Thymol (25–200 mg/kg) was shown to modulate the immune system in cyclosporine-A treated Swiss albino mice by enhancing the expressions of cluster of differentiation 4 (CD4), cluster of differentiation 8 (CD8) and Th1 cytokines via upregulation of IFN-γ expression and enhanced secretion of interleukin-12 (IL-12).
Anti-microbial Properties: Thymol at 2.5 mM inhibits the growth of S. aureus, E. coli, and S. Typhimurium. Furthermore, a synergistic interaction was found for thymol with all antibiotics tested against E. coli, S. Typhimurium, S. aureus, and S. pyogenes (Palaniappan and Holley, 2010). Thymol ester derivatives were found to be more effective against streptococcus species (Mathela et al., 2010). Thymol was found to possess antibacterial activity against selected verocytotoxigenic E. coli (Rivas et al., 2010). Thymol (0.12%) possess antifungal activity against C. albicans MTCC 227 biofilm inhibition (Pemmaraju et al., 2013). Gelatin films containing different thymol concentrations (1–8%) produced inhibitory zones ranging from 30 to 46 mm against several bacteria. Thymol was more effective against Gram-positive strains (Kavoosi et al., 2013). Thymol (15 and 30 mg/kg) was shown to possess cytotoxic and antileishmanial activities in hamsters experimentally infected with Leishmania (Viannia) panamensis (Robledo et al., 2005). Thymol derivative named benzoyl-thymol was the best inhibitor (8.67 ± 0.28 μg/mL) against Leishmania infantum chagasi (de Morais et al., 2014).