title: Production of Two Novel Methoxy-Isoflavones from Biotransformation of 8-Hydroxydaidzein by Recombinant Escherichia coli Expressing O-Methyltransferase SpOMT2884 from Streptomyces peucetius.
abstract: Biotransformation of 8-hydroxydaidzein by recombinant Escherichia coli expressing O-methyltransferase (OMT) SpOMT2884 from Streptomyces peucetius was investigated. Two metabolites were isolated and identified as 7,4'-dihydroxy-8-methoxy-isoflavone (1) and 8,4'-dihydroxy-7-methoxy-isoflavone (2), based on mass, 1H-nuclear magnetic resonance (NMR) and 13C-NMR spectrophotometric analysis. The maximum production yields of compound (1) and (2) in a 5-L fermenter were 9.3 mg/L and 6.0 mg/L, respectively. The two methoxy-isoflavones showed dose-dependent inhibitory effects on melanogenesis in cultured B16 melanoma cells under non-toxic conditions. Among the effects, compound (1) decreased melanogenesis to 63.5% of the control at 25 μM. This is the first report on the 8-O-methylation activity of OMT toward isoflavones. In addition, the present study also first identified compound (1) with potent melanogenesis inhibitory activity.
authors.affiliation: Department of Biotechnology, Chia Nan University of Pharmacy &amp; Science, No. 60, Sec. 1, Erh-Jen Rd., Jen-Te District, Tainan 71710, Taiwan. cmchiang@mail.cnu.edu.tw.
authors.forename: Chien-Min
authors.initials: CM
authors.lastname: Chiang
authors.affiliation: Department of Cosmetics Science, Chia Nan University of Pharmacy &amp; Science, No. 60, Sec. 1, Erh-Jen Rd., Jen-Te District, Tainan 71710, Taiwan. hsiou221@yahoo.com.tw.
authors.forename: Hsiou-Yu
authors.initials: HY
authors.lastname: Ding
authors.affiliation: Department of Biological Sciences and Technology, National University of Tainan, No. 33, Sec. 2, Shu-Lin St., Tainan 70005, Taiwan. s10056024@gm2.nutn.edu.tw.
authors.forename: Ya-Ting
authors.initials: YT
authors.lastname: Tsai
authors.affiliation: Department of Biological Sciences and Technology, National University of Tainan, No. 33, Sec. 2, Shu-Lin St., Tainan 70005, Taiwan. mozyme2001@gmail.com.
authors.forename: Te-Sheng
authors.initials: TS
authors.lastname: Chang
mesh_terms: D000818:Animals; D001711:Biotransformation; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005285:Fermentation; D015870:Gene Expression; D007529:Isoflavones / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D008546:Melanoma, Experimental; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics*
chemical_list: C498104:8-hydroxydaidzein; D007529:Isoflavones; D008780:Methyltransferases
keywords: 7,4′-dihydroxy-8-methoxy-isoflavone; 8,4′-dihydroxy-7-methoxy-isoflavone; 8-hydroxydaidzein; O-methyltransferase; SpOMT2884; inhibition; melanogenesis