flavokawain-b and pinostrobin

Milled Piper methysticum roots were extracted sequentially with hot water and methanol. Cyclooxygenase (COX) enzyme inhibitory assay directed purification of the methanol extract yielded bornyl esters of 3,4-methylenedioxy cinnamic acid (1) and cinnamic acid (2), pinostrobin (3), flavokawain B (4), and 5,7-dimethoxyflavanone (5). The structures of compounds 1-5 were accomplished by spectral experiments. The aqueous extract contained previously reported kava lactones, as confirmed by TLC analysis. Compounds 3 and 5 were isolated for the first time from kava kava roots. Compound 4 showed the highest COX-I inhibitory activity at 100 microg/mL. All the compounds tested gave good COX-I and moderate COX-II enzyme inhibitory activities at 100 microg/mL. This is the first report of COX-I and -II inhibitory activities for compounds 1-5.

Topics: Cinnamates; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Flavanones; Flavonoids; Hydrogen-Ion Concentration; Isoenzymes; Kava; Magnetic Resonance Spectroscopy; Mass Spectrometry; Plant Roots; Prostaglandin-Endoperoxide Synthases