Cytotoxic Iridoid Aldehydes from Taiwanese Viburnum luzonicum

Four new iridoid aldehydes bearing (E)- or (Z)-p-coumaroyl group, luzonial A (1), luzonial B (2), luzonidial A (3), and luzonidial B (4), were isolated from a methanol extract of the dried leaves of Viburnum luzonicum collected in Kaoshiung, Taiwan and their structures were elucidated by analysis of spectroscopic data. Compounds 1-3 exhibited moderate inhibitory activity against HeLa S3 cancer cells.