Extraction, Characterization, and Antimicrobial Evaluation of Plant-Based Natural Dyes from Rosa spp., Allium cepa, and Curcuma longa for Sustainable Textile Applications

The ecological and health aspects of synthetic dyes have brought back interest in the use of natural colorants that are plant based. In the research, Rosa spp. petals, Allium cepa peel onions and Curcuma longa rhizomes were extracted to natural dyes and tested on their textile applicability and functionality. They used aqueous extraction, dyed, cotton and silk fabrics using alum as a natural mordant by pre-simultane-, and post-mordanting. The color stability to washing and rubbing was determined on the basis of ISO standards. Fourier Transform Infrared (FTIR) spectroscopy was used to carry out functional characterization. Agar well diffusion was used to determine antimicrobial activity against Staphylococcus aureus and pH sensitivity of the dyes was also studied. The findings indicated good to moderate color fastness especially in mordanted samples, and silk had high dye affinity than cotton. The presences of phenolic, flavonoid, anthocyanin, and curcuminoid functional groups were confirmed by FTIR spectra. Each dye was antimicrobial and had a change in color with pH. The paper identifies the potential of these natural dyes as environmentally friendly multifunctional substitutes of synthetic dyes in textiles, in order to have sustainable applications.