methyl-p-coumarate and methyl-caffeate

The filamentous fungus Trametes versicolor is a rich source of laccase (Tvlac). Laccases catalyze reactions that convert substituted phenol substrates into diverse derivatives through aromatic oxidation. We investigated methyl p-coumarate, methyl ferulate, and methyl caffeate biotransformation by Trametes versicolor ATCC 200801. Despite substrate similarity, the biotransformation reactions varied widely. Only methyl p-coumarate was converted into three derivatives. We isolated and identified the chemical structures of such derivatives by NMR and IR analysis. Hydroxylation, methylation, and hydrolysis were the main reactions resulting from the studied biotransformation. We also analyzed the interactions between Tvlac (PDB ID: 1GYC) and the three phenolic substrates by molecular docking simulations. The substituents in the phenol ring influenced substrate conformation and orientation in the Tvlac site. The biotransformation reaction selectivity correlated with the different binding energies to the Tvlac site. Our results demonstrated that docking studies successfully predict the biotransformation of cinnamic acid analogs by T. versicolor.

Topics: Biotransformation; Caffeic Acids; Catalysis; Cinnamates; Environmental Restoration and Remediation; Hydrolysis; Hydroxylation; Industrial Microbiology; Laccase; Magnetic Resonance Spectroscopy; Molecular Conformation; Molecular Docking Simulation; Oxygen; Phenols; Polyporaceae; Solvents; Spectrophotometry, Infrared

The study was aimed to identify cytotoxic leads from Abutilon indicum leaves for treating glioblastoma. The petroleum ether extract, methanol extract (AIM), chloroform and ethyl acetate sub-fractions (AIM-C and AIM-E, respectively) prepared from AIM were tested for cytotoxicity on U87MG human glioblastoma cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. These extracts exhibited considerable activity (IC50 values of 42.6-64.5 μg/mL). The most active AIM-C fraction was repeatedly chromatographed to yield four known compounds, methyl trans-p-coumarate (1), methyl caffeate (2), syringic acid (3) and pinellic acid (4). Cell viability assay of 1-4 against U87MG cells indicated 2 as most active (IC50 value of 8.2 μg/mL), whereas the other three compounds were much less active. Interestingly, compounds 1-4 were non-toxic towards normal human cells (HEK-293). The content of 2 in AIM-C was estimated as 3% by HPLC. Hence, presence of some more active substances besides methyl caffeate (2) in AIM-C is anticipated.

Topics: Antineoplastic Agents, Phytogenic; Caffeic Acids; Cell Line, Tumor; Chromatography, High Pressure Liquid; Cinnamates; Fatty Acids, Unsaturated; Gallic Acid; Glioblastoma; HEK293 Cells; Humans; Inhibitory Concentration 50; Malvaceae; Plant Extracts; Plant Leaves

Lactobacillus plantarum is frequently found in the fermentation of plant-derived food products, where hydroxycinnamoyl esters are abundant. L. plantarum WCFS1 cultures were unable to hydrolyze hydroxycinnamoyl esters; however, cell extracts from the strain partially hydrolyze methyl ferulate and methyl p-coumarate. In order to discover whether the protein Lp_0796 is the enzyme responsible for this hydrolytic activity, it was recombinantly overproduced and enzymatically characterized. Lp_0796 is an esterase that, among other substrates, is able to efficiently hydrolyze the four model substrates for feruloyl esterases (methyl ferulate, methyl caffeate, methyl p-coumarate, and methyl sinapinate). A screening test for the detection of the gene encoding feruloyl esterase Lp_0796 revealed that it is generally present among L. plantarum strains. The present study constitutes the description of feruloyl esterase activity in L. plantarum and provides new insights into the metabolism of hydroxycinnamic compounds in this bacterial species.

Topics: Caffeic Acids; Carboxylic Ester Hydrolases; Cinnamates; Gene Expression; Lactobacillus plantarum; Recombinant Proteins