In this study, we evaluated the use of prickly pear seed cake, a by-product of prickly pear seed oil extraction, as a new precursor for producing activated carbon by phosphoric acid activation, and the obtained carbon’s capacity for heavy metal removal from aqueous solution. Response surface methodology based on the full factorial design at two levels (2⁴) was developed to reduce the number of experiments and reach optimal preparation conditions for the removal of cadmium and lead ions from aqueous solutions. Design Expert 11.1.2.0 Trial software was used for generating the statistical experimental design and analyzing the observed data. Factors influencing the activation process, such as carbonization temperature, activation temperature, activation time, and impregnation ratio, were studied. Responses were studied in depth with an analysis of variance to estimate their significance. Each response was outlined by a first-order regression equation demonstrating satisfactory correspondence between the predicted and experimental results as the adjusted coefficients of correlation. Based on the statistical data, the best conditions for the removal of heavy metals from aqueous solution by the obtained activated carbon were indicated. The maximum iodine number and methylene blue index were 2527.3 mg g⁻¹ and 396.5 mg g⁻¹, respectively, using activated carbon obtained at the following conditions: Tc = 500 °C, Ta = 500 °C, impregnation ratio = 2:1 (g H₃PO₄: g carbon), and activation time of two hours. The maximum adsorption reached 170.2 mg g⁻¹ and 158.4 mg g⁻¹ for Cd²⁺ and Pb²⁺, respectively, using activated carbon obtained at the following conditions: Tc = 600 °C, Ta = 400 °C, impregnation ratio = 2:1 (g H₃PO₄: g carbon), and activation time of one hour. The activated carbon obtained was characterized by Boehm titration, pH of point of zero charge (pH_PZC), Brunauer–Emmett–Teller surface area (S_BET), and scanning electron microscopy. Adsorption was performed according to different parameters: pH solution, adsorbent dosage, temperature, contact time, and initial concentration. Regeneration experiments proved that the obtained activated carbon still had a high removal capacity for Cd²⁺ and Pb²⁺ after five regeneration cycles.

Eucalyptus marginata L. has a significant value in traditional medicine and recently has been shown to possess many pharmacological properties in vitro. The main goal of the present study was to optimize the extraction parameters of phenolic compounds from Eucalyptus marginata L. leaves using the extraction technique assisted by ultrasound in comparison with maceration using response surface methodology as a predicted tool. Therefore, total phenolic and flavonoid contents have been optimized, taking into account four variables: extraction time, temperature, liquid-to-solid ratio, and ethanol concentration. The optimum ultrasound-assisted extraction method for total phenolic and total flavonoid contents was obtained by ensuring the following parameters: t=49.9min, T=74.9°C, liquid-to-solid ratio=39.5ml/g, and ethanol=58.48. The optimum extract has been subjected to LC-ESI-MS analysis. This technique allowed us to identify ten phenolic compounds: four phenolic acids mainly gallic acid (27.77±0.06µg/g DW) and protocatechuic acid (37.66±0.04µg/g DW) and six flavonoid compounds such as quercetrin (150.78±0.02µg/g DW) and hyperoside (39.19±0.03µg/g DW). These green and efficient procedures should be a promising option to guide industrial design for the production of phenolic-rich plant extracts.

This study aimed to evaluate Pinus halepensis Mill. seeds oil as well as methanolic‐aqueous extract on fatty acid and phenolic's composition as well as antioxidant activities with regard to the cones drying methods: convection and sun methods. The highest amounts of total phenols (14.63 ± 0.05 mg GAE/g DW), flavonoids (3.3 ± 0.02 mg QE/g DW), and condensed tannins (0.36 ± 0.05 mg CE/g DW) were showed in the seeds obtained by sun‐dried method. Methanolic‐aqueous seeds extracts were subjected to LC‐ESI‐MS analysis in order to identify and quantify the phenolic composition. This technique allowed us to identify eleven phenolic compounds: two phenolic acids and nine flavonoid compounds such as cirsiliol, catechin (+), luteolin, and luteolin‐7‐O‐glucoside, which were present in the two studied samples while apigenin, naringenin, and cirsilineol were only identified in the extract obtained from sun‐drying method seeds. The chemical components of the oils were analyzed using GC, and significant differences were found between the two studied seeds oil (p < .05). Furthermore, the antioxidant activities were investigated using DPPH and ABTS.⁺ assays. The results showed that the methanolic‐aqueous extract from seeds dried by sun method had the highest antioxidant activities (0.08 and 0.05 mg/ml, respectively). This study could provide useful information for industry to produce potentially bioactive plant extract.

For the first time, the current study was designed to evaluate growing location on the chemical composition as well as the DPPH capacity of Crataegus azarolus L. (var. aronia (Willd.) Batt.) methanolic aqueous extracts. It was found that Crataegus azarolus L. collected from Neber (Governorate of Kef) had the highest total phenolic, flavonoids, condensed and hydrolysable tannin contents while the same genus growing in Jdidi (Governorate of Zaghouan) were characterized by the highest content of sugar (15.27 mg Gluc g⁻¹ DW). Moreover, the plants contents’ in P, K, and Na was investigated. Accordingly, the genus origins have shown to highly affect their content in the former minerals. In vitro, antioxidant activity was also determined using DPPH radical and expressed as concentration of each extract in order to inhibit 50% of DPPH radicals. The obtained values ranged from 55.22 to 138.66 μg mL⁻¹. From a nutritional and antioxidant point of view, Crataegus azarolus L. (var. aronia (Willd.) Batt.) can be considered as a valuable variety.