Effect of Phenols in Tobacco Pigments-protein Complex on Anti-uv Function

Anti-Ultraviolet properties and mechanism of pigments protein complex from tobacco leaves were studied. Proteins were precipitated by ammonium sulphate solution of 85% saturation or isoelectric point precipitation from tobacco leaves. The profiles of binding phenolic acids such as chlorogenic acid, rutin, scopoletin and caffeic acid were analyzed by High Performance Liquid Chromatography, the anti-UV function of pigments-protein were determined with UV spectrum after being irradiated by sunshine, and the speed of its degradation under UV was observed. The data showed that the pigments-protein precipitated at pH 4.5，pH 5.0，pH 5.3 contained higher total levels of polyphenols, and pigments-protein at pH 4.5 had the strongest anti-UV function due to the richest content of phenolic acids. Meanwhile, proteins sedimentated by ammonium sulphate solution of 85% saturation from tobacco leaves exhibited low anti-UV activity, containing low total levels of polyphenols. Polyphenols was the major anti-UV substance. Under the long time exposure under UV, pigments-protein performed high stabilility.