Hydroxysesamone and 2,3-epoxysesamone from roots of Sesamum indicum.

A red naphthoquinone, named hydroxysesamone, was isolated from the roots of Sesamum indicum together with a known yellow naphthoxirene derivative, 2,3-epoxy-2,3-dihydro-5,8-dihydroxy-2-(3-methyl-2-butenyl)-1,4-naphthoquinone, named 2,3-epoxysesamone. The structure of the naphthoquinone was characterized as 2,5,8-trihydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone on the basis of spectral evidence. Full assignments of NMR resonances of 2,3-epoxysesamone were also confirmed by two-dimensional NMR spectroscopic experiments. Chlorosesamone, hydroxysesamone and 2,3-epoxysesamone all showed antifungal activities toward Cladosporium fulvum.