Chemical composition and antibacterial activity of Clinopodium nepeta subsp. glandulosum (Req.) Govaerts essential oil

Abstract

Clinopodium nepeta subsp. glandulosum (Req.) Govaerts is a natural perennial grass belonging to the Lamiaceae family, growing spontaneously on the Mediterranean coast. It is locally known as “kedi fesleğeni” in Turkey. This aromatic plant is used as a mint-like spice in food preparations and in the composition of some recipes during religious feasts. In folk medicine, it is used as stimulant, antiseptic and antispasmodic. Aerial parts of C. nepeta subsp. glandulosum were collected from Bilecik in July 2017, and was air dried. The essential oil was isolated by hydrodistillation using a Clevenger-type apparatus and the composition of the essential oil was simultaneously analysed by GC-FID and GC-MS. Piperitenone oxide (47.8%), limonene (18.6%) and piperitone oxide II (13.6%) were found as major components. Antibacterial activity of the essential oil was tested against Escherichia coli NRRLB-3008, Pseudomonas aeruginosa ATCC 27853, Salmonella typhimurium ATCC 13311, Bacillus cereus NRRL-B3711 and Streptococcus sanguinis ATCC 10556 were used by broth microdilution method. Ciprofloxacin was used as control and Minimal Inhibitory Concentrations (MIC) were determined. The highest activity was found against S. typhimurium (1250 µg/mL). The essential oil is more effective against B. cereus (2500 µg/mL) and S. sanguinis (2500 µg/mL). The lowest activities were determined against E. coli (5000 µg/mL) and P. aeruginosa (10000 µg/mL).