Anti-inflammatory effect of flavonoids from Brugmansia arborea L. flowers.

Brugmansia arborea 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. B. arborea is also reported to show anti-cholinergic activity, for which many alkaloids were reported to be principally responsible. However, to the best of my knowledge, a phytochemical study of B. arborea flowers has not yet been performed. Four flavonol glycosides (1-4) and one dihydroflavanol (5) were for the first time isolated from B. arborea flowers in this study. The flavonoids showed significant antioxidant capacities, suppressed nitric oxide production in LPS-treated RAW264.7, and reduced inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) protein expression increased by LPS treatment. The contents of compounds 1-4 in n-BuOH fraction were determined to be 3.8±0.9%, 2.2±±0.5%, 20.3±1.1%, and 2.3±0.4%, and that of compound 5 in EtOAc fraction was determined to be 12.7±0.7%, respectively, by HPLC experiment. These results suggest that flavonol glycosides 1-4 and dihydroflavanone 5 can serve as index components of B. arborea flowers in standardizing anti-inflammatory materials..