Effect of Plantain Bulb's Extract-Beverage Blend on Blood Glucose Levels, Antioxidant Status, and Carbohydrate Hydrolysing Enzymes in Streptozotocin-Induced Diabetic Rats

Abstract

The pharmacological properties of various parts of plantain trees have directed its use in folkloric management of diabetes and other human ailments. However, little is known about plantain bulb extract (PBE) and their mechanisms of action. This study evaluated the effect of PBE-beverage blends (including 1% and 2 % cocoa powder) sweetened with honey on blood glucose levels, antioxidant status, and carbohydrate hydrolysing enzyme activities in streptozotocin (STZ)-induced diabetic rats. Animals were selected at random and distributed into 7 groups (n=7), as follows: normal control (NC), untreated diabetic rats, diabetic rats treated with acarbose (STZ-ACA), diabetic rats administered PBE (STZ- PBE), diabetic rats administered honey and PBE (STZ-HPBE), diabetic rats administered 1% cocoa powder-with HPBE blend (STZ-CHPBE-1), and diabetic rats administered 2% cocoa powder with HPBE blend (STZ-CHPBE-2). Compared with the controls, untreated diabetic rats exhibited increased blood glucose levels and hydrolysing enzyme activities, and significant decreases in the activities of antioxidant (catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase) enzyme and non-enzymatic (glutathione) antioxidants. However, changes in activities were comparatively reversed in all rats administered plantain bulb formulations. CHPBE-2 was slightly more effective than CHPBE-1. Overall, both blends could serve as nutraceutical and/or functional drinks in the management of diabetes.

Keywords: cocoa powder; hyperglycaemia; oxidative stress; plantain bulb; therapeutic agents.

Fig. 1

Effect of plantain bulb extract-beverage blend on blood glucose level of streptozotocin (STZ)-induced diabetic rats. Bars represent mean±SD (n=7). Different letters (a-d) are significantly different at P<0.05. ns, not significant. Group abbreviations are the same as Table 1.

Fig. 2

Effect of plantain bulb extract-beverage-blend on (A and B) catalase (CAT) and (C and D) superoxide dismutase (SOD) activities in the liver and kidney homogenates of streptozotocin (STZ)-induced diabetic rats. Bars represent mean±SEM (n=7). Values are statistically different at ^*P<0.05, ^**P<0.01, and ^***P<0.001 vs NC; ^#P<0.05, ^##P<0.01, and ^###P<0.001 vs STZ-IND; ^†P<0.05 vs STZ+ACA. Group abbreviations are the same as Table 1.

Fig. 3

Effect of plantain bulb extract-beverage-blend on (A and B) glutathione-S-transferase (GST) and (C and D) glutathione peroxidase (GPx) in the liver and kidney homogenates of streptozotocin (STZ)-induced diabetic rats. Bars represent mean±SEM (n=7). Values are statistically different at ^*P<0.05, ^**P<0.01, and ^***P<0.001 vs NC; ^#P<0.05, ^##P<0.01, and ^###P<0.001 vs STZ-IND; ^†P<0.05, ^††P<0.01, and ^†††P<0.001 vs STZ+ACA. Group abbreviations are the same as Table 1.

Fig. 4

Effect of plantain bulb extract-beverage-blend on (A and B) glutathione (GSH) and (C and D) thiobarbituric acid reactive species (TBARS) levels in the liver and kidney homogenates of streptozotocin (STZ)-induced diabetic rats. Bars represent mean±SEM (n=7). Values are statistically different at ^*P<0.05, ^**P<0.01, and ^***P<0.001 vs NC; ^#P<0.05, ^##P<0.01, and ^###P<0.001 vs STZ-IND; ^†P<0.05, ^††P<0.01, and ^†††P<0.001 vs STZ+ACA. Group abbreviations are the same as Table 1.

Fig. 5

Effect of plantain bulb extract-beverage-blend on nitric oxide level in the liver and kidney homogenates of streptozotocin (STZ)-induced diabetic rats. Bars represent mean±SEM (n=7). Values are statistically different at ^*P<0.05, ^**P<0.01, and ^***P<0.001 vs NC; ^#P<0.05, ^##P<0.01, and ^###P<0.001 vs STZ-IND; ^†††P<0.001 vs STZ+ACA. Group abbreviations are the same as Table 1.

Fig. 6

Effect of plantain bulb extract-beverage-blend on pancreatic α-amylase and intestinal α-glucosidase activities of streptozotocin (STZ)-induced diabetic rats. Bars represent mean±SEM (n=7). Values are statistically different at ^***P<0.001 vs NC; ^###P<0.001 vs STZ-IND; ^†P<0.05 vs STZ+ACA. Group abbreviations are the same as Table 1.