Anti-Candida albicans biofilm activity by Cassia spectabilis standardized methanol extract: an ultrastructural study

Candida (C.) albicans infection in its biofilm mode of growth has taken centre point with the increasing recognition of its role in human infections due to the development of resistance to the commonly used antibiotic or phenotypic adaptation within the biofilm. Hence, in this study the inhibitory effect of methanol extract of Cassia (C.) spectabilis leaves was evaluated against biofilm forming C. albicans.

Anti-yeast activities were carried out using disc diffusion assay and broth dilution method against biofilm forming C. albicans. C. spectabilis leaves extract was assessed using XTT (2,3-bis [2-Methoxy-4-nitro-5-sulphophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay for biofilm quantification with positive control fluconazole. Scanning electron microscopic (SEM) and confocal scanning laser microscopy (CLSM) analysis further revealed reduction in C. albicans biofilm by C. spectabilis leaves extract.

The methanol extract of C. spectabilis showed a favorable antiyeast activity against C. albicans with MIC (Minimum Inhibitory Concentration) value of 6.25 mg/ml. Fluconazole and leaves extract showed 95.4% and 96.9% biofilm reduction respectively. The main changes observed under scanning electron microscopy after C. spectabilis leaves extract treatment were cellular damage and disruption in biofilms of C. albicans. The ultrastructural changes visualized by SEM were further confirmed using CLSM study.

The results from this research conclusively exhibit the in vitro anti-biofilm potential of C. spectabilis leaves extract against Candida biofilm.