A Sustainable Approach to Study on Antimicrobial and Mosquito Repellency Properties of Silk Fabric Dyed with Neem (Azadirachta indica) Leaves Extractions

The present research work was conducted on developing sustainable production of mulberry filament silk fabric dyed with different extracted dye solutions based on extraction ratios of 1:4, 1:6, 1:8, and 1:10 from neem (Azadirachta indica) leaves. The research work focused on evaluating the antimicrobial and mosquito repellent properties of dyed silk fabric. In the experiment, the samples were dyed using the exhaust method at different dye bath concentrations i.e., 15 g/L, 20 g/L, and 25 g/L in the presence and absence of mordant at 80 °C maintaining 1:60 dyeing liquor ratio. The absorbance of the extracted dye solutions was determined with a UV/VIS spectrophotometer, which detected the highest absorbance of 7.73 at the peak 490 nm of λmax of 1:4 extracted dye solution. Fourier transform infrared (FTIR) spectroscopy was used to investigate the chemical structure of dyed fabrics; however, no chemical changes or bond formation occurred; instead, dye particles were deposited on the fabric layer, indicating the presence of bioactive components. Allergy test was also performed to confirm allergic reactions of neem extract on human skin. The antimicrobial activity of extracted dye solutions and dyed samples was estimated against Gram-positive ( Staphylococcus aureus ) and Gram-negative ( Escherichia coli ) bacteria using the agar diffusion method and mosquito repellency of fabrics were examined by the cage method. The results emphasized that dyed fabric with the highest concentrated dye solution, 1:4 extraction, and highest dye bath concentration, 25 g/L along with mango bark mordant solution, possesses the highest antimicrobial activity in terms of an inhibition zone of 0.67 mm against Gram-negative bacteria and 0.53 mm against Gram-positive bacteria obtained after incubation, and the highest mosquito repellent of 75% due to the absorption of active bio constituents. The experimental results also determined that the dyed fabric with 1:4 extracted dye solution exhibited good antimicrobial (inhibition zone, 0.65 mm against E. coli and 0.52 mm against S. aureus ) and mosquito repellent property (66.67%). The experimental study also revealed that Potassium dichromate mordant reduced the antimicrobial (inhibition zone, 0.05 mm against E. coli and no inhibition against S. aureus ) and mosquito repellent action (33.33%). In conclusion, the data revealed that the increase in the extraction ratio of dye solution and dye bath concentration has no impact on the silk fibroin; it only impacts what is deposited on the fabric layer that improves its antimicrobial and mosquito repellency. The current research showed that neem leaves were found to have a beneficial effect in controlling microorganisms and mosquitoes through a sustainable approach.