Glycosidic phenylpropanoid dimers and trimers from Castanopsis choboensis and their anti-inflammatory activities.

The first phytochemical study of Castanopsis choboensis Hickel & A. Camus (Paul Robert Hickel & Aimée Camus) leaves resulted in the isolation and structural characterization of nine previously undescribed glycosidic phenylpropanoid dimers and trimers, designated Choboensins A-I (1-9), along with nine known analogues (10-18). Comprehensive spectroscopic analysis, including HRESIMS and NMR spectroscopy, enabled full structural elucidation of these compounds. Absolute configurations were unambiguously assigned through comparison of experimental and calculated ECD spectra. Of particular structural significance, compound 8 represented the first reported glycosidic phenylpropanoid trimer featuring an unprecedented scaffold formed through the fusion of an aryltetralin-type lignan and a dihydrobenzofuran-type neolignan. Eyerin E exhibited moderate anti-inflammatory activity by inhibiting NO production (IC50 = 15.1 μM) in LPS-stimulated macrophages, highlighting its pharmacological potential.