Actinidiosides A-E: Five New Iridoid Glycosides From the Gall Fruits of Actinidia polygama

By phytochemically profiling the methanolic extract of Actinidia polygama gall fruits, we isolated six iridoid glycosides, comprising five new derivatives named actinidiosides A-E (1, 3-6), and one known analogue, actinidin A (2). Their planar structures were established by comprehensive 1D/2D NMR and high-resolution mass spectrometry analyses, while stereochemical assignments were achieved through electronic circular dichroism spectroscopy, and GIAO/DP4+ NMR chemical shift calculations. The isolated compounds were screened for cytotoxicity and inhibition of NO production in RAW264.7 macrophage cells. An MTT assay demonstrated no cytotoxicity at concentrations up to 100 µM. However, none of the isolates inhibited lipopolysaccharide-induced nitric oxide production under the evaluated conditions. This work expands the secondary metabolite profile of A. polygama and provides fully characterized iridoid scaffolds for future chemical and pharmacological investigations.