In our search for a good natural yellow dye, Reseda luteola L fresh extract of the flower, stem and leaves was found to have good colorant quality. As the dyed cotton, silk and wool fabrics as well as yarn showed very good wash and light fastness properties, exploration of dyeing potential of this wonderful dye extract under different pretreatment conditions, mordanting- pre and post with metal mordants, biomordant, enzymes and surfactants were carried out. Our study with Reseda extract showed the following results- bright yellow color with alum, olive green with copper sulphate and dark brown with ferrous sulphate. Sodium salt of Dodecyl benzene-sulphonic acid (SDBS) and Cetyl trimethyl ammonium bromide (CTAB) as pretreatment have also been used. Combination of other natural dye extracts with Reseda extract has been attempted. A wide spectrum of colors has been obtained ranging from canary yellow to olive green to orange.

Keywords: reseda dye, mordants, biomordants, surfactants, combination of natural dyes

Yellow dyes have always been used from ancient times and have been a color of marking festivity. Most of the yellow dyes are flavonoids which are not stable to UV radiation. The dyed fabric shows very poor wash and light fastnesses. In our quest for a stable yellow dye we started exploring all the possible sources of yellow natural dyes ranging from Curcuma rhizome, Eucalyptus barck Super Critical Fluid Extract (SCFE), Gaillardia flower, Thevetia peruviana flower, Tegetus flower, Punica granatum fruit epicarp, Cassia fistula flower, Cosmos sulphuerus flower, Carthamus flower and Reseda luteola flower, stem and leaves extracts. Since a lot of work had already been done for the identification of colorant in Reseda extract, some very pertinent questions arose to understand the mode of attachment of this colorant molecule on the fabric for stable dye adherence and unusual good fastness properties. Owing to its good thermal stability, the colorant can be extracted easily with water at alkaline pH or even with methanol: water mixtures.

A method was applied to evaluate the influence of soil fertility on the production of flavonoids in Reseda dye. The results showed that dye capacity is dependent on soil fertility and the origin of seeds. HPLC-diode array detector (DAD) methodology was developed to allow the simultaneous identification and quantification of Reseda luteola L. (weld) dye flavonoids, luteolin, apigenin, luteolin 7-O-glucoside, apigenin 7-O-glucoside, luteolin 3',7-O-diglucoside and luteolin 4'-O-glucoside¹ as shown in Figure 1. The method was developed by Gaspar et al, for the simultaneous identification of Reseda luteola L. (weld) flavonoids and quantification of the main compounds responsible for the yellow color. This method was applied to a large number of wild Portuguese welds to evaluate its potential application as dyestuff for textile factories, as a substitute for the synthetic dyes currently used. All these molecules had good chelation with metals due to presence of oxo and hydroxyl groups. The complex stoichiometry ratio of aluminium and luteolin was found to be 1:2.²

Figure 1 Reseda luteola L. (weld) dye flavonoids, luteolin, apigenin, luteolin 7-O-glucoside.

The most appropriate leaching solvent for luteolin from leaves, stems and flowers of Reseda luteola was found to be methanol optimal luteolin extraction was 8.6g/kg of plant material. Preliminary dyeing tests on pre-mordanted raw cotton and wool standard specimens gave greenish-yellow hue, acid perspiration fastness was found to be resistant to fading of dyed wool specimens was generally greater than that of cotton dyed samples.³

The structural difference in the various yellow flower extracts gives further insight into the uniqueness of Reseda extract. Curcuma rhizome has main colorant as Curcumin with some Rutin flavonoid⁴ as shown in Figure 2.

Figure 2 Curcuma rhizome has main colorant as Curcumin with some Rutin flavonoid.

Gaillardia flower extract consists of Sesqiterpene lactones, aglycones and glycosilated flavonoids, dihydroxy flavonol and 6-methoxyethers⁵ as shown in Figure 3.

Figure 3 Gaillardia flower extract consists of glycosilated flavonoids, dihydroxy flavonol.

Thevetia peruviana flowers have main flavonoids as quercetin, Kaempferol and quercetin-7-O-galactoside⁶ as shown in Figure 4.

