Oxyphyllones A and B, novel sesquiterpenes with an unusual 4,5-secoeudesmane skeleton from Alpinia oxyphylla

Two novel 4,5-secoeudesmane sesquiterpenoids, oxyphyllones A (1) and B (2) were isolated from the fruits of Alpinia oxyphylla. Their structures were established by spectroscopic methods including 1D and 2D NMR spectra. These two compounds are the first example of naturally occurring sesquiterpenoids with a 4,5-secoeudesmane skeleton in the family of Zingiberaceae and oxyphyllone A (1) is the first 4,5-secoeudesmane type of 13-norsesquiterpenoid. Compounds 1 and 2 exhibited no cytotoxicities against three cancer cell lines at 10 μg/mL.