Natural phenol dimers

Amentoflavone is a biflavonoid (bis-apigenin coupled at 8 and 3 positions, or 3,8-biapigenin) constituent of a number of plants including Ginkgo biloba, Chamaecyparis obtusa (hinoki), Biophytum sensitivum, Selaginella tamariscina, Hypericum perforatum (St. John's Wort) and Xerophyta plicata.

Xylindein is a quinone pigment, a dimeric naphthoquinone derivative. It is produced by fungi in the genus Chlorociboria. This pigment causes green staining of wood infected by the fungi.