Figure 4 Thevetia peruviana flowers have main flavonoids as quercetin, Kaempferol and quercetin-7-O-galactoside.

Cosmos sulphureus flower extract consisted of as Fustin and quercetin^7,8 as shown in Figure 5.

Figure 5 Cosmos sulphureus flower extract consisted of as Fustin and quercetin.

Tegetus flower consists of Patuletin and Patulitrin flavonoids as their main constituents⁹ as shown in Figure 6.

Figure 6 Tegetus flower consists of Patuletin and Patulitrin flavonoids.

Punica granatum consist of Myricetin, quercetin, Luteolin and Kaempferol in the epicarp of its fruit¹⁰ as shown in Figure 7.

Figure 7 Punica granatum consist of Myricetin, quercetin, Luteolin and Kaempferol.

Cassia fistula yellow flower has Kaempferol, Catechin and proanthocyanidins as the main flavonoids¹¹ as shown in Figure 8.

Figure 8 Cassia fistula yellow flower has Kaempferol, Catechin and proanthocyanidins.

Carthamus tinctorius is also another plant with flavonoids such as acacetin, luteolin, quercetin, and their glucuronide, cinaroside, 5-O-methylluteolin and rutin¹² as shown in Figure 9.

Figure 9 Carthamus tinctorius is also another plant with flavonoids such as acacetin, luteolin, quercetin, and their glucuronide, cinaroside, 5-O-methylluteolin.

The Supers Critical fluid extract of Eucalyptus Bark also is rich in flavonoids such as Eriodictyol, naringenin and isorhamentin^13,14 as shown in Figure 10.

Figure 10 Eucalyptus Bark is rich in flavonoids such as Eriodictyol, naringenin and isorhamentin.

It well known that flavonol based molecules- quercetin and kaempferol are found to be more prone to light induced fading than flavones based luteolin and apigenin.¹⁵ Infact the latter ones darken with time.

The preferred binding site depends on the flavonoids, metal and the pH. Even the binding sites differ for flavonol and flavones with Al⁺³ at different pH. At alkaline pH flavonols have strongest affinity with Al⁺³ through their ortho dihydroxy group while flavones show binding through site 4 and 5 of A and C rings or the catechol sites in ring B^16,17 and shown in Figure 11.

Figure 11 Ortho dihydroxy group while flavones show binding through site 4 and 5 of A and C rings or the catechol sites in ring B.

Most of the yellow dye plants contain colorant molecule from the group of hydroxyl flavones, however the combination of components may differ from plant to plant and species to species.¹⁸ Some plausible explanation can be given to the fact that the Table 1 shows such vast difference in wash, light fastnesses, solubility and dyeability of the natural extracts (Figure 12) (Figure 13). It is very apparent that among 10 different sources, Reseda excels in all the three parameters (Tables 2) (Table 3) (Figure 14).

Figure 12 Reseda extract with different mordants.

Figure 13 Reseda plant.

Figure 14 Reseda extract combination with different natural dyes.

UV-Visible analysis of reseda dye and other yellow dye yielding plants: The UV- Vis spectra of most of the flavonoids show two main absorption bands such as a) the benzoyl band at 240-280 nm range and b) the cinnamoyl band at 320-385 nm range.¹⁵

Figure 15 Reseda dye shows two very prominent peaks in the UV region at 287nm (1.84OD), 312 nm (1.83 OD) and a peak at 394-401nm (1.07OD).

Reagents: all reagents should be of analytical purity: Methanol, Reseda dye and other natural yellow extracts

Apparatus and equipment: Ultra Violet -Visible spectrophotometer machine, Quartz sample tube (cuvette) having 1.00 cm light path.

Sample preparation: The Reseda dye was weighed separately (0.1gm) in 1000 ml methanol and scanned through UV-Visible spectrometer. For visible spectrum this solution is used and for UV spectrum the solution is further diluted by 5 times. Identification of the dye by this method is through the ultraviolet (UV) region scanning from 200 to 400 nm, and the visible portion is from 400 to 800 nm (Table 4) (Figures 15−21).

