Dyeing Property of Four turl Iridoids to Methylmine nd Protein Fiers Dhi He, Xiojun Zho, Jingsong Chen, Peng Lin, Keyi Ding* College of Chemistry & Environmentl Protection Engineering, Southwest University for tionlities, Chengdu 00, Sichun, P.R.Chin Astrct: Dyeing rections of four iridoids, genipin(gp), lognin glucon(la), oleuropein glucon(a) nd E-- -methoxycinnmoyl scndoside methyl este glycone(ea) with methylmine (MA) nd protein fiers such s hide powder, silk nd white hir, were reserched in this pper. The color chnging tendency in different dyeing period were detected y UV-vis, the color-forming mechnism were deduced. The results showed tht: () The pigmentforming rection of iridiods with MA ws considerly complicted process. Before the formtion of the finl pigment, lot of intermed ites would e formed nd ccompnied with continuous color chnging, nd different iridoids would form pigments with different color. (2) The result of comintion dyeing experiments indicted tht the clssicl color-mtching principles would e oserved when mixing the pigments formed y GP or A rected with MA respectively; however, when GP, A nd MA rected in one solution, the sitution would e different. () The results of single dyeing nd comined dyeing experiments to protein fiers showed tht the resultnt s color formed y ech iridoid ws the sme s tht formed y ech iridoid recting with MA. This result indicted tht the chemicl structure of iridoids ws the dominte fctor for the resultnt s color. The clssicl color-mtching principle would e oserved when two kinds of iridoids were pplied to dye protein fiers step y step seprtely. However, during the comintion dyeing process y two iridoids in one step, clssicl color-mtching principle ws not oserved. Key words: iridoid; methylmine; protein fiers; nturl rective dye Introduction The rection of genipin (GP), n iridoid glycone prepred from Grdeni jsminoides Ellis, with primry mines, such s mino cids, could produce edile lue pigments. This principle hs een pplied y the food industry of Est Asi, including Kore nd Jpn []. The previous reserch work lso reported tht,esides GP, three other novel iridoids could dye protein fiers to lck or yellow [2-]. These results hve suggested the possiility of iridoid compounds s potentil nturl rective dyes specil for mterils contining primry minol-group, such s lether, wool, silk, etc. More thn 00 of iridoid compounds hve een isolted from nture t present nd their contents in some plnts re firly undnt []. In the present study, four iridoid compounds, genipin (GP), lognin glucon(la), oleuropein glucon(a) nd E---methoxycinnmoyl scndoside methyl este glycone(ea), which were prepred from Grdeni jsminoides Ellis, Lonicer jponic Thun, le europre Linn nd Hedyotis diffus (Willd) Rox respectively, were pplied to rect with methylmine(ma), the simplest primry mines, nd protein fiers such s hide powder, silk nd white hir. By single dyeing rection nd comintion dyeing rection, the color chnging tendency in different dyeing period were detected vi UV-vis, the color-forming mechnism of iridoids with methylmine (MA) or protein fiers were deduced. 2 Experimentl 2. Mterils * Corresponding uthor. Emil: keyiding2000@yhoo.com.cn
