Enzymatic Effects of Pancreatic Amylase Inhibition by Kombucha Tea

Kombucha is a fermented tea beverage produced through use of a symbiotic culture of bacteria and yeast (SCOBY). The purported health benefits of this drink are being assessed through the use of an assay simulating breakdown of starches in the mouth.1 Analysis with spectrophotometry at 540 nm for porcine pancreas amylase using 0.100 mg/mL reported a Km of 0.440 mg/mL and Vmax of 0.00451 mg/min. Breakdown of starches was compared to a standard using maltose for comparison.2 Kombucha inhibition using IC50 inhibition analysis with a dose response curve of dilutions determined a value of 6.70x10-3 mL. Further IC50 analysis was performed using pH adjusted Kombucha and black tea samples determined values of 7.24x10-1 mL and 6.92x10-4 mL respectively. Using the Gallic Acid Equivalence method, black tea was prepared with similar phenolic concentration to that used in Kombucha during the fermentation process. In adjusting the pH of Kombucha and black tea samples, an acidified solution demonstrated the highest inhibitory function on pancreatic amylase. This data provides relevant information related to the absorption of starches in the mouth during intake of the beverage. The slowed breakdown of carbohydrates to monosaccharides could be pertinent in the overall health and digestive effects of Kombucha during consumption.

Characterization of Active Compounds Produced in the Biotransformation of Metabolites in Kombucha Tea

Kombucha is a fermented black tea that has been hypothesized to provide many health benefits. The exact origin of these benefits, however, is continually being investigated. This study aims to identify the various active compound produced in the biotransformation of the metabolites during the fermentation process of the tea beverage, as well as quantify functions such as antioxidant capacity. Hydrophilic and hydrophobic liquid-liquid extractions were performed on a filtered sample of GT’s Organic Raw Kombucha® using acetonitrile and ethyl acetate. Ferric reducing/antioxidant power (FRAP) assays were run on both the Kombucha tea and the extracts to determine their antioxidant capacity. The Kombucha tea, acetonitrile extract, and ethyl acetate extract were found to have FRAP values of 146.9, 102.7, and 71.04, respectively. The high retention of FRAP in the acetonitrile extract gives evidence that a polar hydrophobic molecule is functioning as an antioxidant in the Kombucha tea. Antioxidant capacity was further tracked using a variety of chromatographic techniques including the use of silica gel and C-18 functionalized silica flash chromatographies, as well as reverse-phase C-18 HPLC. These studies aim to further purify and characterize the compounds responsible for antioxidant capacity

Intermediate filament cytoskeleton of the liver in health and disease

Intermediate filaments (IFs) represent the largest cytoskeletal gene family comprising ~70 genes expressed in tissue specific manner. In addition to scaffolding function, they form complex signaling platforms and interact with various kinases, adaptor, and apoptotic proteins. IFs are established cytoprotectants and IF variants are associated with >30 human diseases. Furthermore, IF-containing inclusion bodies are characteristic features of several neurodegenerative, muscular, and other disorders. Acidic (type I) and basic keratins (type II) build obligatory type I and type II heteropolymers and are expressed in epithelial cells. Adult hepatocytes contain K8 and K18 as their only cytoplasmic IF pair, whereas cholangiocytes express K7 and K19 in addition. K8/K18-deficient animals exhibit a marked susceptibility to various toxic agents and Fas-induced apoptosis. In humans, K8/K18 variants predispose to development of end-stage liver disease and acute liver failure (ALF). K8/K18 variants also associate with development of liver fibrosis in patients with chronic hepatitis C. Mallory-Denk bodies (MDBs) are protein aggregates consisting of ubiquitinated K8/K18, chaperones and sequestosome1/p62 (p62) as their major constituents. MDBs are found in various liver diseases including alcoholic and non-alcoholic steatohepatitis and can be formed in mice by feeding hepatotoxic substances griseofulvin and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDBs also arise in cell culture after transfection with K8/K18, ubiquitin, and p62. Major factors that determine MDB formation in vivo are the type of stress (with oxidative stress as a major player), the extent of stress-induced protein misfolding and resulting chaperone, proteasome and autophagy overload, keratin 8 excess, transglutaminase activation with transamidation of keratin 8 and p62 upregulation