Figure 16 Cosmos dye shows three prominent peaks in the UV Vis region at 326 nm (1.090 OD), 366 nm (1.029 OD) and 396 nm (0.801 OD).

Figure 17 Punica dye shows three prominent peaks in the UV Vis region at 227 nm (1.401 OD), 306 nm (1.488 OD) and 364 nm (0.566OD).

Figure 18 Tegetus.

Figure 19 Curcuma.

Figure 20 Eucalyptus bark Supercritical extract.

Figure 21 Cosmos.

Different yellow flowers and natural reseda dye by HPLC method

Reagents: All reagents should be of analytical purity: Methanol, De-ionised water, Ethyl acetate (HPLC grade)

Apparatus and equipment: HPLC Machine (Waters), Ultra Violet-Visible Detector (Waters 2998), C-18 reverse phase column (RPC -C18), Binary pump system, Micro syringe

Sample preparation: All the different types of yellow flowers were extracted in methanol, while Reseda dye sample was weighed separately (0.1gm) in 1000 ml of methanol and then the sample is diluted to 100 times, 1μL of this diluted prepared solution was injected to the C-18 reverse phase column and eluted through column. The base line showed response within a run of 15 mins for natural Reseda dye. The parameters of this assay were made to be such that a clean peak of the both the samples are observed from the chromatograph.

Method used

The experimental conditions are as following: Column C18, 150×4.6 mm; flow rate: 1.0 ml/min; detection wavelengths 255 nm (band width 16 nm), Solvent System: Methanol: Deionised water (97: 03) in method-I and EtOAc: MeOH (10:90) in method -II has been used, Pump Pressure: 15 MPa, Machine Brand: Waters. Clear observation was made from the analysis of Reseda dye by two different methods as mentioned below:

Method-I

Commercial reseda powder: Solvent System: 97:03 MeOH: H₂O, Run Time: 12 min, Sample prepared in MeOH, Chromatogram taken on 366nm (Figures 22−27).

Figure 22 Commercial reseda powder.

Figure 23 Reseda stamen.

Figure 24 Reseda flower.

Figure 25 Reseda powder: Chromatogram taken on 268 nm.

Figure 26 Reseda stamen: chromatogram taken on 268nm.

Figure 27 Reseda flower: chromatogram taken on 268nm.

Cosmos flower: Solvent System: 97:03 MeOH: H₂O, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken on 255nm (Figures 28) (Figure 29).

Figure 28 Cosmos flower: chromatogram taken on 255nm.

Figure 29 Cosmos flower: chromatogram taken on 280nm.

Punica granatum: Solvent System: 97:03 MeOH: DW, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 255nm (Figures 30−35).

Figure 30 Punica granatum: chromatogram taken at 255nm.

Figure 31 Thevetia (kaner flower): chromatogram taken at 255nm.

Figure 32 Gaillardia flower: chromatogram taken at 255nm.

Figure 33 Gaillardia flower: chromatogram taken on 280nm.

Figure 34 Cassia fistula (Amaltas flower): chromatogram taken on 255nm.

Figure 35 Tegetus flower: chromatogram taken at 255nm.

Carthamus flower: Solvent System: 95:5 MeOH: DW, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 255nm (Figure 36).

Figure 36 Carthamus flower: chromatogram taken at 255nm.

Carthamus flower: Solvent System: 95:5 MeOH: DW, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 280nm (Figure 37).

Figure 37 Carthamus flower: chromatogram taken at 280nm.

Eucalyptus bark CO₂ extract: Solvent System: 95:5 MeOH: DW, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 255nm (Figure 38).

Figure 38 Eucalyptus bark CO2 extract: chromatogram taken at 255nm.

Eucalyptus bark CO₂ extract: Solvent System: 95:5 MeOH: DW, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 280nm (Figure 39).

Figure 39 Eucalyptus bark CO2 extract: chromatogram taken at 280nm.

Punica: Solvent System: 95:5 MeOH: DW, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 255nm (Figure 40).

Figure 40 Punica: chromatogram taken at 255nm.

Punica: Solvent System: 95:5 MeOH: DW, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 280nm (Figure 41).

