Isatin inhibits adhesion and Biofilm formation in Candida albicans Isatin as anti-Candida albicans agent

Background: Isatin possesses various biological activities. Isatin inhibit virulence factors in C. albicans . Method: Micro broth dilution method was used to determine the minimum inhibitory concentration of Isatin against two strains of C. albicans ATCC 90028 and GMC 3 clinical isolate. Biofilm was formed on 96 well polystyrene plates with different concentrations of Isatin (2 mg/ml to 0.062 mg/ml) and biofilm growth was quantified by using XTT-metabolic assay for both the strains. Light and scanning electron microscopy (SEM) were used to observe biofilm architecture. To study the effect of isatin on gene expression during biofilm formation qRT-PCR was used. Results: : Isatin exhibited concentration dependent inhibition against planktonic growth, adhesion and biofilm formation of C. albicans in both the strains. It inhibited the growth significantly (P < 0.05) at 0.5 mg/ml (MIC50) in ATCC 90028. Isatin exhibited anti-biofilm activity (MIC50) at 0.5 mg/ml and 1 mg/ml against ATCC 90028 and GMC3 respectively. Isatin treated (0.5 mg/ml) cells showed about 47 % increase in G2/M phase and 4 % increase in cell number in S phase compared to control. Down regulation of genes involved in Ras-cAMP-MAPK and Cek1-MAPK pathway except Tec 1 was found after treatment with Isatin. Conclusion: The current study reveals that Isatin can be repositioned as an antifungal agent against C. albicans pathogenesis by confirming its potential by in vivo studies. It may represent a potential novel anti-virulence agent in C. albicans.