COMPARATIVE STUDY OF ANTIOXIDANT, ANTI-INFLAMMATORY, AND ANTIMICROBIAL ACTIVITIES OF LAC DYE AND D&C RED No. 27

Lac dye and D&C red No. 27, natural and synthetic dye, are commonly used in pharmaceuticals and cosmetics. Their antioxidant, anti-inflammatory, and antimicrobial activities were investigated using the DPPH, the thermal inhibition of egg albumin protein denaturation and the agar diffusion methods, respectively. Lac dye demonstrated stronger antioxidant activity than ascorbic acid (the positive control) and D&C red No. 27, with EC50 values of 2.03±0.08, 8.28±0.02, and 397.87±1.16 µg/ml, respectively. D&C red No. 27 exhibited anti-inflammatory activity (EC50 value 114.61±8.46 µg/ml) higher than diclofenac sodium (EC50 754.11±1.42 µg/ml), whereas lac dye induced inflammation with an IC50 value of 136.40±2.31 µg/ml. At a concentration of 0.25% w/v, lac dye effectively inhibited the growth of Staphylococcus aureus, Escherichia coli, and Porphyromonas gingivalis, producing clear inhibition zones of 17.7±0.6, 18.3±0.6, and 24.3±0.6 mm, respectively. However, lac dye displayed antifungal activity against Candida albicans and Candida tropicalis compared to the solvent (PEG 400) at a concentration of 2% w/v. D&C red No. 27 inhibited against S. aureus, E. coli, and P. gingivalis, with clear zones of 15.3 ± 0.6, 15.3 ± 0.6, and 22.3 ± 0.6 mm, respectively, at a concentration of 0.25%. Notably, D&C red No. 27 demonstrated strong antimicrobial activity against Propionibacterium acnes, with an inhibition zone of 41.0±1.0 mm, which surpassed the 24.0±1.7 mm zone produced by lac dye at the same concentration of 0.25% w/v. However, D&C red No. 27 exhibited only a limited ability to inhibit both types of fungi. These findings suggest that both dyes may offer valuable benefits for the development of future formulation.