Hum Psychopharmacol 2004 (Mar); 19 (2): 91–96
Nathan PJ, Tanner S, Lloyd J, Harrison B,
Curran L, Oliver C, Stough C
Brain Sciences Institute,
Extracts of Ginkgo biloba and Bacopa monniera have been shown to produce positive effects on cognitive function in healthy subjects. While the exact mechanisms are not known, it has been suggested that antioxidant properties and cholinergic modulation may play a role. In the current study the sub-chronic (2 weeks) and chronic (4 weeks) effects of an extract containing Ginkgo biloba (120 mg) and Bacopa monniera (300 mg) (Blackmores Ginkgo Brahmi) on cognitive function were examined. The study was a randomized, double-blind, placebo-controlled, independent group design in which 85 healthy subjects were allocated to one of two treatment conditions (placebo or combined Ginkgo biloba and Bacopa monniera extract). Testing was conducted at baseline and 2 and 4 weeks post treatment. The results showed that the combined extract relative to placebo did not demonstrate any significant effects on tests investigating a range of cognitive processes including attention, short-term and working memory, verbal learning, memory consolidation, executive processes, planning and problem solving, information processing speed, motor responsiveness and decision making. These findings suggest that at least within the current treatment duration and doses, an extract containing Ginkgo biloba and Bacopa monniera had no cognitive enhancing effects in healthy subjects.