Biological activities (antimicrobial, anti-inflammatory, anti-coronavirus (229E)) and chemical composition of some...

Microbial drug resistance represents one of the major causes of death today. Traditional medicine provides an important health care service and can be applied as alternative therapy. The growing interest in essential oils (EOs) has led to extensive research, due to their diverse applications in pharmaceuticals, food products and cosmetics. The current study evaluated the antimicrobial activity of menthol, lemon, clove and camphor EOs against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Enterococcus faecalis, Bacillus subtilis, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. The tested EOs exhibited a broad spectrum of antimicrobial activity with inhibition zone diameter ranged from 11 to 22 mm. The highest inhibition was observed against P. aeruginosa and A. niger. The anti-inflammatory activity of the EOs was also assessed and was as 64.5 ± 4.1%, 10 ± 1%, 10 ± 2.1% and 7.5 ± 3.1% for menthol, camphor, lemon and clove EOs, respectively. Examination of antiviral activity of the EOs against Coronavirus 229E showed varied antiviral potency with IC₅₀ values of 16.248, 9.90, 4.645 and 2.256 μg/mL for camphor, menthol, clove and lemon, respectively. Chemical constituents of menthol and camphor essential oils were detected using gas chromatography coupled with mass spectrometry (GC-MS). Results indicated the dominance of eucalyptol (29.17%), camphor (7.96%) in camphor EO and 9,12-Octadecadienoic acid (Z,Z), (12.24%), levomenthol (10.94%) in menthol EO samples.