Physiological and biochemical study of the drought tolerance of 14 main olive cultivars in the Mediterranean basin.

A complete study of 14 olive cultivars of great economic importance was carried out. These cultivars are Arbequina, Arbosana, Chemlali, Cornicabra, Cornezuelo de Jaén, Empeltre, Frantoio, Hojiblanca, Koroneiki, Manzanilla de Sevilla, Martina, Picual, Sikitita1 and Sikitita 2. All of them are certified by the World Olive Germplasm Bank of Córdoba (Spain). They are predominant cultivars in the olive groves of different locations throughout the Mediterranean basin, and they were subjected to total water deficit for a minimum of 14 days and a maximum of 42 days in the present study. Data such as chlorophyll content, soil moisture and specific leaf area were gathered. Photosynthetic parameters measured at the respective saturation irradiance of each cultivar were also analysed: assimilation rate, transpiration, stomatal conductance, photosynthetic efficiency, photochemical and non-photochemical quenching, photonic flux density, electron transference ratio, efficient use of water and amount of proline and malondialdehyde as indicators of oxidative stress. In addition to the control, two different experimental conditions were analysed: moderate drought, after 14 days of lack of irrigation, and severe drought, after 28-42 days of total absence of irrigation, depending on the tolerance of each cultivar. Based on the results, the cultivars were characterised and divided into four groups according to their drought tolerance: tolerant, moderately tolerant, moderately sensitive and sensitive to drought. This work represents the first contribution of drought tolerance of a considerable number of olive cultivars, with all of them being subjected to the same criteria and experimental conditions for their classification.

Comprehensive Metabolite Profiling of Chemlali Olive Tree Root Extracts Using LC-ESI-QTOF-MS/MS, Their Cytotoxicity, and Antiviral Assessment.

The large quantity of olive roots resulting from a large number of old and unfruitful trees encouraged us to look for ways of adding value to these roots. For this reason, the current research work is devoted to the valorization of olive roots by identifying active phytochemicals and assessing their biological activities, including the cytotoxicity and antiviral potential of different extracts from the Olea europaea Chemlali cultivar. The extract, obtained by ultrasonic extraction, was analyzed using the liquid chromatography-mass spectrometry technique (LC-MS). The cytotoxicity was evaluated through the use of the microculture tetrazolium assay (MTT) against VERO cells. Subsequently, the antiviral activity was determined for HHV-1 (Human Herpesvirus type 1) and CVB3 (Coxsackievirus B3) replication in the infected VERO cells. LC-MS analysis allowed the identification of 40 compounds, classified as secoiridoids (53%), organic acids (13%), iridoids (10%), lignans (8%), caffeoylphenylethanoid (5%), phenylethanoids (5%),sugars and derivatives (2%), phenolic acids (2%), and flavonoids (2%). It was found that extracts were not toxic to the VERO cells. Moreover, the extracts did not influence the appearance of HHV-1 or CVB3 cytopathic effects in the infected VERO cells and failed to decrease the viral infectious titer.

Isolation of an antiviral compound from Tunisian olive twig cultivars.

(1) Many studies demonstrated that olive oil and the leaves have several biological activities, but the works on olive twigs remain very limited. In this report, we investigated for anti-coxsackievirus B-3 (CVB-3) and anti-herpes virus type 2 (HSV-2) activities of olive twigs from two Tunisian varieties: Chemlali (CM) and Chétoui (CT). Extraction from the olive twigs was carried out using successively hexane, dichloromethane, ethyl acetate and methanol. The obtained extracts were evaluated for their anti-CVB-3 and anti-HSV-2 activities by MTT and plaque reduction assays, respectively. Only hexane extracts exhibited significant activity with a selectivity index of 6.32±0.67 and 5.24±0.82 for CM and CT, respectively. The active compound was isolated through bio-guided assays using Thin Layer Chromatography (TLC) and identified as 2,4-di-tert-butylphenol (2,4-DTBP) by gas chromatography coupled with mass spectrometry (GC-MS). This work is the first study that demonstrated an antiviral activity of both olive twigs and DTBP.

RP-HPLC-DAD-ESI-QTOF-MS based metabolic profiling of the potential Olea europaea by-product "wood" and its comparison with leaf counterpart.

