Nizar Tlili

Antioxidant Capacities of Phenolic Compounds and Tocopherols from Tunisian Pomegranate (Punica granatum) Fruits

This article aims to determine the phenolic, tocopherol contents, and antioxidant capacities from fruits (juices, peels, and seed oils) of 6 Tunisian pomegranate ecotypes. Total anthocyanins were determined by a differential pH method. Hydrolyzable tannins were determined with potassium iodate. The tocopherol (α-tocopherol, γ-tocopherol, and δ-tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry seed. Four phenolic compounds were identified and quantified in pomegranate peel and pulp using the high-performance liquid chromatography/ultraviolet method: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p-coumaric acids). Juice, peel, and seed oil antioxidants were confirmed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) methods. The highest values were recorded in peels with 25.63 mmol trolox equivalent/100 g and 22.08 mmol TE/100 g for FRAP and ORAC assay, respectively. Results showed that the antioxidant potency of pomegranate extracts was correlated with their phenolic compound content. In particular, the highest correlation was reported in peels. High correlations were also found between peel hydroxybenzoic acids and FRAP ORAC antioxidant capacities. Identified tocopherols seem to contribute in major part to the antioxidant activity of seed oil. The results implied that bioactive compounds from the peel might be potential resources for the development of antioxidant function dietary food.

The caper (Capparis L.): Ethnopharmacology, phytochemical and pharmacological properties

Caper (Capparis L.), a shrub plant with a large natural distribution, is used in traditional medicines to cure various illnesses. Phytochemicals studies have shown the presence of many beneficial compounds such as spermidine, rutin, quercetin, kaempferol, stigmasterol, campesterol, tocopherols, and carotenoids. Biological studies reveal important antimicrobial, anti-oxidative, anti-inflammatory, immunomodulatory and antiviral properties. The presented review summarizes information concerning the morphology, ethnopharmacology, phytochemistry, and biological activities of caper plants.

Phenolic compounds and vitamin antioxidants of caper (Capparis spinosa).

Capparis spinosa shows strong resistance to the adverse Mediterranean conditions and it has nutritional and medicinal value. The aim of this study was to evaluate the contents of total phenolic compounds, rutin, tocopherols, carotenoids and vitamin C in leaves and flower buds of C. spinosa from different locations in Tunisia. Results showed the richness of caper with these compounds, especially phenolic compounds. Interestingly, it was also found the presence of both α- and γ-tocopherol in buds. Moreover, C. spinosa contained an appreciable level of vitamin C. The significant amounts of these antioxidants confirm the nutritional and medicinal value of caper.

Content of carotenoids, tocopherols, sterols, triterpenic and aliphatic alcohols, and volatile compounds in six walnuts (Juglans regia L.) varieties

The aim of this work was to study the content of tocopherols, sterols, triterpenic and aliphatic alcohols, carotenoids, and volatile compounds in the kernel oils from six walnut (Juglans regia L.) varieties. The levels of β-carotene ranged between 0.22 and 0.62 mg/kg, followed by lutein (0.01-0.06 mg/kg). The total content of tocopherol ranged from 186.5 to 436.2 mg/kg of the extracted oil and the major isoform in all samples was γ-tocopherol. The most abundant phytosterol was β-sitosterol (974-1494 mg/kg) followed by campesterol then Δ-5-avenasterol. The major triterpenic alcohol was cycloartenol (226.4-532.1 mg/kg). Hexacosanol (9.71-28.15 mg/kg) was the major aliphatic alcohol. The detected volatile compounds were pentanal, hexanal, nonanal, 2-decenal and hexanol. The statistical analysis showed significant differences between varieties, which are probably due to genetic factors.

Carotenoid and Tocopherol Composition of Leaves, Buds, and Flowers of Capparis spinosa Grown Wild in Tunisia

High-performance liquid chromatography was used to determine carotenoids (beta-carotene, lutein, neoxanthin, and violaxanthin) and tocopherols of leaves, buds, and flowers of Tunisian Capparis spinosa. This plant shows strong resistance to hard environmental conditions, and it is one of the most commonly found aromatics in the Mediterranean kitchen. In this study, the means of the total carotenoids were 3452.5 +/- 1639.4, 1002 +/- 518.5, and 342.7 +/- 187.9 microg/g fresh weight (FW) in leaves, buds, and flowers, respectively. Lutein accounts for the high content. Violaxanthin provided the lowest portion of the total carotenoids. The principal form of tocopherol detected in leaves was alpha-tocopherol (20.19 +/- 10 mg/100 g FW). In buds and flowers, there were both alpha- (49.12 +/- 17.48 and 28.68 +/- 9.13 mg/100 g FW, respectively) and gamma-tocopherol (48.13 +/- 15.08 and 27.8 +/- 16.01 mg/100 g FW, respectively). The combined content of pro-vitamin A and vitamin E in capers encourages researchers to more explore and find developments for this plant.