The four iridoid glycones (Figure ), GP, LA, A nd EA were prepred from Grdeni jsminoides Ellis, Lonicer jponic Thun, le europre Linn nd Hedyotis diffus (Willd) Rox respectively in our lortory, their chemicl structures were identified y ESI-MS, H MR, C MR nd compring their chemicl evidence with figures from relted reference []. Bovine hide powder ws provided y the Key Lortory for Lether Chemistry & Engineering of Eduction Ministry, Sichun University. Silk nd white hir were common smples. β- glucosidse ws the product of Sim nd provided y Shnghi Bio-chemicl Co. Ltd. ther chemicls re nlyticl clss from Chengdu Chemicl gents Co. Ltd. All experiments were performed t lest twice to evlute reproduciility. H 0 9 GP H H H 2 Fig. H 9 H C 0 LA H CCH H H '' '' '' '' A '' '' 0 2'' ' ' 9 C H H ' ' ' 2' ' ' E A H H2C 0 Chemicl structures of the four iridoid d glycones 2.2 Rection of MA with iridoid glycones [] 2.2. Echiridoid glycone rects lone with MA Ech iridoid glycone ws dissolved in 0% EtH-H 2 (v/v) to otin 20mg/ml solution. ne ml of this solution ws put in ml of PBS (ph=.) nd stirred in 20 ml tue t for min, then 20 mg H 2.HCl were dded nd incresed temperture to 0 nd rected for h. UV-vis spectr of the rection solution (colornt) ws detected every 0 min. 2.2.2 UV-vis spectr of the mixture colornt from GP nd A Mix the finl colornts produced y GP nd A with MA in 2.2. t different rtios, UV-vis spectr of ech mixture ws detected. 2.2. GP nd A rected with MA in one solution Different rtios (w/w) of GP nd A were dissolved in 0% EtH-H 2 (v/v) nd keeping the totl conc. of iridoids t 20mg/ml. ne ml of these mixture solutions were put in ml of PBS (ph=.) nd stirred in 20 ml tue t for min, then 20 mg H 2.HCl were dded nd incresed temperture to 0. UV-vis spectr of the rection solutions (colornts) were detected fter h. 2. Dyeing rection of four iridoids with protein fiers 2.. Dyeing rection of ech iridoid lone with protein fiers Pretretment of smples: Silk nd white hir were soked in 0% 2 C t 0 C for 0 min, then they were wshed with common shmpoo nd rinsed with wter, dried in mient temperture. Ech protein fier (hide powder, silk nd white hir) ws first hydrted with 00% distilled wter in flsk overnight t mient temperture, filtered nd resuspended in phosphte uffered sline (PBS) t ph =.-.0. The dyeing processes were evluted using 0. g protein fier in. ml in thermostted shking th. Recting prmeters were dopted the optimized conditions in the previous work [] : The dosge for ech iridoid ws % (w/w) (sed on the dry weight of protein fier), T= C, t = h nd mintined the ph t.-.0 during the whole process. At the completion of dyeing, the resulting mixture ws filtered nd wshed with distilled wter until the effluent ws cler. The dyed protein fier ws then dried t mient temperture. 2..2 Dyeing of GP nd A to hide powder in two steps 9 C H 2
Tking hide powder s n exmple of protein fiers, dyed it with 2.%,.%,.%,.0% of GP (w/w, sed on the dry weight of hide powder) first, then dyed the light lue hide powder with 2.%,.%,.%,.0% of A. The dyeing process for ech step were s the sme s 2... 