Diterpenoid-rich reddish-purple bellyache bush ( <i>Jatropha gossypiifolia</i> L) leaf extract for functional colouring of cotton yarns

Global environmental concerns on synthetic dyes (SDs) have promoted the consumption of natural dyes (NDs) for industrial applications. This study was designed for promoting the circular economic practice, where natural dyeing of 4 min microwave (MW) irradiated (ICY) and non-irradiated cotton yarns (NCY) were optimised by varying the dyeing pH, liquor ratio, temperature, and time. Dye exhaustion (€) increased by 20.88% and tint strength (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>K</mml:mi><mml:mo>/</mml:mo><mml:mi>S</mml:mi></mml:math>) of dyed cotton yarns increased by 23.37%, with MW treatment at pH 8, temperature of 80 °C, liquor ratio 1:25, and contact time of 40 min as optimal conditions for dyeing. The involvement of less toxic mordants led to obtaining desired dye-fibre fixation, and different colours on bellyache bush (BB) dyed cellulosic yarns. Favourable tint, colourfastness, antimicrobial properties of dyed cotton yarns have established BB extract as a sustainable material for colouring cellulosic-textiles.