Cinnamomum triplinerve essential oil as an amikacin carrier agent to combat a polymyxin-resistant Klebsiella pneumoniae strain

Essential oils (EOs) are a complex mix of chemical compounds and can have antibacterial activity. Thus, they can improve the delivery and effectiveness of antimicrobials and are promising candidates for the development of antimicrobial alternatives against resistant microorganisms. In this study, we investigated the chemical composition of Cinnamomum triplinerve essential oil (CtEO), as well as the in vitro and in vivo antimicrobial activity alone and in combination with amikacin (AMK). The results of gas chromatography and mass spectrometry (GCMS) analyses showed that the main components of CtEO were (E) – nerolidol (28.0 %) (the major compound), β–selinene (13.6 %), β–elemene (12.0 %), α–selinene (10.9 %), viridiflorol (6.4 %), (E)-caryophyllene (6.3 %), and spathulenol (4.8 %). In vitro, CtEO along with amikacin (AMK) showed synergistic activity against a polymyxin-resistant K. pneumoniae strain. CtEO + AMK can extravasate proteins and nucleic acids within 3 h of treatment. Effective concentrations showed hemocompatibility, no signs of toxicity in vivo in Caenorhabditis elegans and ensured the survival of infected nematodes. Our results suggested that the association of CtEO and AMK exhibited antimicrobial activity against K. pneumoniae; thus, it is a promising therapeutic alternative as an antimicrobial agent.