Anticancer Effect of the Iridoid Glycoside Fraction from Dipsacus fullonum L. Leaves

Species of Dipsacus have been widely used in folk medicine for their neuroprotective, antiosteoporotic, antioxidative, anticomplementary, and antibacterial activities. However, there has been but a limited amount of research on the anticancer effect of one of the most popular representatives of this genus, D. fullonum. Also, the cytotoxic activity has not yet been investigated of the constituents of D. fullonum leaves. The purpose of this study was to evaluate the cytotoxic activity of the bis-iridoid glycosides isolated from D. fullonum leaves against murine fibroblast NIH/3T3, mouse melanoma B16F10, HeLa human cervical cancer, human breast cancer MCF7 and MDB-MB-231 cells. The bis-iridoids, obtained by chromatographic fractionation of the extract of D. fullonum leaves, were characterized by thin-layer chromatography and high-performance liquid chromatography-mass spectrometry (HPLC-MS)/MS analysis. The cytotoxicity of the iridoid fraction was evaluated by WST-1 assay, and the number of dead cells was determined by the propidium iodide test. HPLC-MS/MS analysis showed the isolated bis-iridoid fraction to consist mainly of sylvestroside III and/or sylvestroside IV. This fraction was applied to cell cultures and kept for 48 and 72 hours. The results demonstrated that the iridoid glycosides had a differential ability to induce cell death in normal and cancer cells. The study confirmed that the bis-iridoids extracted from D. fullonum leaves had a selective cytotoxic effect on human breast cancer cell lines MCF7 and MDB-MD-231, while their cytotoxic effect on noncancer cells was low.