Cosmulescu Sina, Trandafir Ion, Nour Violeta
Department of Horticulture & Food Science, Agriculture & Horticulture Faculty and.
Pharm Biol. 2014 May;52(5):575-80. doi: 10.3109/13880209.2013.853813. Epub 2013 Nov 20.
Walnut [Juglans regia L. (Juglandaceae)] is a rich source of phenolic compounds, including phenolic acids, naphtoquinones and flavonoids. The increasing interest in the powerful biological activities of plant phenolics has outlined the necessity of determining their content in leaves of different walnut cultivars.
In this study, walnut leaves from walnut cultivars, originating from the same orchard and from the same year of production, were analyzed for their content in ellagic acid, rutin, myricetin and juglone. In addition, the seasonal variation of these major individual phenolics from June to August was determined.
An HPLC method was used for identification and quantification of ellagic acid, rutin, myricetin and juglone contained in the methanol extract of walnut leaves in nine different cultivars grown under the same agricultural, geographical and climatic conditions.
Cultivars and sampling date had statistically significant influence on the phenolics contents in walnut leaves. The results showed that ellagic acid, rutin, myricetin and juglone were more abundant in July 15th samples (average content is 84.62 mg/100 g FW, 98.9 mg/100 g FW, 178.09 mg/100 g FW and 73.81 mg/100 g FW, respectively). Their contents increases similarly in all the cultivars; therefore, the walnut leaves should preferentially be collected until early August, when phenolics content is higher.
The results reported here show that genotype and its interaction with the environment could make significant differences in leaf polyphenols. Walnut leaves may become a noticeable source of compounds with health protective potential.
核桃[胡桃科胡桃属（Juglans regia L.）]是酚类化合物的丰富来源，包括酚酸、萘醌和黄酮类化合物。人们对植物酚类物质强大的生物活性越来越感兴趣，这凸显了测定不同核桃品种叶片中酚类物质含量的必要性。
本研究分析了来自同一果园、同一年生产的核桃品种叶片中鞣花酸、芦丁、杨梅素和胡桃醌的含量。此外，还测定了6月至8月这些主要单一酚类物质的季节性变化。
采用高效液相色谱法对在相同农业、地理和气候条件下种植的9个不同品种核桃叶甲醇提取物中的鞣花酸、芦丁、杨梅素和胡桃醌进行鉴定和定量分析。
品种和采样日期对核桃叶中酚类物质含量有统计学显著影响。结果表明，7月15日的样品中鞣花酸、芦丁、杨梅素和胡桃醌含量更高（平均含量分别为84.62mg/100g鲜重、98.9mg/100g鲜重、178.09mg/100g鲜重和73.81mg/100g鲜重）。它们在所有品种中的含量均以类似方式增加；因此，核桃叶应优先在8月初之前采集，此时酚类物质含量更高。
本文报道的结果表明，基因型及其与环境的相互作用可能会使叶片多酚产生显著差异。核桃叶可能成为具有健康保护潜力化合物的重要来源。