INTRODUCTION: Olea europaea L. organs such as leaves, stems and roots have been associated with numerous in vivo and in vitro biological activities and used for traditional medicinal purposes. However, tree wood is an untapped resource with little information about their chemical composition. OBJECTIVE: That is why, the objective of this study is to increase the knowledge about phytochemicals from 'Chemlali' olive wood by means of mass spectrometry-based analyses. Its comparison with by-products derived from leaves was also studied. METHODOLOGY: Hydromethanol extracts from wood and leaves with stems of 'Chemlali' olive cultivar were analysed using reversed-phase (RP) high-performance liquid chromatography (HPLC) coupled to two detection systems: diode-array detection (DAD) and quadrupole time-of-flight (QTOF) mass spectrometry (MS) in negative ion mode. Tandem MS experiments were performed to establish the chemical structure of olive phytochemicals. RESULTS: A total of 85 compounds were characterised in the studied olive parts and classified as: sugars (3), organic acids (5), one phenolic aldehyde, simple phenolic acids (6), simple phenylethanoids (5), flavonoids (14), coumarins (3), caffeoyl phenylethanoid derivatives (6), iridoids (5), secoiridoids (32), and lignans (5). To our knowledge, the major part of these metabolites was not previously reported in olive tree wood, and 10 olive chemical constituents were identified for the first time in the Oleaceae family. CONCLUSION: The results presented here demonstrated the usefulness of the methodology proposed, based on RP-HPLC-DAD-ESI-QTOF-MS and MS/MS, to develop an exhaustive metabolic profiling and to recover new biologically active compounds in olive wood with pharmacologic and cosmetic potential. Copyright © 2017 John Wiley & Sons, Ltd.

Genetic similarity among Tunisian olive cultivars and two unknown feral olive trees estimated through SSR markers.

We used eight informative microsatellite markers for fingerprinting and evaluation of genetic similarity among 15 Tunisian olive (Olea europaea L.) cultivars and two feral unknown trees named Soulela 1 and Soulela 2. Thirty-one alleles were revealed, and the number of alleles per SSR varied from 2 (UDO12) to 6 (GAPU71A). Cluster analysis grouped cultivars into three main clusters. The two unknown varieties could not be reliably classified into any of these cultivar groups. SSR analysis indicated the presence of three erroneous denominations of cultivars. We resolved two synonymy cases (Zalmati and Chemlali; Rkhami and Chetoui) and one case of homonymy (Chemlali Tataouine). Genetic analyses of DNA extracted from leaves, oils, and embryos of the two unknown cultivars and the two major Tunisian olive cultivars (Chemlali and Chetoui) were also studied. We conclude that the reliable identification of these two feral cultivars needs to be addressed by a larger set of markers.

Effects of irrigation with treated wastewater on root and fruit mineral elements of Chemlali olive cultivar.

Twenty-year-old "Chemlali" olive trees trained to vase and rainfed were investigated in either "on" (2004) or "off" (2003) year. A randomized block design with three blocks and three treatments was used and each experimental plot consisted of nine olive trees. Three treatments were applied: (1) rainfed conditions (RF, used as control treatment); (2) irrigation with well water (WW); and (3) irrigation with treated wastewater (TWW). Irrigation with TWW led to a significant increase of root N, P, Ca, Zn, Mn, Na, and Cl concentrations, in particular in the on-year. Data showed significant differences, between the two years, for the concentration of the mineral elements in the roots, with general lower values in the on-year, probably as a consequence of nutrients movement upward in the tree. Fruit N, P, K, Zn, Mn, and Cl contents were significantly higher in TWW irrigated trees with respect to both RF and WW trees, whereas similar values for Ca, Mg, Na, and Cl contents were measured for WW and TWW irrigated trees. The irrigation with TWW allowed to reuse problematic waters and to save nutrients inputs in the olive orchard thus moving towards a more sustainable management of olive orchards in countries where water is the major limiting factor for agriculture.

Characterisation of phenolic compounds by HPLC-TOF/IT/MS in buds and open flowers of 'Chemlali' olive cultivar.

