5-Lipoxygenase and cyclooxygenase inhibitory active constituents from Qianghuo (Notopterygium incisum).

The n-hexane extract of Qianghuo (underground parts of Notopterygium incisum Ting x H.T. Chang, Umbelliferae) showed inhibitory activity in vitro in 5-lipoxygenase (5-LO) and cyclooxygenase (COS) assays. Two major constituents, phenethyl ferulate and falcarindiol, and one minor compound (-)-bornyl ferulate, were identified as the main active principles. The correlation between the content of active constituents and the inhibitory activity of the extracts was examined with seven commercial drug samples from different sources. It was obvious that the content of phenethyl ferulate was mainly responsible for the COX inhibitory activity of the extracts and falcarindiol for 5-LO inhibitory activity. Since the main active constituents phenethyl ferulate and falcarindiol can easily be quantified by HPLC, this is a suitable method for standardization and characterization of the drug.