Eco-Friendly Dyeing Using Natural Mordant Extracted from Emblica officinalis G. Fruit on Cotton and Silk Fabrics with Antibacterial Activity

Fibers and Polymers 2011, Vol.12, No.6, 753-759 DOI 10.1007/s12221-011-0753-5 Eco-Friendly Dyeing Using Natural Mordant Extracted from Emblica officinalis G. Fruit on Cotton and Silk Fabrics with Antibacterial Activity K. H. Prabhu*, M. D. Teli, and Nilesh G. Waghmare Department of Fibers and Textile Processing Technology, Institute of Chemical Technology (formerly U.D.C.T), Matunga, Mumbai-400 019, India (Received February 10, 2011; Revised April 18, 2011; Accepted April 21, 2011) Abstract: Emblica officinalis G. dried fruit tannin was extracted and applied as a natural mordant alone and in combination with metal mordant namely copper sulphate for dyeing on cotton and silk fabrics using natural dyes. The color strength, color-coordinates, wash and light fastness were also evaluated for cotton and silk fabrics with and without mordanting. The pre-mordanted cotton and silk fabrics on dyeing gave better color strength, wash and light fastness than those dyeing obtained without mordanting. The total phenolic content of the extract was calculated. Cotton and silk fabrics resulted in good antibacterial activity using the Emblica officinalis G. mordant. When mordant was used along with 0.5 and 1 % copper sulphate mordant and the activity enhanced and was active up to 20 washes. Keywords: Antibacterial, Emblica officinalis G., s, Natural mordant, Textiles Introduction Emblica officinalis G. (Hindi: Amla) is a member of a small genus Emblica of trees which are native of India, Ceylon, Malaya and China [1]. It belongs to the family Euphorbiaceae and the parts of E. officinalis such as leaves, stem, roots, fruits, flowers and bark have been used traditionally to treat board spectrum of disorders. Many scientifically published data concerning pharmacology and toxicology of E. officinalis were reported including antifungal, antibacterial and antioxidant properties [2-4]. It is known that emblica is a good source of flavones, tannins and other bioactive substances. The fruits have 28 % of the total tannins distributed in the whole plant. The fruit contains two hydrolysable tannins Emblicanin A and B, which have antioxidant properties, one on hydrolysis gives gallic acid, ellagic acid and glucose wherein the other gives ellagic acid and glucose [5-8]. Tannins are defined as water soluble polyphenolic compound with high molecular weight ranging from 500 to 3000 and contain sufficient hydroxyl and other suitable groups (i.e., carboxyl) to form effectively strong complex with protein chains and other macromolecules under particular environmental conditions [9]. Tannins have been the most widely used natural mordant ever since the colorations of the textile started. The important natural tannin employed in natural dyeing as mordant is myrobolan commonly known as Harda [10]. By first mordanting with natural tannins, one introduces additional hydroxyl and carboxyl groups in the fiber and these groups increase the affinity of fibers towards different natural dyes and enhance the fixation of the natural colorant on the fiber by the formation of the complex with the dye. *Corresponding author: khprabhu@gmail.com Tannins are astringent and antimicrobial in nature [11-13]. Today, coloration of textiles is characterized by a high level of water pollution and health risk due to the use of synthetic dyes and harmful chemicals. Due to increasing awareness of environmental issues and pollution controls, natural dyes are once again gaining importance as they are obtained from renewable resources and they have no health hazards and some of them sometimes act as a health care product. Most of the natural dyes have less affinity towards textile substrate, hence they require mordants. Mordants are the substance