Chemical Composition and Antimicrobial Activities of Essential Oil of Nepeta Cataria L. Against Common Causes of Oral Infections

Objectives: Over the past two decades, there has been a growing trend in using oral hygienic products from natural resources such as essential oils and plant ex- tracts. Nepeta cataria L. is a member of the mint family (Labiatae) with several medicinal properties. The objective of this study was to determine the chemical composition and antimicrobial activities of essential oils (EOs) from N. cataria leaves against pathogens causing oral infections. Materials and Methods: The chemical composition of EOs from N. cataria was analyzed by gas chromatography/mass spectrometry (GC/MS). The antimicrobial activity of the essential oil was evaluated by broth micro-dilution in 96 well plates as recommended by the Clinical and Laboratory Standards Institute (CLSI) me- thods. The plates were incubated at 30°C for 24-48 h (fungi) or at 37°C for 24 h (bacteria). Results: The analysis of the EOs indicated that 4a-α, 7-α, 7a-β-nepetalactone (55- 58%), and 4a-α, 7-β, 7a-α-nepetalactone (30-31.2%) were the major compounds of the EOs at all developmental stages. The tested EOs exhibited antimicrobial ac- tivities against the tested bacteria at concentrations of 0.125-4 µL/mL. Moreover, the oils entirely inhibited the growth of Candida species at a concentration less than 1 µL/mL. Conclusion: Based on these results, the EO of N. cataria can possibly be used as an antimicrobial agent in the treatment and control of oral pathogens.