2.. Dyeing rection of GP nd A with hide powder in one step Tking hide powder s n exmple of protein fiers, dyed it with GP nd A in the sme solution. The rtios of GP/A were /, /2, /, /, /(w/w); nd kept the totl dosge of iridoids t % (w/w, sed on the dry weight of hide powder). The dyeing process were s the sme s 2... Results nd discussion. Iridoids rect with MA.. Echiridoid rects lone with MA To review the previous work y J. E. Prk et l [] nd R. Touym et l [, ], the forming mechnism of lue pigments from GP rected with MA could e summrized s tht, whether under n inert tmosphere or under n oxygen tmosphere, efore the formtion of the finl lue pigment, intermedites such s, 2,,,, would e formed, while ws colorless ut 2,,, were rownish-red. The finl lue pigment is considered to e mixture of polymers consisting on verge of 0- monomer units such s. C C H C C H H H 2C C C CH H H2C C CH 2 C CH C H 2H HC H C CH 2H H H 2C C Fig. 2 CH CH2H C 2 C C Intermedi tes during the formti on of lue pigments from GP recting with MA Besides GP, our experiments with the other three iridoids confirmed the previous work y R. Touym nd J. E. Prk et l. For exmple, during the rection of EA with MA (Figure, (d)), the chrcteristic pek of EA t 29 nm disppered within 0 min, while the sor peks in long-wve region, 29nm nd nm would pper. At 0 min, the pek t nm disppered, the pek t 29 nm ecme stronger nd new pek t 0 nm ppered. After tht, the peks t 29nm nd 0 nm incresed continuously until the finl muve pigment formed. The color nd UV-vis spectr for the other three iridoids rected with MA t different time were illustrted in Figure. Tle Colors of the pigments from iridoi ds rected with MA Iridoid GP LA A EA Color drk lue light yellow yellow muve
2.0 0 0 0 n m 2.0 0 0 2 2 n m 2 9 0 n m 0 n m 2 2 9 n m n m n m.0 0 0 0m in.0 0 0 0 m in 0m i n 0 m in 0m i n 2 2 n m 2 9 0 n m n m 0 n m () 0m i n 0 m in 0m i n ( ) 2 2 9 n m 0 n m n m ( ) () 2.0 0 0 2 2 n m 2 0 n m n m 2.0 0 0 2 9 n m 2 9 n m 0 n m n m.0 0 0 Fig. 2 2 n m 2 0 n m n m (c) 2 0 m in 0 m in 0 m in 0 m in ( c).0 0 0 2 n m n m 0 n m UV spectr for iridoids ds rected with methylmine t different time (: GP; : LA; c: A; d: EA)..2 UV-vis spectr nlysis for the mixture colornts from GP nd A rected with MA From the result showed in Tle 2, we could see tht, with the incresing dosge of yellow pigment, the mixture s color chnged from lue-green, light-green to lemon yellow. From the UV spectr for the mixture (Figure ), we could see tht, the peks t 290 nm nd 0 nm were elonged to the lue pigment of GP nd the pek t nm ws elonged to the yellow pigment of A. These results indicted tht the clssicl color-mtching principles were still oserved when mixing the pigments formed y GP nd A rected with MA respectively. The UV-vis spectrum of the mixture ws the superposition of tht of the two pigments. Tle2 of the mixture of lue pigment from GP nd yellow pigment from A o. Blue pigment(μl) yellow(μl) Color of mixtu re J- 20 20 Blue-green J-2 20 Light-green J- 20 0 Lemon-yello w (d) 20m in 0m in 0m in 0m in 20m in 0m in ( d) Fig. UV spectr for the mixture of lue pigment nd yellow pigment.. UV-vis spectr nlysis for GP nd A rect with MA in one solution Color nd UV-vis spectr of the pigments from GP nd A rected with MA in one solution were illustrted in Tle nd Figure (). With the decresing of GP/A rtio (/, /2, /), color of the pigments chnged from light yellow to yellow, nd two new chrcteristic peks t 20nm nd 0nm ppered, they were different with tht produced y GP nd A rected with MA seprtely(figure () nd (c)). These results indicted tht, new chromophores polymerized y the intermedites formed y GP nd A rected with MA, might e produced (Figure ()). During this process, clssicl color-mtching principle would not e oserved.