capable of binding natural dyes to textile substrate. The objectives of this study was to extract tannin from Emblica officinalis G. dried fruit and its application as a natural mordant alone and in combination with metal mordant namely copper sulphate for natural dyeing on cotton and silk fabrics. The total phenolic content of the extract was calculated. The color strength, color-coordinates, wash and light fastness were evaluated for cotton and silk fabrics with and without mordanting. The antibacterial activity of extracted tannin against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were determined qualitatively. Further, the antibacterial activity of mordanted and natural dyed cotton and silk fabrics against both micro-organisms were evaluated quantitatively and durability of activity for repeated washing was investigated. Experimental Materials The cotton fabric (124GSM) was purchased from Premier Mills, Mumbai, India. Ready for dyeing silk (42 GSM) fabric was purchased from Kiran Threads, Vapi, India. For 753

754 Fibers and Polymers 2011, Vol.12, No.6 K. H. Prabhu et al. microbiological testing, Gram-positive bacteria Staphylococcus aureus (S. aureus) (NCTC 3570) Gram-negative bacteria Escherichia coli (E. coli) (ATCC 10148) were procured from Haffkine s Institute, Parel, Mumbai, India. The natural dyes namely Curcuma longa L. (), Punica granatum L. (Pomegranate ), Lawsonia inermis L. () and Rubia cordifolia L. ( madder) were purchased from local ayurveda market in powder form, Mumbai, India. Emblica officinalis G. (Amla) dried fruit was purchased from local Ayurveda market, Mumbai, India. Ethanol (99 %), ethyl acetate, chloroform, acetic acid, gallic acid, copper sulphate were of analytical grade supplied by S.D.Fine chemicals Ltd., Mumbai. Auxipon NP non ionic detergent was was supplied by Auxichem Ltd., Mumbai. Methods Extraction of Natural Mordant The dried samples of Emblica officinalis G. fruits were grounded in mixer and stored in plastic bottle at room temperature (25-27 o C). The fine powder of Emblica officinalis (1000 g) was extracted with 5 l of ethanol on shaker for 12 h. The ethanol extract was concentrated under vacuum using Rota evaporator and the semi solid mass obtained on concentration was diluted with 3 l of distilled water. A brown flocculent precipitate which was thrown out on keeping it at 5 o C for 3 days was filtered. The filtrate free from impurities was extracted with ethyl acetate. The ethyl acetate extract was vacuum distilled and was finally evaporated to dryness to yield tannin (mordant) and this procedure was repeated twice and the final dark brown powder was dried at oven at 75 o C and used for further procedures. Determination of Total Phenolic Content The total phenolic content (TPC) in the ethyl extract was determined by the Folin-Ciocalteu method [14]. 20 µl of the extract solution was taken into separate cuvettes, 1.58 ml water was added followed by the addition of 100 µl of the Folin-Ciocalteu reagent, and mixed well. It was allowed to stand for 8 min and 30 sec, and then 300 µl of the sodium carbonate solution was added, shaken to mix. The solutions were left to stand at 20 o C for 2 h and absorbance of each solution at 765 nm against the blank (the 0 ml solution) was determined. All determinations were carried out in triplicate. The calibration curve was plotted using concentrations of 0, 50, 100, 150, 250, 500, and 1000 mg/l Gallic acid. The total content of phenolic compounds in the extracts in Gallic acid equivalents (GAE) was calculated by the following formula: T=C V/M Where in T=total content of phenolic compounds, milligram per gram plant extract, in GAE; C=the concentration of Gallic acid established from the calibration curve, milligram per liter; V=the volume of extract, milliliter; M=the weight of plant extract, gram. Extraction of Natural Colorants