Measurement of selected trace elements in Olea europaea L. cv. 'Sigoise'

New Insights into Trace Element Accumulation in Kernels of Two Algerian Populations of Argan (Argania spinosa (L.) Skeels): An Endangered Endemic Tree

Argan is one of the valuable oilseed trees in the Northwest Africa area, with important ecological and socioeconomic benefits; however, information underlying its elemental status remains absent . The current work was performed for the first time to quantify the mineral status of Argania spinosa kernels collected from two different geographic Algerian regions (Mostaganem and Tindouf). Elemental investigation (As, Br, Ca, Ce, Co, Cr, Fe, K, La, Na, Rb, Sb, Sc, Sm, Th, and Zn) was performed using neutron activation analysis (NAA). Two standard reference materials from the National Research Center for certified reference materials (China), namely, CRM-GBW 07605 (GSV-4 tea leaves), and the National Institute of Standards and Technology (USA), namely, NIST (SRM 1573a, tomato leaves), were used to ensure precision and validation of NAA measurements. A computational calculation of data including principal component analysis (PCA) and Pearson correlation coefficient (r) was applied. The extents of essential elements in Mostaganem kernels were found to be in the order of K (7185 μg g-1) > Ca (2079 μg g-1) > Na (205 μg g-1) > Fe (84.33 μg g-1) > Zn (73.41 μg g-1) > Cr (0.66 μg g-1) > Co (0.035 μg g-1), whereas the overall order of these elements in Tindouf kernels was K (7206 μg g-1) > Ca (3725 μg g-1) > Fe (114.69 μg g-1) > Zn (67.37 μg g-1) > Na (56.29 μg g-1) > Cr (0.54 μg g-1) > Co (0.11 μg g-1). PCA results revealed that Tindouf population was highly loaded with Br, Cr, Cu, Mn, Sr, V, and Zn, while Mostaganem population was associated only with Ce and Sm contents. These findings can be useful for making new formulations for cosmetic and culinary usage and contribute to the nutritional database and food safety.

Antioxidant Extracts from Greek and Spanish Olive Leaves: Antimicrobial, Anticancer and Antiangiogenic Effects

Olea europaea L. is the most valuable species of the Olea type, and its products offer a wide range of therapeutical uses. The olive tree has been extensively studied for its nourishing qualities, and the "Mediterranean diet", which includes virgin olive oil as a key dietary component, is strongly associated with a reduced risk of cardiovascular disease and various malignancies. Olive leaves, a by-product in the olive harvesting process, are valued as a resource for developing novel phytomedicines. For this purpose, two ethanolic extracts obtained from Olivae folium from Spain (OFS) and Greece (OFG) were investigated. Our findings contribute to a wider characterization of olive leaves. Both extracts displayed important amounts of phenolic compounds and pentacyclic triterpenes, OFG having higher concentrations of both polyphenols, such as oleuropein and lutein, as well as triterpenes, such as oleanolic acid and maslinic acid. The antioxidant capacity is similar for the two extracts, albeit slightly higher for OFG, possibly due to metal polyphenol complexes with antioxidant activity. The extracts elicited an antimicrobial effect at higher doses, especially against Gram-positive bacteria, such as Streptococcus pyogenes. The extract with lower inorganic content and higher content of polyphenols and triterpenic acids induced a strong anti-radical capacity, a selective cytotoxic effect, as well as antimigratory potential on A375 melanoma cells and antiangiogenic potential on the CAM. No irritability and a good tolerability were noted after evaluating the extracts on the in vivo Hen's Egg Test-Chorioallantoic Membrane (HET-CAM). Therefore, the present data are suggestive for the possible use of the two types of olive leaf products as high-antioxidant extracts, potentially impacting the healthcare system through their use as antimicrobial agents and as anticancer and anti-invasion treatments for melanoma.

Trace Elements Analysis of Tunisian and European Extra Virgin Olive Oils by ICP-MS and Chemometrics for Geographical Discrimination

The aim of this study was to investigate the levels of trace elements in olive oils from different locations and their use for geographical authentication. Concentrations of seventeen elements were determined in a total of 42 olive oils from Tunisia, Spain (Basque country), and southern France, and in nine soil samples from Tunisia by quadrupole inductively plasma mass spectrometry. The compilation of appropriate techniques integrated into the analytical procedure achieved a precision (RSD) between 2% and 15% and low limits of detection (between 0.0002 and 0.313 µg kg^-1). The accuracy of the analytical method applied for olive oil analysis was evaluated using SRM NIST 2387 Peanut butter. The recoveries obtained after microwave-assisted digestion for the certified elements ranged between 86% and 102%. Concentrations of non-certified elements (V, Cr, Co, Ni, Ba, Rb, Sr, Cd, Pb, and As) were presented. The use of Pearson correlation applied on paired Tunisian oil/soil samples has shown that several elements (Mg, Mn, Ni, and Sr) were significantly correlated. The multivariate statistics using principal component analysis have successfully discriminated against three studied origins. The most significant variables were the elemental concentrations of Cu, Cr, Fe, Mn, Sr, V, and Zn. This study shows the potential of applying trace elements profiles for olive oil geographical discrimination.

Determination of Some Major and Trace Elements in Cladodes of Barbary fig (Opuntia ficus-indica Mill.) by X-ray Fluorescence Spectrometry

Barbary fig (Opuntia ficus-indica) has attracted great attention in extensive rural agriculture for its potential agronomic, medicinal, and environmental benefits. However, there is only incomplete information about its chemical profile. Energy-dispersive X-ray fluorescence (EDXRF) spectrometry was applied to determine the concentrations of 11 major and trace elements (Br, Cr, Cu, Fe, K, Mn, P, Rb, Sr, Yb, and Zn) in cladodes of O. ficus-indica and the adjacent soil. For analytical accuracy, the standard reference materials CRM-IAEA 336 (Lichen) and CRM-NIST 1646a (Estuarine Sediment) were used. The relationships between the chemical elements were established by Pearson's correlation coefficient (r) and principal component analysis (PCA). The results show that K, P, Fe, and Mn were the dominant essential elements in O. ficus-indica cladodes; however, Br, Cr, Cu, Rb, Yb, and Zn were present at low concentrations. The cladodes showed high enrichment with K, Sr, and Br (BEF > 1), but the values of this coefficient were below 1 for the remaining elements. The PCA showed that in the O. ficus-indica cladodes, the higher concentrations of Br, K, and Sr were correlated; conversely, the highest contents of Cr, Cu, Fe, Mn, P, Rb, Yb, and Zn were retained in the soil. The present findings enabled us to determine that O. ficus-indica has a high ability to accumulate K, P, Fe, and Mn in its cladodes. Therefore, the data obtained from the analysis of this cactus will be useful for nutritional and medicinal purposes.