INTRODUCTION: Plant phenolics are secondary metabolites that constitute one of the most widely occurring groups of phytochemicals that play several important functions in plants. In olive (Olea europaea L), there is not enough information about the occurrence of these compounds in buds and flowers. OBJECTIVE: To conduct a comprehensive characterisation of buds and open flowers from the olive cultivar 'Chemlali'. METHODS: The polar fraction of buds and open flowers was extracted using solid-liquid extraction with hydro-alcoholic solvent. Then extracts were analysed using high performance liquid chromatography (HPLC) coupled to electrospray ionisation time-of-flight mass spectrometry (ESI/TOF/MS) and electrospray ionisation ion-trap tandem mass spectrometry (ESI/IT/MS²) operating in negative ion mode. RESULTS: Phenolic compounds from different classes including secoiridoids, flavonoids, simple phenols, cinnamic acid derivatives and lignans were tentatively identified in both extracts. Qualitatively, no significant difference was observed between flower buds and open flowers extracts. However, quantitatively the secoiridoids presented higher percentage of total phenols in open flowers (41.7%) than in flower buds (30.5%) in contrast to flavonoids, which decreased slightly from 38.1 to 26.7%. Cinnamic acid derivatives and simple phenols did not show any change. Lignans presented the lowest percentage in both extracts with an increase during the development of the flower bud to open flower. CONCLUSION: The HPLC-TOF/IT/MS allowed the characterisation, for the first time, of the phenolic profile of extracts of 'Chemlali' olive buds and open flowers, proving to be a very useful technique for the characterisation and structure elucidation of phenolic compounds.

Analytical evaluation of two monovarietal virgin olive oils cultivated in the south of Tunisia: Jemri-Bouchouka and Chemlali-Tataouin cultivars.

BACKGROUND: The characterisation of virgin olive oils from two Tunisian cultivars, growing in the Tataouin zone, namely Jemri-Bouchouka, a rare olive cultivar, and Chemlali-Tataouin, was carried out. Several analytical parameters were evaluated; these include quality index, fatty acids, phenolic, chlorophyll, carotenoid, squalene, α-tocopherol compositions and oxidative stability. RESULTS: Jemri-Bouchouka olive oil had the highest value of oleic acid (74.50%) while Chemlali-Tataouin olive oil had the highest value of oleic acid (69.39 %) and also was characterized by a high percentage of palmitic acid (14.75 %) which makes this oil freeze at a low temperature [corrected]. On the other hand, Jemri-Bouchouka oil was characterised by a low phenolic and α-tocopherol content (267.72 mg GAE kg⁻¹ and 278.34 mg kg⁻¹, respectively). Ten phenolic compounds were identified. The main phenols found in the two olive oils were oleuropein aglycon and pinoresinol. All phenolic compounds showed significant correlations with oxidative stability. CONCLUSION: The analytical parameters of virgin olive oil that were determined in this study were greatly influenced by cultivar.

Physiological Responses of Two Olive Cultivars to Salt Stress.

The olive tree (Olea europaea L.) is the main fruit tree in most of the arid and semi-arid regions of Tunisia, which is where the problem of salinity is more pronounced. Salinity is one of the main factors that affects the productivity of olive trees, so the objective of this experiment was to study the effects of salinity on the photosynthesis, water relations, mineral status, and enzymatic activity of two cultivars of Olea europaea L., 'Chemlali' and 'Koroneiki'. The trial was conducted under controlled conditions in a greenhouse for a period of 49 days and included two treatments: T0 control and T100 (irrigation with 100 mM of NaCl solution). Under salinity stress, the photosynthesis, stomatal conductance, and leaves of both cultivars were negatively affected. 'Chemlali' showed greater tolerance to NaCl salinity, based on a progressive decrease in osmotic potential (Ψπ) followed by a progressive and synchronous decrease in gs, without a comparable decrease in photosynthesis. The water use efficiency (WUE) improved as a result. In addition, the K+/Na+ ratio in 'Chemlali' rose. This appears to be crucial for managing stress. Conversely, enzymatic activity showed an accumulation of glutathione peroxidase (GPX) in stressed plants. The catalase (CAT) and ascorbate peroxidase (APX) content decreased in both stressed varieties. It can be concluded that the cultivar 'Koroneiki' is more susceptible to salt stress than the cultivar 'Chemlali', because the accumulation of GPX and the decreases in CAT and APX were more pronounced in this cultivar.

Evaluation of Tunisian Olive Leaf Extracts to Reduce the Bioavailability of Acrylamide in Californian-Style Black Olives.