All the natural colorants were extracted using water as the medium. The natural colorants in the form of fine powder (5 g) were mixed with 100 ml of water and allowed to soak for half hour and the mixture was then boiled for one hour. The contents were cooled and filtered. The filtrate was used for dyeing. Mordanting Pre-mordanting technique was used for this study. Cotton and silk fabrics were treated with Emblica officinalis G. mordant solution using 15 % concentrations on weight of fabric (owf) and this treatment was carried out at 95 o C for 45 min, keeping the liquor to material ratio 20:1. The cotton and silk fabrics mordanted with 15 % Emblica officinalis G. mordant concentration were further treated with 0.5 % and 1 % (owf) Copper sulphate (Cu) solution at 85 o C for 45 min, keeping the liquor to material ratio 20:1. Cotton and silk fabrics, only mordanted with Emblica officinalis G. mordant and in combination with copper sulphate mordants, were squeezed and subjected to dyeing. Dyeing of Cotton and Silk Fabrics Shade used for dyeing on cotton and silk were 20 % on weight of the fabric (owf). Dyeing was carried out in Rota Dyer machine, Rossari Labtech, Mumbai keeping the liquor to material ratio 20:1. Fabrics were introduced into the dyeing solution at room temperature and slowly the temperature was raised to 85 o C. The dyeing was continued at this temperature for 60 min. After dyeing, the fabrics were rinsed and air-dried. Evaluation Color Strength Dyed samples were evaluated for their color strength by determining K/S values using a Spectra flash SF 300, Computer Color Matching System supplied by Data Color International, USA. An average of four readings taken at four different sample areas was used to get the reflectance values, and Kubelka Munk function (K/S) [15]. K --- ( 1 R) 2 = ----------------- S 2R Where R is the reflectance at complete opacity; K is absorption coefficient; S is the Scattering coefficient. Dyed fabrics were also evaluated in terms of CIELAB color space. Antimicrobial Activities of Mordanted and Dyed Fabrics Quantitative assessment of antimicrobial activity exhibited on mordanted and dyed cotton and silk fabrics against both microorganisms were carried out by AATCC Test 100-2004 [16]. To evaluate the antimicrobial activities of the treated fabrics, the reduction in number of bacterial colonies formed

Natural Mordants and Its Antibacterial Activity Fibers and Polymers 2011, Vol.12, No.6 755 with respect to the untreated control after incubation (37±1 o C, 24 h) was determined. The percentage reduction was calculated with the following equations: Reduction rate (%) R= (B A)/B 100 where R=% reduction in bacterial count; A=the number of bacterial colonies recovered from the inoculated treated test specimen swatches in the jar incubated for 24 h contact period, B=the number of bacterial colonies recovered from the inoculated untreated control test specimen swatches in the jar immediately after inoculation (at 0 contact time). Durability of Antibacterial Activity to Washing The samples were washed in a Launderometer by using Standard Test Method ISO 105-C06 A1M. The one wash of standard method is equivalent to five home launderings. The Specimen size (100 40 mm) was first transferred to pot containing soap solution (Auxipon NP non ionic detergent) 4 gpl and 10 steel balls. The temperature was raised to 40 o C and washing carried out for 45 min. Four washes were given one by one. The samples were then dried in air and the fabric was tested for antibacterial activity as mentioned above. Wash and Light Fastness Properties Dyed fabrics were tested for colorfastness to washing according to ISO Test Method, ISO 105-C10-2006. Dyed fabrics were tested for colorfastness to light according to AATCC Test Method 16-2004. Results and Discussion Total Phenolic Content Tannins are phenolic compounds