Synthesis and Immunostimulatory Activity of Xanthone C‑β-Glucosides

Xanthone C-glycosides are widely distributed
in
various plants and exhibit a broad spectrum of biological activities.
However, existing synthetic strategies have been restricted to general
applicability to structurally diverse xanthone C-glycosides.
To address this limitation, we developed a versatile synthetic method
based on nucleophilic addition of brominated xanthene to a glycosyl
lactone to construct the C–C glycosidic bond. Using this strategy,
four novel xanthone C-β-glucosides
(20a–d) were synthesized. Xanthone
4-C-β-glucoside 20a exhibited
preliminary immunostimulatory activity by promoting dendritic cell
maturation and activation. This strategy enables preparation of a
variety of xanthone C-β-glucosides, facilitating
structural diversification and subsequent biological evaluation.