THE CHEMICAL COMPOSITION AND BIOACTIVITIES OF QUERCUS CANARIENSIS FLOUR ACORNS EXTRACTS GROWING IN TUNISIA

The current study was conducted to investigate the chemical composition of Quercus canariensis flour acorns extracts as well as its biological activities in regards to the growing area using spectrophotometric and chromatographic techniques. The phenolic profile was composed of 19 compounds identified through HPLC-DAD analysis. Coumarin was the most abundant compound quantified in BniMtir, Nefza and ElGhorra and gallic (12.58-20.52 %), syringic (4.70-7.64 %) and trans-ferulic (2.28-2.94 %) acids were the abundant phenolic acids while kaempferol was the major flavonoid compounds quantified only in Quercus canariensis growing in BniMtir. On the other hand, Ain Snoussi acorn extract was characterized by its high content in luteolin-7-O-glucoside (58.46 %). The in-vitro antioxidant activities of the studied extracts were investigated and the results showed that Nefza ethanolic extract's has the highest activities. A bactericidal effect against Staphylococcus aureus was observed only by Elghorra population. On the other hand, Ain Snoussi acorn extract was efficient to inhibit growth of pathogenic bacteria, mentioned the highest activity against Escherichia coli. These results is the first study highlighted that zeen oak acorns are an excellent source of natural antioxidants and antibacterial compounds related to their lysozyme activity which could be exploited in the pharmaceutical and food sectors.

Tunisian Native Mentha pulegium L. Extracts: Phytochemical Composition and Biological Activities

Mint species (Lamiaceae family) have been used as traditional remedies for the treatment of several diseases. In this work, we aimed to characterize the biological activities of the total phenolic and flavonoid contents of Mentha pulegium L. extracts collected from two different regions of Tunisia. The highest amounts of total phenols (74.45 ± 0.01 mg GAE/g DW), flavonoids (28.87 ± 0.02 mg RE/g DW), and condensed tannins (4.35 ± 0.02 mg CE/g DW) were found in the Bizerte locality. Methanolic leaf extracts were subjected to HPLC-UV analysis in order to identify and quantify the phenolic composition. This technique allowed us to identify seven phenolic compounds: two phenolic acids and five flavonoid compounds, such as eriocitrin, hesperidin, narirutin, luteolin, and isorhoifolin, which were found in both extracts with significant differences between samples collected from the different regions (p < 0.05). Furthermore, our results showed that the methanolic extract from leaves collected from Bizerte had the highest antioxidant activities (DPPH IC₅₀ value of 16.31 μg/mL and 570.08 μmol Fe²⁺/g, respectively). Both extracts showed high radical-scavenging activity as well as significant antimicrobial activity against eight tested bacteria. The highest antimicrobial activities were observed against Gram-positive bacteria with inhibition zone diameters and MIC values ranging between 19 and 32 mm and 40 and 160 µg/mL, respectively. Interestingly, at 10 μg/mL, the extract had a significant effect on cell proliferation of U87 human glioblastoma cells. These findings open perspectives for the use of Mentha pulegium L. extract in green pharmacy, alternative/complementary medicine, and natural preventive therapies for the development of effective antioxidant, antibacterial, and/or antitumoral drugs.

Identification and quantification of phenolic and fatty acid profiles in Pinus halepensis mill. seeds by LC-ESI-MS and GC: Effect of drying methods on chemical composition

This study aimed to evaluate Pinus halepensis Mill. seeds oil as well as methanolic-aqueous extract on fatty acid and phenolic's composition as well as antioxidant activities with regard to the cones drying methods: convection and sun methods. The highest amounts of total phenols (14.63 ± 0.05 mg GAE/g DW), flavonoids (3.3 ± 0.02 mg QE/g DW), and condensed tannins (0.36 ± 0.05 mg CE/g DW) were showed in the seeds obtained by sun-dried method. Methanolic-aqueous seeds extracts were subjected to LC-ESI-MS analysis in order to identify and quantify the phenolic composition. This technique allowed us to identify eleven phenolic compounds: two phenolic acids and nine flavonoid compounds such as cirsiliol, catechin (+), luteolin, and luteolin-7-O-glucoside, which were present in the two studied samples while apigenin, naringenin, and cirsilineol were only identified in the extract obtained from sun-drying method seeds. The chemical components of the oils were analyzed using GC, and significant differences were found between the two studied seeds oil (p < .05). Furthermore, the antioxidant activities were investigated using DPPH and ABTS.+ assays. The results showed that the methanolic-aqueous extract from seeds dried by sun method had the highest antioxidant activities (0.08 and 0.05 mg/ml, respectively). This study could provide useful information for industry to produce potentially bioactive plant extract.

