Phytomedicine 19 (2011) 48–55 Contents lists available at ScienceDirect Phytomedicine jou rn al hom epage: www.elsevier.de/phymed In vitro antifungal, anti-elastase and anti-keratinase activity of essential oils of Cinnamomum-, Syzygium- and Cymbopogon-species against Aspergillus fumigatus and Trichophyton rubrum Mohd Sajjad Ahmad Khan, Iqbal Ahmad ∗ Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, India a r t i c l e i n f o Keywords: Essential oils Growth inhibition Electron microscopy Virulence factors Elastase activity Keratinase activity Cinnamomum-, Syzygium-, Cymbopogon-species a b s t r a c t This study was aimed to evaluate effects of certain essential oils namely Cinnamomum verum, Syzygium aromaticum, Cymbopogon citratus, Cymbopogon martini and their major components cinnamaldehyde, eugenol, citral and geraniol respectively, on growth, hyphal ultrastructure and virulence factors of Aspergillus fumigatus and Trichophyton rubrum. The antifungal activity of essential oils and their major con- stituents was in the order of cinnamaldehyde > eugenol > geraniol = C. verum > citral > S. aromaticum > C. citratus > C. martini, both in liquid and solid media against T. rubrum and A. fumigatus. Based on promising antifungal activity of eugenol and cinnamaldehyde, these oils were further tested for their inhibitory activity against ungerminated and germinated conidia in test fungi. Cinnamaldehyde was found to be more active than eugenol. To assess the possible mode of action of cinnamaldehyde, electron micro- scopic studies were conducted. The observations revealed multiple sites of action of cinnamaldehyde mainly on cell membranes and endomembranous structures of the fungal cell. Further, test oils were also tested for their anti-virulence activity. More than 70% reduction in elastase activity was recorded in A. fumigatus by the oils of C. verum, C. martini, eugenol, cinnamaldehyde and geraniol. Similar reduction in keratinase activity in A. niger was recorded for the oils of C. martini and geraniol. Maximum reduction (96.56%) in elastase activity was produced by cinnamaldehyde whereas; geraniol caused maximum inhi- bition (97.31%) of keratinase activity. Our findings highlight anti-elastase and anti-keratinase activity of above mentioned essential oils as a novel property to be exploited in controlling invasive and superficial mycoses. © 2011 Elsevier GmbH. All rights reserved. Introduction Fungal infections caused by various pathogenic and opportunis- tic groups are on the rise in the different parts of the world. Invasive aspergillosis caused by Aspergillus is considered as a major cause of morbidity and mortality in immunocompromised hosts and mor- tality rates may range from 40 to 90% in high risk populations (Dagenais and Keller 2009). Other chronic infections associated with the immunocompromised patients are caused by dermato- phytes mainly Trichophyton sp, and had shown increased incidence in recent years especially in the tropical countries (Venkatesan et al. 2007). With the increasing number of immunosuppressed patients at an unprecedented rate, the management of these fungal infec- tions would be a definite challenge to mankind. ∗ Corresponding author at: Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, India. E-mail address: ahmadiqbal8@yahoo.co.in (I. Ahmad). Current antifungal therapy for such fungal infections has been threatened by the development of drug resistant strains, host tox- icity of available polyenes and fungistatic mode of action of azoles (Barker and Rogers 2006). Therefore, development of newer drugs with improved efficacy and safety or alternative mode of combat- ing infections is needed. Recent developments in fungal genomics have provided unprecedented opportunities for identifying new antifungal drug targets and subsequently exploiting in disease con- trol. Targeting virulence and pathogenicity are now considered as valuable anti-pathogenic approaches (Gauwerky et al. 2009). Establishment of infection by fungi depends on the host–cell inter- action with complex interplay of secretion of virulence factors mainly proteinases including elastinases, keratinases, gelatinases, lipases and phospholipases. These extracellular enzymes are prob- ably essential for these organisms to degrade structural barrier and to obtain nutrient and in establishing infections (Voltan et al. 2008). Plant products traditionally being used in ethnomedicine have been expected to deliver newer antifungal compounds. Anti- fungal activities of the essential oils or their major constituents against Aspergillus and Trichophyton spp. have been reported by 0944-7113/$ – see front matter © 2011 Elsevier GmbH. All rights reserved. doi:10.1016/j.phymed.2011.07.005