beta-glucosyltransferase in cell cultures of Verbesina caracasana

(E)-3,4-Dimethoxycinnamic acid, inoculated in cell cultures of Verbesina caracasana, was converted to the corresponding beta-glucopyranoside ester, revealing the presence of an exoglucosyltransferase. An extensive study on other cinnamic acid derivatives showed that the aromatic ring must contain at least one methoxy substituent, but no hydroxy group, for the esterification to be performed. Moreover, the presence of the double bond was shown to have no influence. The glucosylation reaction may involve also the hydroxyl of benzyl alcohols, with the same specificity towards the substitution of the aromatic ring as shown by the cinnamic acids.