Short-term oral ingestion of Ginkgo biloba extract (EGb 761) reduces malondialdehyde levels in washed platelets of type 2 diabetic subjects

Abstract

We have recently reported that ingestion of Ginkgo biloba extract (EGb 761) (a) significantly reduced collagen-induced platelet aggregation and thromboxane B 2 (TXB 2) production in both non-diabetic individuals as well as those with type 2 diabetes mellitus (T2DM), (b) significantly reduced platelet malondialdehyde (MDA), an index of lipid peroxidation, in non-diabetic subjects. In the present study we report that ingestion of EGb 761 (120 mg daily for 3 months), significantly decreased platelet MDA-thiobarbituric acid reacting substances (TBARS) (41 ± 9 pmol/10 7 platelets versus 30 ± 11 pmol/10 7 platelets) ( p < 0.005) in T2DM subjects with normal cholesterol levels (total cholesterol, 164 ± 22 mg/dl; age, 54 ± 9 years; BMI, 35.0 ± 8.8 kg/m 2, n = 12). In T2DM subjects with high cholesterol (total cholesterol, 218 ± 15 mg/dl; age, 52 ± 5 years; BMI, 36.2 ± 6.6 kg/m 2, n = 7), EGb 761 ingestion reduced the platelet TBARS from 29 ± 9 to 22 ± 9 pmol/10 7 platelets ( p < 0.04). Because ingestion of EGb 761 did not alter platelet counts it is concluded that EGb 761, probably due to the flavonoid fraction, reduced the TBARS by inhibiting cyclooxygenase (COX)-1-mediated arachidonic acid oxygenation or by reducing the arachidonic acid pool. This is likely to lead to a reduction of platelet hyperactivity, a significant contributor to the development of cardiovascular disease in T2DM patients. Because of other reported beneficial properties of EGb 761, such as stimulation of pancreatic β-cell function in T2DM subjects with pancreatic exhaustion, it appears that T2DM subjects might benefit from ingesting EGb 761 as a dietary supplement.