Phytochemicals and antioxidant activities of Rhus tripartitum (Ucria) fruits depending on locality and different stages of maturity

The phytochemical content (total phenolic compounds, total flavonoids, condensed tannins and phenolic composition) and the antioxidant potential of Rhus tripartitum fruits collected from different localities were screened during maturity. Significant variability was detected. HPLC analyses revealed the presence of 24 compounds with notable differences. Flavone and betulinic acid, which have numerous benefits, were the main detected compounds (more than 73%). This work highlights the importance of R. tripartitum fruits as dietary sources of natural antioxidants, and might be appropriate for the development of reliable index to estimate fruit richness with bioactive molecules.

Screening of Natural Antioxidants from Selected Medicinal Plants

Medicinal plants contain high levels of natural antioxidants and exhibited strong antioxidant activity. In order to find new sources of natural antioxidants, a screening of natural antioxidants from some Tunisian medicinal plants commonly associated with treatment of some diseases were conducted. The total phenolic compounds, flavonoids, anthocyanins, and hydrolysables tannins were measured, and the antioxidant capacities were evaluated using DPPH and Trolox equivalent antioxidant capacity assays. Results prove that there are important quantities of these compounds in Tunisian medicinal plants. A positive linear correlation between Trolox equivalent antioxidant capacity and the phenolic compound contents suggested that these compounds were a major contributor of antioxidant activity of these plants. The results from this study will help us understand the antioxidant capacity profiles of these medicinal plants, and also investigate new sources of natural antioxidants.

Minor lipid components of some Acacia species: potential dietary health benefits of the unexploited seeds

BackgroundOilseed samples from four Acacia species ( A. cyclops, A. ligulata, A. salicina and A. cyanophylla) were analyzed in order to evaluate the potential nutritional value of their unexploited seeds.MethodsSamples were collected from different Tunisian geographic locations. Seed oils were extracted and carotenoids, tocopherols and sterols were analyzed using chromatographic methods.ResultsThe studied Acacia seeds seem to be quite rich in lipids (from 6% to 12%). All Acacia species contain mainly the xanthophylls zeaxanthin and lutein compounds: from ca. 38 mg.kg-1 of total lipids (A. cyclops) to ca. 113 mg.kg-1 of total lipids (A. cyanophylla). Total tocopherols varied from ca. 221 mg.kg-1 of total lipids (A. cyclops) to ca. 808 mg.kg-1 of total lipids (A. ligulata). Sterols are highly present and their contents ranged between ca. 7 g. kg-1 of total lipids (A. salicina) and 11 g. kg-1 of total lipids (A. cyclops).ConclusionThis 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.

Chemical compounds from Phoenician juniper berries (Juniperus phoenicea)

Natural chemical compounds are a widely researched topic worldwide because of their potential activity against cerebrovascular diseases. Chemicals from Juniperus phoenicea berries are reported in this study. Lipids (11%) from seeds are mainly unsaturated (86%). Minerals are also quantified like Na (63.8 mg per 100 g DW) or K (373.9 mg per 100 g DW). Total reduced sugars are ca 192.6 mg g−1 DW. Polyphenols and flavonoids from berries are highly present with an average of 1764 ± 174.3 mg gallic acid per 100 g DW and 890 ± 47.6 mg rutin per 100 g DW, respectively. Mean free radical scavenging activities, determined by DPPH and ABTS, are 1337 ± 126.2 mM TEAC per 100 g DW and 1105.7 ± 95.9 mM TEAC per 100 g DW, respectively. All findings improve the possible presence of biologically active fractions in phytocomplex that could be used as such and/or extracted for the formulation of supplements and/or ingredients for the pharmaceutical industry.

Capparis spinosa leaves extract: Source of bioantioxidants with nephroprotective and hepatoprotective effects

Capparis spinosa, Capparidaceae, is largely distributed all over the Mediterranean Basin and is traditionally used to treat many illnesses, such as liver and kidney diseases. The aim of the current study was to explore the antioxidant, nephroprotective and hepatoprotective effects of methanolic extract of Capparis spinosa leaves (MECS) associated with its phytochemical content. The levels of total phenolics, flavonoids and condensed tannins were 23.37mgGAE/g, 9.05mgQE/g and 9.35mgTAE/g, respectively. HPLC analysis revealed nine compounds, namely rutin, resveratrol, coumarin, epicatechin, luteolin, catechin, kaempferol, vanillic acid and gallic acid. The MECS showed interesting antioxidant capacity. The MECS-treatment significantly reduced the increased plasma levels of creatinine, urea and uric acid, reduced the elevated MDA levels, significantly reduced the antioxidant enzyme activities and restored the kidney damage, provoked by cisplatin-treatment. Furthermore, MECS-treatment significantly prevented the increase in serum ALT, AST and LDH levels in acute liver damage induced by CCl4, decreased the amount of hepatic malondialdehyde (MDA) formation and elevated the activities of SOD, CAT and GPx, and restored liver injury. This study supports the traditionally use of C. spinosa to cure kidney and liver diseases. The obtained results highlighted the possible use of C. spinosa as a source of phytochemical with important biological advantages.