Aim: Despite its therapeutic value almost nothing is known about potential adverse health effects of Olea europea L. We therefore investigated the in vitro toxicity and genotoxicity of leaf extracts of this plant.
Material and methods: Extracts from olive tree leaves were obtained from four different regions in Tunisia. We investigated the in vitro toxicity, genotoxicity and antigenotoxicity of their aqueous extracts using the neutral red (NR) uptake, Vitotox and alkaline comet assays.
Results: None of the extracts were found to be toxic and none of them were genotoxic, although some doubt exists for the extract obtained at Meski (North of Tunisia). On the basis of the Vitotox test only, none of the extracts appeared to have antigenotoxic (or cogenotoxic) properties.
Discussion: The negative genotoxicity underline the safe use of the leaves, for example, as hypoglycemic and antidiabetic preparations. Lack of antigenotoxicity may indicate that the previously reported anticancer effects do not result from protection against genotoxicity.
Highlights: We investigated the in vitro toxicity and genotoxicity of aqueous extracts of olivesThe neutral Red Uptake test, Vitotox and alkaline comet assay were usedLeaf extracts from 4 different origins were investigatedNone of them showed in vitro toxicity or genotoxicityThe extracts also didn't have antigenotoxic properties Abbreviation list: BaP: benzo(α)pyrene, EMS: ethyl methane sulfonate, LMP: low melting point, NI50: 50% inhibition of NRU, NR: neutral red, NRU: neutral red uptake, OD: optical density, PBS: phosphate buffer saline, SDS: sodium dodecyl sulphate, S/N: signal to noise ratio, 4NQO: 4-nitroquinoline oxide.
Keywords: Olea europaea L; Vitotox test; antigenotoxicity; comet assay; genotoxicity.