Department of Chemistry, Islamic Azad University-Central Tehran Branch, Tehran, Iran.
DNA Cell Biol. 2012 Jan;31(1):114-21. doi: 10.1089/dna.2011.1287. Epub 2011 Nov 10.
Glycyrrhizin (GL), a molecule of glycyrrhetinic acid (GA), is an aqueous extract from licorice root. These compounds are well known for their anti-inflammatory, hepatocarcinogenesis, antiviral, and interferon-inducing activities. This study is the first attempt to investigate the binding of GL and GA with DNA. The effect of ligand complexation on DNA aggregation and condensation was investigated in aqueous solution at physiological conditions, using constant DNA concentration (6.25 mM) and various ligands/polynucleotide (phosphate) ratios of 1/240, 1/120, 1/80, 1/40, 1/20, 1/10, 1/5, 1/2, and 1/1. Fourier transform infrared and ultraviolet (UV)-visible spectroscopic methods were used to determine the ligand binding modes, the binding constants, and the stability of ligand-DNA complexes in aqueous solution. Spectroscopic evidence showed that GL and GA bind DNA via major and minor grooves as well as the backbone phosphate group with overall binding constants of K(GL-DNA)=5.7×10(3) M(-1), K(GA-DNA)=5.1×10(3) M(-1). The affinity of ligand-DNA binding is in the order of GL>GA. DNA remained in the B-family structure, whereas biopolymer aggregation occurred at high triterpenoid concentrations.
甘草酸（GL）是甘草次酸（GA）的分子，是从甘草根中提取的水溶性提取物。这些化合物以其抗炎、肝癌发生、抗病毒和干扰素诱导活性而闻名。本研究首次尝试研究 GL 和 GA 与 DNA 的结合。在生理条件下，使用恒定的 DNA 浓度（6.25 mM）和各种配体/多核苷酸（磷酸）比为 1/240、1/120、1/80、1/40、1/20、1/10、1/5、1/2 和 1/1，在水溶液中研究了配体络合对 DNA 聚集和缩合的影响。傅里叶变换红外和紫外（UV）可见光谱法用于确定配体结合模式、结合常数以及配体-DNA 配合物在水溶液中的稳定性。光谱证据表明，GL 和 GA 通过主要和次要沟以及骨架磷酸基团与 DNA 结合，总体结合常数为 K(GL-DNA)=5.7×10(3) M(-1)，K(GA-DNA)=5.1×10(3) M(-1)。配体-DNA 结合的亲和力顺序为 GL>GA。DNA 仍保持 B 型结构，而在高三萜浓度下生物聚合物发生聚集。