and they exist widely in plants. The total phenolic content of the Emblica officinalis G. extract was 728.17 mg/g gallic acid equivalent. The extracts confirmed the presence of phenolic (-OH) groups and thus can be effectively used as a mordant for natural dyes on cotton and silk fabrics. Color Characteristics Results with respect to color depth i.e., K/S values of dyeing of cotton and silk fabrics with natural dyes namely turmeric, pomegranate, henna and madder (shade, 20 %) obtained using with and without mordants are given in Tables 1 and 2. The results indicate that the K/S value of the cotton and silk fabrics pre-mordanted with Emblica officinalis G. mordant and dyed with all four natural dyes were higher than that of only natural dyed cotton and silk fabrics. The enhancement in the depth of dyeing was due to the presence of Emblica officinalis G. tannin acting as mordant containing phenolic hydroxyl group which forms complex with the dye molecules and leads to higher fixation of dye on the cotton fabric. Also, it can be observed that the K/S values of natural dyed cotton and silk fabrics increases with an increase of addition of copper sulphate mordant concentration from 0.5 to 1 % for all four natural dyes. In this case, the enhancement in the color depth was due to the presence of copper sulphate, a metal mordant which forms Table 1. K/S values, color co-ordinates and color of natural dyes dyed cotton fabric with and without mordanting Mordants Color co-ordinates K/S value (%) L * a * b * Color obtained Nil 1.6690 83.76-2.13 50.01 Light yellow 15 % A 3.4921 77.07 0.06 55.32 Dark yellow 15 %A + 0.5 % Cu 4.6869 68.63 0.38 50.48 Deep greenish yellow 15 %A + 1 % Cu 5.5368 64.91 1.1 48.11 Deep greenish yellow Nil 0.8726 74.02 3.26 19.97 Beige Pomegranate 15 % A 1.2176 72.47 1.55 22.92 Greenish beige 15 %A + 0.5 % Cu 1.6372 64.83 2.91 19.44 Greenish khaki 15 %A + 1 % Cu 2.2839 60.93 4.79 21.27 Greenish khaki Nil 0.5491 75.78 1.94 9.63 Light grey 15 % A 0.8944 71.67 2.53 10.57 Deep grey 15 %A + 0.5 % Cu 1.6882 64.9 2.48 15.24 Greenish yellow 15 %A + 1 % Cu 2.3577 61.52 3.91 17.46 Greenish yellow Nil 0.3776 76.6 12.75 4.84 Pale pink 15 % A 0.6667 75.87 6.71 11.79 Dull pink 15 %A + 0.5 % Cu 0.8298 64.16 4.44 12.62 Deep reddish brown 15 %A + 1 % Cu 1.0061 61.71 5.02 12.82 Deep reddish brown A: Emblica officinalis G. mordant, Cu: copper sulphate, L * : lightness (0=black, 100=white), a * : red-green coordinates (positive values=red, negative values=green), b * : yellow-blue coordinates (positive values=yellow, negative values=blue).

756 Fibers and Polymers 2011, Vol.12, No.6 K. H. Prabhu et al. Table 2. K/S values, color co-ordinates and color of natural dyes dyed silk fabric with and without mordanting Mordants Color co-ordinates K/S value Color obtained (%) L * a * b * Nil 2.6676 79.99-0.72 5000. Bright yellow 15 % A 9.5900 67.56 0.08 51.67 Golden yellow 15 %A + 0.5 % Cu 9.9614 57.95 3.11 42.17 Dark golden yellow 15 %A + 1 % Cu 11.1477 56.65 3.76 43.06 Dark golden yellow Pomegranate Nil 2.1673 67.72 5.97 30.26 Light khaki 15 % A 4.8456 61.73 5.59 34.07 Dark khaki 15 %A + 0.5 % Cu 6.4887 54.07 6.70 31.80 Golden khaki 15 %A + 1 % Cu 8.4632 49.8 7.83 31.48 Deep golden khaki Nil 0.9577 72.31 7.17 17.1 Light brown 15 % A 3.2773 61.87 8.12 22.98 Reddish brown 15 %A + 0.5 % Cu 5.5259 53.37 7.44 24.50 Golden brown 15 %A + 1 % Cu 5.6659 53.44 8.03 25.09 Dark golden brown Nil 0.3068 79.06 10.28 7.30 Pale pink 15 % A 2.4584 65.19 8.77 21.30 Yellowish brown 15 %A + 0.5 % Cu 4.5966 55.04 7.12 22.22 Deep yellowish brown 15 %A + 1 % Cu 5.1577 53.86 7.41 23.14 Deep yellowish brown A: Emblica officinalis G. mordant, Cu: copper sulphate, L * : lightness (0=black, 100=white), a * : red-green coordinates (positive values=red, negative values=green), b * : yellow-blue coordinates (positive values=yellow, negative values=blue). insoluble