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 ß-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.

Hexane Extract of Echinops spinosissimus Turra subsp. spinosus from Tunisia: A Potential Source of Acetylated Sterols - Investigation of its Biological Activities.

The hexane extract of Echinops spinosissimus Turra subsp. spinosus flower heads was analyzed for its fatty acid and sterol composition. Its physicochemical characteristics were also studied. The saponification, iodine and peroxide values were determined as 255 mg KOH/g, 42.57 g I2 /100 g and 110 m equiv. O2 /kg of oil, respectively. The oleic (C18:1; 61.14%), palmitic (C16:0; 21.36%) and linoleic (C18:2; 10.45%) acids were the dominant fatty acids. This extract was also found to contain high levels of ß-sitosterol and stigmasterol (44.97% and 34.95% of total sterols, respectively). On the other hand, the identification of terpenoid compounds was investigated by using GC/MS, which revealed fourteen major terpenoids mainly taraxasterol, lupeol, pseudotaraxasterol, lup-22(29)-en-3-yl acetate, taraxasteryl acetate, α-amyrin, ß-amyrin, pseudotaraxasteryl acetate, hop-20(29)-en3-ß-ol, α-amirenone, along with ß-sitosterol and stigmasterol. Moreover, we have evaluated the in vitro antibacterial and antifungal activities of the unsaponifiable matter and a fraction isolated from this extract. These activities were conducted using the diffusion disc methods and broth microdilution assay. The resulted fraction from this extract showed the highest antibacterial activity with significant minimum inhibitory concentrations (MIC) values 125.0 µg/ml against Staphylococcus aureus, Micrococcus luteus and Bacillus cereus. However, it did exhibit no substantial antifungal activity.