Sensitivity of Candida albicans to essential oils: are they an
alternative to antifungal agents?
, S. Cantamessa
, M. Pavan
, G. Novello
, N. Massa
, A. Rocchetti
, G. Berta
1 Dipartimento di Scienze e Innovazione Tecnologica, Universit
a del Piemonte Orientale, Alessandria, Italy
2 Azienda Sanitaria Santi Antonio, Biagio e Cesare Arrigo, Alessandria, Italy
Candida albicans, electron microscopy,
essential oils, metabolic activity inhibition,
minimal inhibitory concentration, Satureja
montana, Thymus capitatus.
Elisa Bona, Dipartimento di Scienze ed Inno-
vazione Tecnologica, Universit
a del Piemonte
Orientale, Viale Teresa Michel, 11, 15121
2016/0562: received 13 May 2016, revised
14 July 2016 and accepted 25 August 2016
Aims: Candida albicans is an important opportunistic pathogen, responsible
for the majority of yeast infections in humans. Essential oils, extracted from
aromatic plants, are well-known antimicrobial agents, characterized by a broad
spectrum of activities, including antifungal properties. The aim of this work
was to assess the sensitivity of 30 different vaginal isolated strains of
C. albicans to 12 essential oils, compared to the three main used drugs
(clotrimazole, ﬂuconazole and itraconazole).
Methods and Results: Thirty strains of C. albicans were isolated from vaginal
swab on CHROMagar
Candida. The agar disc diffusion method was
employed to determine the sensitivity to the essential oils. The antifungal
activity of the essential oils and antifungal drugs (clotrimazole, itraconazole
and ﬂuconazole) were investigated using a microdilution method.
Transmission and scanning electron microscopy analyses were performed to
get a deep inside on cellular damages. Mint, basil, lavender, tea tree oil, winter
savory and oregano essential oils inhibited both the growth and the activity of
C. albicans more efﬁciently than clotrimazole. Damages induced by essential
oils at the cellular level were stronger than those caused by clotrimazole.
Conclusions: Candida albicans is more sensitive to different essential oils
compared to the main used drugs. Moreover, the essential oil affected mainly
the cell wall and the membranes of the yeast.
Signiﬁcance and Impact of the Study: The results of this work support the
research for new alternatives or complementary therapies against vaginal
Candida spp. are commensal yeasts found on the skin,
mucous membranes, gastrointestinal tract, blood and
vagina of animals and humans (Odds 1988). In the last
decades, the incidence of human fungal infections has
orl 2009) with Candida spp. being the
major agents of nosocomial ones (Cleveland et al. 2015).
Among them, Candida albicans is the most frequently
isolated in human candidiasis (Maresca et al. 2013). The
proliferation of C. albicans is usually controlled by the
immune system of the host; however, in immuno-com-
promised patients, especially AIDS ones or those
undergoing chemotherapy and immunosuppressive ther-
apy, this yeast causes severe opportunistic infections
(Pfaller and Diekema 2004; Maresca et al. 2013). Candida
spp. virulence is determined by the expression of adhe-
sion proteins and hydrolytic enzymes (Mitchell 2016), by
the characteristics of the cell wall, and by the morpholog-
ical modiﬁcation from yeast to pseudohyphal and hyphal
forms (Williams et al. 2011) that have an important role
in tissue penetration and invasion (Jayatilake et al. 2006).
Fungal infections are commonly treated with antifungal
drugs, mainly belonging to the azoles (clotrimazole, ﬂu-
conazole, itraconazole, ketoconazole) and polyenes (am-
photericin B, nystatin) categories (Williams et al. 2011).
Journal of Applied Microbiology 121, 1530--1545 © 2016 The Society for Applied Microbiology
Journal of Applied Microbiology ISSN 1364-5072