Confirmation, Through Structural Modifications, of Tri-Acyl-Glyceride (TAG) Obtained by Extraction from the Seed of Joanesia princeps (Cutieira a Euphorbiaceae)

Abstract

In the present work, we report the characterization, after isolation, of a triglyceride (TAG) from seeds of Joannesia princeps vell, a Euphorbiaceae, through extraction in a soxhlet apparatus, using hexane as an extracting solvent. The proposed structure of TAG was determined by spectrometric analyses: high-resolution GC/MS; I.V.; R.M.N. 1H and 13C. Spectra of RMN ( 1 H; 13 C; H x H COSY e DEPT-45) indicate that all signals observed in the spectra belong to a single compound, a TAG containing two identical units and one different. A structure is proposed that, through hydrolysis in methanol/sodium methoxide, leads to two units of methyl linoleate ester and one of methyl oleate ester. Therefore, a molecular weight of 880g.mol-1 and formula C57H100O6 can be proposed. Confirmation of the structure is also done by comparing the proposed structure with another TAG described in the literature. Reaction of the mixture produced by basic hydrolysis with dimethyl-disulfide (CH3-S-S-CH3) confirms the positions of the unsaturations of the oleic and linoleic units; in addition to demonstrating the obtaining of a product originating from a thermal mechanism, under mass spectroscopy analysis. Therefore, in general, this TAG with a mild and slightly yellowish aroma is a mix of omega-9 and omega-6; which corresponds to approximately 40% of the seed mass, in addition to being probably one of the main responsible for physiological activities described in the literature. Another predominant TAG with a molecular mass of 878g.mol -1 , was detected by high-resolution mass spectroscopy, after a period of seed storage in a desiccator.