metal tannates with Emblica officinalis G. tannin phenolic hydroxyl group and further the metal tannates present on the cotton and silk material forms a insoluble lake with the reactive group of the dye molecules and leads to further higher fixation of natural dyes on the cotton and silk fabrics. Silk fabric mordanted and dyed with all four natural dyes showed higher color strength than the mordanted and natural dyed cotton samples. This is due to silk being protein fiber and having more functional group than cotton. The color co-ordinates L *, a * and b * values results obtained for cotton and silk fabrics mordanted and dyed with natural dyes are given in Tables 1 and 2 respectively. In all premordanted and natural dyed cotton and silk fabrics, the brightness or L * values decreased highly resulting in deepening of shades as compared to only natural dyed samples. From a * and b * values, the incorporation mordant namely Emblica officinalis G. mordant alone and in combination with copper sulphate mordant onto cotton and silk fabrics produced good improvement and their values were positive and thus showed shifts in their tones resulting in beautiful colors as compared to only natural dyed cotton and silk fabrics and the color obtained are mentioned in Tables 1 and 2 respectively. Antimicrobial Activity of Mordanted and Dyed Fabrics In order to find the effectiveness of the antimicrobial activity of the mordanted and natural dyed fabrics were evaluated quantitatively using AATCC Test 100-2004 and the results for percent reduction of bacteria for cotton and silk fabrics dyed with all four natural dyes with and without Table 3. Antibacterial activity of natural dyes dyed cotton, silk fabrics with and without mordants s Mordants Reduction (%) (%) S. aureus E. coli Nil 89.58 (92.46)* 87.50 (88.19)* 15 % A 95.83 (97.89)* 94.44 (95.78)* 15 %A +0.5 % Cu 100 (100)* 100 (100)* Nil 90.27 (91.52)* 88.88 (90.96)* Pomegranate 15 % A 96.52 (98.43)* 93.75 (96.98)* 15 %A +0.5 % Cu 100 (100)* 100 (100)* Nil 30.55 (42.77)* 20.83 (39.75)* 15 % A 89.58 (95.48)* 86.30 (92.46)* 15 %A +0.5 % Cu 99.30 (100)* 98.61 (100)* Nil 37.50 (41.26)* 30.55 (39.45)* 15 % A 87.50 (94.57)* 84.02 (92.01)* 15 %A +0.5 % Cu 98.33 (100)* 97.91 (100)* A: Emblica officinalis G. mordant, Cu: copper sulphate, *Values corresponds to silk fabrics. mordants are given in Table 3. From Table 3, the results clearly indicate that the cotton

Natural Mordants and Its Antibacterial Activity Fibers and Polymers 2011, Vol.12, No.6 757 pre-mordanted with Emblica officinalis G. mordant and dyed with turmeric showed higher antibacterial activity as compared to only turmeric dyed cotton fabric against S. aureus and E. coli. The activity increased from 89.58 to 95.83 % for S. aureus and for E. coli, activity increased from 87.50 to 94.44 %. It is clear from the results that the mordanting with Emblica officinalis G. mordant showed a definite increase in reduction of growth of both types of microorganisms. When cotton and silk fabrics per-mordanted with Emblica officinalis G. mordant in combination with 0.5 and 1 % copper sulphate mordant and natural dyed, the reduction percentage was 100 % against both the microorganisms. The increase in antibacterial activity is due to the presence of copper, which is an excellent antibacterial, antiseptic and germicidal agent as mentioned in the literature [17,18]. Hence, it can be inferred that 15 % Emblica officinalis G. mordant in combination with 0.5 or 1 % copper sulphate mordant concentration can act as a good antibacterial agent against S. aureus and E. coli bacteria. Similar trend was obtained in case of pre-mordanted cotton fabric and dyed with pomegranate, henna and madder. In case of silk fabrics with respect to antibacterial activity for both gram-positive (S. aureus) and gram-negative (E. coli), similar results were obtained