Purification and structure analysis of mammosphere-forming inhibitors derived from Cynanchum auriculatum

Abstract

Many studies have supported the existence of cancer stem cells (CSCs) as a subpopulation of cancer cells. CSCs are drug-resistant and radiation-resistant cancer cells to be responsible for tumor progress, maintenance and recurrence of cancer, and metastasis. The breast CSCs inhibitor that inhibits cancer stem cell derived from MCF-7 cells was isolated from the root parts of C. auriculatum. The ethyl acetate fraction obtained from methanol extracts exhibited the outstanding inhibitory effect on mammospohere formation. From the ethyl acetate fraction, a new compound named DH was purified through Silica gel column chromatography, ODS open column chromatography, Sephadex LH-20 column chromatography, and preparative thin-layer chromatography. DH-1 and DH-2 were purified using reversed-phase high performance liquid chromatography. Compound DH-1 and DH-2 are steroidal glycoside called kidjoranin-3-O-β-D-cymaropyranoside and Caudatin-3-O-β-D-cymaropyranoside. We purified CSCs inhibitor from C. auriculatum. Thus, the isolated compounds exhibited a strong anti-CSCs activity, which may contribute to the interpretation of the pre-pharmacological and clinical effects of C. auriculatum.