(P30-026-24) A Study Protocol Investigating the Impact of the New Zealand Pine Bark Extract (Enzogenol®) on Sucrose Metabolism and Glycaemic Responses in Healthy Adults – A Randomised, Placebo-Controlled, Crossover Trial

Objectives: The New Zealand pine bark extract (Enzogenol®) has been shown to reduce postprandial glucose after an oral glucose tolerance test (OGTT) in normoglycaemic, healthy participants at concentrations of 50 and 400 mg. Further, an in vitro study demonstrated that Enzogenol® was able to inhibit digestive enzymes (alpha-amylase, alpha-glucosidase, and dipeptidyl-peptidase 4 (DPP-4)), which are responsible for carbohydrate metabolism and have potential to improve glycaemic responses in starch-based meals. This study aims to further investigate the inhibitory effects of Enzogenol® on sucrose digestion in humans and its impact on glucose and insulin responses in healthy adults.

Methods: This is a single-blind, randomised, placebo-controlled, crossover trial consisting of healthy adults (n=40), aged 18 to 60 years, BMI 18.5-29.9kg/m², with no known illnesses nor food or plant extract allergies. There are four intervention treatments: placebo (only 75 g of sucrose powder), 250 mg of Reducose® (mulberry extract known for inhibiting carbohydrate-digesting enzymes as comparison), and two doses of Enzogenol® 50 and 400 mg), with at least a week of washout period. Each intervention treatment will be well mixed with 250 mL of water containing 75 g of sucrose. After an overnight fast (12 h), a baseline blood sample will be taken via finger prick test. Participants will then be given the treatment to consume within 5 min. Further blood samples will be collected at 15, 30, 45, 60, 90, and 120 min. Blood samples will be analysed for postprandial plasma insulin and glucose. Repeated-measures analysis of variance (ANOVA, SPSS v29, IBM) will be performed with Bonferroni post-hoc test for multiple comparisons if applicable. Data are presented as mean ± SEM.

Results: The study outcomes will help elucidate the underlying mechanistic action of Enzogenol® in improving postprandial glycaemic responses in humans, and whether it is through its inhibitory effect on sucrose digestion.

Conclusions: The study will elucidate whether Enzogenol® may be a potential adjunct to the diet for regulating glycaemic responses.

Funding Sources: The study is sponsored by ENZO Nutraceuticals Limited, New Zealand.