as in the case of cotton and their results are given in Table 3. In general, the antibacterial activity of mordanted and dyed cotton and silk fabrics were higher than that of only natural dyed fabrics. Durability of Antibacterial Activity An important issue to be considered in any functional treatment is the durability to washing of the functional treatment. For disposable material, it only requires temporary functional property. For all other application, the functional property should be reasonably resistance to washing. To test the durability to home laundering, the antibacterial activity of pre-mordanted and dyed cotton and silk fabrics were tested after 5, 10, 15 and 20 washes. The findings are given in Tables 4 and 5. From Table 4, it can be observed that the antibacterial activity of cotton fabric pre-mordanted with Emblica officinalis G. mordant and dyed with turmeric shows a 95.83 and 94.44 % reduction in S. aureus and E. coli bacteria respectively but that reduces to 60.36 and 58.33 % after 5 washes and further decreased to 33.71 and 29.16 % after 10 washes respectively. Similar trend were observed in case of pomegranate dyed cotton fabrics. In general, Emblica officinalis G. pre-mordanted and turmeric, pomegranate dyed cotton fabrics are found to have good resistance to bacterial attack. At the same time, these fabrics are found to have a wash durability of up to 5 washes. In case of henna, before washing the % reduction values for S. aureus and E. coli are 89.58 and 86.80 % respectively. After 5 washes, the activity was decreased drastically up to 33.63 and 30.55 % against S. aureus and E. coli respectively. Further after 10 washes the activity reduced heavily up to 20.89 and 18.75 % against S. aureus and E. coli respectively. The same trend was observed in case of pre-mordanted and madder dyed cotton fabric. However, the cotton samples pre-mordanted with Emblica officinalis G. mordant in combination with 0.5 or 1 % copper sulphate and dyed with all four natural dyes retain almost around 70 % antibacterial activity even after 20 washes. This is perhaps due to the presence of copper ions which forms insoluble copper tannates with Emblica officinalis G. tannin phenolic hydroxyl group and further forms insoluble lake with the dye molecules and retains the antibacterial activity after repeated washings. Similar results were obtained in case of natural dyed silk against S. aureus and E. coli and their results are shown in Table 5. Overall it was found that the Emblica officinalis G. mordant alone can be used to impart a temporary finish to cotton and silk fabrics dyed Table 4. Wash durability of antibacterial activity of natural dyes dyed cotton fabrics with mordants against S. aureus and E. coli Pomegranate Mordants Reduction (%) (%) Treated 5 washes 10 washes 15 washes 20 washes 15 % A 95.83 (94.44)* 60.36 (58.33)* 33.71 (29.16)* - - 15 %A + 0.5 % Cu 100 (100)* 90.27 (89.95)* 82.63 (81.94)* 78.47 (77.08)* 70.83 (69.44)* 15 %A + 1 % Cu 100 (100)* 91.66 (90.97)* 83.05 (82.63)* 79.16 (78.47)* 72.22 (70.13)* 15 % A 96.52 (93.75)* 61.90 (56.25)* 35.63 (26.38)* - - 15 %A + 0.5 % Cu 100 (100)* 88.88 (88.19)* 83.33 (81.94)* 79.44 (79.16)* 71.52 (70.83)* 15 %A + 1 % Cu 100 (100)* 89.58 (88.88)* 84.72 (84.72)* 79.86 (80.00)* 74.30 (73.61)* 15 % A 89.58 (86.80)* 33.63 (30.55)* 20.89 (18.75)* - - 15 %A + 0.5 % Cu 99.30 (98.61)* 87.50 (86.11)* 80.00 (79.44)* 75.27 (74.30)* 70.69 (69.44)* 15 %A + 1 % Cu 100 (100)* 87.77 (85.41)* 81.52 (79.86)* 76.38 (75.00)* 71.11 (70.13)* 15 % A 87.50 (84.02)* 36.68 (32.63)* 19.89 (16.66)* - - 15 %A + 0.5 % Cu 98.33 (97.91)* 85.41 (84.02)* 77.77 (76.38)* 73.88 (72.91)* 69.44 (68.05)* 15 %A + 1 % Cu 100 (100)* 89.02 (84.86)* 81.11 (77.08)* 78.05 (73.61)* 70.13 (68.75)* A: Emblica officinalis G. mordant, Cu: copper sulphate, *Values corresponds to antibacterial activity against E. coli.

