Anti-Inflammatory Effect of Flavonoids from L. Flowers.

L. (Solanaceae), commonly known as "angel's trumpet," is widely grown in North America, Africa, Australia, and Asia. It has been mainly used for ornamental purposes as well as analgesic, anti-rheumatic, vulnerary, decongestant, and anti-spasmodic materials. is also reported to show anti-cholinergic activity, for which many alkaloids were reported to be principally responsible. However, to the best of our knowledge, a phytochemical study of flowers has not yet been performed. Four flavonol glycosides () and one dihydroflavanol () were for the first time isolated from flowers in this study. The flavonoids showed significant antioxidant capacities, suppressed nitric oxide production in lipopolysaccharide (LPS)-treated RAW 264.7 cells, and reduced inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) protein production increased by LPS treatment. The contents of compounds in -BuOH fraction were determined to be 3.8 ± 0.9%, 2.2 ± 0.5%, 20.3 ± 1.1%, and 2.3 ± 0.4%, respectively, and that of compound 5 in EtOAc fraction was determined to be 12.7 ± 0.7%, by HPLC experiment. These results suggest that flavonol glycosides () and dihydroflavanol () can serve as index components of flowers in standardizing anti-inflammatory materials.