Evaluation of Polyphenolic Profile and Antioxidant Activity of Pistacia lentiscus L. Leaves and Fruit Extract Obtained by Optimized Microwave-Assisted Extraction

Abstract

Pistacia lentiscus L. is a Mediterranean shrub known for its health promoting effects attributed to a large extent to polyphenols accumulated in all parts of the plant. Microwave-assisted extraction is a green extraction technique enabling fast and effective isolation of plant polyphenols. Therefore, the aim of this research was to optimize the microwave-assisted extraction of polyphenols from Pistacia lentiscus L. leaves and fruit in terms of temperature, extraction time and microwave power and to evaluate their polyphenolic profile by UPLC/ESI-MS2 and antioxidant capacity by ORAC assay. Optimal extraction conditions for leaf polyphenols were 69 °C, 512 W and 12 min, while for fruit were slightly more intensive—75 °C, 602 W and 15 min. Obtained total phenolic content in leaves and fruit was similar to that obtained after 30 min of the heat-reflux method. The polyphenolic profile of extracts included 34 compounds, with myricetin glycosides being the most abundant compounds among flavonoids in Pistacia lentiscus L. leaves and fruit and gallic acid and its derivates among the phenolic acids. ORAC assay showed higher antioxidant capacity for Pistacia lentiscus L. leaves extract than for fruit, which is in correlation with their respective phenolic content.

Microwave Assisted Extraction and Pressurized Liquid Extraction of Sulfated Polysaccharides from Fucus virsoides and Cystoseira barbata

“…The antioxidant capacity was evaluated by the oxygen radical absorbance capacity (ORAC) assay according to the research of Elez Garofulić et al (2020) [ 22 ]. The ORAC procedure used an automated plate reader (BMG LABTECH, Offenburg, Germany) with 96-well plates, and the data were analyzed using MARS 2.0 software.…”

Phenolic Profile, Antioxidant Capacity and Antimicrobial Activity of Nettle Leaves Extracts Obtained by Advanced Extraction Techniques

“…In order to evaluate the influence of MAE parameters on the isolation of nettle leaves' polyphenols, a full factorial design was employed, varying the extraction temperature (40, 60 and 80 • C), irradiation time (5 and 10 min) and microwave power (300 and 600 W). The range of parameters considered for this research was selected upon previous studies and literature reports focused on isolation of plant polyphenols [13,[15][16][17][18]. Additionally, extractions were carried out with three different solvents, water, 30% aqueous ethanol and 30% aqueous acetone.…”

“…An increase in TPC was observed with temperature elevation from 40 to 60 • C, while a further increase to 80 • C showed no positive effect on total isolated polyphenols (Figure 1). Although higher temperatures generally enhance the extraction efficiency by increasing solute solubility, facilitating molecular motion, providing better mass transfer and reducing solvent viscosity [15,26,27], excessive exposure could also cause degradation and oxidation of polyphenols, so its selection should be based on the characteristics and polyphenolic composition of the subjected plant material. Similar to our conclusions, Alara et al (2021) [28] found 60 • C to be the optimal temperature for MAE of polyphenols from Carica papaya leaves, as a further increase to 70 • C and above caused their degradation.…”

Valorization of Agri-Food Waste from Pistachio Hard Shells: Extraction of Polyphenols as Natural Antioxidants

“…The Pistacia genus belongs to the Anacardiaceae, a widespread family with about 70 genera and over 600 species. P. vera is the only species cultivated as food for commercial purposes [11,12] and P. lentiscus is exploited for food products, cosmetics and health products [13,14]. Italy produces less than 0.6% of P. vera world production.…”