Activity assessment of Tunisian olive leaf extracts against the trophozoite stage of Acanthamoeba

Abstract

The olive tree (Olea europaea, Oleaceae) has historically provided huge economic and nutritional benefits to the Mediterranean basin. In fact, olive leaf extracts have also been used by native people of this area in folk medicine to treat fever and other diseases such as malaria. Recently, several studies have focused on the extraction of high-added-value compounds from olive leaves. However, no previous studies have been developed in order to evaluate the activity of these extracts against Acanthamoeba. In the present work, olive leaf extracts from five different Tunisian varieties of olive trees (Chemlali Tataouine, Zarrazi, Toffehi, Dhokkar, and Limouni) were obtained by using three different solvents, and their activity against the trophozoite stage of Acanthamoeba castellanii Neff was screened. The IC50/96 h (50% parasite growth inhibition) was chosen as the appropriate and comparable data to give as previously described. It could be observed that the amoebicidal activity was dose dependent. Trophozoite growth was inhibited by all the tested extracts with IC50 ranging from 8.234 ± 1.703 μg/ml for the alcoholic mixture of the Dhokkar extract to 33.661 ± 1.398 μg/ml for the methanolic extract of the Toffehi variety. The activity in fact was affected especially by the tested variety and not by the solvent extraction, the Dhokkar variety being the most active one as mentioned above.

Programmed cell death in Acanthamoeba castellanii Neff induced by several molecules present in olive leaf extracts

“…The Olive tree has been used by native people from the Mediterranean basin to treat different diseases such as malaria and ulcers. Phytochemical investigations of this plant correlate its benefits to its richness on bioactive molecules including phenolic compounds and triterpenic acids among others [ 4 , 5 ].…”

“…Our preliminary work with OLE from Tunisian origin showed that the ethyl acetate fraction presented high activity against the trophozoïte stage of Acanthamoeba spp [ 4 ]. Thus, in this work it was aimed to evaluate the activity of the major molecules present in OLE and secondly to elucidate key factors involved in the mechanism of action of these molecules against Acanthamoeba spp.…”

Activity Assessment of Tunisian Olive Leaf Extracts Against Survival and Virulence in vitro of Candida glabrata

“…In our study, similar pattern of biofilm formation and enzymes production was also recorded for test leaves and fluconazole drug against C. glabrata 362BC. Comparably to several papers, OLE provides a stronger activity against fungi and parasite [6][7][8][28][29][30][31]. Masoko and makgapeetja when tested O. Africana extracts against C. albicans and Cryptococcus neoformans demonstrated that both were sensitive to the plant extracts with average MIC values of 0.37 and 0.30 mg/ ml [28].…”

“…The MIC is greater than that previously described for C. albicans [28]. However, many authors confirmed that the biological activity of plant extract depends on the plant variety and/or extraction procedure which determines the success of isolating compounds from plant material [28,29]. Indeed, Markin et al reported that OLE extracted with water succeeded in elimination of some GRAMbacteria such as Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia with Minimum Bactericidal Concentration (MBC) varied between 0.13% to 0.6% and also some yeast such C. albicans with Minimum Fungicidal Concentration (MFC) equal to 15% [30].…”

“…Moreover, Karygianni, et al [31] demonstrated that OLE extracted with acetone eradicated microbial strains with MIC value between 0.07 mg/ ml for Streptococcus oralis and 10 mg/ ml for C. albicans and Escherichia coli. In our study, we used methanol to extract compounds from olive leaves which was proven the most polar solvent according to several publications [29,32]. The slight difference between the activities of the extracts from many studies could be attributed to the different chemical profile due to plant variety and/or the extraction solvent.…”