Six Pairs of Diarylheptanoid Enantiomers from the Rhizomes of Curcuma kwangsiensis

The genus Curcuma (Zingiberaceae) has about 70 species widely distributed throughout the world, many of which are used in different traditional medicines for various purposes. In China, the rhizomes of Curcuma kwangsiensis S.G.Lee et C.F.Ling used as a traditional Chinese and Japanese medicine to treat stomach trouble and „Oketsu“ [1]. In our continuous search for bioactive compounds from C. kwangsiensis, we isolated six pairs of diarylheptanoid enantiomers, namely, (3S)- and (3R)-1,7-bis(4-hydroxyphenyl)-(6E)-6-hepten-3-ol (1a and 1b), (3S)- and (3R)-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-(6E)-6-hepten-3-ol (2a and 2b), (3S)- and (3R)-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl) heptan-3-ol (3a and 3b), (3R)-1-(3,4-dihydroxyphenyl)-7-phenyl-(6E)-6-hepten-3-ol (4a and 4b), (3S)- and (3R)-3-acetoxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-(6E)-6-heptene (5a and 5b), and (3S)- and (3R)-3-acetoxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl) heptane (6a and 6b). The structures of the isolated compounds were elucidated using different spectroscopic techniques (1D and 2D NMR, IR and UV) and HRESIMS, meanwhile, the absolute configuration of them was determined using the modified Mosher's method. The enantioseparation of six pairs of enantiomeric mixtures was achieved on the Chiralpak AD-RH column. The inhibitory effect of the isolated compounds on NO production in LPS-activated macrophages were evaluated [2].

Acknowledgements: The research was supported by the Program for Liaoning Excellent Talents in University (LR201037).

References: [1] Sasaki Y, et al. (2003) Biol Pharm Bull, 26: 1135–1143. [2] Li J, et al. (2010)J Nat Prod, 73: 1667–1671.