Biotransformation of 4-Chromanone, 4-Flavanone, and their Analogs by Fungi

Abstract

We conducted the biotransformation of 4-chromanone and 4-chromanol using two kinds of fungi, Botrytis cinerea and Colletotrichum acutatum, as biocatalysts. The biotransformation of 4-chromanone using B. cinerea yielded 98.6% 4-chromanol by day 3. This chiral compound was identified as (R)-4-chromanol (76.4% yield) and its enantiomer excess was 52.8%ee. The reaction was accelerated by the addition of the coenzyme NADPH. In contrast, the same reaction using C. acutatum was initially slow but increased from days 3 to 8, as indicated by the gradual reduction in the substrate and increased production of 4-chromanol. No rapid change was observed from days 12 to 18. The reaction generated 4-chromanol at 86.0% yield after 28 days. Conversely, there was no evidence of a reverse reaction with either biocatalyst when 4-chromanol was used as the substrate. Mimicking similarly natural environmentally friendly methods would be useful for the synthetic production of natural compounds.

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

“…Evidence indicates that callus cells act as biocatalysts for oxidation reactions [19]. These reactions are surprisingly slow, with the oxidation of geranylgeraniol yielding 18% geranylgeranoic acid and geraniol yielding only 5% geranoic acid after 20 days [18]. Similarly, in the present study, it took 70 days to yield 24.8% 4-flavanone from 4-flavanol.…”

“…In contrast, we previously reported that biotransformation of acetophenone yielded 1-phenylethanol at 98% in 3 days using fungi (Botrytis cinerea or Colletotrichum acutatum) as biocatalysts [18]. Furthermore, we showed that 4flavanone was converted to 4-flavanol at 97% yield in 11 days [19].…”

“…For callus induction of C. maxima and P. neapolitanum, tissues were obtained by surface sterilization of young shoots and leaves for 10 s in 70% ethanol and 5 min in 1% sodium hydrochloride. The tissues were washed three times with sterile distilled water and transferred onto agar MS medium supplemented with 3% sucrose, 2.1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D), and 0.2 mg/mL kinetin [17,18]. After successive subculturing, the cell-suspensions were cultured in 100 mL of liquid MS medium on an orbital shaker at 70 rpm at 24 • C in the dark.…”

“…Furthermore, the Hamada group at the Okayama University of Science has investigated organic synthesis methods using tissue culture cells of higher plants as biocatalysts for reactions such as the glycosylation of terpenes [12][13][14][15][16]. We previously showed that biotransformations using mold could reduce carbonyl compounds to their alcohol form [17,18]. Conversely, cells in plant tissue cultures produced the reverse reaction; that is, the oxidation of the alcohol derivative to its carboxylic acid, such as geraniol to geranoic acid (geranic acid) [19].…”

Biotransformation of citronellal, geranial, citral and their analogs by fungus and their antimicrobial activity

“…In particular, fungi, bacteria and tissue-cultured cells have been used as biocatalysts to produce substances using green chemistry [6][7]. We recently conducted research using the mold Botrytis cinerea as a biocatalyst [8,9]. Grapes infected with B. cinerea (Gray mold fungus) are used to produce so-called precious wine [10][11][12].…”