iNOS inhibitory activity of sesquiterpenoids and a monoterpenoid from the rhizomes of Curcuma wenyujin

Eleven new sesquiterpenoids, wenyujinins A-K (1-11), and a new monoterpenoid, wenyujinin L (12), were isolated from the rhizomes of Curcuma wenyujin. Their structures and relative configurations were elucidated using 1D and 2D NMR, X-ray crystallographic analysis, and HRESIMS data. The absolute configurations of 1, 2, 3, 4, 6, 8, 9, and 10 were determined by comparison of the experimental and calculated ECD spectra. The absolute configuration of 5 was determined from the ECD data of the [Rh2(OCOCF3)4] complex, whereas those of 7 and 12 were determined from the ECD spectra of the compounds alone. Compounds 7 and 7a strongly inhibited the induction of NO production by LPS, with IC50 values of 7.6 and 8.5 μM, respectively. Compounds 6 and 10 moderately inhibited NO production with IC50 values of 47.7 and 48.6 μM, respectively.