Curcumaromins A, B, and C, Three Novel Curcuminoids from Curcuma aromatica

Three novel curcuminoids, curcumaromins A–C (1–3, resp.), along with a known compound, longiferone B (4) were isolated from Curcuma aromatica Salisb. The structures of the new compounds were elucidated as (1E,4Z,6E)-5-hydroxy-7-{4-hydroxy-3-[(1R*,6R*)-3-methyl-6-(propan-2-yl)cyclohex-2-en-1-yl)phenyl}-1-(4-hydroxyphenyl)hepta-1,4,6-trien-3-one (1), 2,3-dihydro-2-(4-hydroxyphenyl)-6-[(E)-2-(4-hydroxyphenyl)ethenyl]-5-[(1R*,6R*)-3-methyl-6-(propan-2-yl)cyclohex-2-en-1-yl]-4H-pyran-4-one (2), and (1E,6E)-1,7-bis(4-hydroxyphenyl)-4-[(1R*,6R*)-3-methyl-6-(propan-2-yl)cyclohex-2-en-1-yl]hepta-1,6-diene-3,5-dione (3) on the basis of spectroscopic analysis. Curcumaromins A–C (1–3) represented the first examples of menthane monoterpene-coupled curcuminoids. The known compound, longiferone B (4), was the first daucane sesquiterpene isolated from the genus Curcuma.