Isolation and characterization of isomeric tibetin spiroethers from the roots of (Kitam.) Kitam.

The roots of (Kitam.) Kitam. (syn. (Kitam.) K.Bremer & Humphries) were collected from high altitude area of Munsyari, district Pithoragarh (Uttarakhand, India) yielded essential oil by steam distillation method and the oil was analysed by TLC and GC-MS. The GC-MS analysis of the essential oil sample showed the dominance of two constituents visible in sesquiterpene range. These constituents were isolated by column chromatography. The structures of these compounds were determined on the basis of H-NMR,C NMR, COSY, 135-DEPT, and HRMS (ESI-TOF) spectral data. The two major compounds were identified as isomeric C-Tibetin spiroethers, namely ()-2-(2',4'-heptadiyn-1'-ylidene)-1,6-dioxaspiro[4.4]non-3-ene and ()-2-(2',4'-heptadiyn-1'-ylidene)-1,6-dioxaspiro[4.4]non-3-ene.