Formation and Structure Research of a Molecular Conjugate in the L-Ascorbic Acid – Isomaltite System

Abstract

The formation of L-ascorbic acid molecular complexes with various biologically active substances opens the way to the production of a new drug type promising for the pharmaceutical, food and cosmetic industries use. The research concerns the possibility study of obtaining a conjugate of L-ascorbic acid with isomaltite in an aqueous ethanol (40 %) medium. The method of the target product isolating involves thermostating a solution containing equimolar amounts (0.001 mmol) of components (50 °C, 1 hour), followed by slow solvent removal for 24 hours (25 °C). The authors examined formation processes dynamics by molecular spectroscopy methods through sequential sampling. The optical density values at 350 Nm in the electronic spectra and 1,674 and 1,754 cm−1 bands position in the IR-Fourier solution spectra indicate the components destruction absence during thermostate control. When treated with carbon tetrachloride or diethyl ether, the syrupy mass obtained after solvent removal containing significant solvent amounts crystallizes a yellowish powder (0.32 g, ice point at 146.6 °C). A man studied its structure by the IR-Fourier spectroscopy. The authors recorded the spectra in the transmission mode (in the KBr tablets) and using the diffusion reflection method enabling to record changes in the absorption bands characteristic positions of the molecular complex formation. The transmission spectra of the high-frequency area indicate the 1-O-glycosylated isomaltite component involvement in the conjugation with ascorbic acid. The shifts of the C=C, C−O and C−O−H bond oscillation bands in the diffusion reflection spectrum of the isolated product relative to their position in the initial component spectra in the low-frequency area indicate the endiol ascorbic acid fragment interaction with the secondary OH groups of the acyclic isomaltite component. Structural analogues of the studied molecular conjugate are promising antioxidant preparations. This determines the further study relevance of its properties.