Absolute stereostructures of betavulgarosides III and IV, inhibitors of glucose absorption, from the roots of Beta vulgaris L. (sugar beet)

Abstract

The absolute stereostructures of betavulgarosides III and IV, which were isolated from the roots of Beta vulgaris L. (sugar beet) and exhibited inhibitory activity on glucose absorption, were determined by the chemical correlation of betavulgaroside IV with a known saponin momordin I, which included the conversion from the α-L-arabinopyranosyl moiety of momordin I to the acidic acetal-type substituent of betavulgarosides III and IV via the α-L-ribopyranosyl derivative. Furthermore, four acidic acetal-type substituent analogues were synthesized from L- and D-arabinose.