Assessment of antibacterial activity of wool fabrics dyed with natural dyes

Antimicrobial textiles and polymers have received more and more attention due to different health problems. Using antibacterial dyes in textiles integrates the dyeing and finishing process and results in a more efficient technique in terms of less water and energy usage. Historically, natural dyes are known to have some antibacterial effects, thus they can be considered as a green eco-friendly substitute. In this study, five different natural dyes obtained from green tea, madder, turmeric, saffron petals, and henna on wool fabric were used. Their antibacterial activity as well as dyeing properties including colorimetric values, light and wash fastness were investigated. As natural dyes inherently have low fastness, premordanting of fabric was done by using aluminum sulfate. Results showed that all these natural dyes could provide some antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa bacteria on wool fabric. Furthermore, pretreatment with aluminum sulfate led to improved and durable antibacterial effects after five cycles of washing and 300 min of light exposure.