Pereira José Alberto, Oliveira Ivo, Sousa Anabela, Valentão Patrícia, Andrade Paula B, Ferreira Isabel C F R, Ferreres Federico, Bento Albino, Seabra Rosa, Estevinho Letícia
CIMO/Escola Superior Agrária, Instituto Politécnico de Bragança, Campus Sta Apolónia, Apt. 1172, 5301-855 Bragança, Portugal.
Food Chem Toxicol. 2007 Nov;45(11):2287-95. doi: 10.1016/j.fct.2007.06.004. Epub 2007 Jun 12.
Different cultivars of walnut (Juglans regia L.) leaves (Cv. Lara, Franquette, Mayette, Marbot, Mellanaise and Parisienne) grown in Portugal, were investigated in what concerns phenolic compounds and antimicrobial and antioxidant properties. Phenolics analysis was performed by reversed-phase HPLC/DAD and 10 compounds were identified and quantified: 3- and 5-caffeoylquinic acids, 3- and 4-p-coumaroylquinic acids, p-coumaric acid, quercetin 3-galactoside, quercetin 3-pentoside derivative, quercetin 3-arabinoside, quercetin 3-xyloside and quercetin 3-rhamnoside. The antimicrobial capacity was screened against Gram positive (Bacillus cereus, B. subtilis, Staphylococcus aureus) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). Walnut leaves selectively inhibited the growth of Gram positive bacteria, being B. cereus the most susceptible one (MIC 0.1mg/mL). Gram negative bacteria and fungi were resistant to the extracts at 100mg/mL. Lara walnut leaves were also submitted to antibacterial assays using 18 clinical isolates of Staphylococcus sp. Antioxidant activity was accessed by the reducing power assay, the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and beta-carotene linoleate model system. In a general way, all of the studied walnut leaves cultivars presented high antioxidant activity (EC(50) values lower than 1mg/mL), being Cv. Lara the most effective one.
对生长在葡萄牙的不同核桃（胡桃）品种（拉腊、弗朗凯特、马耶特、马尔博、梅拉奈斯和巴黎ienne）叶片进行了酚类化合物、抗菌和抗氧化特性方面的研究。通过反相高效液相色谱/二极管阵列检测法进行酚类分析，鉴定并定量了10种化合物：3 - 和5 - 咖啡酰奎尼酸、3 - 和4 - 对香豆酰奎尼酸、对香豆酸、槲皮素3 - 半乳糖苷、槲皮素3 - 戊糖苷衍生物、槲皮素3 - 阿拉伯糖苷、槲皮素3 - 木糖苷和槲皮素3 - 鼠李糖苷。针对革兰氏阳性菌（蜡样芽孢杆菌、枯草芽孢杆菌、金黄色葡萄球菌）、革兰氏阴性菌（铜绿假单胞菌、大肠杆菌、肺炎克雷伯菌）和真菌（白色念珠菌、新型隐球菌）筛选了抗菌能力。核桃叶选择性抑制革兰氏阳性菌的生长，蜡样芽孢杆菌最为敏感（最低抑菌浓度为0.1mg/mL）。革兰氏阴性菌和真菌对100mg/mL的提取物具有抗性。还使用18株葡萄球菌临床分离株对拉腊核桃叶进行了抗菌试验。通过还原能力测定、对DPPH（2,2 - 二苯基 - 1 - 苦基肼）自由基的清除作用以及β - 胡萝卜素亚油酸酯模型系统评估抗氧化活性。总体而言，所有研究的核桃叶品种均表现出高抗氧化活性（半数有效浓度值低于1mg/mL），拉腊品种最为有效。
