Four new iridoid glycoside derivatives (1-4), along with ten known iridoid glycosides (5-14), were isolated from Callicarpa nudiflora Hook et Arn. The structure of the new iridoid glycosides was elucidated as 5″-methoxy-ampicoside (1), 6″-O-trans-caffeoylcatalpol (2), 6″-O-trans-feruloylcatalpol (3) and 3″-methoxy-agnucastoside C (4) on the basis of spectroscopic analysis. Compounds 1-11 were reported from this plant for the first time. The cytotoxic activity of the isolated compounds against human cervical carcinoma Hela cells and ovarian carcinoma HeyA8 cells was evaluated using the microculture tetrazolium assay. Compounds 4, 5, 8, 12 and 13 showed cytotoxic activity against the Hela cell line with IC50 values of 25.3, 48.1, 17.3, 38.3 and 28.2 μM, respectively. While only compound 8 showed cytotoxicity against the HeyA8 cell line, with an IC50 of 35.5 μM.
Keywords: Callicarpa nudiflora; cytotoxic activity; iridoid glycosides.