Antibacterial Activity Against Staphylococcus aureus and Colorfastness of Siam Weed ( Chromolaena odorata ) Extracts Dyed on Cotton and Silk Fabrics

This research investigated the antibacterial activity of Siam weed (Chromolaena odorata) leaf extracts, used as a natural dye, against Staphylococcus aureus. Fresh and dried leaves were extracted using distilled water and ethanol. The disc diffusion method was employed to measure the diameter of clear zones indicating bacterial inhibition. The study also evaluated the colorfastness to laundering and antibacterial efficacy of cotton and silk fabrics dyed with the most effective extract, using alum and tannin as post-mordants. The results showed that the ethanol extract of fresh leaves produced the largest clear zone (9.67 ± 0.88 mm), followed by the ethanol extract of dried leaves (8.96 ± 0.14 mm), while extracts prepared with distilled water exhibited no significant antibacterial activity (p ≤ .05). The dyed fabrics displayed a yellowish-brown hue, with silk demonstrating superior colorfastness to laundering (level 2), whereas all cotton samples remained at level 1. Notably, dyed silk exhibited larger clear zones compared to cotton. After laundering, silk mordanted with tannin showed the highest antibacterial activity, with a clear zone of 9.67 ± 0.29 mm. These findings indicate the potential of Siam weed as a natural dye with antibacterial properties, supporting the development of sustainable, eco-friendly, and health-conscious textile innovations.