Synthesis of flavonoid glycosides. Part X. Synthesis and taste of flavanone and dihydrochalcone glycosides containing 3-O-.ALPHA.-L-rhamnopyranosyl-D-glucopyranose or 4-O-.ALPHA.-L-rhamnopyranosyl-D-glucopyranose in the sugar moiety.

Abstract

In order to clarify the relationships between the taste and chemical structures of naringin, neohesperidin and their dihydrochalcone (DHC) derivatives, the following glycosides were synthesized. Naringenin 7-O-(3-O-α-L-rhamnopyranosyl-β-D-glucopyranoside) (I), hesperetin 7-O-(3-O-α-L-rhamnopyranosyl-β-D-glucopyranoside) (II), naringenin 7-O-(4-O-α-L-rhamnopyranosyl- β-D-glucopyranoside) (III), hesperetin 7-O-(4-O-α-L-rhamnopyranosyl-β-D-glucopyranoside) (IV), naringenin DHC 4'-O-(3-O-α-L-rhamnopyranosyl-β-D-glucopyranoside) (V), hesperetin DHC 4'-O-(3-O-α-L-rhamnopyranosyl-β-D-glucopyranoside) (VI), naringenin DHC 4'-O-(4-O-α-L-rhamnopyranosyl-β- D-glucopyranoside) (VII), and hesperetin DHC 4'-O-(4-O-α-L-rhamnopyranosyl-β- D-glucopyranoside) (VIII). I, II, III and IV are 0.05, 0.05, 0.05 and 0.01 times as bitter as naringin whereas V, VI, VII and VIII are 0.3, 0.2, 0.2 and 0.2 times as sweet as naringin DHC. As a result, the α-(1-2) linkage in rhamnosylglucose seems to be an essential factor in eliciting the bitter and sweet taste in naringin, neohesperidin and their DHC glycosides.