The aim of this work was analyzing the use of olive leaf extracts (OLE) obtained from two local Tunisian olive tree cultivars 'Chemlali' and 'Sayali' to reduce the acrylamide in Californian-style black olives. The phenol profile, antioxidant, and antibacterial activity of the two OLE extracts were evaluated. The principal phenols found were hydroxytyrosol (1809.6 ± 25.3 mg 100 g-1), oleuropein (2662.2 ± 38 mg 100 g-1) and luteolin-7-O-glucoside (438.4 ± 38 mg 100 g-1) presented higher levels in 'Sayali' variety. Small differences were observed between the two kinds of extracts used; the greatest activity of OLE was observed against S. choleraesuis, with values up to 50% inhibition. The extract of 'Chemlali' cultivar was added to the Californian-style table olive, improving its phenol content and its antioxidant characteristics without negatively affecting its sensorial characteristics; these olives showed the highest firmness and proper quality characteristics. The gastrointestinal activity on the acrylamide concentration showed a partial degradation of this compound through the digestion, although the addition of the extract does not seem influence in its gastrointestinal digestion. These findings prove the usefulness of by-products to generate a high-quality added-value product, and this would also be relevant as a step towards a more sustainable, circular economy model.

Triacylglycerols composition and volatile compounds of virgin olive oil from Chemlali cultivar: comparison among different planting densities.

The present study focused on the comparison the chemical composition of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivar (Chemlali) grown in four planting densities (156, 100, 69, and 51 trees ha(-1)). Despite the variability in the triacylglycerols and volatile compounds composition, the quality indices (free fatty acids, peroxide value, and spectrophotometric indices K(232) and K(270)) all of the virgin olive oils samples studied met the commercial standards. Decanal was the major constituent, accounting for about 30% of the whole volatiles. Moreover, the chemical composition of the volatile fraction of the oil from fruits of trees grown at the planting density of 156, 100, and 51 trees ha(-1) was also characterised by the preeminence of 1-hexanol, while oils from fruits of trees grown at the planting density of 69 trees ha(-1) had higher content of (E)-2-hexenal (20.3%). Our results confirm that planting density is a crucial parameter that may influence the quality of olive oils.

Saline water irrigation effects on soil salinity distribution and some physiological responses of field grown Chemlali olive.

The shortage of water resources of good quality is becoming an issue in arid and semi arid regions. Per consequent, the use of water resources of marginal quality is becoming an important consideration, particularly in arid regions in Tunisia, where large quantities of saline water are used for irrigation. Nevertheless, the use of these waters in irrigated lands requires the control of soil salinity and a comprehensive analysis even beyond the area where water is applied. The aim of this study was to investigate the effects of saline water irrigation on soil salinity distribution and some physiological traits of field-grown adult olive trees (Olea europaea L. cv. Chemlali) under contrasting environmental conditions of the arid region in the south of Tunisia. The plants were subjected, over two growing seasons, to two drip irrigated treatments: fresh water (ECe=1.2 dS m(-1), FW) and saline water (ECe=7.5 dS m(-1), SW). Saline water irrigation (SW) has led to a significant increase in soil salinity. Furthermore, these results showed that soil salinity and soil moisture variations are not only dependent on water salinity level but are also controlled by a multitude of factors particularly the soil texture, the distance from the irrigation source and climatic conditions (rainfall pattern, temperature average, …). On the other hand, salt treatment reduced leaf midday water potential (LMWP), relative water content and photosynthetic activity and increased the leaf proline content, and this increase was season-dependent. Indeed, LMWP in SW plants decreased to -3.71 MPa. Furthermore, the highest level of proline in SW plants was registered during summer period (2.19 µmol/mg Fw). The proline accumulation recorded in stressed plants has allowed them to preserve appropriate leaf water status and photosynthetic activity. More to the point, this olive cultivar seems to be more sensible to soil salinity during the intense growth phase. Such tendencies would help to better manage water resources for irrigation, particularly under actual climatic conditions of water scarcity. For example, in the case of the availability of different water qualities, it would be better to preserve those of high quality for olive irrigation during the intense vegetative growth phase, in coincidence with high salt sensitive period, and those of low quality for irrigation during partial growth and plant rest phases. What's more, the urgent use of saline water for irrigation should not be applied without taking into consideration the different surroundings conditions where it is used, particularly the water salinity level, the soil type, the adopted irrigation system, the degree of the crop salt tolerance, the plant growth phase and the climatic conditions of the experimental site.

Use of High-Performance Liquid Chromatography/Electrospray Ionization Mass Spectrometry for Structural Characterization of Bioactive Compounds in the Olive Root Bark and Wood of Chemlali Cultivar.