Figure 41 Punica: chromatogram taken at 280nm.

Curcuma powder: Solvent System: 95:5 MeOH: H₂O, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 255nm (Figure 42).

Figure 42 Curcuma powder: chromatogram taken at 255nm

Reseda powder: Solvent System: 97:3 MeOH: H₂O, Time: 15 min, Sample prepared in MeOH, Chromatogram taken on 255nm (Figure 43).

Figure 43 Reseda powder: chromatogram taken on 255nm.

Reseda powder: Solvent System: 97:3 MeOH: H₂O, Time: 15 min, Sample prepared in MeOH, Chromatogram taken on 280nm (Figure 44).

Figure 44 Reseda powder: chromatogram taken on 280nm.

Reseda powder: Solvent System: 90:10 MeOH: EtOAc, Time: 10 min, Sample prepared in MeOH, Chromatogram taken on 255nm (Figure 45).

Figure 45 Reseda powder: chromatogram taken on 255nm.

Reseda powder: Solvent System: 90:10 MeOH: EtOAc, Time: 10 min, Sample prepared in MeOH, Chromatogram taken on 280nm (Figure 46).

Figure 46 Reseda powder: chromatogram taken on 280nm.

Solvent System: 97:03MeOH: H₂O, Run Time: 15 min, Sample prepared in MeOH, Chromatogram taken at 255nm (Figure 47).

Figure 47 Solvent system: 97:03MeOH: H₂O, run time: 15 min, sample prepared in MeOH, chromatogram taken at 255nm.

Method-II: Solvent System: 10:90 EtOAc: MeOH, Run Time: 8 min, Chromatogram taken at 255nm, Sample prepared in EtOAc (Figure 48).

Figure 48 Solvent system: 10:90 EtOAc: MeOH, run time: 8 min, chromatogram taken at 255nm, sample prepared in EtOAc.

Cold dyeing experiments on silk and cotton with fresh reseda extract

Dyeing method for silk and cotton: In the present study Silk and Cotton fabrics were dyed with Reseda extract from stem, flower and leaves using alum and protease enzyme for silk as pretreatment, while for cotton only alum mordant was used.

Pure Silk-The munga silk of GSM-45 fabric was scoured with solution containing 0.5 g/L sodium carbonate and 2 g/L non-ionic detergent (Labolene) solution at 40-45˚C for 30 min, keeping the material to liquor ratio at 1:50. The scoured material was thoroughly washed with tap water and air dried at room temperature. The scoured material was soaked in clean water prior to dyeing or mordanting. Cotton fabric was also scoured by standard process similar to the process mentioned herein Enzymes (Protease) was procured from TFF Speciality Chemicals, Kanpur. Alum as Metal mordant was procured from SD Fine Chemicals, Kanpur.

Dye material

The extract was prepared by using dry matter powder of stem .leaves and flowers (100g) were soaked in sufficient water 300 mL at 70-75˚C. The pH of the dyeing solution was 6.99.

Two step processes with premordanting followed by dyeing was carried out. Dyeing was carried by a stepwise dyeing process using either alum or enzyme- Protease, 1% w/w of the fabric). Similarly experiments were carried out for metal mordant--alum, and comparison of dyed swatches with enzyme treated swatches in the case of Silk fabric and only with alum 2% in the case of Cotton fabric.

The enzyme pre-treated silk fabric was used for dyeing with Reseda extract (10 %, w/w with respect to the wt. of the fabric). The dyeing time was 3 hours at a temperature of 30-40˚C.¹⁹ Dyeing was also carried out for metal mordanted silk piece (in the ratio of 2 % mordant, w/w with respect to the fabric) in a similar way keeping the dyeing time and temperature same.

Similarly premordanting with alum followed by dyeing under same conditions was carried out for cotton fabric as well.

Samples of Silk and cotton:

1. Sample 0: Silk control
2. Sample 1: Silk pretreated with Alum
3. Sample 2: Silk Pretreated with protease enzyme
4. Sample 3: Cotton control
5. Sample 4: Cotton pretreated with Alum (Figure 49) (Table 5).

