Acta Pharm. 66 (2016) 411-421

 

full paper

Original research paper

 

Olive leaf extract activity against Candida albicans and C. dubliniensis – the in vitro viability study

NATAŠA ZORIĆ, NEVENKA KOPJAR, KLARA KRALJIĆ, NADA ORŠOLIĆ, SINIŠA TOMIĆ and IVAN KOSALEC

natasa.zoric@halmed.hr

1 Agency for Medicinal Products and Medical Devices of Croatia (HALMED), Zagreb, Croatia

2 Institute for Medical Research and Occupational Health, Zagreb, Croatia

3 University of Zagreb, Faculty of Food Technology and Biotechnology, Zagreb, Croatia

4 University of Zagreb, Faculty of Science Division of Biology, Zagreb, Croatia

5 University of Zagreb, Faculty of Pharmacy and Biochemistry, Zagreb, Croatia

Accepted March 11, 2016

Published online June 21, 2016

 

Olive leaf extract is characterized by a high content of polyphenols (oleuropein, hydroxytyrosol and their derivatives), which is associated with its therapeutic properties. The objective of the present research was to evaluate the antifungal activity of olive leaf aqueous extract against Candida albicans ATCC 10231 and C. dubliniensis CBS 7987 strains. Minimum inhibitory concentration (MIC) of the extract was determined by several in vitro assays. The extract showed a concentration dependent effects on the viability of C. albicans with MIC value of 46.875 mg mL–1 and C. dubliniensis with MIC value 62.5 mg mL–1.

Most sensitive methods for testing the antifungal effect of the extract were the trypan blue exclusion method and fluorescent dye exclusion method while MIC could not be determined by the method according to the EUCAST recommendation suggesting that herbal preparations contain compounds that may interfere with this susceptibility testing. The fluorescent dye exclusion method was also used for the assessment of morphological changes in the nuclei of the treated cells. According to the obtained results, olive leaf extract is less effective against the tested strains than hydroxytyrosol, an olive plant constituent tested in our previous study.

 

Keywords: antifungal activity, Candida albicans, Candida dubliniensis, olive leaf extract