The effects of acute doses of standardized Ginkgo biloba extract on memoryand psychomotor performance in volunteers

This study investigated the effects of acute doses of Ginkgo biloba extract (GBE) on memory and psychomotor performance in a randomized, double-blind and placebo controlled 5-way cross-over design. Thirty-one volunteers aged 30-59 years received GEE 150 mg (50 mg t.d.s), GEE 300 mg (100 mg t.d.s.), GEE 120 mg mane and GEE WO mg mane and placebo for 2 days. Following baseli ne measures, the medication was administered at 0900 h for the single doses and at 0900, 1500 and 2100 h for the multiple doses. The psychometric test battery was administered pre-dose (0830 h) and then at frequent intervals until 11h post dose. The results confirm that the effects of GEE extract on aspects of cognition in asymptomatic volunteers are more pronounced for memory, particularly wo rking memory. They also show that these effects may be dose dependent thoug h not in a linear dose related manner, and that GEE 120 mg produces the mos t evident effects of the doses examined. Additionally, the results suggest that the cognitive enhancing effects of GEE are more likely to be apparent in individuals aged 50-59 years. Copyright (C) 1999 John Wiley & Sons, Ltd.