Biocatalytic Synthesis of Novel Partial Esters of a Bioactive Dihydroxy 4-Methylcoumarin by Rhizopus oryzae Lipase (ROL)

Abstract

Abstract:Highly regioselective acylation has been observed in 7,8-dihydroxy-4-methylcoumarin (DHMC) by the lipase from Rhizopus oryzae suspended in tetrahydrofuran (THF) at 45 • C using six different acid anhydrides as acylating agents. The acylation occurred regioselectively at one of the two hydroxy groups of the coumarin moiety resulting in the formation of 8-acyloxy-7-hydroxy-4-methylcoumarins, which are important bioactive molecules for studying biotansformations in animals, and are otherwise very difficult to obtain by only chemical steps. Six monoacylated, monohydroxy 4-methylcoumarins have been biocatalytically synthesised and identified on the basis of their spectral data and X-ray crystal analysis.

Anti-inflammatory Activities of 7,8-Dihydroxy-4-Methylcoumarin Acetylation Products via NF-κB and MAPK Pathways in LPS-Stimulated RAW 264.7 Cells

“…The results confirmed that the acetylated products were 8AMC and DAMC, which is consistent with previously published nuclear magnetic resonance (NMR) results. 31 Acylation of 7,8-Dihydroxy-4-methylcoumarin through the addition of acid anhydride resulted in the synthesis of 8-Acetoxy-7-hydroxy-4-methylcoumarin.…”

“…The results confirmed that the acetylated products were 8AMC and DAMC, which is consistent with previously published nuclear magnetic resonance (NMR) results. 31 Effects of DHMC, 8AMC, and DAMC on the Viability of RAW 264.7 Cells and Their Ability to Reduce NO Production RAW 264.7 cells stimulated with LPS were incubated with various concentrations of DHMC, 8AMC, and DAMC to determine their cytotoxicity. The results of 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays revealed that no compound was cytotoxic up to a concentration of 25 µM (Figure 1A).…”