Classification of Ginkgo biloba extract

Dicyclohexyl lignans
Ginkgo Biloba Extract is a kind of lignans with two epoxy structures formed by the connection of two phenylpropanoid side chains. The natural bicyclo lignans have CIS linked double parallel tetrahydrofuran rings.
Forsythin and Capsicum Oleoresin in Forsythia suspensa are bicyclo lignans.
Biphenylcyclooctene lignans
The lignans in Schisandra chinensis belong to this kind of lignans, which are composed of biphenyl and side chain. [Bitter Melon Extract type]
Neolignans
In this kind of lignans, the two phenylpropanoids are usually connected by benzene ring and side chain or by oxygen bond. The Gardenia Yellow atoms of the side chain are mostly non oxidized.