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.

Elfalleh W ，Tlili N ，Nasri N ，Yahia Y ，Hannachi H ，Chaira N ，Ying M ，Ferchichi A ... -  《-》

Pomological features, nutritional quality, polyphenol content analysis, and antioxidant properties of domesticated and 3 wild ecotype forms of raspberries (Rubus idaeus L.).

The raspberry (Rubus idaeus L.) is an economically important berry crop that contains many phenolic compounds with potential health benefits. In this study, important pomological features, including nutrient content and antioxidant properties, of a domesticated and 3 wild (Yayla, Yavuzlar, and Yedigöl) raspberry fruits were evaluated. Also, the amount of total phenolics and flavonoids in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were calculated as gallic acid equivalents (GAEs) and quercetin equivalents (QE). The highest phenolic compounds were found in wild Yayla ecotype (26.66 ± 3.26 GAE/mg extract). Whilst, the highest flavonoids were determined in wild Yedigöl ecotype (6.09 ± 1.21 QA/mg extract). The antioxidant activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were investigated as trolox equivalents using different in vitro assays including DPPH(•), ABTS(•+), DMPD(•+), and O(•-)(2) radical scavenging activities, H(2)O(2) scavenging activity, ferric (Fe(3+)) and cupric ions (Cu(2+)) reducing abilities, ferrous ions (Fe(2+)) chelating activity. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid, and ascorbic acid in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were detected by high-performance liquid chromatography and tandem mass spectrometry (LC-MS-MS). The results clearly show that p-coumaric acid is the main phenolic acid responsible for the antioxidant and radical scavenging activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits.

Gülçin I ，Topal F ，Çakmakçı R ，Bilsel M ，Gören AC ，Erdogan U ... -  《-》

Analysis of phenolic compounds in different parts of pomegranate (Punica granatum) fruit by HPLC-PDA-ESI/MS and evaluation of their antioxidant activity: application to different Italian varieties.

Russo M ，Fanali C ，Tripodo G ，Dugo P ，Muleo R ，Dugo L ，De Gara L ，Mondello L ... -  《-》

Antioxidant capacity and lipid characterization of six Georgia-grown pomegranate cultivars.

Pande G ，Akoh CC 《-》

Physicochemical characterization of oil, antioxidant potential, and phenolic profile of seeds isolated from Tunisian pomegranate (Punica granatum L.) cultivars.

Pomegranate (Punica granatum L.) seeds oils (PSO) from three Tunisian varieties namely Jebali, Testouri, and Gabsi were extracted by ultrasonic-assisted extraction and analyzed for their physicochemical properties, fatty acids (FA) profile, and sterol composition. PSO of Gabsi and Testouri showed the best quality indexes in terms of peroxide and acid values and the highest oxidative stability index was observed for PSO of Gabsi ecotype (2.534 hr). Polyphenol content of PSO of Gabsi ecotype (886.909 mg/kg) was roughly 3 and 23 times higher than that of Jebali and Testouri ecotypes, respectively. Twelve FAs were identified by GC/FID. Punicic acid was the major compounds ranged from 81.53% (Testouri) to 86.41% (Gabsi). The unsaturated/saturated FA ratios of PSO were 14.53, 15.95, and 18.68, respectively for Gabsi, Testouri, and Jebali, respectively. Phytosterols were also identified and β-sitosterol was the major compound in PSO. In addition, the phytochemical and antioxidant properties of phenolic extracts obtained from pomegranate seeds residues were investigated. Pomegranate seeds extract (PSE) of Gabsi cultivar showed the highest content of polyphenols (64.762 mg CAE/g) and flavonoids (7.127 mg RE/g). Antioxidant potential of extracts was performed using DPPH test and total antioxidant capacity (TAC). Results revealed that Gabsi cultivar was the most reactive extract with EC50 of 0.105 mg/mL for DPPH test and 40.622 mg AA/g for TAC. Phenolic profiles of PSE were also investigated. Results showed the importance of cultivar selection in the potential use of bioactive compounds of seeds as nutraceutical ingredients in food and chemical industries. PRACTICAL APPLICATION: Three Tunisian pomegranate cultivars namely Jebali, Testouri, and Gabsi were investigated for their seeds oil and phenolic composition. Pomegranate seeds oil (PSO) are rich in bioactive polyunsaturated fatty acids and phytosterols that can be of interest in several food and chemical industrial applications. Moreover, pomegranate seeds extracts are a natural source of antioxidant components, such as phenolic compounds, that can be used by the pharmaceutical industry as promising nutraceutical ingredients. The obtained results can be used to provide guidance on cultivar selection during industrial applications.

Khemakhem M ，Zarroug Y ，Jabou K ，Selmi S ，Bouzouita N ... -  《-》