This report aims to provide complete knowledge on the polyphenol composition and biological activities of the olive tree. The extraction of the root bark and wood of Olea europaea. L (Chemlali cultivar) was realized by solid-liquid ethanolic extraction, whose analysis was conducted via high-performance liquid chromatography equipped with photodiode array detection and mass spectrometry (HPLC-ESI-DAD and MS/MS). Moreover, radical scavenging and antibacterial activities were determined. The results present a total of 14 phenolic compounds belonging mainly to secoiridoid and flavonoid subclasses. Oleuropein was found to be the most abundant compound at an amount of up to 7000 mg/kg followed by ligstroside and oleuropein derivatives. In addition, we found oleocanthal at a great amount (2115 mg/kg). Higher individual polyphenolic concentrations were recorded in root wood extracts compared to bark ones, except for the flavonoid group. Likewise, the total phenolic compound contents increased in the olive root wood. This trend was reflected in biological activities. In fact, root wood extracts exert more important antioxidant and antibacterial activities than bark extracts due to their high bioactive compounds.

Effect of processing technology on chemical, sensory, and consumers' hedonic rating of seven olive oil varieties.

This study established physicochemical and sensory characteristics of virgin olive oils (VOOs) and linked them to consumers' liking using external preference mapping. We used five Tunisian and two foreign VOO varieties produced by two processing systems: discontinuous (sp) and continuous three-phase decanter (3p). The samples were analyzed and evaluated by a panel of 274 consumers. The external preference mapping revealed five VOO clusters with a consumer preference scores rating from 40% to 65%. Consumers highly appreciated the foreign Coratina cultivar's olive oil; the main drivers being richness in polyphenols (markers of bitterness and pungency), mainly the oleuropein aglycone, and volatile compounds (markers of green fruity, green leaves, green apple, cut grassy almond, and bitterness), particularly the trans-2-hexenol. The Tunisian Chemlali (3p) oil was second highly preferred (scoring 55%). The positive drivers for olive oil preference (a profile of almond fruity green and low bitterness and pungency) are the richness in hexanal compounds. Arbequina (sp and 3p) and Chemlali (sp) were the least appreciated due to the fact that Arbequina VOO is not in the tradition of Tunisian consumers, whereas Chemchali VOO is a minor variety representing only 2% of olive oil production in Tunisia and consumed mostly in blends. The differentiation between the two processing systems depends on the variety of cultivar; consumers are able to identify the two processing system in the case of Chetoui, Leguim, and Chemchali.

Comparison of the chemical composition and the organoleptic profile of virgin olive oil from two wild and two cultivated Tunisian Olea europaea.

With the aim to select new olive cultivars with superior physical and chemical properties than the cultivar Chemlali Sfax, the present study focused on the comparison of the chemical composition and the sensory profile of the virgin olive oils (VOOs) of two wild olive trees (Oleasters K and M) with those of VOOs obtained from Chemlali Sfax and Neb Jmel olive cultivars, all growing in the coastal region of Tunisia. Despite the variability in the chemical composition (fatty acids, pigments, and phenolic and volatile compounds) and the organoleptic profile of the VOOs of the oleasters and the cultivars, the quality indices (free fatty acids, peroxide value, and spectrophotometric indices K232 and K270) as well as the fatty acid composition of all VOOs studied met the commercial standards. Both the α-tocopherol and phenol contents varied between the genotypes. The Neb Jmel and Oleaster K VOOs had more than two times higher total phenol levels than the Chemlali Sfax and Oleaster M VOOs. Also the contents of volatile compounds differed between the olive oils studied. Chemlali Sfax and Oleaster K oils were more abundant in aldehydes, whereas Oleaster M VOO had higher contents of alcohols. These results were confirmed by a sensorial analysis showing that the later oil was deprived for consumption despite its abundance in α-tocopherol. In conclusion, the oleasters studied revealed to be interesting, since they produced oils with good quality characteristics in terms of minor compounds (phenols and volatiles) compared to the Chemlali Sfax cultivar.

Olea europaea L. Flowers as a new promising anticancer natural product: phenolic composition, antiproliferative activity and apoptosis induction.

