Biotransformation of 4-Chromanol, 4-Flavanol, Xanthydrol, and their Analogs by Tissue Cultured Cells

Abstract

We conducted the biotransformation of 4-chromanol, 4-flavanol and xanthydrol using Italian parsley ( Petroselinum neapolitanum) callus or soybean ( Glycine max) callus as biocatalysts. The biotransformation of 4-chromanol using P. neapolitanum yielded 4-chromanone at 5% on day 3, 12% on day 5, 23% on day 8, 21% on day 11, 25% on day 14, 22% on day 17, and a final yield of 22% on day 20. Although the reaction appeared to level off between days 8 and 20, we verified that the oxidation reaction continued to progress, albeit very gradually, until day 20. Furthermore, biotransformation of 4-flavanol using G. max callus yielded flavanone at 24.8% after 70 days. Moreover, biotransformation of xanthydrol using G. max yielded xanthone at 19.8% on day 1, 72.8% on day 2, 93.1% on day 4, and 96.3% on day 6. Addition of NADP accelerated the reaction, suggesting that an oxidoreductase may be involved. In contrast, there were no observable reverse reactions for 4-chromanone, 4-flavanone, or xanthone using the respective biocatalysts. Therefore, callus cells can be used as biocatalysts for the oxidation of alcohols to ketones. Organic synthetic reactions mimic environmentally-friendly reactions using biocatalysts found in nature.