Terpinen-4-ol, An Active Constituent of Kewda Essential Oil, Mitigates Biofilm Forming Ability of Multidrug Resistant Staphylococcus aureus and Klebsiella pneumoniae

Abstract The increased incidence of microbial resistance to traditional antibiotics has urged the scientific community to look for alternative therapeutic regimens. In this context, mitigation of biofilm formation is considered as viable alternative. Since, plant derived essential oils are rich heritage of bioactive phytochemicals with widespread pharmacological values, in the present study Terpinen-4-ol, bioactive constituent of Kewda essential oil (KEO) extracted from Pandanus odorifer male flower was evaluated for its antimicrobial and antibiofilm activities against Staphylococcus aureus and Klebsiella pneumoniae and their reference strains, MTCC-740 and MTCC-109. The minimum inhibitory concentration (MIC) of Terpinen-4-ol against S. aureus and K. pneumoniae was 50 and 25 mM, respectively. At MIC level, Terpinen-4-ol exhibited antibacterial activities against both the reference strains i.e. MTCC-740 and MTCC-109 with a zone of 16 and 14 mm, respectively. On treatment with sub-MIC of Terpinen-4-ol, a significant reduction in exopolysaccharides (EPS) production was observed as evident from qualitative Congo red agar (CRA) assay. Further, the reduction in EPS production was quantified with a reduction of 67.51±1.29% against S. aureus. The light and fluorescence microscopic analysis also corroborated the antibiofilm potential of Terpinen-4-ol as a significant reduction in the thickness of biofilm formation was observed. In silico studies provided an insight into the action of Terpinen-4-ol in binding to target proteins associated with biofilm formation and drug resistance. Thus, Terpinen-4-ol could be considered as putative drug candidate in the fight against biofilm associated chronic infections and drug resistance. GRAPHICAL ABSTRACT