Pistacia atlantica Desf. roots extract: LC-ESI-MS Analysis, antioxidant activity and gastroprotective effect on experimentally-induced ultrastructural gastric ulcers in mice

Pistacia atlantica Desf. (Atlas Pistachio) is an Anacardiaceae tree traditionally used in Tunisia for the treatment of ophthalmic, stomatitis, and digestive tract diseases. In the present study, the Pistacia atlantica Desf. roots extract (PR) was phytochemically analyzed, for the first time, by LC-ESI-MS for phenolic and flavonoid contents, in vitro tested for its potential antioxidant activity based on the 2.2-diphenyl-1-picrylhydrazyl (DPPH) and the reduced power essays (FRAP), and in vivo tested for its ability to shield against ethanol-induced gastric ulcer in mice. The LC-ESI-MS analysis proved the identification of 12 compounds, including Quinic, Gallic, and Protocatechuic, as major phenolic acids and high levels of flavonoids, such as Catechin, Epicatechin, and Cirsiliol. PR also exhibited a mild in vitro antioxidant activity when compared with ascorbic acid. In vivo pretreatment of ethanol-ulcerated mice with PR doses 50 mg/kg and 100 mg/kg body weight (b.w) significantly reduced (P< .05) gastric lesions at a rate of 20.10% and a rate of 40.90%, respectively, when compared with 60.70% rate of sucralfate (50 mg/kg b.w) evidenced by a dose-dependent manner increase in the gastric mucosa enzymatic (SOD, CAT, GPx) antioxidant levels, the decline of the lipid peroxidation, and the preservation of normal gastric superficial epithelium. The underlying mechanism of PR antiulcerogenic activity could be due to a synergistic effect of phenolic acids and flavonoid contents which enhances the gastric antioxidant defense system.Abbreviations: BHT: butylated hydroxytoluene, b.w: body weight, CAT: catalase, DPPH:1-Diphenyl-2-picrylhydrazyl, DW: dry weight, EtOH: ethanol, FRAP: Ferric reducing antioxidant power, GAE: gallic acid equivalents, GPx: Glutathione peroxidase, QE: quercetin equivalents, LC-ESI-MS: Liquid chromatography-Electrospray Ionization-Tandem Mass Spectrometry, MDA: malondialdehyde, PR: Pistacia root, TBA: thiobarbituric acid reagent, TBARS: thiobarbituric acid reactive substances, TCA: trichloroacetic acid, SOD: Superoxide dismutase.

Phenolic profile (HPLC-UV) analysis and biological activities of two organic extracts from Echinops spinosissimus Turra roots growing in Tunisia

Echinops spinosissimus Turra subsp. roots was investigated, after extraction with two different solvents: ethanol and ethyl acetate, for its phenolic profile as well as biological activities. Echinops spinosissimus Turra subsp. spinosus roots ethanolic extract was characterized by the highest content of total polyphenols (19.3 mg GAE/100 g of DW). In addition, the phenolic profiles of the two studied extracts were analysed using HPLC-UV, where p-coumaric (8.59 mg/kg of DW) and cinnamic acids (4.68 mg/kg of DW) were detected as the most abundant phenolic acids, and kaempferol was the predominant flavonoids (30.37 mg/kg of DM) followed by quercetin and rutin in the ethanolic extract. While, only p-coumaric acid, epicatechin, kaempferol and quercetin were identified and quantified in ethyl acetate roots extract. All tested extracts exhibited an antimicrobial effect against Gram-positive and Gram-negative bacteria. These findings indicate that Echinops spinosissimus Turra subsp. spinosus roots can be regarded as a new source of edible oil having health benefits and nutritional properties.

Change in some quality parameters and oxidative stability of olive oils with regard to ultrasound pretreatment, depitting and water addition

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In this study we propose an innovative application of ultrasounds in virgin olive oil processing.

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Ultrasound treatment was applied to olive in order to reducing the malaxation step.

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This study will bring useful data to get optimum parameters of ultrasound application.

Ultrasound pretreatment with different times (0, 4, 8, 10 min) on olive paste previous malaxation of olive oil extraction along with depitting and water application procedures were studied. The effects of these procedures on oil yield, quality parameters and oxidative stability have been studied. Therefore, the olive oil yield increase with increasing time of ultrasound treatment. On the other hand, the application of ultrasound did not adversely affect the quality characteristics, as well as the antioxidant activity, when comparing with untreated paste. Furthermore, the oxidative stability data, we can conclude that ultrasound treatment can affect the olive oil oxidative stability. This study could provide useful information for industry to produce olive oil with high yield and quality.

