Title: Alternative Sweeteners

228 Kinghorn and Compadre
Figure 18 Structure of gymnemic acid I. (GlcA d-glucuronopyranosyl; tga tiglic
acid.)
three plants are, respectively, gymnemic acid I (Fig. 18), zizyphin (Fig. 19), and
hoduloside I (Fig. 20). Nearly 20 analogs of gymnemic acid I (a group of
oleanane-type triterpene glycosides) have been reported from G. sylvestre leaves,
with most of these compounds being less potent as sweetness-inhibitory substances
than gymnemic acid I itself (65). In addition, a sweetness-inhibitory
peptide of 35 amino acids, gurmarin, has been isolated from the leaves of G. sylvestre
(24, 65, 66), and 10 additional triterpene glycoside sweetness inhibitors,
Figure 19 Structure of ziziphin. (Ara l-arabinopyranosyl; rha l-rhamnopyranosyl.)