Abstract
BACKGROUND: Alkaloid- and polyphenol-rich white mulberry leaf and apple peel extracts have been shown to have potential glucose-lowering effects, benefitting the control of postprandial blood glucose levels. This study aimed to determine the effect of the combination of Malus domestica peel and Morus alba leaf extracts (GLUBLOC(TM)) on postprandial blood glucose and insulin-lowering effects in healthy adults after a carbohydrate-rich meal or sucrose drink intake. METHODS: This study was designed as a randomized, crossover, single-blinded clinical trial. Out of 116 healthy participants, 85 subjects (aged 18-60 years) completed the day 1 and 5 crossover study. On day 1, subjects were supplemented with a placebo or GLUBLOC(TM) tablet 10 min before the carbohydrate-rich meal (300 g of tomato rice) or sucrose drink intake (75 g of sucrose dissolved in 300 mL water). On day 5, the treatments were crossed over, and the same diet was followed. Postprandial blood glucose and insulin levels were measured on days 1 and 5 (baseline 0, post-meal 30, 60, 90, and 120 min). Differences in iAUC, Cmax, and Tmax were determined between the placebo and GLUBLOC(TM)-treated cohorts. RESULTS: Significant changes in total iAUC (0-120 min), Cmax, and Tmax of postprandial blood glucose and insulin levels were noticed upon GLUBLOC(TM) supplementation. The percentage reduction in the iAUC of blood glucose levels was 49.78% (iAUC(0-60min)) and 43.36% (iAUC(0-120min)), respectively, compared with the placebo in the sucrose drink intake study. Similarly, there was a 41.13% (iAUC(0-60min)) and 20.26% (iAUC(0-120min)) glucose-lowering effect compared with the placebo in the carbohydrate-rich meal intake study. CONCLUSIONS: Premeal supplementation with GLUBLOC(TM) significantly reduced the postprandial surge in blood glucose and insulin levels after a carbohydrate-rich meal or sucrose drink intake over 120 min in healthy individuals. This study proves that GLUBLOC(TM) can manage steady postprandial blood glucose levels.