RESUMEN
Postprandial blood glucose lowering effect of vitamin B6 (pyridoxine) was evaluated in healthy individuals with normal blood glucose levels. Blood glucose levels were measured every 30 min for 2 h after oral sugar administration with or without 50 mg of pyridoxine. Pyridoxine significantly lowered the postprandial blood glucose levels at 30 min (from 165.95 ± 17.19 to 138.36 ± 20.43, p < 0.01) and 60 min (from 131.40 ± 17.20 to 118.50 ± 15.95) after administration. In addition, the area under the concentration-time curve (AUCt) was reduced by about 8.3% (from 257.08 ± 22.38 to 235.71 ± 12.33, p < 0.05) and the maximum concentration of blood glucose (Cmax) was reduced by about 13.8% (from 165.95 ± 17.19 to 143.07 ± 11.34, p < 0.01) when compared with those of the control group. Our findings suggest that pyridoxine supplementation may be beneficial for controlling postprandial hyperglycemia.
RESUMEN
In the current study, we investigated the inhibitory activity of pyridoxine, pyridoxal, and pyridoxamine, against various digestive enzymes such as α-glucosidases, sucrase, maltase, and glucoamylase. Inhibition of these enzymes involved in the absorption of disaccharide can improve post-prandial hyperglycemia due to a carbohydrate-based diet. Pyridoxal (4.14 mg/mL of IC50) had the highest rat intestinal α-glucosidase inhibitory activity, followed by pyridoxamine and pyridoxine (4.85 and 5.02 mg/mL of IC50, respectively). Pyridoxal demonstrated superior inhibition against maltase (0.38 mg/mL IC50) and glucoamylase (0.27 mg/mLIC50). In addition, pyridoxal showed significant higher α-amylase inhibitory activity (10.87 mg/mL of IC50) than that of pyridoxine (23.18 mg/mL of IC50). This indicates that pyridoxal can also inhibit starch hydrolyzing by pancreatic α-amylase in small intestine. Based on these in vitro results, the deeper evaluation of the anti-hyperglycemic potential of pyridoxine and its derivatives using Sprague-Dawley (SD) rat models, was initiated. The post-prandial blood glucose levels were tested two hours after sucrose/starch administration, with and without pyridoxine and its derivatives. In the animal trial, pyridoxal (p < 0.05) had a significantly reduction to the postprandial glucose levels, when compared to the control. The maximum blood glucose levels (Cmax) of pyridoxal administration group were decreased by about 18% (from 199.52 ± 22.93 to 164.10 ± 10.27, p < 0.05) and 19% (from 216.92 ± 12.46 to 175.36 ± 10.84, p < 0.05) in sucrose and starch loading tests, respectively, when compared to the control in pharmacodynamics study. The pyridoxal administration significantly decreased the minimum, maximum, and mean level of post-prandial blood glucose at 0.5 h after meals. These results indicate that water-soluble vitamin pyridoxine and its derivatives can decrease blood glucose level via the inhibition of carbohydrate-hydrolyzing and absorption-linked enzymes. Therefore, pyridoxal may have the potential to be used as a food ingredient for the prevention of prediabetes progression to type 2 diabetes.
