Coreolanceolins A–E, new flavanones from the flowers of coreopsis lanceolate, and their antioxidant and anti‐inflammatory effects

(1) Background: Many flavonoids derived from natural sources have been reported to exhibit antioxidant and anti‐inflammatory effects. Our preliminary study suggested that Coreopsis lanceolata flowers (CLFs) include high flavonoid content; (2) Methods: CLFs were extracted in 80% (v/v) aqueous methanol and fractionated into ethyl acetate, n‐butanol, and water fractions. Repeated column chromatographies for the organic fractions led to the isolation of seven flavanones. Quantitative analysis of the flavanones was carried out using reversed‐phase high‐performance liquid chromatography. All flavanones were evaluated for their antioxidant and pro‐inflammatory inhibition effects; (3) Results: Spectroscopic analyses revealed the chemical structure of five new flavanones, coreolanceolins A−E, and two known ones. The content of the seven flavanones in extracts were determined from 0.8 ± 0.1 to 38.8 ± 0.3 mg/g. All flavanones showed radical scavenging activities (respectively 104.3 ± 1.9 to 20.5 ± 0.3 mg vitamin C equivalents (VCE)/100 mg and 1278.6 ± 26.8 to 325.6 ± 0.2 mg VCE/100 mg) in the DPPH and 2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐ sulfonic acid) (ABTS) assays and recovery activities in Caco‐2 (59.7 to 41.1%), RAW264.7 (87.8 to 56.0%), and PC‐12 (100.5 to 69.9%) cells against reactive oxygen species. Furthermore, all flavanones suppressed nitric oxide production (99.5% to 37.3%) and reduced iNOS and COX‐2 expression in lipopolysaccharide‐treated RAW 264.7 cells; (4) Conclusions: Five new and two known flavanones were isolated from CLF, and most of them showed high antioxidant and pro‐inflammatory inhibition effects.