Vitamin E: Natural Antioxidant in the Mediterranean Diet

Oxidation has been related to several diseases in humans. Indeed, to protect the body from high free radical damages, organism requires natural resources of antioxidant compounds, such as phenols, tocopherols (α, β, γ, and σ) which have important roles in the cell antioxidant defense system. In Mediterranean areas, olive oils and pepper fruits are considered among the best foods in a diet, which keeps on attracting the interest of scientists due to the health benefits linked with its consumption. The Olive oil and pepper fruits are among the most consumed nutrients in the Mediterranean diet; their richness in naturally powerful antioxidants, such as alpha-tocopherols, polyphenols, carotenoïds, and capsaicinoïds (specific of capsicum species), and monounsaturated fatty acids in olive and seed pepper oils, constitutes good health protection against oxidative damages and inflammation. Also, these phytochemicals shield and prevent the human body from many diseases such as cardiovascular, coronary, Alzheimer’s diseases, and cancers

The Effects of Ripening Stage and Mode of Culture of Chemlali, Arbequina and Koroneiki on the Capacities of Oils to Scavenge ABTS Free Radicals

The aim of this study is to evaluate the antioxidant power of the olive oil against the cation radical ABTS•+, according to cultivars: Chemlali, Arbequina and Koroneiki; culture modes: extensive and intensive; ripening stages: November and December corresponding stages and study year: 2017 and 2018. Radical percentage inhibition (PI), Trolox equivalent antioxidant capacity (TEAC), inhibitory concentration required to scavenge 50% of radicals (IC50) and principal component analysis (ACP) were determined.  The oil of the Tunisian main cultivar Chemlali, cultivated in extensive mode, has the best scavenging power with the lowest IC50 values of 9.3, 10.8, 9.65 and 10.4 µg/ml respectively in all the ripening stages. Also, at the lowest tested concentration of 20 µg/ml, this oil has the highest TEAC values, respectively 2.28 and 2.20 in November of 2017 and 2018. For the introduced cultivars, Koroneiki presents better performance than Arbequina, in intensive mode, with IC50 ranged from 9.6 to 13.8 against 12.40 to 22.35 for Arbequina. Furthermore, the principal component analysis proves that the oils of Chemlali in extensive mode and Koroneiki in intensive have the best scavenging capacity of ABTS•+. This study proves that the extensive mode is the best culture mode and the ripening stage of November is the best stage in order to get oils with a height antioxidant capacity

The Effects of Ripening Stage and Mode of Culture of Chemlali, Arbequina and Koroneiki on the Capacities of Oils to Scavenge ABTS Free Radicals

The aim of this study is to evaluate the antioxidant power of the olive oil against the cation radical ABTS•+, according to cultivars: Chemlali, Arbequina and Koroneiki; culture modes: extensive and intensive; ripening stages: November and December corresponding stages and study year: 2017 and 2018. Radical percentage inhibition (PI), Trolox equivalent antioxidant capacity (TEAC), inhibitory concentration required to scavenge 50% of radicals (IC50) and principal component analysis (ACP) were determined.  The oil of the Tunisian main cultivar Chemlali, cultivated in extensive mode, has the best scavenging power with the lowest IC50 values of 9.3, 10.8, 9.65 and 10.4 µg/ml respectively in all the ripening stages. Also, at the lowest tested concentration of 20 µg/ml, this oil has the highest TEAC values, respectively 2.28 and 2.20 in November of 2017 and 2018. For the introduced cultivars, Koroneiki presents better performance than Arbequina, in intensive mode, with IC50 ranged from 9.6 to 13.8 against 12.40 to 22.35 for Arbequina. Furthermore, the principal component analysis proves that the oils of Chemlali in extensive mode and Koroneiki in intensive have the best scavenging capacity of ABTS•+. This study proves that the extensive mode is the best culture mode and the ripening stage of November is the best stage in order to get oils with a height antioxidant capacity

24-Epibrassinolide ameliorates the adverse effect of salt stress (NaCl) on pepper (Capsicum annuum L.)

The present study investigates the role of 24-epibrassinolide (EBL) in inducing plant tolerance to salinity. Seedlings of pepper (Capsicum annuum L.) were grown in the presence of 70 mM NaCl and were sprayed with 10-6 M EBL at 7 days after transplantation and were sampled at 28 day. The plants exposed to NaCl exhibited a significant decline in relative growth rate, net CO2 assimilation, stomatal conductance, transpiration and water use efficiency. However, the follow up treatment with EBL significantly improved the above parameters. EBL treated plants had greater relative growth rate compared to untreated plants when exposed to salt stress. Application of EBL increased photosynthesis by increasing stomatal conductance in both control and salt stressed plants and may have contributed to the enhanced growth. The water use efficiency was improved because CO2 assimilation is more important than the transpiration

Estimation and comparison of reference evapotranspiration using different methods to determine olive trees irrigation schedule in different bioclimatic stages of Tunisia

[eng] The study of olive trees water requirements allows a better water management by using more accurate methods including maximum parameters of the continuum soil-plant- atmosphere. The Penman-Monteith equations is consideredas the most rational approach and the most reliable for calculating evapotranspiration. Only this approach necessarily requires an important number of climate parameters. The use of other equations, less complicated and using less climate parameters may be a reliable and efficient alternative. This experimental study was carried out on two cultivars cv. 'Meski' and cv. 'Chemlali' conducted in the intensive system in different bioclimatic stages (Subhumid, Semi-Arid and Arid) in Tunisia. This work aims to estimate olive trees water needs using evapotranspiration calculation in three different bioclimatic stages. For that, we compared the Penman-Monteith formula with Blaney-Criddel, Hargreaves-Temperature, Hargreaves- Radiation and Priestley-Taylor formulas to estimate reference evapotranspiration (ET0). Results show that ET0 values calculated by Priestley-Taylor and Blaney-Criddel formulas were more or less similar to Penman-Monteith. The ET0 values found by Hargreaves-Temperature and Hargreaves-Radiation were twice the values calculated by Penman-Monteith formula. We also found good correlations between the reference evapotranspiration calculated by the Penman-Monteith equation and that calculated by Priestley-Taylor and Blaney-Criddel equations in all bioclimatic stages (R2 more than 0.85, p < 1%). The ET0 sensitivity analysis has shown that solar radiation and air temperature (energetic climatic parameters) have the dominant effect on the ET0 at the level of the different climatic regions. Accordingly, in the case of lack of some climatic parameters and in sub-humid, semi-arid and arid conditions and for the different phenological stages of the olive tree, we can use Priestley-Taylor and/or Blaney-Criddle formulas to estimate water needs

Assessment of Antioxidant and Antimicrobial Compounds of Volatiles from Leaves, Stems and Flowers of Olives

Protection of olive cultivars, Olea europaea L., from diseases and the development of more sophisticated control methods are indispensable for a renovated and competitive olive sector. In this context, the volatiles obtained by the main Tunisian oil cultivar Chemlali and both the introduced cultivars Arbequina and Koroneiki were tested for their antimicrobial activity against several dangerous pathogens by diffusion and dilution methods (in 2014). To evaluate the adaptation to biotic stress, the antioxidant potential was additionally evaluated. The volatiles extracted from leaves, stems and flowers of the tested cultivars exhibited interesting antimicrobial and antioxidant activities, reaching in many cases 100% of inhibition. To identify the bioactive compounds, GC-FID and GC-MS were performed, permitting to identify up to 97.8% of total compounds. Both non-terpene hydrocarbons and terpenes were present in important proportions among volatiles