Bioassay-guided isolation of cyclooxygenase-2 inhibitory and antioxidant phenylpropanoid derivatives from the roots of Dendropanax dentiger

The root of Dendropanax dentiger (Harms) Merr. is a traditional Chinese medicine that has been used to treat inflammation-related diseases with little scientific validation. In this study, a bioassay-guided phytochemical investigation of D. dentiger led to the isolation of 19 phenylpropanoid derivatives including one new compound (1) and 18 known ones (2-19). Their structures were elucidated by NMR and HRMS as well as comparison with literature data. The ability of cyclooxygenase-2 (COX-2) inhibition and antioxidant of all isolated compounds were measured in vitro. Chlorogenic acid derivatives (14-19) exhibited outstanding COX-2 inhibitory (IC₅₀ = 5.1-93.4 μM) and antioxidant (IC₅₀ = 13.2-31.9 μM) activities. Moreover, the tight structure-activities relationships were proposed. This is the first report on the COX-2 inhibitory activity of phenylpropanoids and D. dentiger.

Keywords: Antioxidant activity; COX-2 inhibitory activity; Chlorogenic acid derivatives; Dendropanax dentiger; Phenylpropanoids.