Agricultural crop of Scrophularia striata as a new dye for eco- friendly dyeing and bioactive finishing of handwoven piles

Today, great efforts were carried out to introduce sustainable colorants with low cost and high ef-ficiency to protect the environment as much as possible. In this study, an agricultural crop (Scro-phularia striata) was introduced as a new source of natural colorant for the dyeing wool yarns. The response surface method was used to deduce optimum dyeing conditions and to investigate the interactive effects of main dyeing parameters. Obtained results show that the total flavonoid and polyphenolic contents of the hydroalcoholic extract of S. striata were estimated to be equal to 44.37 mg quercetin equivalent/g of extract and 98.47 mg gallic acid equivalent/g of extract, re-spectively, thereby suggesting S. striata to be an ecological and low-cost novel dye for woolen col -oration process. A statistically predictive model of the dyeing procedure was developed to corre-late the operating variables and the dependent factors. The results also reveal that the dyed sam-ples at the optimized dyeing condition show relatively high colorfastness and noticeable antibac-terial properties against Gram-positive and negative bacteria. This means that the extract of S. striata could be considered a natural dye for the wool dyeing process with remarkable antibacter-ial performance and low energy consumption and environmental impact. Hence, the introduced colorant in the present work seems to be of potential use for a value-adding green waste manage-ment.

Automated summary

In this study, an agricultural crop (Scrophularia striata) was introduced as a new source of natural colorant for dyeing wool yarns. The optimal dyeing conditions were determined using a response surface method, which resulted in high colorfastness and antibacterial properties against Gram-positive and negative bacteria.