Safflopentsides A-C (1-3), three highly oxidized rearranged derivatives of quinochalcone C-glycosides, were isolated from the safflower yellow pigments. Their structures were determined based on a detailed spectroscopic analysis (UV, IR, HR-ESI-MS, 1D and 2D NMR), and the absolute configurations were confirmed by the comparison of experimental ECD spectra with calculated ECD spectra. Compounds 1-3 have an unprecedented cyclopentenone or cyclobutenolide ring A containing C-glucosyl group, respectively. The plausible biosynthetic pathways of compounds have been presented. At 10 μM, 2 showed strong inhibitory activity against rat cerebral cortical neurons damage induced by glutamate and oxygen sugar deprivation.
Keywords: Carthamus tinctorius; Compositae; Neuroprotective activity; Safflopentside A; Safflopentside B; Safflopentside C.
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