Effect of genotype and extraction method on polyphenols content, phenolic acids, and flavonoids of olive leaves (Olea europaea L. subsp. europaea)

Polyphenol’s extraction varied according to various factors. In this study, the effect of genotype and method of polyphenols extraction were investigated using leaves of two cultivated and two wild olive varieties and four hydromethanolic extraction methods. Quantitatively, significant differences were observed according to the extraction method, the genotype, and the interaction genotype-method of extraction. The heat reflux extraction showed the highest polyphenols content in wild olive leaves having an amount of 841.17 mg GAE/100 g DM. The qualitative phytochemical examination using high performance liquid chromatography (HPLC) of olive leaves showed some significant differences of phenolic compounds between genotypes. For the same oleaster genotype, the extraction method seemed to influence qualitatively the polyphenols profiles. The quinic acid was the dominant phenolic acid and the luteolin-7-O-glucoside was the major flavonoid observed in wild olive leaves having, respectively, 618.24 and 3211.44 mg/kg DM. The quinic acid has an amount of 400.15 and 275.39 mg/kg and the luteolin-7-O-glucoside has an amount of 2059.62 and 1214.49 mg/kg in cultivars leaves. The extraction by Soxhlet of wild olive leaves showed the highest quinic acid (1085.80 mg/kg DM) and luteolin-7-O-glucoside (3720.15 mg/kg DM) amounts. The hydromethanolic extraction assisted by Soxhlet of wild olive leaves constituted the optimal method to obtain high polyphenols contents enriched with phenolic acids and flavonoids

Flowering in the wild olive (Olea europaea L.) tree (oleaster): Phenology, flower abnormalities and fruit set traits for breeding the olive

Although, the olive trees produce hermaphrodite flowers, abnormal flowers (flowers with absence or reduced stamens and flowers with absence of pistil) are frequently observed and may reduce fruit set.This study investigates the phenology evolution and the male and female abortion of the oleaster tree (or the wild olive tree) flowers (Olea europaea L. subsp. europaea var. sylvestris) from natural ecosystems represented in two Tunisian Parks. The female abortion was evaluated by the percentage of flowers lacking pistil, and male abortion by differential staining for the cytoplasm of pollen grain. Flower abortion was examined and compared for eight oleaster trees in two different natural sites. At the beginning of flowering (the last two weeks of April), the flower numbers ranged from 15 to 26 flowers per inflorescence. However, one month after blossoming, the fruit set ranged from 1 to 3 drupesper inflorescence. Thus, a significant decrease of flowers per inflorescence was observed on all trees. The percentage of flowers without stamens and flowers without pistil per inflorescence ranged from 5.7 to 38.8% and from 4.9 to 88.1%, respectively depending on the oleaster tree. Moreover, abnormal flowers had effect on fruits number per inflorescence. Indeed, the r2 linear regression values were 0.89and 0.83, respectively. Therefore, due to the similar flower abnormalities occurring for the olive trees, the transfer of a low rate of abnormal flowers to cultivated olive may improve the crop.Keywords: Olea europaea, oleaster, wild olive trees, stamen abortion, flower without pistil, pollen grain, natural site, drupe abscissio

Stone diversity in wild and cultivated olive trees (Olea europaea L.)

14 páginas, 7 figuras, 7 tablasThe olive tree is represented in Tunisia by two varieties: var. sylvestris (wild olive trees) and var. europaea (cultivated olive trees including diverse cultivars). Seed (stone) size and shape analysis may provide the basis for relationships between varieties and cultivars as well as to study the responses to environmental conditions. A semi-automated method of image analysis allows to obtain data related with magnitudes descriptive of stone size and shape and to compare between wild and cultivated olives. Also, the effect of bioclimate on size and shape was analyzed in some cultivars. Stone size and shape presents high variability. In cultivated trees stones are larger. Mean seed image area is 0.38 and 0.75 cm² for wild and cultivated plants respectively. Roundness and circularity were compared as to their potential to define seed shape. Mean values were higher for circularity, but roundness is more variable reaching higher values in some individuals and varieties. Roundness is more useful to compare seed shape variations. In addition, climate factors affect the stone characteristics in cultivars; those of sub-humid region having larger stones. Phenotypic parameters of stone are discriminating parameters for the analysis of intra-specific, intra-varieties and intra-cultivars variability in Olea europaea.Peer reviewe

Oxidative stability of olive oil enriched with oleaster leaves under accelerated storage conditions: Improvement of olive oil stability

Olive oil is rich in natural antioxidants that conserve its quality under storage conditions. However, there is a growing need to improve the quality of olive oil under storage conditions using phenol-enriched olive oil. In the present study, olive oil from the Chemlali cultivar was enriched with wild olive tree leaves or oleaster. The oil composition was analyzed before and after accelerated storage conditions using a Schaal test. Standard oil parameters, including free acidity; peroxide value; iodine value; specific extinction K232 and K270; fatty acid profile, and polyphenolic, chlorophyll, and carotenoid content, were evaluated for the control olive oil (COO) and the enriched olive oil (EOO). Polyphenolic compounds were identified for COO, EOO, and oleaster leaf extracts (OLE) using high-performance liquid chromatography. Antioxidant activity was analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’ azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) tests. The results showed that enriching the olive oil quantitatively and qualitatively improved the polyphenolic composition, pigment contents, and the antioxidant activity. The EOO was more resistant to oxidation under accelerated storage conditions. The addition of wild olive leaves also significantly improved the resistance of the olive oil to oxidation and can, therefore, be used as a source of natural antioxidants to improve the oxidative stability of edible oils

Genetic diversity of <i>Vicia faba</i> L. based on random amplified polymorphic DNA and simple sequence repeat markers

