Ju Kumanotani

Urushi (oriental lacquer) — a natural aesthetic durable and future-promising coating☆

Abstract What is oriental lacquer? This article attempts an answer to this question from the viewpoint of materials chemistry and coatings technology of the lacquer in Japan and also describes a strategy for developing oriental lacquers in harmony with the natural environment.

Resolution of the enantiomers of aldoses by liquid chromatography of diastereoisomeric 1-(N-acetyl-α-methylbenzylamino)-1-deoxyalditol acetates

Abstract Acyclic diastereoisomers, namely, 1-( N -acetyl-α-methylbenzylamino)-1-deoxyalditol acetates are readily obtained by reductive amination of aldoses with chiral α-methylbenzylamine (MBA) in the presence of sodium cyanoborohydride, and may be separated by reversed-phase 1.c. and, more effectively, by adsorption 1.c. According to this procedure, enantiomers of the common, neutral aldoses are resolved. In adsorption 1.c., l-l * [defined as an adduct of an l -aldose and l -(-)-MBA] is eluted before d-l * for erythrose, xylose, ribose, glucose, 4- O -methylglucose, galactose, and fucose, and the elution order is the reverse for arabinose, lyxose, mannose, rhamnose, and glyceraldehyde. This behavior is probably related to the configuration of C-2 of the aldoses.

Reversed-phase liquid chromatographic separation and identification of constituents of uroshiol in the sap of the lac tree, Rhus vernicifera

Abstract Uroshiol in the sap of lac tree, Rhus vernicifera , is directyly into more than ten components by reversed-phase liquid chromatography using acetonitrile—water—acetic acid (80:20:2 of 90:10:2) as the eluent. The 1 H NMR parameters, especially those for the triolefinic components, are presented. New substances, 3-(10′ Z , 13′ E , 15′ Z -heptadecatrienyl)catechol and 4-(8′ Z , 11′ E , 13′ z -pentadecatrienyl)catechol, were found, although they were contaminated with 3-(10′ Z , 13′ Z , 16′-heptadecatrienyl)catechol and 4-(8′ Z , 11′ Z 14′-pentadecatrienyl)catechol, respectively. The quantitation by this separation system with refractive index dection nearly coincides with the weight content of each component. Samples from two different sources, Hupei and Kiangsi in China, were analysed by this method.

Enzyme catalyzed durable and authentic oriental lacquer: a natural microgel-printable coating by polysaccharide–glycoprotein–phenolic lipid complexes

Abstract The chemistry and technology of oriental lacquer, proof of long-term durability by a laboratory test, and morphological features of the closely packed shell (polysaccharides–glycoproteins)–core (polymerized urushiol) microgel particles, which are chiefly responsible for degradation due to efflorescence outdoors, are described. The dimerization mechanism of urushiol was demonstrated by separation of over 20 urushiol dimer derivatives. Physiological dimerization of urushiol in the lacquer is very much influenced by the humidity in drying, and the interaction of semiquinone radicals with metal ions, hydrophilic polysaccharides and amphipathic glycoproteins contained in the lacquer. A mechanism for renewable oriental lacquer is proposed, involving harmony of technology and nature within the lacquer tree plantations in south-east Asia. A brief review of studies of lacquer chemistry and synthetic coatings is given.

Configuration of the olefinic bonds in the heteroolefinic side-chains of japanese lacquer urushiol: separation and identification of components of dimethylurushiol by means of reductive ozonolysis and high- performance liquid chromatography

Abstract The configuration of the olefinic bonds in the heteroolefinic side-chains of japanese lacquer urushiol components has been determined. Dimethylurushiol is resolved into ten components by combined high-performance liquid chromatography (HPLC) with Unisil QC18 and Hitachi 3043Ag gel columns due to the difference in the degree of unsaturation and the cis and trans configuration. Each resolved di- or triolefinic dimethylurushiol component was partially rreduced with hydrazine, and the monoelfinci side-chain dimethylurushiol formed was separated by HPLC on a Unisil QC18 gel column and submitted to reductive ozozolysis, followed by derivatization of the resulting aldeydes into the 2,4-dinitrophenylhydrazones. The hydrazones were identified by HPLC using a Hewlett-Packard 1084B chromatograph with a Deveosil ODS-3 gel column.

