The effect of 3-month ingestion of Ginkgo biloba extract on pancreatic β-cell function in response to glucose loading in normal glucose tolerant individuals

Ginkgo biloba extract is ingested on a chronic basis for enhancing mental focus and improving cognitive function in the elderly. This study was undertaken to determine the effect of Ginkgo biloba extract on glucose-stimulated pancreatic β-cell function in normal glucose-tolerant individuals. Twenty individuals (14 females and 6 males, ages 21-57 years) underwent a 2-hour 75 g oral glucose tolerance test (OGTT) before and after ingestion of Ginkgo biloba extract (120 mg/day at bedtime) for 3 months. Ginkgo biloba extract ingestion caused a decrease in systolic blood pressure from 125 ± 15 to 118 ± 12 mmHg (p < 0.05) and in diastolic blood pressure from 86 ± 10 to 68 ± 10 (p < 0.01). Fasting plasma insulin and C-peptide were increased, and the insulin and C-peptide areas under the curve during the OGTT changed from 136 ± 55 to 162 ± 94 μU/ml/h (p = 0.1232) and 9.67 ± 5.34 to 16.88 ± 5.20 ng/ml/h (p < 0.001), respectively. The observed dissimilar insulin/C-peptide response curves may be due to Ginkgo biloba-induced increase of the rate of insulin metabolic clearance. (C) 2000 American College of Clinical Pharmacology.