Flavans with potential anti-inflammatory activities from Zephyranthes candida

Three new flavans, (2R,3R)-7-methoxy-flavan-3-ol (1), (2S)-7,3'-dihydroxy-4'-methoxyflavan 3'-O-β-d-glucopyranoside (2), (2S)-7,3'-dihydroxy-4'-methoxyflavan 7-O-β-d-glucopyranoside (3), and one known flavan (4) were isolated from the whole plants of Zephyranthes candida (Amaryllidacea). The structures of the new flavans 1-3 were determined by extensive spectroscopic analyses including HRESIMS, NMR, and electronic circular dichroism (ECD), and the absolute configuration of 1 was confirmed by single-crystal X-ray diffraction analysis with Cu Kα irradiation. Flavans 1-3 displayed significant inhibitory effects on the LPS-induced NO production in RAW264.7 mouse macrophages with IC₅₀ values of 17.34, 16.14, and 21.52μM, respectively, suggesting their potentials for anti-inflammatory agents.