Essential oil of the malagasy grass Elionurus tristis Hack. contains several undescribed sesquiterpenoids

Abstract

Essential oils (EOs) obtained from aerial parts and roots of Elionurus tristis were investigated by GC, GC-MS, pc-GC and NMR. Both aerial parts and roots EOs contained common molecules such as α-pinene, camphene, trans-α-bergamotene and calarene. Moreover, we identified several unusual sesquiterpenes and four undescribed compounds, 7-epi-khusian-2-ol, 4,8-di-epi-acorone, 2-epi-ziza-5-en-2-ol and antsorenone. The last one exhibits an undescribed natural sesquiterpene skeleton. All undescribed compounds were isolated and fully characterized by MS, 1D and 2D-NMR. Furthermore, the formation pathway of the Antsorane skeleton is discussed.

Keywords: 2-epi-Ziza-5-en-2-ol; 4,8-di-epi-Acorone; 7-epi-Khusian-2-ol; Antsorane skeleton; Antsorenone; Elionurus tristis Hack.; NMR; Poaceae; pc-GC.