Bisabolane-type sesquiterpenoids from the rhizomes of Glochidion coccineum

A novel bisabolane-type sesquiterpenoid lactone, glochicoccin A (1), and three new norbisabolane sesquiterpenoids, glochicoccins B-D (2-4), together with two known norbisabolane sesquiterpenoids, phyllaemblic acid (5) and phyllaemblic acid methyl ester (6), were isolated from the rhizomes of Glochidion coccineum. Their structures were elucidated by different spectroscopic (IR, UV, NMR) and mass-spectrometric (MS) techniques. The structure and relative configuration of I was confirmed by single-crystal X-ray diffraction (Fig. 2). None of the compounds were found to exhibit cytotoxic or antioxidant activities.