Machaerinic acid 3-O-β-D-glucuronopyranoside from Calendula officinalis.

Machaerinic acid 3-O-β-D-glucuronopyranoside (1), along with ten known compounds (2-11) were isolated from the methanol extract of Calendula officinalis L. aerial parts. Their structures were confirmed by 1D and 2D NMR analysis and HRESIMS. Compound 1 was evaluated for the anti-proliferative activity against 95D and HT29 cancer cell lines and showed no cytotoxicity at the concentration of 100 µM.