Isolation and Characterization of a Novel p-Coumaric Acid Ester of myo-Inositol from Needles of Taxus baccata

Abstract

A novel derivative of myo-inositol was isolated from the needles of Taxus baccata and identified as p-coumaric acid ester. By means of its levorotatory optical activity and formation of a borate complex, the compound was designated tentatively as a 1L-4-p-coumaroyl-myo-inosi-tol. Chemotaxonomic investigations have shown this ester to be present in needles of 14 out of 34 tested species of gymnosperms. When 14C02 or 14C-myo-inositol were fed to young needles of T. baccata, there was a rapid incorporation of label in the p-coumaroyl ester, and a pulse-chase experiment indicated a substantial turnover of this compound over a 4-month period. Myo-inositol is a carbohydrate which occurs in all biological systems, since phosphatidylinositol is an essential component of membrane structure. A number of other myo-inositol derivatives such as phosphates, glycosides, methyl ethers, and esters of organic acids also occur in plants (2, 3, 8, 9). The dominant group of ester derivatives is the indoleacetic acid esters, found so far only in seeds, where they might constitute a storage form of IAA during germination and early stages of plant development (2). Besides these IAA derivatives, only one acetic acid ester of myo-inositol was described to occur in Campanula (9). During our investigation of myo-inositol metabolism in gymnosperms and in Taxus baccata in particular, we detected a novel derivative of myo-inositol, namely an ester of p-coumaric acid. Our purpose in this paper is to describe the isolation of this compound , the elucidation of its structure, and its tentative role in metabolism. MATERIALS AND METHODS Plant Material. All plants used in this investigation were obtained from the Botanical Garden Munich. Isolation of pCI.' Needles of T. baccata were freeze-dried, ground to a fine powder, and extracted with ethylacetate to remove resins and other lipophilic compounds, and then extracted with hot methanol until all carbohydrates and phenolic compounds were eluted. The extract was concentrated at 50 C under vacuum and the resulting brown syrup (100 ml) was subjected to column chromatography in five batches on micro-crystalline cellulose with acetone-water (9:1, v/v) as eluting solvent. Samples of the fractions were dried on filter paper and examined for a compound, whose pale blue fluorescence in UV light of 350 nm reversibly changed to a bright blue color after exposure to ammonia vapors. The cellulose column chromatography was repeated three times to improve separation; the com

Neolignans and Caffeoyl Derivatives from Selaginella moellendorffii

“…However, only a few inositol hydroxycinnamates were reported. As far as known, myo-inositol trans-and cis-p-coumarates were isolated from two Taxus plants [21] [22] and several myo-insitol ferulate derivatives were synthesized [23]. Compounds 10 and 11 represent the first examples of inositol caffeate derivatives.…”