Antioxidant Activity and Isolation of Luteoline from Centaurea behen L. Grown in Iran

Flavonoids are secondary metabolites providing Ultraviolet-visible (UV) spectroscopy protection and color in almost all terrestrial plants and fruits. They have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. As their biological activities have an impact on human health, they serve as target molecules in the development of new drugs. The objective of this research was to study the antioxidant activity and chemical analysis of the luteoline from Centaurea behen L. (Compositae family). The aerial parts of powdered and dried C. behen were extracted with methanol (MeOH) in a Soxhlet apparatus over a period of 2 days. The concentrated total extract was extracted with petroleum ether, diethylether, and methanol. From the methanol extract of the aerial parts of C. behen, the flavonoid derivative (luteoline) was identified. The aerial parts’ extract demonstrated effective antioxidant activity measured in terms of half-maximal inhibitory concentration (IC50). The product extract has been isolated by UV, column chromatography (CC), and preparative high-performance liquid chromatography (HPLC). The structures involved were elucidated by 1H and 13C nuclear magnetic resonance (NMR) and heteronuclear multiple-bond correlation (HMBC) spectra. The compound identified had not been reported in previous studies of C. behen L