Macathioureas A-D, four new thiourea analogues from the roots of Lepidium meyenii.

ABSTRACT

Macathioureas A-D (1-4), four new thiourea derivatives with a carbamothioylpyrrolidine-2-carboxamide framework, were isolated from the roots of Lepidium meyenii (Maca) collected from Qujing, Yunnan Province of China. Their structures were identified based on extensive spectroscopic data, including 1D NMR, 2D NMR, and HRESIMS techniques. Their absolute configurations were assigned as 7S by the comparison of the experimental and predicted electronic circular dichroism (ECD) spectra. All the thiourea analogues were tested for their cytotoxicities against five human cancer cell lines. However, no significant activities were detected at concentrations up to 40 µM.