Functional papaya beverage increases healthy gut microbiota in Streptozotocininduced diabetic Sprague Dawley rats

Abstract

Diabetes mellitus is a silent killer illness, characterized by hyperglycaemia effect and can cause many health complications. A new functional papaya beverage was produced via selected pure symbiotic culture of bacteria and yeast (SCOBY) which offers an alternative food therapy in regulating blood glucose and its efficacy was evaluated using Streptozotocin (STZ)-induced diabetic Sprague Dawley rats for one month treatment. Under moderate diabetes condition, SCOBY papaya beverage was shown able to reduce high blood glucose in diabetic rats to normal level, comparably effective with commercial drug, Metformin. Not only that, it also helped restore body weight of diabetic rats to a healthier state with a gradual increment of body weight observed weekly. In contrast, untreated diabetic rats experienced a sharp rise in blood glucose with stunted body weight. Nutrigenomic studies were conducted to identify the mechanisms that support the effectiveness of SCOBY papaya beverage as an anti-diabetic therapy. Evidence from quantitative polymerase chain reaction (qPCR) analysis disclosed significant higher expression on gene markers related to insulin receptor substrate 1 (Irs1), glucose transporter (Slc2a8) and glutathione S-transferase mu 1 (Gstm1), but lower expression of gene markers indicative of diabetes complications and inflammation e.g., tissue inhibitors of metalloproteinase 1 (Timp1), nuclear factor kappa B subunit 1 (Nfkb1) and nitric oxide 2 (NOS2) in diabetic rats treated with SCOBY papaya beverage and Metformin (p<0.05). SCOBY papaya treated diabetic rats showed an increment of short chain fatty acids content and gut microbiota enriched with some beneficial microbes particularly for Alloprevotella, Ruminococcus 1, Lachnospiraceae NK4A136, Prevotellaceae UCG-001 and Prevotellaceae NK3B31 compared to untreated diabetic rats. These data support the effectiveness of SCOBY papaya as a functional beverage in improving intestinal health by changing the environment of the microbiome of diabetic rats, in turn offering costeffective food therapies in blood glucose regulation.