative damage of intestinal cells when human intake excessive AA, causing a series of intestinal diseases. Digging safe and effective functional natural plant as antioxidant has become a hot spot in the field of functional food and natural medicine research in recent years.In this paper, the method of in vitro digestion was used to explore the protective and mechanism of red raspberry against oxidative damage in intestinal cells from three aspects in vitro, cellular and molecular level respectively. The main results were as follows:(1) The content of active ingredients in red raspberry changed after in vitro digestion. Compared with undigested material (OR), after pepsin digestion (PG), the content of total phenolics, flavonoids and anthocyanins increased; and Following pancreatic digestion (PI), the content of total phenolics and flavonoids also increased obviously. Three samples (OR, PG, PI) of red raspberry had strong antioxidant activity and showed obvious concentration dependence. The half growth inhibitory concentration (IC50) of OR, PG and PI was3.55mg/mL,4.22mg/mL and2.27mg/mL respectively, and the PI sample showed the highest antioxidant activity.(2) Dynamic fluorescence visualization technology, molecular probes and other modern molecular cytology technique were used to evaluate the mechanism of protective effect against oxidative damage in Caco-2. The results showed that AA (2.5mM) induced a decrease in GSH concentration and an increase in the levels of ROS. The excessive ROS caused oxidative damage to the mitochondria membranes and impaired the membrane integrity and cell nucleus, which can adversely affect cell function and potentially lead to cell damage and death. Meanwhile, the red raspberry could reduce AA-induced ROS generation, recover GSH depletion and prevent the damage to the mitochondria membranes and cell nucleus.(3) By analyzing RT-PCR, we found the red raspberry treatment increased the mRNA expression for heme oxygenase1(HO-1) and CAT, which is regulated by Nrf2-ARE signaling pathway; Moreover the red raspberry treatment was also discovered to significantly inhibit AA-induced decline of SOD and CAT activity.In summary, the results of this research provided an idea and method for assessing the potential bioavailability of foods. Further research on mechanisms of red raspberry against oxidative damage in Caco-2also provided certain scientific basis of developing red raspberry to a natural, safe and effective product.