Plant-based nutraceutical interventions against cognitive impairment and dementia: meta-analytic evidence of efficacy of a standardized Gingko biloba extract.

Among nutraceuticals and nutritional bioactive compounds, the standardized Ginkgo biloba extract EGb 761 is the most extensively clinically tested herbal-based substance for cognitive impairment, dementia, and Alzheimer's disease (AD). In the last three years, notwithstanding negative meta-analytic findings and the discouraging results of preventive trials against AD, some randomized controlled trials focusing particularly on dementia, AD, and mild cognitive impairment (MCI) subgroups with neuropsychiatric symptoms (NPS) and some recent meta-analyses have suggested a renowned role for EGb 761 for cognitive impairment and dementia. Meta-analytic findings suggested overall benefits of EGb 761 for stabilizing or slowing decline in cognition of subjects with cognitive impairment and dementia. The safety and tolerability of EGb 761 appeared to be excellent at different doses. Subgroup analyses showed that these clinical benefits of EGb 761 were mainly associated with the 240 mg/day dose, and also confirmed in the AD subgroup. More importantly, one of these meta-analyses showed clinical benefits in cognition, behavior, functional status, and global clinical change of EGb 761 at a dose of 240 mg/day in the treatment of patients with dementia, AD, and MCI with NPS. The inclusion of the recent randomized controlled trials focusing on dementia, AD, and MCI subgroups with NPS may partly explain the conflicting results of these recent meta-analyses and previous pooled findings.