Antimicrobial properties of the linalol-rich essential oil ofHyssopus officinalis L. vardecumbens (Lamiaceae)

Abstract

The antimicrobial activity of essential oil of Hyssopus ocinalis L. var decumbens (Jordan & Fourr.) Briq. from France (Banon) and Hyssopus ocinalis L. from Italy (Piedmont) was studied taking account of their chemical composition determined by GC and GC±MS. Pinocamphone and isopinocamphone are present in H. ocinalis (4.4% and 43.3%, respectively), according to the ISO 9841 Standard (1991 E) but they are lacking in var. decumbens, where linalol (51.7%), 1,8-cineole (12.3%) and limonene (5.1%) instead are predominant. The disc diusion tests carried out on Gram-positive (Staphylococcus aureus and Enterococcus spp.) and Gram-negative bacteria (Klebsiella oxytoca, Escherichia coli, Proteus mirabilis, Pseudomonas spp. and two strains of Salmonella spp.) showed an antimicrobial activity generally negligible for H. ocinalis, but broader, and in a few cases more evident (Enterococcus spp. and E. coli), for var. decumbens. All yeasts (seven strains of Candida albicans, C. krusei and C. tropicalis) were strongly inhibited by both species. In liquid medium the MIC of H. ocialis was always 41.2% v/v for bacteria and between 0.6 and 1.2% v/v for yeasts, while the MIC of var. decumbens was between 0.15 and 0.6% v/v for the Gram-positive bacteria, 0.3 and 1.2% v/v for the Gram-negative bacteria and 0.15 and 0.3% v/v for the yeasts. The eect of var. decumbens was generally bactericidal. Linalol, and in a lesser way, 1,8-cineole, may contribute to the greater antimicrobial activity of var. decumbens in comparison with H. ocinalis, while limonene may be responsible for the antimycotic action observed in both oils, as suggested by results of the disc diusion tests carried out on the pure reference substances. #

Chemical Composition of Vintage Preban Absinthe with Special Reference to Thujone, Fenchone, Pinocamphone, Methanol, Copper, and Antimony Concentrations

“…Briq. is morphologically different from Hyssopus officinalis L. and is peculiar for its lack of pinocamphone (34).…”

“…The chemical composition of hyssop oil varies considerably, even between oils obtained from different samples of the same variety of hyssop (34). Volatile oil composition of hyssop varies also in dependence on growth stage or climatic conditions (35).…”

Chemical composition and antifungal activity of essential oil ofHyssopus officinalisL. from Bulgaria against clinical isolates ofCandidaspecies

“…[17À19, 31,32] Most reports about the antifungal activity of hyssop oil are focused on its inhibitory effect against phytopathogenic and mycotoxin-producing fungi. [20,33À35] In contrast, there are only scarce studies about its anticandidal activity.…”

“…To the best of our knowledge, the anticandidal activity of hyssop oil has mostly been determined against reference strains of C. albicans, but less is known about its activity against clinical isolates, especially against NAC species. For example, Mazzanti et al [31] and Kizil et al [19] reported strong antimicrobial activity of essential oil from H. officinalis L. against C. albicans, C. tropicalis and C. krusei. On the contrary, according to other authors, hyssop oil demonstrates only moderate to weak antifungal activity.…”

Genus Hyssopus L. - recent knowledge: A review

“…decumbens was rather bactericidal. This higher antibacterial activity can be caused by linalool and higher content of 1,8-cineole while limonene is apparently responsible for the effect of volatile oil against molds in both variants of hyssop (MAZZANTI et al 1998).…”