Protti Michele, Gualandi Isacco, Mandrioli Roberto, Zappoli Sergio, Tonelli Domenica, Mercolini Laura
Pharmaco-Toxicological Analysis Laboratory (PTA Lab), Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum - University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy.
Department of Industrial Chemistry "Toso Montanari", INSTM, UdR Bologna, Alma Mater Studiorum - University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy.
J Pharm Biomed Anal. 2017 Sep 5;143:252-260. doi: 10.1016/j.jpba.2017.05.048. Epub 2017 Jun 3.
Goji berries and derived products represent a relevant source of micronutrients, most of which are natural antioxidants and contribute to the high nutritional quality of these fruits. Three brands of dried goji berries have been analysed by a multidisciplinary approach to get an insight into both their content of selected antioxidants and their antioxidant capacity (AC). The former goal has been achieved by developing a liquid chromatographic method coupled to mass spectrometry and combined to a fast solid phase extraction. Several significant representative antioxidant compounds belonging to the following classes: flavonoids, flavan-3-ols, phenolic acids, amino acids and derivatives, and carotenoids have been taken into account. Quercetin and rutin were found to be the predominant flavonoids, chlorogenic acid was the most abundant phenolic acid and zeaxanthin was the major carotenoid. The AC of the goji berries has been evaluated by four analytical methods in order to estimate the contributions of different reactions involved in radicals scavenging. In particular, AC has been determined using 3 standardised methods (DPPH, ABTS, ORAC) and a recently proposed electrochemical method, which measures the scavenging activity of antioxidants towards OH radicals generated both by hydrogen peroxide photolysis and the Fenton reaction. The results obtained from chemical composition and antioxidant capacity assays confirm the high nutritional and commercial value of goji berries and highlight that the three brands do not exhibit significant differences.
枸杞及其衍生产品是微量营养素的重要来源，其中大部分是天然抗氧化剂，有助于提升这些水果的高营养价值。通过多学科方法对三个品牌的干枸杞进行了分析，以深入了解其选定抗氧化剂的含量及其抗氧化能力（AC）。通过开发一种与质谱联用并结合快速固相萃取的液相色谱方法实现了前一个目标。已考虑了几类重要的代表性抗氧化化合物：黄酮类化合物、黄烷-3-醇、酚酸、氨基酸及其衍生物和类胡萝卜素。发现槲皮素和芦丁是主要的黄酮类化合物，绿原酸是含量最丰富的酚酸，玉米黄质是主要的类胡萝卜素。通过四种分析方法评估了枸杞的抗氧化能力，以估计自由基清除中不同反应的贡献。具体而言，使用3种标准化方法（DPPH、ABTS、ORAC）和一种最近提出的电化学方法测定了抗氧化能力，该电化学方法测量抗氧化剂对过氧化氢光解和芬顿反应产生的OH自由基的清除活性。化学成分和抗氧化能力测定结果证实了枸杞的高营养和商业价值，并突出表明这三个品牌没有显著差异。