Figure 49 Samples of silk and cotton.

The dyeing results of Silk and cotton show the following: While dyeing silk fabric with Reseda dye extract, alum mordanting is superior to use of Protease enzyme in terms of dE* values and K/S values. For cotton fabric with Reseda dye extract alum mordanting shows better K/S value as well as Chroma C* and Hue color H* higher than control sample (unmordanted cotton fabric). Thus through this experiment it can be concluded that for Reseda dye extract alum mordanting is most suited for both silk and cotton fabrics and use of enzyme did not give expected results. Thus we started exploring other metal mordants with Reseda dye extract and the results are given below.

Dyeing experiments on silk and cotton with reseda samples with different metallic mordants

In the present study Silk and Cotton fabrics were dyed with Reseda extract derived from stem, leaves and flowers using alum, copper sulphate, ferrous sulphate, potassium dichromate and stannous chloride as mordant in two step dyeing process. Silk and Cotton fabrics were also scoured by standard process similar to the process mentioned earlier. Metal mordants were procured from SD Fine Chemicals, Kanpur.

Dye material

The extract was prepared by using dry matter powder of stem leaves and flowers (100g) was soaked in sufficient water 300 mL at 70-75˚C. The pH of the dyeing solution was 6.99.

Two step processes with premordanting followed by dyeing was carried out. Dyeing was carried by a stepwise dyeing process using metal mordants mentioned above in 2 %. The pre-mordanted silk fabric was used for dyeing with Reseda extract. The dyeing time was 3 hours at a temperature of 30-40˚C. Dyeing was also carried out for metal mordanted cotton in a similar way keeping the dyeing time and temperature same (Figures 50−53) (Table 6) (Table 7).

Figure 50 Samples of Silk and cotton: Standard 0: Control cotton Unmordanted, Sample 1: Alum mordanted, Sample 2: Copper sulphate mordanted, Sample 3: Ferrous Sulphate mordanted, Sample 4: Potassium dichromate mordanted, Sample 5: Stannous chloride mordanted.

Figure 51 Dyeing cotton with Reseda luteola.

Figure 52 Samples of Silk and cotton: Standard 0: Control Silk Unmordanted, Sample 1: Alum mordanted, Sample 2: Copper sulphate mordanted, Sample 3: Ferrous Sulphate mordanted, Sample 4: Potassium dichromate mordanted, Sample 5: Stannous chloride mordanted.

Figure 53 Dyeing cotton with Reseda luteola.

The dyeing results of Silk and cotton show the following: Dyeing silk and cotton fabrics with Reseda dye extract different mordanting shows highest K/S for ferrous sulphate mordanted fabrics. For cotton fabric with Reseda dye extract the order of effective dyeing in terms of K/S values is Ferrous sulphate > >Copper> Alum> Potassium dichromate> Stannous chloride. With silk fabric with Reseda dye extract the order of effective dyeing in terms of K/S values is Ferrous sulphate > > Alum> Copper> Potassium dichromate> Stannous chloride. We did more experiments with different surfactants and Reseda dye.

Dyeing experiments on silk and cotton with reseda samples with alum metallic mordant and surfactant

In the present study Silk and Cotton fabrics were dyed with Reseda extract using alum, as well as surfactants such as Sodium salt of Dodecylbenzenesulphonic acid (SDBS) and Cetyl trimethyl ammonium bromide (CTAB) as pretreatment have been used in two step dyeing process.

Silk and Cotton along with knitted variety D100% fabrics were also scoured by standard process similar to the process mentioned earlier. Metal mordant and Surfactants were procured from SD Fine Chemicals, Kanpur.

Pretreatment with surfactant

Aqueous solution of the surfactant (0.02 gm/ml) was prepared in 1:30 M:L. Silk fabric was dipped in 25 ml of surfactant solution and heated on water bath at 60-70˚C for 30-45 mins. Cotton was heated for 40 mins at 80-90˚C. Then the fabrics were left for aerial oxidation.

