Anti-Diabetic And Probiotic Effect of Kombucha on Alloxan-Induced Diabetic Rats

ABSTRACT 

Diabetes mellitus, is a metabolic disorder caused by the inability of the beta pancreatic cells to adequately produce insulin or due to insulin resistance of cells. As a result of the increasingly high incidence of diabetes globally, the World Health Organization (WHO) has set timelines and guidelines for the reduction of the risk of mortalities and morbidities associated with noncommunicable diseases including diabetes, by the year 2030. However, this agenda is hinged on the availability of affordable, safe and effective alternatives for the management and treatment of these diseases. Hence, there is a need to explore other alternatives to the conventional oral antihyperglycemic agents driven by factors such as patient’s preference, demand among others. Kombucha is tea fermented by a symbiotic culture of bacteria and yeasts (SCOBY). Consumers of Kombucha have reported several anecdotal evidences of its medicinal potential. This study seeks to investigate its anti-diabetic and probiotic effect on alloxan-induced diabetic rats. It was hypothesized that Kombucha, being a complex matrix of microorganisms and nutraceuticals, would play an essential role in the management of diabetes. Molecular characterization of the microbiome of Kombucha using shotgun metagenomics (Oxford Nanopore MINION sequencing technology) showed Brettanomyces bruxellensis CBS 2499 as the most abundant species within the microbial community accounting for about 51 % of all reads. Brettanomyces anomalus, Komagataeibacter xylinus NBRC 15237, Bacillus nealsonii AAU1, Zygosaccharomyces bailii CLIB 213, Acetobacter, Gluconobacter and over 300 other genera and species of microorganisms including archaea and viruses were also detected using a combination of REFSEQ and One Codex data bases (OXCDB). In-vivo experiment was used to evaluate the anti-diabetic property, safety and gut microbiome changes of Kombucha. Kombucha was found to perform better than the conventional antidiabetic drugs, metformin and glibenclamide in lowering the fasting blood glucose (FBG) of the diabetic rats. Daily administration of 25 mg/kg and 100 mg/kg of freeze-dried Kombucha tea demonstrated a 5 fold reduction in FBG (p0.05). Further analyses demonstrated that Kombucha decreases the relative organ (liver and kidney) to body weight ratio in treated animals. In addition, Kombucha was able to reduce significantly the elevated levels of liver enzymes such as Alkaline phosphatase (ALP), Alanine transaminase (ALT) and Aspartate Aminotransferase (AST) as well as renal toxicity indices, creatinine and urea in treated animals. Histology of the kidney and liver also showed that Kombucha has no adverse effect on the morphology and cellular integrity of these organs suggesting its hepatoprotective and renal protective potentials. Urinanalysis also showed reduction of glucose in urine for the 100 mg/kg Kombucha-treated animals. Additionally, Kombucha protects the gut microbiome, most significantly by enhancing the Lactobaccillaceae family of bacteria within the gut and reduces the possibilities of colonization of the gut by other opportunistic bacterial species. The study demonstrated that Kombucha is enriched with diverse microbial population with probiotic value and daily intake of Kombucha may be potentially helpful in the management of diabetes, protection against renal and liver toxicity and offer gut microbiome protection.