758 Fibers and Polymers 2011, Vol.12, No.6 K. H. Prabhu et al. Table 5. Wash durability of antibacterial activity of natural dyes dyed silk fabrics with mordants against S. aureus and E. coli Pomegranate Mordants Reduction (%) Treated 5 washes 10 washes 15 washes 20 washes 15 % A 97.89 (95.78)* 70.20 (69.87)* 37.71 (36.74)* - - 15 %A + 0.5 % Cu 100 (100)* 92.53 (92.01)* 80.72 (80.27)* 74.39 (76.35)* 70.20 (69.87)* 15 %A + 1 % Cu 100 (100)* 93.37 (93.37)* 82.22 (82.83)* 75.90 (77.40)* 72.59 (72.13)* 15 % A 98.43 (96.98)* 74.90 (71.38)* 38.63 (38.55)* - - 15 %A + 0.5 % Cu 100 (100)* 93.07 (92.46)* 81.91 (80.87)* 76.35 (76.80)* 69.75 (70.18)* 15 %A + 1 % Cu 100 (100)* 94.42 (94.12)* 83.43 (83.88)* 77.71 (78.31)* 69.87 (72.89)* 15 % A 95.48 (92.46)* 60.28 (59.97)* 29.89 (24.69)* - - 15 %A + 0.5 % Cu 100 (100)* 91.41 (90.51)* 81.32 (78.46)* 72.59 (75.30)* 70.48 (69.42)* 15 %A + 1 % Cu 100 (100)* 93.07 (92.16)* 83.72 (81.17)* 73.19 (76.95)* 71.38 (69.27)* 15 % A 94.57 (92.01)* 59.50 (59.63)* 26.89 (23.19)* - - 15 %A + 0.5 % Cu 100 (100)* 92.53 (89.45)* 80.32 (78.91)* 70.33 (69.87)* 68.97 (68.37)* 15 %A + 1 % Cu 100 (100)* 93.72 (90.60)* 81.47 (80.42)* 71.75 (72.89)* 69.27 (69.57)* A: Emblica officinalis G. mordant, Cu: copper sulphate; *Values corresponds to antibacterial activity against E. coli. Table 6. Light and wash fastness ratings of dyed cotton, silk fabrics with and without mordants Mordants (%) Light fastness 1 2 Wash fastness Change in colour Staining on cotton/wool Nil 2 (2)* 2-3 (2-3)* 4 (4)* 15 % A 4 (4)* 4 (4-5)* 5 (5)* 15 %A+0.5 % Cu 5 (5)* 5 (5)* 5 (5)* 15 %A+1 % Cu 6 (6)* 5 (5)* 5 (5)* Nil 3 (3)* 2 (2)* 4 (4)* Pomegranate 15 % A 5 (5)* 4-5 (4-5)* 5 (5)* 15 %A+0.5 % Cu 5 (6)* 5 (5)* 5 (5)* 15 %A+1 % Cu 6 (6)* 5 (5)* 5 (5)* Nil 1(1)* 2 (2)* 5 (5)* 15 % A 4 (4)* 4 (4-5)* 5 (5)* 15 %A+0.5 % Cu 5 (5)* 5 (5)* 5 (5)* 15 %A+1 % Cu 5 (6)* 5 (5)* 5 (5)* Nil 2 (2)* 2 (2)* 5 (5)* 15 % A 4 (4)* 4-5 (4-5)* 5 (5)* 15 %A+0.5 % Cu 5 (6)* 5 (5)* 5 (5)* 15 %A+1 % Cu 6 (6)* 5 (5)* 5 (5)* A: Emblica officinalis G. mordant, Cu: copper sulphate, 1 light fastness rating: (1) poor, (2) fair, (3) moderate, (4) good, (5) better, (6) very good, (7) best, and (8) excellent, 2 wash fastness rating: (1) poor, (2) fair, (3) good, (4) very good, and (5) excellent, *Values corresponds to silk fabrics. with all four natural dyes. This type of finish may be required for materials which do not need laundering as in the case of hygiene market such as wound healing purpose. However, for a durable antibacterial finish to washing for cotton and silk fabrics with all four natural dyes, the Emblica officinalis G. mordant has to be used in combination with copper sulphate mordant. Out of the two concentration of copper sulphate, even 0.5 % (owf) copper sulphate mordant concentration can be sufficiently enough to obtain a good antibacterial activity against S. aureus and E. coli bacteria. Wash and Light Fastness Properties The wash and light fastness properties of cotton and silk mordanted and dyed with all four natural dyes were given in Table 6. The wash fastness properties with respect to change in color were of the order of 4-5 was observed. The staining on all the four natural dyed samples revealed good fastness with a grade range between 4 and 5. The light fastness was in the range of 4-5 for cotton and