Effect of storage on refined olive oil composition: stabilization by addition of chlorophyll pigments and squalene

Refined olive oil has been analyzed in order to evaluate the influence of storage time on their quality after enrichment with chlorophyll pigments and squalene. At the end of the storage, chlorophyll pigments decomposed for more than 90%, while, carotene pigment loss was lower showing up to 75% in all oil samples stored at 20°C and 50°C. The reduction of total phenolic compounds exhibited similar degradation profiles, reducing by 81% for enriched refined olive oil stored at 20°C and 50°C after six months. For all studied samples, squalene content decreased significantly (p< 0.05) only after four months of storage. Oils with added pure squalene had the lower peroxide values (52 meq O2 · kg(-1)) at the end of storage at 20°C. After six months of storage the oxidative stability increased to 1 h 28 min and 2 h 06 min for refined olive oil stored at 20°C enriched with chlorophyll + squalene and only by squalene, respectively. Therefore, squalene supplemented with 800 mg · kg(-1) exhibited favorable antioxidant effects and is preferable for effectively avoiding oxidation. This study could provide useful information for industry to produce high-stability vegetable oil.

Analytical evaluation of two monovarietal virgin olive oils cultivated in the south of Tunisia: Jemri-Bouchouka and Chemlali-Tataouin cultivars

BACKGROUND

The characterisation of virgin olive oils from two Tunisian cultivars, growing in the Tataouin zone, namely Jemri-Bouchouka, a rare olive cultivar, and Chemlali-Tataouin, was carried out. Several analytical parameters were evaluated; these include quality index, fatty acids, phenolic, chlorophyll, carotenoid, squalene, α-tocopherol compositions and oxidative stability.

RESULTS

Jemri-Bouchouka olive oil had the highest value of oleic acid (74.50%) while Chemlali-Tataouin olive oil had the highest value of oleic acid (69.39 %) and also was characterized by a high percentage of palmitic acid (14.75 %) which makes this oil freeze at a low temperature [corrected]. On the other hand, Jemri-Bouchouka oil was characterised by a low phenolic and α-tocopherol content (267.72 mg GAE kg⁻¹ and 278.34 mg kg⁻¹, respectively). Ten phenolic compounds were identified. The main phenols found in the two olive oils were oleuropein aglycon and pinoresinol. All phenolic compounds showed significant correlations with oxidative stability.

CONCLUSION

The analytical parameters of virgin olive oil that were determined in this study were greatly influenced by cultivar.

Characterisation and phenolic profiles of two rare olive oils from southern Tunisia: Dhokar and Gemri-Dhokar cultivars

BACKGROUND

The aim of this work was to study the chemical characteristics of two Tunisian cultivars, namely Dhokar and Gemri-Dhokar, to analyse the fatty acids, sterols, triacylglycerols, triterpenic alcohols, and to determine the phenolic composition and oxidative stability.

RESULTS

Among the rare varieties, Gemri-Dhokar olive oil had the highest value of oleic acid (69.39%) whereas Dhokar oil was noteworthy for its lower content of phenolic compounds (94.56 mg kg(-1) gallic acid equivalents of oil) and presented the highest level of palmitic acid (19.37%). The main sterols found in all olive oil samples were β-sitosterol and Δ5-avenasterol, whereas cholesterol and 24-methylenecholesterol were also found in all samples but in lower amounts. Two triterpenic dialcohols (erythrodiol and uvaol) were also detected and their content ranged from 1.45 to 2.30%, in Gemri-Dhokar and Dhokar olive oil, respectively. Ten phenolic compounds were identified. In all samples, the main phenols found were oleuropein aglycon and pinoresinol. These phenolic compounds showed significant correlations with oxidative stability.

CONCLUSION

The analytical parameters of two oils that were determined in this study were greatly influenced by genetic factors (cultivar).

Recovery of hydroxytyrosol rich extract from two-phase Chemlali olive pomace by chemical treatment

A very simple method is proposed to produce hydroxytyrosol, a commercially unavailable compound with well-known biological properties which justify a potential commercial application. The 2-phase Chemlali olive pomace is selected as substrate for chemical treatment. Different conditions of chemical treatment, including concentration of acid and alkaline solutions, time and temperature, were assayed. A high amount of hydroxytyrosol (1360 mg/kg of fresh 2-phase olive pomace) was obtained using water bath after treatment at 80 °C for 90 min with 1 M of H(3) PO(4) . However, treatment of 2-phase Chemlali olive pomace using autoclave apparatus could produce a large amount of hydroxytyrosol (1993.60 and 1515.88 mg/kg of fresh alperujo, 1 M acid and basic catalyst, respectively). By taking into consideration practical and economic aspects, acid-catalyzed treatment was more effective using autoclave conditions, whereas the alkali catalyzed conditions were not very suitable. This study could provide useful information for industry to produce the potentially bioactive compound.

PRACTICAL APPLICATION

The 2-phase Chemlali olive pomace is selected as substrate for chemical treatment. Treatment of "alperujo" using water bath or autoclave apparatus was carried out. A high amount of hydroxytyrosol was obtained using autoclave apparatus.