Bilobalide is a main constituent of organic chemicals called terpenoids which are found in the leaves of Ginkgo biloba, a tree which has leaves that are used in herbal medicine. Its exact synthesis pathway from farnesyl pyrophosphate is still unknown. Source : Wikipedia

It has been widely used for many years as a 'herbal remedy' in treatment of strokes and other disorders, and is now a research subject for 'conventional' medicine. Its mechanism of action, however, is currently unknown.

Evidence which has accumulated during the last few years indicates that bilobalide may have neuroprotective effects. Further studies seem warranted to determine its possible usefulness in developing therapy for disorders involving cerebral ischemia and neurodegeneration."

Source : Pharmacological Research Volume 46, Issue 6, Pages 565-568