silk per-mordanted with Emblica officinalis G. mordant and natural dyed fabrics. However, the light fastness improved by a rating 5-6 for cotton and silk per-mordanted with Emblica officinalis G. mordant in combination with 0.5 and 1 % (owf) copper sulphate mordant concentration and natural dyed fabrics, which is quite acceptable. Conclusion In summary, Emblica officinalis G. dried fruit extract can be successfully employed as natural mordant for dyeing cotton and silk fabrics with all four natural dyes. The Emblica officinalis G. mordanted alone, and in combination with copper sulphate mordant and natural dyed cotton and silk fabrics showed higher K/S values as compared to only natural dyed fabrics. It is possible to produce cotton and silk fabrics with good antibacterial activity using the Emblica officinalis G. mordant against Gram-positive and Gramnegative bacteria. The only limitation is that such treated

Natural Mordants and Its Antibacterial Activity Fibers and Polymers 2011, Vol.12, No.6 759 fabric does not have good wash durability. The activity was greatly enhanced when Emblica officinalis G. mordant was used along with 0.5 or 1 % copper sulphate mordant and the activity were active even after 20 washes for both cotton and silk natural dyed fabrics. Even 0.5 % (owf) copper sulphate mordant concentration can be sufficiently enough to obtain a good antibacterial activity against S. aureus and E. coli bacteria. The wash and light fastness properties of the dyeing on cotton and silk fabrics were found to be enhanced when mordanting was done. Acknowledgements The authors express their thanks to The Technical Education Quality Improvement Programme (TEQIP), New Delhi, India for the financial support. References 1. The Wealth of India-Raw Material (B. N. Sastri Ed.), Vol.3, pp.168-170, CSIR, New Delhi, 2003. 2. P. Scartezzini and E. Seproni, J. Ethanopharmacol, 71, 23 (2000). 3. B. K. Dutta, I. Rahman, and T. K. Das, Mycoses, 41, 535 (1998). 4. P. G. Ray and S. K. Majumdar, Economic Botany, 30, 317 (1976). 5. Y. J. Zhang, T. Abe, T. Tanaka, C. R. Yang, and I. Kouno, Journal of Natural Products, 64, 1527 (2001). 6. L. Anila and N. R. Vijayalakshmi, Food Chemistry, 83, 569 (2003). 7. M. Majeed, B. Bhat, A. N. Jadhav, J. S. Srivastava, and K. Nagabhushanam, J. Agric. Food Chem., 57, 220 (2009). 8. S. Ghosal, V. K. Triphati, and S. Chauhan, Ind. J. Chem., 35B, 941 (1996). 9. K. S. Ramakrishnan, R. Selve, and R. Shubha, Ind. Chem. Eng. Section A, 48, 88 (2006). 10. M. L. Gulrajani, Colourage, 7, 19 (1999). 11. G. Nalankilli, Application of Tannin in the Colouration of Textiles, pp.13-15, Textile Dyers & Printer, January, 1997. 12. R. Mongkholrattanasit, J. Krystufek, and J. Wiener, Fiber. Polym., 11, 346 (2010). 13. P. S. Vankar, Handbook on Natural Dyes for Industrial Applications, National Institute of Industrial Research, Delhi, 2007. 14. V. L. Singleton, R. Orthofer, and R. M. Lamuela Raventos, Methods of Enzymology, 299, 152 (1999). 15. J. N. Etters and M. D. Hurwitz, Textile Chemist and Colorist, 18, 19 (1986). 16. AATCC Technical Manual, Vol.82, pp.145-147, American Association of Textile Chemists and Colorists, USA, 2007. 17. H. H. A. Dollwet and J. R. J. Sorenson, Trace Elem. Med., 2, 80 (2001). 18. K. E. Parry and R. K. S. Wood, Annals of Applied Biology 46, 446 (1958).