L'oliveraie tunisienne d'olivier s'étend du nord au sud, témoignant d'une grande richesse. Cependant, cette oléiculture est axée sur deux principaux cultivars : le cultivar Chétoui, dans le Nord, et le cultivar Chemlali, dans le Centre et le Sud du pays. À l'instar des pays du bassin méditerranéen, la Tunisie doit se plier aux exigences agronomiques et technologiques de son oléiculture. Notre étude porte sur la caractérisation pomologique et technologique de quatre cultivars d'olivier, Chétoui, Chemlali, Gerboui et Chaïbi, implantés dans trois milieux différents. Les caractères pomologiques des fruits sont influencés par le patrimoine génétique et par le site géographique. Chaque individu, dans son milieu, exprime différemment ses potentialités génétiques, ce qui se traduit par une importante variabilité intra-variétale. Nous avons noté une importante fluctuation du pourcentage de pulpe de trois individus Chaïbi en fonction de leurs sites géographiques ; il varie de 49,06 à 82,19%. Les trois individus de Gerboui ont montré une variabilité importante du poids moyen du fruit, qui passe de 1,13 à 3,17 g. Des fluctuations de la teneur en huile par rapport à la matière fraîche et à la matière sèche sont notées. La composition en acides gras totaux a connu une variation. Les teneurs en acides oléique et linoléique varient énormément chez les individus Chétoui et Chaïbi dans les trois sites géographiques. Les individus du cultivar Chemlali montrent une variation des teneurs en acides palmitique et palmitoléique. Le deuxième site géographique semble être plus favorable pour les caractéristiques technologiques de tous les cultivars étudiés. Ainsi, chaque individu d'un même cultivar montre des potentialités qui se répercutent sur les caractères pomologiques et technologiques de ses fruits.

In this study, the phytochemical profile including the fatty acids composition and the minerals, the polyphenols, and the proteins contents were quantified on leaves, pulp, and stone of two oleasters trees from southern Tunisia. Two olive cultivars (Zarrazi and Chemlali) were used for comparisons. The antioxidant activities were conducted using the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and the 2,2-diphenylpicrylhydrazyl (DPPH) assays. Results showed that the pulp and the stone of oleasters (wild olives) were richer in total lipid having, respectively, 16.30% and 9.42% of Dry Weight basis (DW). Qualitatively, the fatty acids profile of pulp and stone from cultivars and oleasters was identical. The oleic acid is the major fatty acid having the highest percentage in the oils from the stone of oleaster1 (69.08%) followed by linoleic acid. However, quantitatively, significant differences in fatty acids composition were noted. The oleaster stones were richer in storage proteins showing that the globulin is the major fraction (50.47%), followed by albumin (25.72%), prolamin (17.61%), and glutelin (6.19%) fractions. Concerning the minerals, results showed that the pulp is richer in potassium (862.87 mg/100 g DW) than leaves (526.50 mg/100 g DW) and stone (136.50 mg/100 g DW). In contrast, the leaves have the highest phosphorus content (42.74 mg/100 g DW). The highest polyphenols content was 711.55 mg/100 g DW in the pulp followed by the leaves and stone. The leaves, pulp, and stone extracts showed high antioxidant activities using DPPH and ABTS assays. The oleasters seem to be a potential source of edible oil, protein, and antioxidants. They could be used as supplements and/or ingredients in oil and fat industries.

Novel silver nanoparticles were synthesized based on a simple and non-toxic method by applying the green synthesis technique, using, for the first time, the aqueous extract of an extremophile plant belonging to the Achillea maritima subsp. maritima species. AgNP characterization was performed via UV-Visible, front-face fluorescence spectroscopy, and FTIR and XRD analyses. AgNP formation was immediately confirmed by a color change from yellow to brown and by a surface plasmon resonance peak using UV-Vis spectroscopy at 420 nm. The biosynthesized AgNPs were spherical in shape with a size ranging from approximatively 14.13 to 21.26 nm. The presented silver nanoparticles exhibited strong antioxidant activity following a DPPH assay compared to ascorbic acid, with IC50 values of about 0.089 µg/mL and 22.54 µg/mL, respectively. The AgNPs showed higher antidiabetic capacities than acarbose, by inhibiting both alpha amylase and alpha glucosidase. The silver nanoparticles could affect various bacterial mechanisms of virulence, such as EPS production, biofilm formation and DNA damage. The silver nanoparticles showed no lysozyme activity on the cell walls of Gram-positive bacteria. The AgNPs also had a strong inhibitory effect on the Candida albicans virulence factor (extracellular enzymes, biofilm formation). The microscopic observation showed abnormal morphogenesis and agglomeration of Candida albicans exposed to AgNPs. The AgNPs showed no cytotoxic effect on human cells in an MTT assay. The use of novel silver nanoparticles is encouraged in the formulation of natural antimicrobial and antidiabetic agents.

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.

The present paper described the first green synthesis of silver nanoparticles (AgNPs) from the extremophile plant Aeonium haworthii. The characterization of the biosynthesized silver nanoparticles was carried out by using UV-Vis, FTIR and STM analysis. The antioxidant, antidiabetic and antimicrobial properties were also reported. The newly described AgNPs were spherical in shape and had a size of 35–55 nm. The lowest IC50 values measured by the DPPH assay indicate the superior antioxidant behavior of our AgNPs as opposed to ascorbic acid. The silver nanoparticles show high antidiabetic activity determined by the inhibitory effect of α amylase as compared to the standard Acarbose. Moreover, the AgNPs inhibit bacterial growth owing to a bactericidal effect with the MIC values varying from 0.017 to 1.7 µg/mL. The antifungal action was evaluated against Candida albicans, Candida tropicalis, Candida glabrata, Candida sake and non-dermatophytic onychomycosis fungi. A strong inhibitory effect on Candida factors’ virulence was observed as proteinase and phospholipase limitations. In addition, the microscopic observations show that the silver nanoparticles cause the eradication of blastospores and block filamentous morphogenesis. The combination of the antioxidant, antimicrobial and antidiabetic behaviors of the new biosynthesized silver nanoparticles highlights their promising use as natural phytomedicine agents.

Olive (Olea europaea L.) includes cultivated olive trees (var. europaea) and wild olive trees or oleaster (var. sylvestris) as two botanical varieties. These olive varieties were widely spread in the Mediterranean Region. The aim of this study was to determine fatty acid compositions, sterols, polyphenols, and chlorophylls of oils obtained from 12 wild olive trees from Northern Tunisia. Two dominated oil cultivars in Tunisia (Chétoui and Chemlali) were also used to compare results. The fatty acid methyl ester and the sterol compositions were analyzed using gas-liquid chromatography and thin layer chromatography methods, respectively. The polyphenols and chlorophylls were determined using the calorimetrical method. Results indicated that oils extracted from wild olives displayed good balanced fatty acid compositions, sterols, polyphenols, and chlorophylls. Qualitatively, for wild and cultivated olive oils, the oil has an identical composition, whereas the quantitative variation showed that some wild trees seem to be interesting oil sources as two Tunisian dominated cultivars. The highest oleic acid and polyphenol contents were 71.55% and 537.6 mg/kg of oil found in wild olives (OIch2, OIch1). The β-sitosterol was the major sterolic fraction and ranged from 84.72 to 75.70% according to the wild olives. Consequently, wild olives would be a new future edible olive oil source, as well as commonly cultivated ones.