Nafisi Sh, Shadaloi A, Feizbakhsh A, Tajmir-Riahi H A
Department of Chemistry, Azad University, Central Tehran Branch (IAUCTB), Tehran 1467686831, Iran.
J Photochem Photobiol B. 2009 Jan 9;94(1):1-7. doi: 10.1016/j.jphotobiol.2008.08.001. Epub 2008 Aug 30.
Flavonoids are an interesting group of natural polyphenolic compounds that exhibit extensive bioactivities such as scavenging free radical, antitumor and antiproliferative effects. The anticancer and antiviral effects of these natural products are attributed to their potential biomedical applications. While flavonoids complexation with DNA is known, their bindings to RNA are not fully investigated. This study was designed to examine the interactions of three flavonoids; morin (Mor), apigenin (Api) and naringin (Nar) with yeast RNA in aqueous solution at physiological conditions, using constant RNA concentration (6.25 mM) and various pigment/RNA (phosphate) ratios of 1/120 to 1/1. FTIR, UV-visible spectroscopic methods were used to determine the ligand binding modes, the binding constant and the stability of RNA in flavonoid-RNA complexes in aqueous solution. Spectroscopic evidence showed major binding of flavonoids to RNA with overall binding constants of K(morin) = 9.150 x 10(3) M(-1), K(apigenin)=4.967 x 10(4) M(-1), and K(naringin)=1.144 x 10(4) M(-1). The affinity of flavonoid-RNA binding is in the order of apigenin>naringin>morin. No biopolymer secondary structural changes were observed upon flavonoid interaction and RNA remains in the A-family structure in these pigment complexes.
黄酮类化合物是一类有趣的天然多酚化合物，具有广泛的生物活性，如清除自由基、抗肿瘤和抗增殖作用。这些天然产物的抗癌和抗病毒作用归因于其潜在的生物医学应用。虽然黄酮类化合物与DNA的络合作用是已知的，但它们与RNA的结合尚未得到充分研究。本研究旨在研究三种黄酮类化合物：桑色素（Mor）、芹菜素（Api）和柚皮苷（Nar）在生理条件下于水溶液中与酵母RNA的相互作用，使用恒定的RNA浓度（6.25 mM）以及1/120至1/1的各种色素/RNA（磷酸盐）比率。采用傅里叶变换红外光谱（FTIR）、紫外可见光谱方法来确定配体的结合模式、结合常数以及水溶液中黄酮类化合物-RNA复合物中RNA的稳定性。光谱学证据表明，黄酮类化合物与RNA主要发生结合，其总体结合常数分别为：K（桑色素）= 9.150×10³ M⁻¹、K（芹菜素）= 4.967×10⁴ M⁻¹和K（柚皮苷）= 1.144×10⁴ M⁻¹。黄酮类化合物与RNA结合的亲和力顺序为芹菜素>柚皮苷>桑色素。黄酮类化合物与RNA相互作用后未观察到生物聚合物二级结构的变化且这些色素复合物中的RNA仍保持A族结构。