The aim of this study was to characterise phenolic compounds of olive flower obtained from Olive tree cultivar Chemlali and to investigate their anticancer effect on MCF-7 cells. Phenolic characterisation was determined using LC/MS-MS. Cytotoxicity of the extract was determined using MTT. Biochemical markers of apoptosis were evaluated by immunoblotting. Our results showed that olive flower contained significant amounts of phenolic compounds mainly flavonoids, secoiridoids and simple phenols. Furthermore, the phenolic extract exerted a significant reduction in MCF-7 cell viability (EC50 values equal to 220.8 µg/ml). Western blot analysis revealed the presence of the cleaved forms of Parp-1. The DAPI staining analysis demonstrated a significant reduction in the number of cells and a considerable change in the morphology of the treated cells. In conclusion, Olea europaea. L flower contained great amounts of different bio-phenols able to reduce the proliferative activity of breast cancer MCF-7 cells by the induction of apoptosis.

Effect of controlled crossing on the triglyceride and fatty acid composition of virgin olive oils.

Our study reports the triglyceride (triacylglycerol, TAG) composition of five new Tunisian virgin olive oil cultivars obtained through controlled crossings of the cultivar (cv.) Chemlali Sfax. These cultivars have been selected among a progeny of 500 olive descendants, based on an evaluation of the fatty-acid (FA) composition of their oils. Among these samples, two were derived from the crossing with the cv. Sigoise as pollinator (SM634) or pollen acceptor (SM1110) and the others from the crossing with the cv. Meski as pollen acceptor (SM513, SM514, and SM517). The five descendants were characterized by a good fat value, a balanced FA composition, and a high content of triolein, varying between 26.9 (SM514) and 45.46% (SM1110). They had an improved FA composition as compared to that of the cv. Chemlali Sfax and their fruits were slightly bigger. The principal component analysis suggested that the TAG variables were more suitable than the total FAs for an optimum classification of the cultivar samples analyzed. The cultivars obtained through the crossing with the cv. Sigoise (as pollen acceptor or pollinator) had a more favorable composition of FAs and TAG than those obtained through the crossing with the cv. Meski, which indicated that genetic factors had the most important influence on the quality of the virgin olive oils.

Contribution of Major Polyphenols to the Antioxidant Profile and Cytotoxic Activity of Olive Leaves.

AIMS: This study was designed to investigate the phytochemical profile and the cytotoxic activities of the eco-friendly extracts of olive leaves from Chemlali cultivar. MATERIALS AND METHODS: The Phenolic composition of olive leaves extracts, the antioxidant activity and the cytotoxic effects against MCF-7 and HepG2 cells were determined. RESULTS: Olive leaves extracts showed relevant total polyphenols contents. Oleuropein was the major detected phenolic compound reaching a concentration of 16.9 mg/ml. The antioxidant potential of the studied extracts varied from 23.7 to 46.5mM Trolox equivalents as revealed by DPPH and ABTS assays. Cytotoxicity experiments showed similar trends for both HepG2 and MCF-7 cells with the infusion extract being the most active. CONCLUSION: This study denotes that olive leaves may have great potential as endless bioresource of valuable bioactive compounds which may have a wide application.

Influence of olive maturity stage and geographical origin on some minor components in virgin olive oil of the chemlali variety.

Minor compounds such as sterols, aliphatic alcohols, tocopherols, and chlorophylls in virgin olive oil from Chemlali cultivar were analyzed during the maturity process. The study concerns oils from the following three different olive growing areas of Tunisia: Sfax, Sidi Bouzid, and Enfidha. Analytical results showed that both the maturity process and the olive provenances influence the evolution of the content of these compounds.

Geographical Characterization of Tunisian Olive Tree Leaves (cv. Chemlali) Using HPLC-ESI-TOF and IT/MS Fingerprinting with Hierarchical Cluster Analysis.

The olive plant has been extensively studied for its nutritional value, whereas its leaves have been specifically recognized as a processing by-product. Leaves are considered by-products of olive farming, representing a significant material arriving to the olive mill. They have been considered for centuries as an important herbal remedy in Mediterranean countries. Their beneficial properties are generally attributed to the presence of a range of phytochemicals such as secoiridoids, triterpenes, lignans, and flavonoids. With the aim to study the impact of geographical location on the phenolic compounds, Olea europaea leaves were handpicked from the Tunisian cultivar "Chemlali" from nine regions in the north, center, and south of Tunisia. The ground leaves were then extracted with methanol : water 80% (v/v) and analyzed by using high-performance liquid chromatography coupled to electrospray time of flight and ion trap mass spectrometry analyzers. A total of 38 compounds could be identified. Their contents showed significant variation among samples from different regions. Hierarchical cluster analysis was applied to highlight similarities in the phytochemical composition observed between the samples of different regions.