Vigna radiata as a New Source for Biotransformation of Hydroquinone to Arbutin

Background: The suspension culture of Vigna radiata was selected for biotransformation of hydroquinone to its β-D-glucoside form (arbutin) as an important therapeutic and cosmetic compound. Methods: The biotransformation efficiency of a Vigna radiata cell culture in addition to different concentrations of hydroquinone (6-20 mg/100 ml) was investigated after 24 hours in comparison to an Echinacea purpurea cell culture and attempts were made to increase the efficacy of the process by adding elicitors. Results: Arbutin was accumulated in cells and found in the media only in insignificant amounts. The arbutin content of the biomass extracts of V. radiata and E. purpurea was different, ranging from 0.78 to 1.89% and 2.00 to 3.55% of dry weight, respectively. V. radiata demonstrated a bioconversion efficiency of 55.82% after adding 8 mg/100 ml precursor, which was comparable with result of 69.53% for E. purpurea cells after adding 10 mg/100 ml hydroquinone (P>0.05). In both cultures, adding hydroquinone in two portions with a 24-hour interval increased the biotransformation efficiency. Different concentrations of methyl jasmonate (25, 50, and 100 µM) and chitosan (50 and 100 µg/ml) as elicitors increased the bio-efficiency percentage of the V. radiata culture in comparison with the flask containing only hydroquinone. Conclusion: This is the first report of the biotransformation possibility of V. radiata cultures. It was observed the bioconversion capacity increased by adding hydroquinone in two portions, which was comparable to adding an elicitor.