Cytotoxicity-Guided Isolation of Two New Phenolic Derivatives from Dryopteris fragrans (L.) Schott

Dryopteris fragrans is a valuable medicinal plant resource with extensive biological activities including anti-cancer, anti-oxidation, and anti-inflammation activities. This work aims to study further the cytotoxic constituents from Dryopteris fragrans. In this work, two new phenolic derivatives known as dryofragone (1) and dryofracoumarin B (2) with six known compounds (3–8) were isolated from the petroleum ether fraction of the methanol extract of the aerial parts of Dryopteris fragrans (L.) Schott by two round cytotoxicity-guided tracking with the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and cell counting kit-8 (CCK-8) assay. Their structures were elucidated by the extensive spectroscopic analysis ((1)H-NMR, (13)C-NMR, and two dimensions NMR), chemical derivatization, and comparison with data reported in the literature. All the isolates were evaluated for their cytotoxicity against nine cancer cell lines as well as their in vitro immunomodulatory activity. The results showed that compounds have a modest cytotoxicity toward human HeLa cell line with IC(50) value below 30 μM and compounds 4 and 5 may modulate immunity to affect the growth of tumor cells.