Rare Thioglycosides from the Roots of Wasabia japonica

Six new thioglycosides (1–6) were characterized from the roots of Wasabia japonica along with a known analogue (7). Of these compounds, 1–3 possess a disulfide bridge connecting the carbohydrate motif and the aglycone, which is extremely rare in Nature. In particular, compound 1 forms an unusual 1,4,5-oxadithiocane ring system. The structures of the isolated compounds were determined through conventional NMR and HRMS data analysis procedure, and computational methods with advanced statistics were used for the configurational assignments of 1 and two pairs of inseparable epimers, 2/3 and 4/5. All compounds were evaluated for their anti-inflammatory, neuroprotective, and cytotoxic activities, with 1 showing weak anti-inflammatory activity (IC50 41.2 μM).