<div><p></p><p>The genetic diversity of 13 Tunisian faba bean (<i>Vicia faba</i> L.) accessions, and the commercial variety “Aguadulce”, were studied using simple sequence repeats (SSRs) and random amplified polymorphic DNA (RAPD) markers. In comparison to RAPD markers, SSRs showed a higher level of polymorphism and greater information content, as assessed by the expected heterozygosity. One hundred and fourteen bands were amplified using six SSR primer combinations and 376 bands were observed using four RAPD primers. The percentages of polymorphic fragments were 100% and 60.63% for SSR and RAPD markers, respectively. The polymorphism information content, gene diversity and population differentiation test were 0.370, 0.490 and 0.746, respectively, for SSR markers and 0.319, 0.406 and 0.775 for RAPD markers. The correlation coefficients of similarity based on the Mantel test were statistically significant for the both marker systems used, but were higher for SSR data than for RAPD. Dendrogram topologies, conducted separately on polymorphic RAPD and SSR markers, showed minor differences in the grouping of accessions. The dendrogram based on combined RAPD and SSR data sets identified clustering of accessions according to their geographic diffusion. Collectively, these results will aid Tunisian faba bean germplasm management, conservation and breeding.</p></div

Production and Characterization of New Biosurfactants/Bioemulsifiers from <i>Pantoea alhagi</i> and Their Antioxidant, Antimicrobial and Anti-Biofilm Potentiality Evaluations

The present work aimed to develop rapid approach monitoring using a simple selective method based on a positive hemolysis test, oil spreading activity and emulsification index determinations. It is the first to describe production of biosurfactants (BS) by the endophytic Pantoea alhagi species. Results indicated that the new BS evidenced an E24 emulsification index of 82%. Fourier-transform infrared (FTIR) results mentioned that the described BS belong to the glycolipid family. Fatty acid profiles showed the predominance of methyl 2-hyroxydodecanoate in the cell membrane (67.00%) and methyl 14-methylhexadecanoate (12.05%). The major fatty acid in the BS was oleic acid (76.26%), followed by methyl 12-methyltetradecanoate (10.93%). Markedly, the BS produced by the Pantoea alhagi species exhibited antimicrobial and anti-biofilm activities against tested human pathogens. With superior antibacterial activity against Escherchia coli and Staphylococcus aureus, a high antifungal effect was given against Fusarium sp. with a diameter of zone of inhibition of 29.5 mm, 36 mm and 31 mm, obtained by BS dissolved in methanol extract. The DPPH assay indicated that the BS (2 mg/mL) showed a higher antioxidant activity (78.07 inhibition percentage). The new BS exhibited specific characteristics, encouraging their use in various industrial applications

Minor lipid components of some <it>Acacia</it> species: potential dietary health benefits of the unexploited seeds

<p>Abstract</p> <p>Background</p> <p>Oilseed samples from four <it>Acacia</it> species ( <it>A. cyclops</it>, <it>A. ligulata</it>, <it>A. salicina</it> and <it>A. cyanophylla</it>) were analyzed in order to evaluate the potential nutritional value of their unexploited seeds.</p> <p>Methods</p> <p>Samples were collected from different Tunisian geographic locations. Seed oils were extracted and carotenoids, tocopherols and sterols were analyzed using chromatographic methods.</p> <p>Results</p> <p>The studied <it>Acacia</it> seeds seem to be quite rich in lipids (from 6% to 12%). All <it>Acacia</it> species contain mainly the xanthophylls zeaxanthin and lutein compounds: from ca. 38 mg.kg^-1 of total lipids (<it>A. cyclops)</it> to ca. 113 mg.kg^-1 of total lipids <it>(A. cyanophylla)</it>. Total tocopherols varied from ca. 221 mg.kg^-1 of total lipids (<it>A. cyclops</it>) to ca. 808 mg.kg^-1 of total lipids (<it>A. ligulata</it>). Sterols are highly present and their contents ranged between ca. 7 g. kg^-1 of total lipids (<it>A. salicina</it>) and 11 g. kg^-1 of total lipids (<it>A. cyclops</it>).</p> <p>Conclusion</p> <p>This study highlights that these unexploited seeds might have a potential nutritional value and encourages researchers to more explore and find developments for these plants for healthy purposes.</p

First Report of the Biosynthesis and Characterization of Silver Nanoparticles Using <i>Scabiosa atropurpurea</i> subsp. <i>maritima</i> Fruit Extracts and Their Antioxidant, Antimicrobial and Cytotoxic Properties

Candida and dermatophyte infections are difficult to treat due to increasing antifungal drugs resistance such as fluconazole, as well as the emergence of multi-resistance in clinical bacteria. Here, we first synthesized silver nanoparticles using aqueous fruit extracts from Scabiosa atropurpurea subsp. maritima (L.). The characterization of the AgNPs by means of UV, XRD, FTIR, and TEM showed that the AgNPs had a uniform spherical shape with average sizes of 40–50 nm. The biosynthesized AgNPs showed high antioxidant activity when investigated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The AgNPs displayed strong antibacterial potential expressed by the maximum zone inhibition and the lowest MIC and MBC values. The AgNPs revealed a significant antifungal effect against the growth and biofilm of Candida species. In fact, the AgNPs were efficient against Trichophyton rubrum, Trichophyton interdigitale, and Microsporum canis. The antifungal mechanisms of action of the AgNPs seem to be due to the disruption of membrane integrity and a reduction in virulence factors (biofilm and hyphae formation and a reduction in germination). Finally, the silver nanoparticles also showed important cytotoxic activity against the human multiple myeloma U266 cell line and the human breast cancer cell line MDA-MB-231. Therefore, we describe new silver nanoparticles with promising biomedical application in the development of novel antimicrobial and anticancer agents