Alpha-bisabolol inhibits yeast to hyphal form transition and biofilm development in Candida albicans: in vitro and in silico studies.

In recent years, there has been growing concern about infections caused by Candida albicans, which pose a significant threat to human health. This intensifies the concern that can be largely attributed to the increasing number of people with compromised immune systems and the emergence of drug-resistant strains. Natural molecules are considered to be good alternatives to synthetic antifungal agents. The present study explored the effectiveness of alpha-bisabolol as an antifungal agent and its mechanism of action against C. albicans ATCC90028. α-bisabolol effectively inhibited various pathogenic traits of C. albicans like, adhesion, yeast to hyphal switching, and development of biofilm at 1 mg/ml, 0.25 mg/ml, and 0.125 mg/ml concentration, respectively. In addition, α-bisabolol demonstrated inhibition of cell cycle propagation at the G1 phase. Ergosterol production in the C. albicans was suppressed by α-bisabolol treatment in a dose-dependent manner. The molecular docking study revealed α-bisabolol has a good binding energy of - 7.11 kcal/mol with 14-α-demethylase enzyme, which is crucial for ergosterol synthesis. Therefore, the cell membrane integrity may be affected by treatment with α-bisabolol. qRT-PCR studies proved that α-bisabolol treatment affects gene expression in C. albicans. In silico binding affinity was also analyzed for RAS1, TUP1 and CST20 in the signal transduction pathway and exhibited binding affinities for at - 7.7 kcal/mol, - 8.21 kcal/mol, and for - 5.79 kcal/mol respectively. In conclusion, α-bisabolol caused reduced biofilm, ergosterol synthesis along with altered gene expressions in C. albicans with no hemolysis. This study proposed α-bisabolol as an alternative antifungal agent.