Chemical composition, antiviral and antimicrobial activities of the essential oils of Ferula hormonis, Plectranthus coleoides and Magnolia grandiflora

Essential oils were obtained by hydrodistillation from the fresh leaves of Magnolia grandiflora L., aerial part of Plectranthus coleoides Benth. and dried roots of Ferula hormonis and were analyzed by GC/MS. The main constituents of the oil of Ferula were levomenol (23.42%), alpha-humulene (13.80%), cycloisolongifolene (8.35%), spathulenol (7.89%) and beta–oplopenone (7.76%) while the oil of Plectranthus was characterized by thymol (57.57%), gamma-terpinene (15.37%), p-cymene (9.07%) and trans-caryophyllene (5.81%). The major component of Magnolia essential oil were trans-caryophyllene (9.70%), caryophyllene oxide (9.55%), dendrolasin (9.48%), butanoic acid 2-methyl-1-methylpropyl ester (7.38%) and spathulenol (7.23%). Anti herpes simplex virus (HSV-1) was performed using Plaque inhibition assay [1]. The activity was calculated by percentage of viral plaque inhibition at a non-cytotoxic dilution of the oil (1:320 v/v). The most potent oil was obtained from ferula essential oil (81.4%) against HSV-1. Antimicrobial screening was conducted using the disc diffusion assay against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Aspergillus niger, and the human pathogenic yeast, Candida albicans. The minimum inhibitory concentrations (MIC) were determined [2]. The essential oil of Plectranthus was the most active as antimicrobial. At dilution of 1:100 v/v essential oil of Plectranthus inhibited the growth of S. aureus, B. subtilis, A. niger and C. albicans while the dilution of 1:75 v/v inhibited the growth of E. coli. This chemical and biological investigation have not studied previously.

References: 1. Bermejo, P. et al. (2002), Planta Med. 68: 106–110. 2. Gabraith, H. et al. (1971), J. Appl. Bact. 34: 803–813.