Grillo Giorgio, Capaldi Giorgio, Radošević Kristina, Jakopović Željko, Markov Ksenija, Brncic Mladen, Gallina Lorenzo, Calcio Gaudino Emanuela, Cravotto Giancarlo
Department of Drug Science and Technology, University of Turin, Via P. Giuria 9, 10235 Turin, Italy.
Laboratory for Cell Cultures, Applications and Biotransformations, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottojeva Ulica 6, 10000 Zagreb, Croatia.
Antioxidants (Basel). 2023 Sep 23;12(10):1796. doi: 10.3390/antiox12101796.
Pomegranate ( L.) is well known for its high content of bioactives, including polyphenols, flavonoids, and tannins, which have been shown to exhibit a wide range of biological activities, such as antioxidant, antimicrobial, and anticancer effects. It is worth noting that the majority of these molecules are found in the peels, which are usually disposed of after processing, causing a significant amount of waste, amounting to more than 3.6 million t/y. This work investigates microwave-assisted extraction (MAE) in water for the recovery of antioxidants from pomegranate peels (PP), including the optimisation of temperature and extraction times. The total phenolic, anthocyanin, flavonoid, and tannin contents of the recovered extracts were determined, as well as their antioxidant activities, which were found to be 356.35 mgGAE/gExtr, 303.97 µgCy3G/gExtr, 37.28 mgQE/gExtr, 56.48 mgGAE/gExtr, and 5.72 mmolTE/gExtr, respectively (according to the adopted reference). All results were compared with those obtained using a conventional protocol. In addition, the potential for water recycling by means of downstream nanofiltration in optimised MAE was investigated, leading to overall water reuse of approx. 75%. Power consumption (20.92 W/mgGAE) and common green metrics, Reaction Mass Efficiency (RME), E-Factor, and the Process Mass Intensiti/efficiency (PMI, PME), were considered in evaluating the proposed PP valorisation strategy. Finally, the biological activities of the main products were assessed. The antimicrobial properties of the PP extracts against three Gram-positive and three Gram-negative bacteria and their antiproliferative activity towards human cancer cells were tested. bacteria was the most susceptible to the PP extracts. All tested products displayed antiproliferative activity against HeLa cells when higher concentrations were tested, with D-PP/NF (obtained from dried PP and sequential nanofiltration) being the most effective. This result was also confirmed via clonogenic analysis, which generally indicated the possible anti-cancer activity of pomegranate peel extracts obtained using this green approach.
石榴（L.）以其丰富的生物活性成分而闻名，包括多酚、黄酮类化合物和单宁，这些成分已被证明具有广泛的生物活性，如抗氧化、抗菌和抗癌作用。值得注意的是，这些分子大部分存在于果皮中，而果皮通常在加工后被丢弃，造成大量浪费，每年超过360万吨。这项工作研究了在水中进行微波辅助萃取（MAE）以从石榴皮（PP）中回收抗氧化剂，包括温度和萃取时间的优化。测定了回收提取物中的总酚、花青素、黄酮类化合物和单宁含量，以及它们的抗氧化活性，结果分别为356.35 mgGAE/gExtr、303.97 µgCy3G/gExtr、37.28 mgQE/gExtr、56.48 mgGAE/gExtr和5.72 mmolTE/gExtr（根据采用的参考标准）。所有结果都与使用传统方法获得的结果进行了比较。此外，还研究了在优化的MAE中通过下游纳滤进行水回收利用的潜力，总体水回用率约为75%。在评估所提出的石榴皮增值策略时，考虑了功耗（20.92 W/mgGAE）以及常见的绿色指标，反应质量效率（RME）、E因子和过程质量强度/效率（PMI、PME）。最后，评估了主要产品的生物活性。测试了石榴皮提取物对三种革兰氏阳性菌和三种革兰氏阴性菌的抗菌性能以及它们对人类癌细胞的抗增殖活性。细菌对石榴皮提取物最敏感。当测试较高浓度时，所有测试产品对HeLa细胞均显示出抗增殖活性，其中D-PP/NF（由干燥的石榴皮和连续纳滤获得）最为有效。克隆形成分析也证实了这一结果，该分析总体表明使用这种绿色方法获得的石榴皮提取物可能具有抗癌活性。
