coniferyl-alcohol and cinnamyl-alcohol

The catechol alcohols, caffeyl and 5-hydroxyconiferyl alcohol, may be incorporated into lignin either naturally or through genetic manipulation. Due to the presence of o-OH groups, these compounds form benzodioxanes, a departure from the interunit connections found in lignins derived from the cinnamyl alcohols. In nature, lignins composed of caffeyl and 5-hydroxyconiferyl alcohol are linear homopolymers and, as such, may have properties that make them amenable for use in value-added products, such as lignin-based carbon fibers. In the current work, results from density functional theory calculations for the reactions of 5-hydroxyconiferyl alcohol, taking stereochemistry into account, are reported. Dehydrogenation and quinone methide formation are found to be thermodynamically favored for 5-hydroxyconiferyl alcohol, over coniferyl alcohol. The comparative energetics of the rearomatization reactions suggest that the formation of the benzodioxane linkage is under kinetic control. Ring-opening reactions of the benzodioxane groups show that the bond dissociation enthalpy of the α-O cleavage reaction is lower than that of the β-O reaction. The catechol lignins represent a novel form of the polymer that may offer new opportunities for bioproducts and genetic targets.

Topics: Lignin; Molecular Structure; Phenols; Propanols; Thermodynamics

A series of 25 selected oxyprenylated natural phenylpropanoids were synthesized, and their growth inhibitory activities were evaluated in vitro together with 14 other commercially available non-alkylated compounds belonging to the same chemical series. The compounds were tested on six human cancer cell lines using MTT colorimetric assays. The data reveal that of the six chemical groups (G) studied, coumarins (G1), cinnamic and benzoic acids (G2), chalcones (G3), acetophenones (G4), anthraquinones (G5), and cinnamaldehydes and cinnamyl alcohols (G6), G2-related compounds displayed the weakest growth inhibitory activities in vitro, whereas G5-related compounds displayed the highest activities. Quantitative videomicroscopy analyses were then carried out on human U373 glioblastoma cells, which are characterized by various levels of resistance to different pro-apoptotic stimuli. These analyses revealed that compounds 20 (4,2',4'-trihydroxychalcone), and 30 and 31 (two cinnamaldehydes) were cytostatic and able to overcome the intrinsic resistance of U373 cancer cells to pro-apoptotic stimuli.

Topics: Acetophenones; Acrolein; Anthraquinones; Antineoplastic Agents; Apoptosis; Benzoates; Biological Products; Cell Line, Tumor; Chalcones; Cinnamates; Coumarins; Drug Screening Assays, Antitumor; Humans; Prenylation; Propanols

Two methyl esters of fatty acids, namely octadecanoic acid methyl ester (methyl stearate) and hexadecanoic acid methyl ester (methyl palmitate), in addition to four cinnamyl alcohol derivatives, sinapyl alcohol, coniferyl alcohol, p-coumaryl alcohol and coniferyl alcohol 4-O-glucoside (coniferin), were isolated from callus cultures of Wedelia prostrata. The structure of coniferin was established by spectroscopic and chemical methods, while the other compounds were identified by gas chromatography-mass spectrometry and thin layer chromatography in comparison with standards.

Topics: Cell Culture Techniques; Chromatography, Thin Layer; Cinnamates; Coumaric Acids; Esters; Gas Chromatography-Mass Spectrometry; Methanol; Palmitates; Phenols; Phenylpropionates; Plant Shoots; Propanols; Propionates; Stearates; Wedelia

A cDNA encoding cinnamyl alcohol dehydrogenase (CAD), catalyzing conversion of cinnamyl aldehydes to corresponding cinnamyl alcohols, was cloned from secondary xylem of Leucaena leucocephala. The cloned cDNA was expressed in Escherichia coli BL21 (DE3) pLysS cells. Temperature and Zn(2+) ion played crucial role in expression and activity of enzyme, such that, at 18°C and at 2 mM Zn(2+) the CAD was maximally expressed as active enzyme in soluble fraction. The expressed protein was purified 14.78-folds to homogeneity on Ni-NTA agarose column with specific activity of 346 nkat/mg protein. The purified enzyme exhibited lowest Km with cinnamyl alcohol (12.2 μM) followed by coniferyl (18.1 μM) and sinapyl alcohol (23.8 μM). Enzyme exhibited high substrate inhibition with cinnamyl (beyond 20 μM) and coniferyl (beyond 100 μM) alcohols. The in silico analysis of CAD protein exhibited four characteristic consensus sequences, GHEXXGXXXXXGXXV; C(100), C(103), C(106), C(114); GXGXXG and C(47), S(49), H(69), L(95), C(163), I(300) involved in catalytic Zn(2+) binding, structural Zn(2+) binding, NADP(+) binding and substrate binding, respectively. Tertiary structure, generated using Modeller 9v5, exhibited a trilobed structure with bulged out structural Zn(2+) binding domain. The catalytic Zn(2+) binding, substrate binding and NADP(+) binding domains formed a pocket protected by two major lobes. The enzyme catalysis, sequence homology and 3-D model, all supported that the cloned CAD belongs to alcohol dehydrogenase family of plants.

