Antimicrobial effects of catnip (Nepeta cataria L.) essential oil against canine skin infection pathogens

Research (Published online: 08-03-2024)

10. Antimicrobial effects of catnip (Nepeta cataria L.) essential oil against canine skin infection pathogens

Glenn Neville Borlace, Ranee Singh, Supawadee Seubsasana, Pranom Chantaranothai, Eakachai Thongkham, and Jareerat Aiemsaard

Veterinary World, 17(3): 585-592

Glenn Neville Borlace: Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.

Ranee Singh: Division of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.

Supawadee Seubsasana: Division of Pharmaceutical Sciences, Faculty of Pharmacy, Thammasat University, Pathum Thani 12120, Thailand.

Pranom Chantaranothai: Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.

Eakachai Thongkham: Division of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.

Jareerat Aiemsaard: Division of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.

Background and Aim: Catnip essential oils have antimicrobial effects against bacteria, yeast, and fungi; however, there is limited information regarding their antimicrobial activity against pathogens that cause canine skin infections. This study aimed to identify the phytochemical constituents of catnip essential oil and assay its antimicrobial activity against Staphylococcus pseudintermedius, Malassezia pachydermatis, Microsporum canis, Microsporum gypseum, Microsporum gallinae, and Trichophyton mentagrophytes.

Materials and Methods: Catnip essential oil was extracted by hydrodistillation, and its chemical constituents were analyzed by gas chromatography–mass spectrometry (GC–MS). In vitro antimicrobial activity was investigated using broth microdilution and time-kill tests. To evaluate the effect of catnip essential oil on microbial morphology and cell membrane integrity, scanning electron microscopy (SEM) and leakage studies were conducted.

Results: GC–MS analysis revealed that the principal components of catnip essential oil were cis- and trans-nepetalactone (57.09% of peak area), trans-, cis-nepetalactone (39.69% of peak area), trans-caryophyllene (1.88% of peak area), and caryophyllene oxide (1.34% of peak area). The minimum inhibitory concentration, minimum bactericidal concentration, and minimum fungicidal concentration values determined by broth microdilution ranged from 0.0625 mg/mL to 4.0 mg/ mL. Time-kill testing showed that the germicidal effects of catnip essential oil were time and concentration-dependent, respectively. Environmental SEM and cell leakage analysis indicated that catnip essential oil disrupted the integrity of cell membranes in the tested microorganisms.

Conclusion: Catnip essential oil has potential as an alternative antimicrobial against a wide range of canine skin infection pathogens, including S. pseudintermedius, M. pachydermatis, Mi. canis, Mi. gypseum, Mi. gallinae, and T. mentagrophytes.

Keywords: antimicrobial activity, canine dermatitis, catnip, Nepeta cataria.

This document is a research article that discusses the antimicrobial effects of catnip essential oil against canine skin infection pathogens.

Catnip essential oil has antimicrobial effects against a wide range of canine skin infection pathogens, including Staphylococcus pseudintermedius, Malassezia pachydermatis, Microsporum canis, Microsporum gypseum, Microsporum gallinae, and Trichophyton mentagrophytes.

The principal components of catnip essential oil are cis- and trans-nepetalactone, trans-, cis-nepetalactone, trans-caryophyllene, and caryophyllene oxide.

The minimum inhibitory concentration (MIC) values of catnip essential oil ranged from 0.0625 mg/mL to 4.0 mg/mL against the tested microorganisms.

Catnip essential oil has time and concentration-dependent germicidal effects, with higher concentrations and longer contact times resulting in increased antimicrobial activity.

Catnip essential oil disrupts the integrity of cell membranes in the tested microorganisms, leading to leakage of intracellular nucleic acid components.