Methyl ferulate

Finally, a fourth class of alkaloids has been discovered, apparently specific to the leaves of P. Lyallii (57). It consists of two unseparable products, 37 and 38, in the ratio 2 to 1, which readily give lyaloside (23) on mild methanolysis, along with two esters, namely, methyl ferulate and methyl sinapate (39 and 40, respectively). Elucidation of their structure was essentially based on NMR considerations (57). Graphical correlations between 1H- and 13C-NMR spectra, associated with analysis of the residual constant coupling during a step by step [200 Hz per 200 Hz from 0 (TMS) to 2000 Hz] off-resonance procedure, permitted the precise assignment of all the carbon atoms of the products (58). 

Abresoline (66) was prepared recently by Quick and Ramachandra by transesterification of MB-methoxyethoxymethyl (MEM) ether of methyl ferulate with MEM derivative of quinolizidol (63a) and cleavage of protective groups with trifluoroacetic acid (103). 

Five transformants produced a major secreted protein band, with an estimated molecular weight of 40 kDa and no protein was detected in the control. The estimated molecular weight is greater than that predicted or observed from E. coli, which is likely due to post-translational modification. P6 and P10 transformants were retained to perform enzymatic assays. The culture supernatants were assays for activity against methyl caffeate (MCA) and methyl ferulate (MFA). The recombinant proteins were shown to be active as a feruloyl esterase and show the characteristics of a type B ferulic acid esterase.6 Feruloyl esterase activity is reported in Table 1. 

Neither these two compounds nor their acetyl derivatives could be separated by chromatographic procedures however, methanolysis afforded lyaloside and a separable mixture of methyl ferulate and methyl sinapate. 

Activity of the purified en2ymes was assessed on methyl ferulate (methyl 4-hydroxy 3-methoxy cinnamate, MF). Assays were run for 30 min at 50 °C in 50 mM eitrate buffer at pH 4.8 with initial MF concentrations of 50 to 750 pM and an enzyme concentration of 50 nM. The reactions were terminated after 30 min by boiling for 10 min and analyzed for MF and ferulic acid content via C18 high performance liquid chromatography (HPLC) over a 0 to 100% acetonitrile gradient with 0.1% formic acid in all solutions. Preliminary isothermal titration calorimetry (ITC) on both ferulic acid esterase proteins was conducted in SEC buffer on a Microcal VP-ITC system. All reactions were carried out at 37 °C using MF as a substrate. 

Fig. 4 Activity of the two esterases on methyl ferulate. filled circles FaeA empty circles ...

ND=not determined ND =Aw value not determined, but substrate is catalyzed - =no activity MFA=methyl ferulate Ara5F=feruloyl group on the C5 of arabinose Ara2F= feniloyl group on the C2 of arabinose ... 

The mode of fragmentation of the original propenoidic chain was further investigated using an ester of ferulic acid, e.g. E-methyl ferulate 11, as the starting material in the same reaction sequence. The oxidation was repeated at room temperature in methanol using R = 10, Pdioxygen= t = 72 h the reaction... 

The oxidation of E-methyl ferulate 11 was faster in chloroform than in methanol. In pyridine a very slow reaction was observed (Table II). 

Table L Product Yields % in the Reaction of E-Ferulic Acid 1 and E-Methyl Ferulate 11 with Co(II)salen-dioxygen. ...

Table IL Conversion vs Time in the Oxidation of E-Methyl Ferulate 11 with ...

Figure 2. The EPR Signal in the Reaction of E-Methyl ferulate 11 in Chloroform.

The second p-5 dimer studied, the trans dimer 27, was obtained from E-methyl ferulate (23). The oxidation with dioxygen (10 bar) in methanol in the... 

Occurrence in the Solanaceae. p-Coumaric acid, caffeic acid, methyl caffeate, and methyl ferulate as well as certain of their 2,3-dihydro derivatives have been identified as constituents of the leaves of Cestrum parqui L Herit. with good phytotoxic activity against different species (D Abrosca et al. 2004). Family-specific phenylpropanoid acids like tropic acid or 2-hydroxytropic acid as acyl moieties of tropane alkaloids are synthesized via phenylalanine -> phenylpyruvic acid (l )-3-phenyllactic acid (Fig. 3.14 Table 3.1 (T5-T7-B)]. Tropic acid may occur as a metabolite of, e.g., hyoscyamine, but the free acid is not synthesized as such (for details see Sect. 3.4). 

The propenoidic phenols, E-methyl ferulate (1), E-4-hydroxycinnamic acid me yl ester (4) and E-3-chloro-4-hydroxycinnamic acid methyl ester (7), can be catalytically oxidized with dioxygen in the presence of [Co(salen)] (Figure 8) . The yields depend on the solvent and the phenyl substituents. EPR and electronic spectra suggest the involvement of a coordinated o-benzosemiquinone type radical as the active intermediate. 

Isolation of methyl ferulate from rice bran oil. J. Amer. Oil Chem. Soc. 

Based on the results mentioned above, an investigation using lauryl alcohol as phenol carrier was undertaken to discover the active phenols remaining in the wood of Pseudosindora palustris. Besides methyl 77-coumarate, five phenols -methyl ferulate, butein (12) (Fig. 9.3.4), pseudosindorin, sulfuretin, and rengasin - were isolated as those responsible for the colored specks. Two cinnamates, two chalcones, and two aurones all have a common skeleton of phenyl-a,)8-unsaturat-ed-y-carbonyl or methoxycarbonyl group in the molecules (171). 

Methyl ferulate Ferulic add Esterase Lact. acidophilus... 

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