Document Type : Research Paper
Author
Assistant Professor of Carpet Department, Shiraz University of Arts, Iran.
Abstract
Background and objectives: Henna (Lawsonia inermis L.) is one of the plant dyes used for dyeing textiles since ancient times. The active ingredient in this plant is Lawson, which causes its coloring and antibacterial properties. On the other hand, the surface of natural fiber textiles, including handwoven carpets, in the presence of moisture and heat, causes the growth and proliferation of bacteria. This leads to problems with the product's durability, appearance, and hygiene. In this research, in addition to evaluating the color characteristics of fibers dyed with dry henna and its aqueous and alcoholic extracts, the comparison of their antibacterial effect on two Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria has also been investigated.
Methodology: The leaves of the native henna plant of Fars province were picked and dried in spring. Fibers of 4.5 metric meters and 63 deniers were used with Iranian wool and silk fibers. Considering that the extraction of the effective substance in plants depends on the type of solvent used, in addition to dry henna, three different solvents, water, ethanol, and methanol, were applied to prepare henna extracts. In this study, fibers were dyed with henna extracts, applying a simultaneous mordant method with Aluminum sulfate. Aqueous and alcoholic extracts were prepared by percolation and reflux methods in a Soxhlet extractor, respectively. For this purpose, a dyeing bath with L: R=1:50 containing natural fibers, 3% oxalic acid, 5% aluminum sulfate, and 30% dye was used. The dyeing process for both baths took 90 minutes in a bain marie. Color parameters (a*, b*, L*), color strength (K/S), reflective spectrum (R), light fastness, and antibacterial properties of each fiber dyed with dry henna and its extracts were evaluated. To measure the antibacterial properties, 0.03 grams of each dyed fiber was soaked in 1500 microliters of serum containing Staphylococcus aureus and Escherichia coli for 24 hours. Then, by dilution method in plates, Nutrient agar was cultured, and colonies were counted. Quantification of Lawson in the extracts was done using HPLC analysis.
Results: Reflective spectrophotometry showed that all wool and silk fibers dyed with henna and its extracts had positive a* and b* levels, which indicates the red and yellow undertones of the dyed samples. On the other hand, compared to silk fibers, wool fibers dyed with various types of henna dyes showed a higher degree of redness and yellowness and a lower percentage of brightness (L*). The numerical results were consistent with the qualitative and visual evaluations in the optical cabinet. In addition, natural fibers dyed with ethanol extract from henna had the lowest percentage of brightness and reflection and the highest color strength. The ethanol extract produced brilliant golden colors on silk fibers. Fibers dyed with all four types of henna dye had acceptable optical stability (7-8). Wool and silk samples dyed with alcoholic henna extracts, especially ethanol extract, showed a significant inhibition percentage for two types of bacteria, Escherichia coli and Staphylococcus aureus. This is due to secondary metabolites such as Lawson, which was detected using high-performance liquid chromatography. On the other hand, the antibacterial activity against the second type of bacteria was higher than the first type (76-90%), which is due to the difference in the cell wall structure between the two. The amount of Lawson measured in the ethanol extract of henna was higher than the other two extracts (16%), which confirms the color strength, high stability, and antibacterial properties of this extract on fibers.
Conclusion: The findings of this study proved that the use of henna and its extracts in dyeing natural fibers can be a promising factor in preventing infectious diseases caused by E. coli and S. rause bacteria. On the other hand, it seems that the ethanol extract of henna is more effective than the rest of the tested solvents for color strength, brightness, light fastness, and antibacterial effects. In addition, the ethanol extract of henna created a very beautiful golden color on silk in the presence of aluminum mordant. This is a very popular and rare color in handwoven carpet natural dyeing.
Keywords
Main Subjects
9 May: 8.
Al-Mahrooqi, Z.H. and Al-Hashmi, N.A., 2005. In-vitro antimicrobial activity of Lawsonia inermis Linn (henna). A pilot study on the Omani henna. Saudi Medical Journal, 26(1): 69-72.
17: 61-66.
)