1.Laboratory-evolved vanillyl-alcohol oxidase produces natural vanillin.
van den Heuvel RH1, van den Berg WA, Rovida S, van Berkel WJ. J Biol Chem. 2004 Aug 6;279(32):33492-500. Epub 2004 May 28.
The flavoenzyme vanillyl-alcohol oxidase was subjected to random mutagenesis to generate mutants with enhanced reactivity to creosol (2-methoxy-4-methylphenol). The vanillyl-alcohol oxidase-mediated conversion of creosol proceeds via a two-step process in which the initially formed vanillyl alcohol (4-hydroxy-3-methoxybenzyl alcohol) is oxidized to the widely used flavor compound vanillin (4-hydroxy-3-methoxybenzaldehyde). The first step of this reaction is extremely slow due to the formation of a covalent FAD N-5-creosol adduct. After a single round of error-prone PCR, seven mutants were generated with increased reactivity to creosol. The single-point mutants I238T, F454Y, E502G, and T505S showed an up to 40-fold increase in catalytic efficiency (kcat/Km) with creosol compared with the wild-type enzyme. This enhanced reactivity was due to a lower stability of the covalent flavin-substrate adduct, thereby promoting vanillin formation. The catalytic efficiencies of the mutants were also enhanced for other ortho-substituted 4-methylphenols, but not for p-cresol (4-methylphenol).
2.Novel glycoside of vanillyl alcohol, 4-hydroxy-3-methoxybenzyl-α-D-glucopyranoside: study of enzymatic synthesis, in vitro digestion and anti
Veličković D1, Dimitrijević A, Bihelović F, Bezbradica D, Knežević-Jugović Z, Milosavić N. Bioprocess Biosyst Eng. 2012 Sep;35(7):1107-15. doi: 10.1007/s00449-012-0695-3. Epub 2012 Feb 4.
Novel glucoside of physiological active vanillyl alcohol was synthesized for the first time using maltase from Saccharomyces cerevisiae as catalyst, and established its structure as 4-hydroxy-3-methoxybenzyl-α-D: -glucopyranoside. The key reaction factors for this transglucosylation reaction were optimized using response surface methodology and the highest yield so far in maltase catalyzed transglucosylation reaction was obtained. It was found out that optimum temperature of reaction was 37 °C, optimal maltose concentration was 60% (w/v), optimal pH was 6.6, and optimal concentration of vanillyl alcohol was 158 mM. Under these conditions, yield of glucoside was 90 mM with no by product formation. It was shown that this compound posses good antioxidant activity as well as stability in gastrointestinal tract. It was demonstrated that it is hydrolyzed on brush border membrane of enterocytes, so it can serve in protecting gastrointestinal system from oxidation, as well as source of anticonvulsive drug after the hydrolysis of glucoside on brush border membrane of small intestine.
3.Novel phenolic glycosides, adenophorasides A-E, from Adenophora roots.
Koike Y1, Fukumura M, Hirai Y, Hori Y, Usui S, Atsumi T, Toriizuka K. J Nat Med. 2010 Jul;64(3):245-51. doi: 10.1007/s11418-010-0398-5. Epub 2010 Mar 16.
Five novel phenolic glycosides, adenophorasides A (1), B (2), C (3), D (4), and E (5), were isolated from commercial Adenophora roots, together with vanilloloside (6), 3,4-dimethoxybenzyl alcohol 7-O-beta-D: -glucopyranoside (7), and lobetyolin (8). The structures of the new compounds (1-5) were characterized as 4-hydroxy-3-methoxyphenylacetonitrile 4-O-beta-D: -glucopyranoside (1), 4-hydroxy-3-methoxyphenylacetonitrile 4-O-beta-D: -glucopyranosyl-(1-->6)-beta-D: -glucopyranoside (2), 4-hydroxy-3-methoxyphenylacetonitrile 4-O-alpha-L: -rhamnopyranosyl-(1-->6)-beta-D: -glucopyranoside (3), 4-hydroxyphenylacetonitrile 4-O-beta-D: -glucopyranosyl-(1-->6)-beta-D: -glucopyranoside (4), and 4-hydroxy-3-methoxybenzyl alcohol 4-O-beta-D: -glucopyranosyl-(1-->6)-beta-D: -glucopyranoside (5), respectively, by means of spectroscopic and chemical analyses.
4.Anti-inflammatory action of phenolic compounds from Gastrodia elata root.
Lee JY1, Jang YW, Kang HS, Moon H, Sim SS, Kim CJ. Arch Pharm Res. 2006 Oct;29(10):849-58.
Previous screening of the pharmacological action of Gastrodia elata (GE) root (Orchidaceae) showed that methanol (MeOH) extracts have significant anti-inflammatory properties. The anti-inflammatory agents of GE, however, remain unclear. In this experiment, MeOH extracts of GE were fractionated with organic solvents for the anti-inflammatory activity-guided separation of GE. Eight phenolic compounds from the ether (EtOEt) and ethyl acetate (EtOAc) fractions were isolated by column chromatography: 4-hydroxybenzaldehyde (I), 4-hydroxybenzyl alcohol (II), benzyl alcohol (III), bis-(4-hydroxyphenyl) methane (IV), 4(4'-hydroxybenzyloxy)benzyl methylether (V), 4-hydroxy-3-methoxybenzyl alcohol (VI), 4-hydroxy-3-methoxybenzaldehyde (VII), and 4-hydroxy-3-methoxybenzoic acid (VIII). To investigate the anti-inflammatory and anti-oxidant activity of these compounds, their effects on carrageenan-induced paw edema, arachidonic acid (AA)-induced ear edema and analgesic activity in acetic acid (HAc)-induced writhing response were carried out in vivo; cyclooxygenase (COX) activity, reactive oxygen species (ROS) generation in rat basophilic leukemia (RBL 2H3) cells and 1,1-diphenyl-2-picryl-hydroazyl (DPPH) scavenging activity were determined in vitro.