Lipophilic Substances of the Roots and Rhizomes of Leuzea Safflower (Rhaponticum carthamoides (Willd.) Iljin)
T. P. KUKINA1, I. A. ELSHIN2, D. N. SHCHERBAKOV1, O. I. SALNIKOVA1
1Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Novosibirsk, Russia
Keywords: leuzea safflower, GC-MS, triterpenoids, sterols
Abstract
The qualitative composition of lipophilic secondary metabolites in the medicinal plant leuzea safflower ( Rhaponticum carthamoides (Willd.) Iljin) has been studied by gas chromatography - mass spectrometry. The roots and rhizomes of this plant species were used as the raw material. Hexane and methyl tert -butyl ether (MTBE) were used as extractants. Two extraction schemes were used (exhaustive and sequential), which allowed us to obtain more detailed information on the composition of components of the raw material. The obtained lipophilic extracts were separated into acid and neutral components by treating with NaOH and KOH solutions. The acid components were transformed into methyl ethers by treatment with diazomethane. The neutral components of the unsaponifiable residue were analysed without derivatisation. The fractions enriched with hydrocarbons, ketones, sterols, aliphatic and triterpene alcohols were obtained by chromatographic separation through a column with silica gel. A series of low-polar compounds were identified that have not been detected previously in this kind of raw material. By comparing the mass spectra obtained in the work with the available databases, the following compounds were identified: aliphatic acids with chain length 10-30 carbon atoms (including unsaturated and dicarboxylic), the compounds of cinnamic series, as well as benzoic, salicylic, sterculic, 9,10-octadecadienic and phenylpropanoic acids. More than 90 triterpene and aliphatic compounds of the unsaponifiable residue and 33 components of free and bound acids were identified. In addition to n- alkanes, the hydrocarbon fraction contains also squalene, as well as saturated and unsaturated hydrocarbons with shorter chains. Aliphatic and terpene aldehydes and ketones were detected. Highly active triterpene alcohols and ketones are represented mainly by ursane and oleanane derivatives. The major sterol component (β-sitosterol) is accompanied by cholesterol, campesterol, stigmasterol, stigmast-7-en-3-β-ol and stigmastan-3-β-ol.
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