Total polyphenols and antioxidant capacity in kombucha from different teas and their effects on intestinal health in-vitro intestinal epithelial tissue model

英语. Kombucha contains a plethora of compounds that contribute to its health benefits apart from its probiotic effects. This project was conducted to determine the total polyphenolic content (TPC) and total antioxidant content (TAC) of kombucha prepared with black tea, oolong tea, and green tea as a function of fermentation time (day 0 to day 18). Amongst all the kombucha samples, green tea kombucha on day 9 (GTK 9) had the highest TPC (506.97 ± 22.28 µg GAE/mL) and TAC (440.93 ± 1.46 µmoles TE/ mL) and it was chosen to evaluate its effect on the transepithelial electrical resistance (TEER), antioxidative capacity (AOC), tissue permeability and cell viability using a 3D model of the intestinal epithelial tissues. For these analyses, two different concentrations of gallic acid (GA), 500 and 2000 µg/mL were also used since GA, is a simple phenolic compound that is also one of the end-products of polyphenol fermentation and digestion and has known benefits on the intestinal epithelial health. All the results were compared to a negative control (NC), treated with PBS. GTK 9 had a similar effect as 500 µg/ml GA for TEER, where their effect wasn’t significantly different than the NC, and for AOC, where their effect significantly increased the AOC of the tissues. GTK 9 increased the tissue permeability significantly more than the NC, but this increase was not above the threshold level to be harmful to the tissues. All the treatments proved to increase cell viability, making them cytoprotective. Overall, both the concentrations of GA and GTK 9 proved to be beneficial for improving the health of the intestinal epithelial tissues.

英语. Kombucha - A sour, fizzy, and tasty drink that contains components to keep your body healthy! Functional foods and beverages are becoming famous among consumers because of their several health benefits. One of those famous functional foods is kombucha. With its origin in China, kombucha is a fermented tea drink that is non-alcoholic, sweet-sour in taste, and slightly carbonated. The raw materials needed to make kombucha are brewed tea and sugar which are then fermented by a symbiotic mixture of bacteria and yeast to form a sour liquid with a floating bio-cellulose. The type of tea and fermentation time play an important role in determining the properties of the final product. In this project, kombuchas were prepared with 3 types of teas – black, oolong, and green and were fermented for 6, 9, 12, and 18 days. One group of compounds that contribute to the health benefits of kombucha are the polyphenols present in the tea. Polyphenolic content varies depending on the type of tea and also the fermentation time. They are known to lower the risk of or even postpone several diseases like cancer, metabolic syndrome, and neurological diseases. They are also good antioxidants like many vitamins and organic acids. In earlier days, studies used to be conducted on rodents and pigs to evaluate the properties of many food components inside the human body since the genetic makeup of humans and rodents or pigs is very similar. However, these studies cannot be 100% used for humans because of some important differences between them. To solve this problem, many in-vitro models (mimicking the human body in a lab setting) were generated and are now being used. One such model is a 3D intestinal epithelial tissue model, SMI-100 which enables us to conduct experiments on the human epithelial tissues and evaluate how the body reacts to it. Gallic acid, a simple phenolic compound has shown positive effects on the tissue integrity, permeability, antioxidative capacity, and cell viability of these intestinal epithelial tissues. Since kombucha contains polyphenols, both simple and complex, it was thought interesting to see the effect of kombucha and different concentrations of gallic acid on intestinal tissue health to see if they can improve the tissue integrity and permeability, have an antioxidative capacity on the tissues under induced oxidative stress, and if they are cytotoxic or not compared to negative control. This report aims to determine the total polyphenolic content, and total antioxidative capacity of kombuchas made with 3 types of teas (black, oolong, and green) with different fermentation times and to see their effect on the intestinal epithelial tissues.