Preparation, interaction with DNA of the Tannin-Glutamate-Me derivatives

Abstract

Tannic acid, which can be found in natural sources, contains multiple catechol and pyrogallol groups that have strong biological and pharmacological activities. A series of Tannin-Glutamate-Me derivatives (T-G-Ms) with many active groups, such as carboxyl, metal ion, and phenolic hydroxyl, have been prepared from tannic acid, l-glutamic acid, and metal (Me=Mg2+, Cu2+, Zn2+, Mn2+), respectively. The derivatives were characterized via FTIR, UV–Vis, XRD, and TG-DTG analyses. The interactions between T-G-Ms and DNA were studied via ultraviolet spectroscopy, fluorescence spectroscopy, viscosity, and thermal denaturation (Tm). The expected structure T-G-Ms was successfully synthesized. The interaction mode between T-G-Ms and DNA was a partial insertion. The best binding ratios of T-G-Ms and DNA for n(TG−Mg/n(DNA), n(T-G-Cu)/n(DNA), n(T-G-Zn)/n(DNA), and n(T-G-Mn)/n(DNA) were 5.92, 4.55, 11.11, and 6.25, respectively. With increasing DNA concentration, the absorption of ultraviolet spectroscopy from the T-G-Ms-DNA gradually decreased, showing a color reduction effect and a slight red shift. The absorption intensity of fluorescence spectroscopy from the T-G-Ms-DNA gradually increased, and the viscosity gradually decreased. The DNA stability and Tm were enhanced. A novel utilization of tannins was provided.