Topics: Acacia; Alcohol Oxidoreductases; Amino Acid Sequence; Chromatography, Affinity; Cloning, Molecular; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Hydrogen-Ion Concentration; Kinetics; Models, Molecular; Molecular Sequence Data; Phenols; Plant Proteins; Plasmids; Propanols; Protein Structure, Tertiary; Recombinant Proteins; Substrate Specificity; Temperature; Transformation, Bacterial; Xylem

We purified two isozymes of coniferyl alcohol dehydrogenase (CADH I and II) to homogeneity from cell-free extracts of Streptomyces sp. NL15-2K. The apparent molecular masses of CADH I and II were determined to be 143 kDa and 151 kDa respectively by gel filtration, whereas their subunit molecular masses were determined to be 35,782.2 Da and 37,597.7 Da respectively by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Thus, it is probable that both isozymes are tetramers. The optimum pH and temperature for coniferyl alcohol dehydrogenase activity were pH 9.5 and 45 °C for CADH I and pH 8.5 and 40 °C for CADH II. CADH I oxidized various aromatic alcohols and allyl alcohol, and was most efficient on cinnamyl alcohol, whereas CADH II exhibited high substrate specificity for coniferyl alcohol, and showed no activity as to the other alcohols, except for cinnamyl alcohol and 3-(4-hydroxy-3-methoxyphenyl)-1-propanol. In the presence of NADH, CADH I and II reduced cinnamaldehyde and coniferyl aldehyde respectively to the corresponding alcohols.

Topics: Acrolein; Alcohol Oxidoreductases; Aldehydes; Bacterial Proteins; Cell Extracts; Chromatography, Agarose; Hydrogen-Ion Concentration; Isoenzymes; Kinetics; Molecular Weight; NAD; Phenols; Propanols; Protein Subunits; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Streptomyces; Substrate Specificity; Temperature

The thermochemolytic behavior of 4-O-etherified cinnamyl alcohols and aldehydes in lignin was investigated in the presence of tetramethylammonium hydroxide (TMAH) (315 degrees C/4 s), using veratrylglycol-beta-(coniferyl alcohol) ether (1a), veratrylglycol-beta-(sinapyl alcohol) ether (1b), and veratrylglycol-beta-(coniferyl aldehyde) ether (2). The methylated products were monitored with gas chromatography-mass spectrometry. Dimers 1a and 1b provided the coniferyl and sinapyl alcohol dimethyl ethers consisting of three isomers, respectively. Coniferyl alcohol dimethyl ether isomers were also observed in the TMAH thermochemolysis pyrolysates of a bulk dehydrogenation polymer of coniferyl alcohol and a Japanese cedar (Cryptomeria japonica) wood. Coniferyl aldehyde methyl ether was not provided from TMAH thermochemolyses of coniferyl aldehyde, 2, a dehydrogenation polymer of coniferyl aldehyde, and the cedar wood. The former three provided veratryl aldehyde in a large abundance, instead of coniferyl aldehyde methyl ether. Sinapyl aldehyde provided 3,4,5-trimethoxybenzaldehyde in a large abundance and sinapyl aldehyde methyl ether in a trace abundance. The results showed that TMAH thermochemolysis is an effective tool to obtain information on cinnamyl alcohol end groups, but is not applicable to analysis of cinnamyl aldehyde end groups.

Topics: Acrolein; Aldehydes; Dimerization; Ethers; Gas Chromatography-Mass Spectrometry; Lignin; Methylation; Phenols; Phenylpropionates; Propanols; Quaternary Ammonium Compounds; Tracheophyta; Wood