Nizar Nasri

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.

Physico-chemical properties and DPPH-ABTS scavenging activity of some local pomegranate (Punica granatum) ecotypes

Peels and fresh pomegranate extracts were used in the present study for the determination of the physic-chemical properties and DPPH-ABTS scavenging activities. Total sugars of juice are fructose (ca. 7 g/100 ml) and glucose (ca. 8 g/100 ml). Contents of soluble proteins in juice extracts are about 7 g/l (Bradford assays) and 22% (Kjeldhal assays) from dry pulp. Minerals in peel and juice are respectively 9.43±0.93 and 9.46±1.05 mg/100 ml for posphorus and 210.86±10.70 and 271.94±60.59 mg/100 g for potassium. The sodium contents are nearly 7 mg/100 ml in both peel and juice. Highly antioxidant contents in peels were confirmed. Free radical scavenging is about 3.58±0.38 µg/ml in peel. The antioxidant capacity value determined by ABTS was 7.364±0.403 mM Trolox equivalent antioxidant capacity/100 g dry weight. These findings implied that bio-active compounds from the peel might be potential resources for the development of antioxidant function dietary food.

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.

Fatty acids from Tunisian and Chinese pomegranate (Punica granatum L.) seeds

Pomegranate seed oil is considered a powerful health-benefiting agent due to its anti-oxidative and anticarcinogenic properties. Lipids from 21 pomegranate cultivars (15 Tunisian and 6 Chinese) were extracted and fatty acids were identified. Total lipids (16% on a dry weight basis) are mainly unsaturated (ca. 88%). Qualitatively, the pomegranate fatty acid composition is identical. Quantitatively, the predominant fatty acid was linolenic acid (44.51–86.14%), followed by linoleic acid (3.57–13.92%), oleic acid (3.03–12.88%), palmitic acid (3.13–11.82%), stearic acid (1.68–15.64%), gadoleic acid (0.50–4.91%), lignoceric acid ( < 2.53%), arachidic acid ( < 1.70%) and myristic acid ( < 0.85%). Statistical methods revealed how Chinese and Tunisian pomegranate fatty acid contents may be affected by the sampling location.

Fatty acid composition of two Tunisian pine seed oils.

Oils were extracted from fully ripen Pinus pinea L. and Pinus halepensisMill seeds and fatty acid composition has been established by capillary gas chromatography. Seeds are rich in lipids, 34.63–48.12% on a dry weight basis. Qualitatively, fatty acid composition of both species is identical. For P. halepensis linoleic acid is the major fatty acid (56.06% of total fatty acids) followed by oleic (24.03%) and palmitic (5.23%) acids. For P. pinea, the same fatty acids are found with the proportions 47.28%, 36.56%, and 6.67%, respectively. Extracted fatty acids from both species are mainly unsaturated, respectively, 89.87% and 88.01%. Pinus halepensis cis‐5 olefinic acids are more abundant (7.84% compared to 2.24%). Results will be important as a good indication of the potential nutraceutical value of Pinus seeds as new sources of fruit oils rich in polyunsaturated fatty acids and cis‐5 olefinic acids.

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.