Walid Elfalleh

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.

Total phenolic contents and antioxidant activities of pomegranate peel, seed, leaf and flower

Pomegranate (Punica granatumxa0L.) is a nutrient dense food rich in beneficial phytochemicals. The aim of this study is to investigate and to determine antioxidant contents from local and highly consumed pomegranatexa0variety called ‘Gabsi’. Peels, seeds, leaves and flowers were used to quantify total polyphenols, flavonoids, anthocyanins and hydrolysable tannins.xa0Antioxidantsxa0contents were as follows: peel > flower > leaf > seed.Total polyphenols contents from peels werexa085.60 ± 4.87 mgxa0gallic acid equivalents per g dry weightxa0(mg GAE/g DW), flavonoids (51.52 ± 8.14 mg rutin equivalents per g DW (mg RE/g DW), anthocyanins (102.2 ± 16.4 mg cyanidin-3-glucoside equivalents per g DW (mg CGE/g DW)xa0and hydrolysable tannins (139.63 ± 4.25 mg tannic acid equivalent per g of DW (mg TAE/g DW). High free radical scavenging activity is reported in peels and flowers. Effective concentration at 50% (EC50)xa0was 3.88 ± 0.33 µg/ml (peels) and 4.55 ± 0.97 µg/ml (flowers). Antioxidant capacity value was respectively 7.50 ± 0.83 Trolox equivalent antioxidant capacity (TEAC) mg/g DW (peels) and 6.39 ± 0.83 TEAC mg/g DW (flowers). Less important values were obtained from leaves (4.16 ± 1.35 TEAC mg/g DW) and seeds (1.10 ± 0.23 TEAC mg/g DW). Peels and flowers extract exhibited higher activities than seeds and leaves. All of these findings implied that bioactive compounds from pomegranate peels, flowers, leaves and seeds might be potential resources for the development of antioxidant function dietary foods. Extraction process of whole fruits may provide a commercial pomegranate juice with high antioxidants and consequently high usefulness antioxidant activities. n n xa0 n n Key words:xa0Pomegranate fruit and leaves extracts,xa0polyphenols, flavonoids, anthocyanins, total tannins, antioxidant activity.

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.

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.

The Use of ISSR and RAPD Markers for Genetic Diversity among South Tunisian Barley

Random amplified polymorphic DNA (RAPD) and intersimple sequence repeat (ISSR) were assayed to determine the genetic diversity of 80 barley specimens from South Tunisia. The ISSR primers showed variation in the percentage of polymorphism, band informativeness (Ib), and resolving power (Rp). The percentage of polymorphism is 66.67%, the average Ib ranged from 0.24 to 0.39, while Rp ranged from 0.74 to 1.16. In RAPD analysis, three primers yielded a total of 17 scorable bands, which are all polymorphic. The three polymorphic primers exhibited variation with regard to average band informativeness (AvIb) and resolving power (Rp). RAPD and ISSR marker systems were found to be useful for the genetic diversity among the barley specimens. The two dendrograms obtained through these markers show different clustering of 80 barely specimens, but we noted that some clusters were similar in some cases. A poor correlation (𝑟=0.12) was found between both sets of genetic similarity data, suggesting that both sets of markers revealed unrelated estimates of genetic relationships. Therefore, the ISSR and RAPD molecular markers show two genetic grouping of studied barely specimens.

Phenols, Flavonoids, and Antioxidant and Antibacterial Activity of Leaves and Stem Bark of Morus Species

Leaves and stem bark composition from Morus species (M. alba var. alba, M. alba var. rosa and M. rubra) was evaluated for its antioxidant and antimicrobial activities in order to enhance its therapeutic uses. Total phenolics and flavonoids contents were estimated in hydromethanolic and aqueous extracts. Results showed highest content in M. rubra leaves aqueous extract (1129 mg gallic acid equivalent/100 g dry weight and 816 mg gallic acid equivalent/100 g dry weight, respectively). Using 2,2-diphenyl-1-picrylhydrazyl assay, the highest antioxidant activity was obtained in aqueous stem barks extracts. M. alba var. alba has an IC50 of 2.84 mg/ml and the IC50 value of M. rubra was the highest (4.78 mg/ml). ABTS.+ (2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) method and reducing power assay were used to confirm the results from the 2,2-diphenyl-1-picrylhydrazyl test. All extracts expressed considerable free radical-scavenging properties. Hydromethanolic and aqueous extracts were tested against Staphylococcus aureus, Enterococcus feacalis, Staphylococcus epidermis, Escherichia coli, and Salmonella Typhimurium bacteria. Hydromethanolic stem bark extracts have the highest antimicrobial activities, and it may be a good antimicrobial agent for human gastrointestinal infections. This plant could be used as an additive to foods and also as a possible source to obtain new and effective herbal medicines to treat infections of multi-drug resistant strains of microorganisms.

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. 38u2009mg.kg-1 of total lipids (A. cyclops) to ca. 113u2009mg.kg-1 of total lipids (A. cyanophylla). Total tocopherols varied from ca. 221u2009mg.kg-1 of total lipids (A. cyclops) to ca. 808u2009mg.kg-1 of total lipids (A. ligulata). Sterols are highly present and their contents ranged between ca. 7u2009g. kg-1 of total lipids (A. salicina) and 11u2009g. 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.

Analysis of agromorphological diversity of southern Tunisia faba bean ( Vicia faba L.) germplasm

Forty two faba bean landraces (traditional farmers’ varieties) ( Vicia faba L.) from southern Tunisia, belonging to 8 oasis agro-ecosystems were assessed using morphological descriptors. The studied descriptors focused on morpho-phenological and morpho-agronomical traits. The data obtained is extracted on the basis of 35 descriptors of 42 populations from 8 localities, at a rate of 30 replications (plants) per population, in totality of 1260 individuals. The data underwent an analysis of variance and a multivariate analysis. Significant differences among populations for the thirty five descriptors were observed. The multivariate analysis performed on averages of all parameters revealed eight main groups, and variation within the same oasis agro-ecosystems was extremely important. Particularly, the group of ‘Tozeur’ made up of five populations (P38, P39, P40, P41 and P42), and the group of ‘Medenine’ composed of seven populations (P19, P20, P21, P22, P23, P24 and P25) showed a special characters than the other populations especially for seedling characters. The geographical location did not seem to be the main factor structuring the variability of the studied landraces. There proved to be substantial phenotypic variability in the Tunisian faba bean germplasm. Keywords: Diversity analysis, germplasm, faba bean ( Vicia faba L.), oasis agro-ecosystems, Southern Tunisia