French maritime pine bark extract Pycnogenol dose-dependently lowers glucose in type 2 diabetic patients.
P ycnogenol, a standardized extract from the bark of the French maritime pine, consists of phenolic compounds including catechin, taxifolin, procyanidins, and phenolic acids (1). We investigated whether Pycnog-enol has a glucose-lowering effect because of personal verbal communication from patients reporting no need for insulin following supplementation with Pycnogenol. The study was designed as an open, controlled, dose-finding study and was approved by the ethical committee of Guangnamen Hospital. Patients gave written informed consent. We recruited 18 men and 12 women among outpatients of the Guangnamen Hospital and Municipal Dental Hospital. Patients were 28 – 64 years of age and had a BMI 22–34 kg/m 2. Patients with type 2 diabetes were included with fasting plasma glucose between 7 and 10 mmol/l after participation in a diet and sports program for 1 month. Exclusion criteria were type 1 diabetes, manifest or malignant hypertension and any diseases requiring continuous treatment with drugs, and pregnant or lactat-ing women. During the first and last visit, a physical examination and assessment of demographic data, medical history, body weight, height, vital signs, blood pressure , electrocardiogram, diet, and medication was carried out. Samples for fasting blood glucose, HbA 1c , insulin, and endo-thelin-1 were taken. Blood samples were taken to measure postprandial blood glucose 2 h after breakfast. Glucose was measured enzymatically, HbA 1c by high-performance liquid chromatography , and insulin and endothe-lin-1 by immunoassays. Statistical analysis was done with SPSS 16.0 software using one-factorial ANOVA with Fisher projected least significant difference test. Patients received in succession 50, 100, 200, and 300 mg Pycnogenol in intervals of 3 weeks. Every 3 weeks, fasting and postprandial glucose, endothe-lin-1, HbA 1c , and insulin were analyzed. No changes were observed in vital signs, electroencephalogram, or blood pressure over the 12-week period. Fasting blood glucose was lowered dose dependently until a dose of 200 mg Pycnogenol was administered. Increasing the dose from 200 to 300 mg did not further decrease blood glucose. Compared with baseline, 100 –300 mg lowered fasting glucose significantly from 8.64 Ϯ 0.93 to 7.54 Ϯ 1.64 mmol/l (P Ͻ 0.05). Fifty milligrams of Pycnogenol lowered postprandial glucose significantly from 12.47 Ϯ 1.06 to 11.16 Ϯ 2.11 mmol/l (P Ͻ 0.05). Maximum decrease of post-prandial glucose was observed with 200 mg to 10.07 Ϯ 2.69 mmol/l; 300 mg had no stronger effect. HbA 1c levels decreased continuously from 8.02 Ϯ 1.04 to 7.37 Ϯ 1.09%. …