Biotransformation of Flavonols to Flavonols-3-O-glucoside in cell cultures of astragalus sieberi DC

ABSTRACT

One distinct glucosyltransferase [GT] has been partially purified and characterized from cell cultures of Astragalus sieberi DC.; Family Leguminosae. Callus cultures were established from shoots of sterile germinated seeds maintained on solid MS medium supplemented with 4.5 microM 1-naphthylacetic acid [NAA] and 2.3 microM kinetin [KIN]. The cell suspension cultures were obtained by transport of callus cultures to liquid MS medium with the same hormone supplementation. The GT was found to exhibit maximum activity at pH 7.5 and an incubation temperature of 35°. The preferred substrate of GT was found to be kaempferol, the second best substrate was quercetin. The isolated enzymatic products were detected by TLC and HPLC and identified by spectral analysis and comparison with authentic compounds.This experiment from economic point of view provides the best conditions for large scale production of glucosides of kaempferol, quercetin and isorahmnetin