Neurocognitive effects of herbal extracts

The chapter summarises the evidence pertaining to the biobehavioural effects of selected herbal extracts, concentrating on evidence from well-controlled human trials. The focus is on cognition enhancement but will include some relevant material on modulation of mood. There is good evidence that certain extracts have cognition-enhancing properties. These include extracts of Ginkgo, Ginseng, Salvia, Guaraná, Lemon balm, Bacopa and others. In the domain of mood Lemon balm has consistently been shown to have a calming effect. Evidence for other herbals is less clear although cocoa polyphenols may have anti-fatigue effects. One constant challenge for the psychopharmacology of herbal extracts is the use of standardised extracts and the use of multiple extracts in some medicinal systems. New technologies used to meet these challenges will be discussed briefly.