Biological Activities of Chamaecyparis lawsoniana (A.Murray bis) Parl. and Thuja plicata Donn ex D.Don Essential Oils: Toxicity, Genotoxicity, Antigenotoxicity, and Antimicrobial Activity

Abstract

Essential oils (EOs) derived from evergreen conifer trees are recognized as complex sources of agents with various biological activities. In this study, the biological activities of the EOs derived from Chamaecyparis lawsoniana (A.Murray bis) Parl. (CLEO) and Thuja plicata Donn ex D.Don (TPEO) were investigated. The third instar larvae of the fruit fly Drosophila melanogaster were used as a model organism to determine the in vivo toxicity, genotoxicity, and antigenotoxicity of five different concentrations of CLEO and TPEO, ranging from 0.19% to 3%. Artemia salina was used for acute toxicity assessment and determination of LC50 after 24 h and 48 h. The antimicrobial activity of the CLEO and TPEO was tested against fourteen bacterial and two fungal strains using the microdilution method. The larvicidal activity and developmental time of D. melanogaster increased as the concentrations of the EOs rose. CLEO and TPEO produced a dose-dependent increase in DNA damage compared with the negative control. Both oils, at concentrations up to 1.5%, demonstrated the ability to reduce the genotoxic effect induced by ethyl methanesulfonate, with a reduction rate exceeding 60%. CLEO and TPEO were highly toxic against Artemia salina nauplii. The results indicate that the tested EOs act as antimicrobial agents against some pathogenic bacteria and fungi. CLEO and TPEO show promising potential as a source of antimicrobial and antigenotoxic agents and as potential biocides against pest insects and arthropods.