Nervisides I–J: Unconventional side-chain-bearing cycloartane glycosides from nervilia concolor

Abstract

Two new cycloartane glycosides, nervisides I–J, were isolated from Nervilia concolor whole plants. Their structures were unambiguously established by interpretation of their HRESIMS and 1D and 2D NMR data. These cycloartanes comprised a stereogenic center at C-24, the R configuration of which was assigned based on DFT-NMR calculations and the subsequent DP4 probability score. These compounds were tested for cytotoxicity against K562 and MCF-7 tumor cell lines, revealing mild cytotoxic activity.