Tle from pigments of GP nd A recting with MA in one solution o. GP(mg) A(mg) Color L- 0.0 0.0 Light-yello w L-2.. Light-yello w L-.0.0 yellow C CH H H CH H C CH H C CH HH2C H HC CH CCH H HC HC H C CH c HC HC C CCH H H Fig. () () UV spectr nd presumed mechnism for colornt of GP nd A recting with MA in one solution.2 Dyeing rection of four iridoids with protein fiers.2. Dyeing of four iridoids with protein fiers From Tle we could see tht the color formed y ech iridoid recting with ech protein fier ws the sme s tht formed y ech iridoid recting with MA (Tle ). This result indicted tht, the chemicl structure of iridoid ws the dominte fctor for the resultnt s color, which hd no or less reltionship with se (compounds contining primry mines, such s MA or protein fiers). The presumed mechnism for the crosslinking nd polymeriztion y GP rected with hide powder ws illustrted in Figure. Tle from dyeing process of iridoids ds to protein fiers Hide powder silk White hir GP drk lue lue lue LA yellow yellow yellow A light yellow light yellow light yellow EA muve muve muve
col lgen m ol ecu le C col lgen m ol ecule C CH 2 CH 2 C H 2 C C H 2 C C H C CH 2 C H 2 Intr po l y meri zti on Inter po l y meri zti o n C Fig. Presumed mechnism for the crosslinking nd polymeriztion on y GP rected with hide powder.2.2 Comintion dyeing of GP nd A to hide powder The color formed y GP nd A rected with hide powder step y step were showed in Tle. The results indicted tht, with the decresing of GP/A rtio (/, /2, /, /), color of the dyed hide powder chnged from lue, green to lemon yellow, therefore, the clssicl color-mtching principle ws oserved. However, during the comintion dyeing process y GP nd A dyeing hide powder in one step, clssicl color-mtching principle ws not oserved (Tle ). The reson ws tht, new chromophores with different iridoid ckone coupled in the sme or different protein moleculr chin, would e formed (Figure ). This is different with the step-y-step dyeing process using ech iridoid compound respectively (Figure ). Tle of step y step dyeing y GP nd A to hide powder o. GP(%) A(%) Color W- 2. 2. lue W-2.. light lue W-.. green W-.0.0 lemon yellow Tle of hide powder dyed y GP nd A in one step o. GP(%) A(%) Color P- 2. 2. drk lue P-2.. light lue P-.. green P-.0.0 lemon yellow P- 0..2 deep yellow
co llgen molecule col lgen m olecule collgen molecu le H C H H C CH H H 2C H C H H H C CH C H C C c H C C H H Fig. Presumed mechnism for the crosslinking nd polymeriztion on y GP nd A dyeing hide powder with one step Conclusions () The pigment-forming rection of iridiods with MA ws considerly complicted process. Before the producing of the finl pigments, lot of intermedites would e formed nd ccompnied with continuous color chnging; different iridoids would form pigments with different color. The reson might e tht, chromophres with complicted moleculr structure were formed during the process, nd the side groups comined with the ckones of different iridoids were cted s uxochrome. Different uxochromes would form pigments with different colors. (2) The clssicl color-mtching principles would e oserved when mixing the pigments formed y GP nd A rected with MA respectively. The UV-vis spectrum of the mixture ws the superposition of tht of the two pigments; however, when GP, A nd MA rected in one solution, new chromophores coupled y the intermedites formed y the two iridoids rected with MA, would e produced. During this process, clssicl color-mtching principle would not e oserved. ()The resultnt s color formed y ech iridoid recting with ech protein fier ws the sme s tht formed y ech iridoid recting with MA. This result confirmed tht, the chemicl structure of iridoid ws the dominte fctor for the resultnt s color, which hd no reltionship with se (compounds contining primry mines, such s MA nd protein fiers). () During the comintion dyeing process y GP nd A to hide powder, the clssicl colormtching principle would e oserved when they were pplied step y step. However, clssicl colormtching principle ws not oserved when they were pplied to dye hide powder in one step. The Presumed mechnism might e tht, new chromophores with different iridoid ckones coupled in the sme or different protein moleculr chins, would e formed. Acknowledgements The uthors wish to thnk Dr. Xio-ling Wng for her technicl contriutions in ESI-MS, H MR nd C MR nlysis. We lso wish to thnk tionl turl Science Foundtion (Project o.202) for their finncil support. References [] J. E. Prk; J. Y. Lee; H. G. Kim; T. R. Hhn; Y. S. Prk. J. Agric. Food Chem., 2002, 0: -. [2] K. Y. Ding; M. M. Tylor; E. M. Brown. Journl of Americn Lether Chemists Assocition, 200, 0(0): 2-.
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