Triterpene saponins from Calendula arvensis

From the aerial parts of Calendula arvensis a new triterpene saponin arvensoside C (1) was isolated together with four known triterpene saponins. The aglycon moieties had the oleanane skeleton for all of them. Three known flavonol glycosides, isorhamnetin 3-O-β-D-glucopyranoside, quercetin 3-O-β-D-glucopyranoside and quercetin 3-O-β-D-galactopyranoside were also obtained and characterized. Their structures were elucidated by 1D and 2D NMR experiments including 1D-TOCSY, DQF-COSY, HOHAHA, HSQC and HMBC spectroscopy as well as HRESIMS analysis.