29700-22-9Relevant articles and documents
Regioselective Biomimetic Synthesis of Dimeric Oxyresveratrol Derivatives
Ran, Lu,Li, Hongpeng,Chao, Ge,Kang, Xiaodong,Lei, Tian,Li, Wenling
, p. 1809 - 1812 (2020/09/18)
Oxyresveratrol and its methylated derivative as coupling precursors were efficiently prepared in four steps, with Wittig reactions and subsequent isomerization reactions as the key steps. The coupling reactions of oxyresveratrol under various oxidative conditions gave a complex and inseparable mixture of coupling products. The oxidative dimerizations of methylated oxyresveratrols catalyzed by horseradish peroxidase-H 2O 2or FeCl 3·6H 2O in an acetone system predominantly produced the 8-5-coupled and 8-10-coupled dihydrobenzofuran-type dimers, respectively. This regioselective biomimetic strategy might be useful in synthesizing other dimeric oxyresveratrol derivatives.
Selective synthesis of the resveratrol analogue 4,4′-dihydroxy-: Trans -stilbene and stilbenoids modification by fungal peroxygenases
Aranda, Carmen,Ullrich, René,Kiebist, Jan,Scheibner, Katrin,Del Río, José C.,Hofrichter, Martin,Martínez, Angel T.,Gutiérrez, Ana
, p. 2394 - 2401 (2018/05/23)
This work gives first evidence that the unspecific peroxygenases (UPOs) from the basidiomycetes Agrocybe aegerita (AaeUPO), Coprinopsis cinerea (rCciUPO) and Marasmius rotula (MroUPO) are able to catalyze the regioselective hydroxylation of trans-stilbene to 4,4′-dihydroxy-trans-stilbene (DHS), a resveratrol (RSV) analogue whose preventive effects on cancer invasion and metastasis have very recently been shown. Nearly complete transformation of substrate (yielding DHS) was achieved with the three enzymes tested, using H2O2 as the only co-substrate, with AaeUPO showing exceptionally higher total turnover number (200000) than MroUPO (26000) and rCciUPO (1400). Kinetic studies demonstrated that AaeUPO was the most efficient enzyme catalyzing stilbene dihydroxylation with catalytic efficiencies (kcat/Km) one and two orders of magnitude higher than those of MroUPO and rCciUPO, so that 4-hydroxystilbene appears to be the best UPO substrate reported to date. In contrast, the peroxygenase from the ascomycete Chaetomium globosum (CglUPO) failed to hydroxylate trans-stilbene at the aromatic ring and instead produced the trans-epoxide in the alkenyl moiety. In addition, stilbenoids such as pinosylvin (Pin) and RSV were tested as substrates for the enzymatic synthesis of RSV from Pin and oxyresveratrol (oxyRSV) from both RSV and Pin. Overall, lower conversion rates and regioselectivities compared with trans-stilbene were accomplished by three of the UPOs, and no conversion was observed with CglUPO. The highest amount of RSV (63% of products) and oxyRSV (78%) were again attained with AaeUPO. True peroxygenase activity was demonstrated by incorporation of 18O from H218O2 into the stilbene hydroxylation products. Differences in the number of phenylalanine residues at the heme access channels seems related to differences in aromatic hydroxylation activity, since they would facilitate substrate positioning by aromatic-aromatic interactions. The only ascomycete UPO tested (that of C. globosum) turned out to have the most differing active site (distal side of heme cavity) and reactivity with stilbenes resulting in ethenyl epoxidation instead of aromatic hydroxylation. The above oxyfunctionalizations by fungal UPOs represent a novel and simple alternative to chemical synthesis for the production of DHS, RSV and oxyRSV.
Φ-order spectrophotokinetic characterisation and quantification of trans-cis oxyresveratrol reactivity, photodegradation and actinometry
Maafi, Mounir,Al-Qarni, Mohammed Ahmed
, p. 64 - 71 (2017/07/11)
A new Φ-order kinetic method was proposed in this study for the investigation of trans-cis photoisomerization reaction of Oxyresveratrol (ORVT) subjected to non-isosbestic irradiation. In ethanolic media, it has been proven that forward (ΦA?→?Bλirr) and reverse (ΦB?→?Aλirr) reaction quantum yields were dependent on the monochromatic irradiation wavelength according to sigmoid patterns over the spectral ranges of their electronic absorption (260–360?nm). An 11.4- and 6.6-fold increases were recorded for ΦB?→?Aλirr and ΦA?→?Bλirr, respectively. The efficiencies of the former (ΦB?→?Aλirr, ranging between 2.3?×?10??2 and 26.3?×?10??2) were 33 to 60% smaller than those of the respective ΦA?→?Bλirr measured at the irradiation wavelengths selected. Overall, between 57 and 97% degradation of the initial trans-ORVT was observed under relatively weak light intensities, with the highest values recorded at the longest wavelengths. These findings strongly recommend protection from light in all situations of this biologically important phytomolecule that possesses therapeutic value of interest to pharmaceutical applications. The Φ-order kinetics also offered a simple way to develop a reliable actinometric method that proved ORVT to be an efficient actinometer for the dynamic range 295–360?nm. The usefulness of Φ-order kinetics for the investigation and quantification of phytoproducts’ photodegradation was discussed.
