Two novel ceramides with a phytosphingolipid and a tertiary amide structure from Zephyranthes candida

Two novel ceramides, Candidamide A (1) with a phytosphingolipid structure, and Candidamide B (2) with a tertiary amide structure, together with 12 known compounds (3-14) have been isolated from the bulbs of Zephyranthes candida, The structures of 1 and 2 have been elucidated to be 1,3,5,6-tetrahydroxy-2-(2'-hydroxytetracosanoyl amino)-8-(E)-octadecadiene (1) and (2S,3S,4R,8E,2'R)-2-[N-(2'-hydroxyoctadecanoyl)-N-(1'',2''-dihydroxyethyl)-amino]-8-hexacosene-1,3,4-triol (2) on the basis of spectroscopic evidence including IR, MS, NMR ((1)H-NMR, (13)C-NMR, DEPT, (1)H-(1)H COSY, HSQC, HMBC). The known compounds were identified as (2S)-3',7-dihydroxy-4'-methoxyflavan (3), (2S)-4'-hydroxy-7-methoxyflavan (4), (2S)-4',7-dihydroxyflavan (5), 7-hydroxy-3', 4'-methylenedioxyflavan (6), ambrettolide (7), beta-sitostero1 (8), beta-daucosterin (9), rutin (10), pancratistatin (11), lycorine (12), haemanthidine (13), and haemanthamine (14). In the antimicrobial assay, candidamide A (1) and candidamide B (2) displayed moderate activities against bacteria Staphylococcus aureus and Escherichia coli, and fungi Aspergillus niger, Candida albicans and Trichophyton rubrum.