McIntyre Kristina L, Harris Cory S, Saleem Ammar, Beaulieu Louis-Philippe, Ta Chieu Anh, Haddad Pierre S, Arnason John T
Centre for Research in Biotechnology and Biopharmaceuticals, Department of Biology University of Ottawa, Ottawa, Canada.
Planta Med. 2009 Feb;75(3):286-92. doi: 10.1055/s-0028-1088394. Epub 2008 Dec 15.
Diabetic hyperglycaemia promotes the production of advanced glycation end-products (AGEs), which play a significant role in the development of complications associated with type 2 diabetes mellitus. Vaccinium angustifolium, a medicinal plant used for the treatment of diabetes, produces a variety of phenolic metabolites with putative anti-diabetic activities. To assess optimal cultivation time, seasonal changes in the concentration of six phenolic compounds in leaves and twelve compounds in stems were examined using HPLC-DAD and examined in relation to seasonal changes in AGE inhibition activity, assessed with a fluorescence-based assay. A seasonal decline occurred in the concentration of chlorogenic acid, rutin, and quercetin 3-arabinoside in leaves and chlorogenic acid in stems. The concentration of (+)-catechin, and (-)-epicatechin in stems declined within two weeks before rising and fluctuating insignificantly. AGE inhibition activity of leaves was significantly greater at the final compared to the initial collection date whereas the activity of stems did not change significantly. Relative to the leaf extract, the stem was a more potent inhibitor of AGE formation, which could be a result of the unique phytochemistry of stems. Together, these results revealed significant seasonal variation in the phenolic profile and anti-glycation effects of V. angustifolium extracts and indicated late summer as the collection time yielding optimal activity.
糖尿病高血糖会促进晚期糖基化终产物（AGEs）的产生，而AGEs在2型糖尿病相关并发症的发展中起着重要作用。越橘是一种用于治疗糖尿病的药用植物，它能产生多种具有潜在抗糖尿病活性的酚类代谢产物。为了评估最佳种植时间，使用高效液相色谱-二极管阵列检测法（HPLC-DAD）检测了叶片中六种酚类化合物和茎中十二种化合物浓度的季节性变化，并将其与基于荧光测定法评估的AGE抑制活性的季节性变化相关联进行研究。叶片中绿原酸、芦丁和槲皮素3-O-阿拉伯糖苷以及茎中绿原酸的浓度出现季节性下降。茎中（+）-儿茶素和（-）-表儿茶素的浓度在上升并轻微波动前两周内下降。与初始采集日期相比，叶片在最终采集日期的AGE抑制活性显著更高，而茎的活性没有显著变化。相对于叶片提取物，茎是更强效的AGE形成抑制剂，这可能是由于茎独特的植物化学性质所致。这些结果共同揭示了越橘提取物酚类特征和抗糖基化作用存在显著的季节性变化，并表明夏末是采集能产生最佳活性的时间。