Dyeing

After this Silk and Cotton were dipped in 25 ml of 10 % solution of Reseda dye extract using 0.5 % NaOH separately at 1:30 MLR. Two step processes with premordanting followed by dyeing was carried out. Dyeing was carried by a stepwise dyeing process using metal mordants as well as surfactants SDBS and CTAB mentioned above. The pre-mordanted silk fabric was used for dyeing with Reseda extract. The dyeing time was 3 hours at a temperature of 40°C. Dyeing was also carried out for metal mordanted cotton and surfactant pre treated in a similar way keeping the dyeing time and temperature same. .Dyed fabrics were washed with water, followed by mild soap and finally with water (Figure 54) (Figure 55) (Table 8) (Table 9).

Figure 54 Silk and Alum, SDBS and CTAB Surfactants.

Figure 55 Cotton and Knitted and Alum, SDBS and CTAB Surfactants.

The dyeing results of Silk and cotton show the following: Cotton fabrics with Reseda dye extract along with use of surfactant did not show any improvement, infact alum mordanting still remained the best, and Knitted fabric showed better result that ordinary cotton fabric.

1. While dyeing Silk fabric with Reseda dye extract the order of effective dyeing in terms of K/S values Alum> CTAB> SDBS, infact silk fabric showed the order of effective dyeing in terms of K/S values SDBS was even lower than unmordanted fabrics K/S value.
2. We have also used Reseda with Rubia dye to develop different shades of dyed fabric as show below

Dyeing experiments on silk and cotton with reseda and rubia dyes samples with alum metallic mordant

In the present study Silk and Cotton fabrics were dyed with Reseda + Rubia dyes (0.35 gm+ 0.65 gm respectively) extract using alum, as pretreatment in two step dyeing process.

Silk and Cotton fabrics were also scoured by standard process similar to the process mentioned earlier. Metal mordant (Alum) was procured from SD Fine Chemicals, Kanpur.

Dye material

The extract was prepared by using powder 1.0g was soaked in sufficient water 150 mL at 70-75˚C. Mass to liquor ratio: 1.0 g in150 mL at 70˚C for 1.5 hrs.

Two step processes with premordanting followed by dyeing was carried out. Dyeing was carried by a stepwise dyeing process using metal mordant alum in 2 %. The pre-mordanted silk fabric was used for dyeing with Reseda + Rubia dyes extract. The dyeing time was 3 hours at a temperature of 50˚C. Dyeing was also carried out for metal mordanted cotton pre treated with alum in a similar way keeping the dyeing time and temperature same (Figure 56) (Figure 57) (Table 10) (Table 11).

Figure 56 Standard 0: Control cotton Unmordanted Rubia+Reseda, Sample 1: Alum mordanted Rubia+ Reseda.

Figure 57 Standard 0: Control Silk Unmordanted Rubia+Reseda, Sample 1: Alum mordanted Rubia+ Reseda.

The dyeing results of Silk and cotton show the following:

1. While dyeing cotton fabrics with Reseda + Rubia dyes extract along with use of alum mordanting K/S values showed improvement.
2. While dyeing Silk fabric with Reseda+ Rubia dyes extract, alum mordanting in terms of K/S values very pronounced improvement.

Among many yellow colored natural dyes Reseda seems to have the most pronounced dyeing ability and is also very good when combined with other dyes. Most of the yellow dye plants contain colorant molecule from the group of hydroxyl flavones, however the combination of components may differ from plant to plant and species to species. It shows vast difference in wash, light fastnesses, solubility and dyeability of the natural extracts. It is very apparent that among 10 different sources, Reseda excels in all the three parameters.

While analyzing Reseda by HPLC, it showed better separation by method-II, however the resolution needs to be further worked out, method –I is not so good. Better separation of peaks can be seen herein.

Dyeing Silk fabric with Reseda dye extract the order of effective dyeing in terms of K/S values Alum> CTAB> SDBS, in fact silk fabric showed the order of effective dyeing in terms of K/S values SDBS was not found to be good as pretreatment chemical for Reseda. Reseda extract showed bright yellow color with alum, olive green with copper sulphate and dark brown with ferrous sulphate.

None.

Authors declare there is no conflict of interest in publishing the article.

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