Four new phenolic compounds from Curculigo crassifolia (Hypoxidaceae)

Four new phenolic compounds, named crassifogenin A (1), crassifogenin B (2), crassifoside A (3), and crassifoside B (4), were isolated from the EtOH extract of the rhizomes of Curculigo crassifolia, and based on the chemical transformation and modern spectroscopic experiments, including 2D-NMR techniques (HMQC, HMBC, COSY, HMQC-TOCSY, and NOE), their structures were elucidated as 2,5-bis(3,4-dihydroxyphenyl)furan-3-carbaldehyde (1), (3,4-dihydroxyphenyl)(3,6,7-trihydroxynaphthalen-1-yl)methanone (2), (3,4-dihydroxyphenyl)[3-(beta-D-glucopyranosyloxy)-6,7-dihydroxynaphthalen-1-yl]methanone (3), and 1,2-O-[2(3,4-dihydroxyphenyl)-1-[3-(3,4-dihydroxyphenyl)prop-2-ynyl]ethane-1,2-diyl]-beta-D-glucopyranose (4).