Chemical constituents of Narcissus tazetta var. chinensis and their antioxidant activities

Abstract Two new flavan derivatives tazettones C-D ( 1 – 2 ), one new β-coumaranone (tazettone E, 3 ), one new flavan (tazettone F, 4 ), and one new phenylpropanoid (tazettone G, 5 ), together with six known flavonoids ( 6 – 11 ), were isolated from the bulbs of Narcissus tazetta var. chinensis Roem. Their structures were elucidated by spectroscopic analysis. In addition, the structures of 1 – 3 were confirmed by single crystal X-ray diffraction. All isolated compounds were tested for antioxidant activity by Cell Counting Kit-8 (CCK-8) assay. Compounds 6 – 8 and 10 – 11 exhibited potent antioxidant activity against H 2 O 2 -induced impairment in human SH-SY5Y neuroblastoma cells at tested concentrations.