title: DNA adducts with antioxidant flavonoids: morin, apigenin, and naringin.
abstract: Flavonoids have recently attracted a great interest as potential therapeutic drugs against a wide range of free-radical-mediated diseases. The anticancer and antiviral activities of these natural products are implicated in their mechanism of actions. While the antioxidant activity of these natural polyphenolic compounds is well known, their bindings to DNA are not fully investigated. This study was designed to examine the interactions of morin (Mor), naringin (Nar), and apigenin (Api) with calf thymus DNA in aqueous solution at physiological conditions, using constant DNA concentration (6.25 mM) and various drug/DNA(phosphate) ratios of 1/40 to 1. FTIR and UV-Vis spectroscopic methods were used to determine the ligand binding modes, the binding constant, and the stability of DNA in flavonoid-DNA complexes in aqueous solution. Spectroscopic evidence shows both intercalation and external binding of flavonoids to DNA duplex with overall binding constants of K(morin) = 5.99 x 10(3) M(-1), K(apigenin) = 7.10 x 10(4) M(-1), and K(naringin) = 3.10 x 10(3) M(-1). The affinity of ligand-DNA binding is in the order of apigenin > morin > naringin. DNA aggregation and a partial B- to A-DNA transition occurs upon morin, apigenin, and naringin complexation.
authors.affiliation: Department of Chemistry, Azad University, Central Tehran Branch (IAUCTB), Tehran, Iran. drsnafisi@yahoo.com
authors.forename: Shohreh
authors.initials: S
authors.lastname: Nafisi
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Hashemi
authors.forename: Mehdi
authors.initials: M
authors.lastname: Rajabi
authors.forename: Heidar Ali
authors.initials: HA
authors.lastname: Tajmir-Riahi
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism; D047310:Apigenin / Q000737:chemistry* / Q000378:metabolism; D001667:Binding, Competitive; D002417:Cattle; D004247:DNA / Q000737:chemistry; D018736:DNA Adducts / Q000737:chemistry* / Q000378:metabolism; D044950:Flavanones / Q000737:chemistry* / Q000378:metabolism; D005419:Flavonoids / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D017550:Spectroscopy, Fourier Transform Infrared; D047309:Flavones
chemical_list: D000975:Antioxidants; D047310:Apigenin; D004247:DNA; D018736:DNA Adducts; D044950:Flavanones; D005419:Flavonoids; C008548:morin; D047309:Flavones; C427203:calf thymus DNA; C005274:naringin