Determinação quantitativa de taninos em três espécies de Stryphnodendron por cromatografia líquida de alta eficiência

Abstract

A method of separation and quantification by reverse-phase high-performance liquid chromatography (HPLC) was developed, using water (0.05% TFA):acetonitrile (0.05% TFA) as the mobile phase in a gradient system. Flavan-3-ols present in a semipurified extract from the stem bark of Stryphnodendron adstringens, Stryphnodendron polyphyllum and Stryphnodendron obovatum were analyzed. The HPLC was performed with the ethyl-acetate fraction (EAF) using a solid-phase extraction on cartridges C18-E with methanol:water (2:8), filtered through a membrane of 0.5 μm pore size; the column was Phenomenex® Gemini C-18 (5 μm) at 30 ºC, with a flow rate of 0.8 mL/min. The analysis was done at 210 nm. Gallic acid and gallocatechin solutions were used as calibration standards. The proposed method was validated by resolution RE No. 899/2003 of the National Health Surveillance Agency. Quantitative analysis of the EAF showed high contents of flavan-3-ols in the stem bark of all three species. This study demonstrated that it is possible to determine the concentration of individual substances in tannin-rich plants. The system developed can be used as a chromatographic profile for the semipurified fraction of S. adstringens, S. polyphyllum, and S. obovatum.