High‐Yield Formation of Arbutin from Hydroquinone by Cell‐Suspension Cultures of Rauwolfia serpentina

Abstract

High-density cell-suspension cultures of Rauwolfia serpentina cultivated in a nutrition medium optimized for the production of the glucoalkaloid raucaffricine synthesize hydroquinone glycosides from continuously added hydroquinone with a total yield of23.87 g/1(18 g/l of arbutin and 5.87 g/l o f a hydroquinone diglycoside) in 7 days. This arbutin production is by far the highest formation of a natural product by plant-cell-culture systems reported to date.Introduction. -Plant cell-suspension cultures are an excellent tool for the investigation of the biosynthesis of natural products at the enzymatic level. Our recent studies with cultures of Rauwolfia serpentina (L.) BENTH, resulted in the isolation and identification of 33 different monoterpenoid indole alkaloids and 15 novel enzymes involved in their biosynthesis. These enzymes are highly substrate-specific proteins, including those catalyzing rather simple reactions, e.g. the glucosylation of the alkaloid vomilenine [ 13.To search this culture system for enzymes exhibiting more broad substrate acceptance, we conducted cell-free experiments and in vivo feeding experiments with various compounds. Feeding of e.g. the indole alkaloid ajmaline to cultivated Rauwolfia cells led to the detection of six novel alkaloids, named the raumacline group [2].In this paper, we describe, however, the high-yield in vivo biotransformation of hydroquinone (HQ)') into its p-D-glucoside (arbutin) and a hydroquinone diglycoside by the same culture system (Scheme).

Arbutin production in Ruta graveolens L. and Hypericum perforatum L. in vitro cultures

“…Therefore, biotechnological solutions that would utilize plant in vitro cultures are searched for. Cells from in vitro cultures of numerous plant species, representing different taxa that do not naturally accumulate arbutin, e.g., Apocynaceae and Solanaceae species, are capable of performing hydroquinone b-D-glucosylation (Suzuki et al 1987;Lutterbach and Stöckigt 1992;Yokoyama and Inomata 1998;Dusková et al 1999Dusková et al , 2005Skrzypczak-Pietraszek et al 2005;Ekiert and Czygan 2007;Kittipongpatana et al 2007a, b).…”

High cell density cultivation of Escherichia coli with surface anchored transglucosidase for use as whole-cell biocatalyst for α-arbutin synthesis

“…-Arbutin is produced by the glucosylation of hydroquinone in the presence of puriWed enzymes [13,18] or by whole microbial [14] or plant cell biocatalysis [9,15,27]. The use of highly puriWed enzymes in the production process will ultimately result in very expensive -arbutin, and whole cells usage results in lower productivities due to mass transfer limitations imposed by the cellular membrane.…”

Physiological, Biochemical and Modern Biotechnological Approach to Improvement of Rauwolfia serpentina

“…Expression of enzymatically active cloned strictosidine synthesis from R. serpentina in Escherichia coli was reported by Kutchan in 1989. Biotransformation of ajmaline in plant cell culture and new indole alkaloids raumacline and N (β) -methyl raumaclin were reported [42] reflecting high yield formation of arbutin from Hydroquinone by cell suspension culture. The quality and quantity of auxins supplemented to the culture of leaf explants affected the type of regeneration as well as secondary metabolite production, as has been reported in several other organ cultures [43].The low reserpine content of the in vitro regenerated roots found in this work may be attributed to two factors.…”