In vitro Toxicity and Genotoxic Activity of Aqueous Leaf Extracts From Four Varieties of Olea europea (L)

• Luc Verschaeve^2*,
• Hayet Edziri³,
• Roel Anthonissen¹,
• Dalenda Boujnah⁴,
• Fethia Skhiri⁵,
• Hechmi Chehab⁴,
• Mahjoub Aouni³,
• Maha Mastouri³

1. ¹ Scientific Institute of Public Health, Toxicology Unit, Brussels.
2. ² University of Antwerp, Department of Biomedical Sciences, Antwerp, Belgium.
3. ³ Laboratory of Transmissible Diseases and Biologically Active Substances, Faculty of Pharmacy, Monastir.
4. ⁴ The Olive Tree Institute, Sousse Resort, Sousse.
5. ⁵ Laboratory of Genetic Biodiversity and Valorisation of Bio Resources, Higher Institute of Biotechnology of Monastir, Monastir, Tunisia Introduction Olive (Olea europaea L.) is an evergreen sclerophyllous tree cultivated in the Mediterranean region since ancient times. Olive orchards have been reliable producers of food and oil for thousands of years, supporting successive civilizations in the Mediterranean area. Olea europaea (syn. Zaytoun, in Arabic) belongs to the family Oleaceae and is a small evergreen tree, from 12 to 20 ft. high, with hoary, rigid branches, and a grayish bark. It is greatly growing in developed and developing countries for its known healing effects.[1] It is for example widely used in folk medicine in the European Mediterranean area, Arabia peninsula, and other tropical and subtropical regions, as diuretic, hypotensive, emollient, and for urinary and bladder infections.[2] Leaves are taken orally for stomach and intestinal diseases and used as mouth cleanser.[3] Decoctions of the dried fruit and of dried leaf are taken orally for diarrhea and to treat respiratory and urinary tract infections. Leaves decoction has also hypotensive,[4] antidiabetic,[5] anti-inflammatory,[6] diuretic,[7] and anticancer[8] activities. Despite its therapeutic value, this medicinal plant was never tested for its possible adverse health effects the way our modern pharmaceutical products are. It is important to investigate not only its potential adverse effects but also its potential beneficial effects. The aim of this study is therefore to fill this gap by investigating the genotoxic activity of four varieties of Olea europea L leaf extracts and to compare their activities. Material and methods Plant material Olea europea leaf varieties were selected from different regions in Tunisia, Chetoui (North), Meski (North), Oueslati (Center), Jarboui (Sahel). The varieties were identified by Professor Dalenda Boujnah from the olive institute of Sousse, Tunisia and voucher specimen numbers were attributed to each of the samples. Abstract 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. Key words: Olea europaea L, Vitotox test, comet assay, genotoxicity, antigenotoxicity Highlights • We investigated the in vitro toxicity and genotoxicity of aqueous extracts of olives • The neutral Red Uptake test, Vitotox and alkaline comet assay were used • Leaf extracts from 4 different origins were investigated • None of them showed in vitro toxicity or genotoxicity • The extracts also didn’t have antigenotoxic properties NRU test Vitotox test Comet assay OLEA EUROPEA L. No cytotoxicity – No genotoxicity – No antigenotoxicity Correspondence: Dr. Luc Verschaeve, Department of Food, Medicines and Consumers Safety, Toxicology Unit, Scientific Institute of Public health (WIV-ISP), Brussels, Belgium. E-mail: luc.verschaeve@wiv-isp.be, India.

Published in Pharmacognosy Magazine