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Summary

Effects of cultivation variety, collection time, and climate on amounts of oleuropein (OE), a strong antioxidant, in olive leaves were studied. A modified ultrasound-assisted method was used for efficient and quantitative extraction of OE from olive leaf samples before their analysis by a rapid HPLC method. Under the optimized conditions, the extraction was performed in two successive steps with an RSD better than 2.95% (n = 5) and a detection limit of 0.02 μg OE. The amount of OE was determined in twelve samples of olive leaves from Mary Zeitoon, Koroneiki, and Sevillana varieties cultivated in three different regions of Iran after collection in two different seasons. The results confirmed that the amounts of OE varied in different olive varieties with mean values of 127, 115, and 144 μg g−1, respectively, although statistical tests indicated a significant interaction of collection time and climate with olive variety. In general, the OE concentration was significantly higher in the cold season and in the tropical regions than in the hot season and the temperate region.

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The merits of chemometrics in categorizing different Egyptian olive chemovarieties based on their compositional integrity were implemented in this study. Fingerprints of 9 different olive leaves varieties cultivated in Egypt were established using reversed-phase high-performance thin-layer chromatography (RP-HPTLC) prior to and after post-chromatographic derivatization with natural product-polyethylene glycol (NP/PEG) reagent and image analysis using ImageJ® software in order to build 2 separate data matrices. The chromatographic fingerprints were separately subjected to unsupervised pattern recognition multivariate analysis to build 2 separate models using principal component analysis (PCA) and hierarchical clustering analysis (HCA) algorithms to explore the distribution pattern of different chemovarieties. The second model which involved olive samples’ fingerprints after post-chromatographic derivatization exhibited greater ability to reveal a broader spectrum of phytoconstituents with enhanced sensitivity. Densitometric RP-HPTLC quantification of oleuropein marker was compared to image analysis approach using Sorbfil TLC Videodensitometer® by newly developed and validated methods. Densitometry exhibited better performance characteristics than image analysis method and therefore was executed for determination of oleuropein concentration in the 9 Egyptian olive varieties. Oleuropein marker solely was found to be inadequate for standardization of olive leaves varieties. This study demonstrated a comprehensive approach for the rapid classification of different Egyptian olive varieties, which is crucial to warranting their chemical-consistency and, thereafter, effective consistency.

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Abstract  

The energy-dispersive X-ray fluorescence (EDXRF) spectroscopy has been used for the determination of essential and trace elements" contents of some twenty Nigerian medicinal plants. The accuracy and precision of the technique were assured by analyzing the European Community Bureau Reference Standard BCR 62 (Olive Leaves). Fourteen elements, namely K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr were detected with toxic heavy metal such as Cd, As, Pb, Hg were detected in the samples. The ranges of elemental concentrations varied from 7.7.104 to 1.6 mg/kg in the herbs. The results show that many of these plants contain elements of vital importance for human metabolism and prevention and healing of diseases.

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A study was carried out on the root distribution of mature olive trees (olea europaea, L., var. manzanillo) grown on a sandy soil, irrigated by means of drip irrigation, and on the nutrient distribution in the soil and plants. Soil was sampled at a distance of 20-160 cm from the tree trunks at depths of 0-80 cm. Leaves were also analysed for nutrient content. The roots were concentrated in the area 80-140 cm from the trunk at a soil depth of 20-60 cm, i.e. in the zone with the highest soil water content. In the horizontal layer, magnesium, iron, manganese, zinc and copper mostly decreased at the ends of the wet area, while in the vertical layer, the 0-20 cm surface soil layer was the richest in potassium, calcium, manganese, zinc and copper. Phosphorus concentrations fluctuated. The average values of potassium, magnesium, iron, manganese, zinc and copper concentrations in olive leaves were significantly higher in bearing years than in non-bearing ones. For this reason it is important to increase the doses of fertilizers containing these elements after bearing years to replace the high removal.

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, O. ( 2016 ): Beneficial health effects of olive leaves extracts . J. Nat. Sci. Res. , 4 , 1 – 9 . Salah , M. , Ben Abdelmelek

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. , Alami , M. & Khomeiri , M. ( 2012 ): Antioxidant effect of microwave-assisted extracts of olive leaves on sunflower oil . J. Agr. Sci. Tech.-Iran , 14 , 1497 – 1509

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Acta Alimentaria
Authors: A. Dobrinčić, L. Tuđen, M. Repajić, I. Elez Garofulić, Z. Zorić, V. Dragović-Uzelac, and B. Levaj

content of spray dried OLE powder. 1 Materials and methods 1.1 Samples and chemicals Olive leaves, cv. Cipressino, were collected in Split area (Croatia), air dried at room temperature for 4 days, milled with electric grinder, and stored in the dark at 4

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freezing and dehydration of olive leaves (var. Serrana) on extract composition and antioxidant potential . Food Res. Int. , 50 , 189 – 196 . Chan , E

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998 1004 De Leonardis, A. , Aretini, A. , Alfano, G. , Macciola, V. & Ranalli, G. (2007b): Isolation of a hydroxytyrosol-rich extract from olive leaves ( Olea

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products, such as gymnemic acid, cichoric acid, and vitexin ( Zhu et al., 2015; Li et al., 2019; Peng et al., 2020 ). OA is a pentacyclic triterpenoid found in many fruits and vegetables such as, olive leaves, grapes, mistletoe sprouts, and papaya. OA has

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