ANTI-DERMATOPHYTIC ACTIVITY OF Salvia nilotica METHANOLIC LEAF EXTRACT AGAINST Trichophyton mentagrophytes

Abstract

Conventional medicine used against dermatophytosis has resulted in treatment failure, relapses of the fungal infection and side effects due to its use. Herbalist in the Tugen community in Kenya claim that Salvia nilotica leaves have anti-dermatophytic effects however, there is no scientific documentation for these claims. This study therefore sought to determine the phytochemical constituents in S. nilotica methanolic crude leaf extract and its anti-dermatophytic activity against the dermatophyte, Trichophyton mentagrophytes and probable mode of action through the effects on Metalloprotease 2 (MEP2), Sulphite efflux pump (SSU1), Subtilisin 3 (SUB3) and dipeptidyl-peptidases V (DDPV) target genes. The phytochemical constituents of methanolic crude leaf extract of S. nilotica were determined using standard methods. Food- poisoned technique was used to determine anti-dermatophytic activity of S. nilotica extract at different concentrations ranging from 7.76 mg/mL to 77.59 mg/mL. Plausible mode of action was determined using quantitative real time polymerase chain reaction to establish the effect of S. nilotica methanolic leaf extract treatment on MEP2, SSU1, SUB3 and DDPV genes of Trichophyton mentagrophytes versus the standard drug fluconazole. Qualitative phytochemical analysis of the methanolic crude leaf extracts of S. nilotica indicated the presence of tannins, saponins, flavonoids, terpenoids, steroids, alkaloids, carbohydrates, amino acids and glycosides but there was absence of phlobatannins and anthraquinones. This study also found that S. nilotica crude leaf extract has anti-dermatophytic activity against Trichophyton mentagrophytes. The activity of crude leaf extract of S. nilotica on Trichophyton mentagrophytes was not significantly different (p < 0.05) when compared with fluconazole. In addition, all the Trichophyton mentagrophytes genes, which were targeted in this study, were down regulated by different folds depending on the concentration of the antifungal agent used. The down regulation noted was -1.7, -1.9, -1.1 and -1.1 folds for MEP2, SSU1, SUB3, and DPPV genes respectively at 0.30 mg/mL of fluconazole. At 0.50 mg/mL of fluconazole, the genes were down regulated by -4.2, -2.9, -1.6 and -34.4 folds for MEP2, SSU1, SUB3 and DPPV respectively. S. nilotica at 13.97 mg/mL down regulated the target genes by -1, -1.2, -1.2 and -38.4 folds for MEP2, SSU1, SUB3, and DPPV genes respectively. Similarly at the concentration of 77.59 mg/mL of S. nilotica the genes were down regulated by -1.3, -7.9, -2.3 and -2211.8 folds for MEP2, SSU1, SUB3 and DPPV respectively. In conclusion, this study has shown that S. nilotica crude leaf methanolic extract could offer a potential alternative medicine for dermatophytosis treatment.