Substituted dineolignans from Magnolia garrettii.

In the course of a study on lignan profiles of tropical and subtropical members of the Magnoliaceae, Magnolia garrettii, an evergreen tree known from northern Thailand, Vietnam, and southern Yunnan (China), was investigated. The work resulted in the isolation of two dimeric lignans from the dichloromethane extract of the leaves of M. garrettii, garrettilignan A (1) and garrettilignan B (2), each substituted with two additional p-allylphenolic moieties. Garrettilignans A (1) and B (2) represent new skeletal types within the neolignan class. Additionally, four known neolignans, magnolol, honokiol, 4'-methylhonokiol, and obovatol, were identified.