Structural studies of plant gum from sap of the lac tree, Rhus vernicifera

Abstract The plant gum isolated from sap of the lac tree, Rhus vernicifera (China), was separated into two fractions having mol. wt. 84,000 and 27,700 by aqueous-phase gel-permeation chromatography. The fractions contain d -galactose (65 mol%), 4- O -methyl- d -glucuronic acid (24 mol%), d -glucuronic acid (3 mol%), l -arabinose (4 mol%), and l -rhamnose (3 mol%). Smith degradation of the carboxyl-reduced polysaccharides gives products of halved molecular weight, and these consist of a β-(1→3)-linked galactopyranan main chain and side chains made up of galactopyranose residues. Peripheral groups, such as α- d -Gal p -, α- d -Gal p -(1→6)-β- d -Gal p -, 4- O -methyl-β- d -Glc p A-, and 4- O -methyl-β- d -Glc p A-(1→6)-β- d -Gal p -, are attached to this interior core through β-(1→3)- or β-(1→6)-linkages.

Separation of Japanese lac urushiol diacetate on silver nitrate-coated silica gel columns by high-performance liquid chromatography

Abstract Urushiol diacetate, derived from urushiol, a major component of the sap of Japanese lac trees (Rhus vernicifera), was separated into 14–16 peaks by high-performance liquid chromatography on 10% silver nitrate-coated LiChrosorb Si-60 and LiChroprep Si-60 columns (15 cm × 4 mm I.D. and 60 cm × 2.2 cm I.D., respectively) using benzene-chloroform (4:1) as eluent. Peaks were identified from UV and mass spectroscopic data, indicating that the separation of urushiol diacetate was due to the difference in the degree of unsaturation of the side-chain. Hexanol-1 was used for slurry packing the column.

Long chain phenols from the Burmese lac tree, Melanorrhoea usitate

Abstract Twenty eight constituents of the sap of the Burmese lac tree, Melanorrhoea usitate have been identified. The sap consists of homologues of thitsiol ( ca 20 %), laccol ( ca 10 %), urushiol (4 %), 3-substituted catechols with 12-phenyldodecyl ( ca 30 %), or 10-phenyldecyl groups ( ca 8 %), 4-substituted catechols ( ca 3 %), and 5-substituted resorcinols ( ca 1 %), with the same substituents. 3-Substituted phenols with characteristic side chain groups are also contained in smaller amount. The biosynthetic route of these secondary plant metabolites, especially of novel phenolic lipids with (ω-phenylalkyl side chains, is discussed.

Separation of urushiol by high-performance liquid chromatography on an 8% octadecylsilane chemically bonded silica gel column with electrochemical detection : Analysis of urushiol in the sap of lac trees (Rhus vernicifera) and that in the japanese lac-making process

Abstract Urushiol, a major component of a sap of lac trees ( Rhus vernicifera ), is resolved into four components due to differences in the degree of unsaturation by high-performance liquid chromatography on Hitachi 3053 gel (an 8% octadecylsilane chemically bonded silica gel), using 1% lithium perchlorate in acetonitrile-water (7:3) as eluent and electrochemical detection. This method was applied to the analysis of the urushiol components of two samples of sap and in the lac-making process.

3-(ω-Phenylalkyl)catechols: novel phenolic lipids found in sap of the Burmese lac tree, Melanorrhoea usitate

Novel phenolic lipids, 3-(12-phenyldodecyl)catechol (1) and 3-(10-phenyldecyl)catechol (2) have been isolated from sap of the Burmese lac tree, Melanorrhoea usitate.