Leather dye from Trema orientalis (L.) and its antibacterial effects

Synthetic leather dyes are chromatic agents specially formulated to impart color to leather substrates through dyeing. The current study involves the extraction of natural dye from the stem bark of Trema orientalis (L.) at different temperatures using water (with or without the addition of sodium hydroxide and sodium sulfide as additives). The optimal extraction was achieved at 80 °C without additives. Concentrating the extract using a rotary evaporator followed by freeze-drying resulted in a yield of 12.14%. The efficacy of the extracted dye was assessed by measuring the phenolic content, viscosity, and particle size. The highest value of total phenolic content of extract found, 266.13 mg GAE/g of dry extract, indicated the possibility of dyeing leather. The viscosity of the dye showed the temperature range of 51–54 ºC as optimum application criteria. The particle size of the dye exhibited a range spanning from 449 to 867 nanometers, indicating superb penetration ability through the leather pores. The antimicrobial efficacy was observed to be positive against a limited number of gram-positive as well as gram-negative bacteria. Final evaluation of the experimentally dyed sample against a control sample regarding relevant parameters viz. exhaustion, fastness, strength, SEM image indicated its potentiality as a colorant for leather industry.