State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Sciences and Technology, Anhui Agricultural University, Hefei, Anhui 230036, PR China; International Joint Laboratory on Tea Chemistry and Health Effects of Ministry of Education, Anhui Agricultural University, Hefei, Anhui 230036, PR China.
International Joint Laboratory on Tea Chemistry and Health Effects of Ministry of Education, Anhui Agricultural University, Hefei, Anhui 230036, PR China; Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey 08901-8520, USA.
Food Res Int. 2022 Sep;159:111639. doi: 10.1016/j.foodres.2022.111639. Epub 2022 Jul 9.
Predictable tea grading bears not only scientific merit, but also commercial value. Lu'an guapian green tea (LGGT) is one of the most famous green teas in China. Based on morphology and sensory flavour, LGGT was traditionally graded as first premium (FP), second premium (SP), first grade (FG), second grade (SG), third grade (TG) and summer grade (SuG). The chemical profiles and distinct metabolites distinguishing different grades of LGGT are yet to be defined, neither the grade related health benefits be evaluated. In present study, non-targeted metabolomics combined with chemometrics analysis showed that FP and SP, FG and SG exhibited high similarity, respectively. TG and SuG both exhibited great difference from the other grades. Therefore, LGGT could be regrouped into four grades. Furthermore, eight metabolites were identified and displayed grade related bio-markers of LGGT, which are gallic acid, catechin, gallocatechin, salicylic acid, theasinensin B, theasinensin C, kaempferol 3-(6''-rhanmnosylsoporoside) and l-linalool 3-[xylosyl-(1->6)-glucoside]. Quantitative analysis further confirmed that gallic acid, catechin, gallocatechin and salicylic acid were distinct grade-related metabolites. In vitro and in vivo data showed that methanol-extracts of higher grades LGGT exhibited more potent α-amylase and α-glucosidase inhibitory activity and hypoglyceamia effect than that of lower grades.
可预测的茶叶分级不仅具有科学意义，而且具有商业价值。六安瓜片绿茶（LGGT）是中国最著名的绿茶之一。根据形态学和感官风味，LGGT 传统上分为特级（FP）、一级（SP）、二级（FG）、三级（SG）、四级（TG）和夏茶（SuG）。不同等级的 LGGT 的化学特征和独特代谢物尚未确定，也未评估与等级相关的健康益处。在本研究中，非靶向代谢组学结合化学计量学分析表明，FP 和 SP、FG 和 SG 分别表现出高度相似性。TG 和 SuG 与其他等级均表现出很大差异。因此，LGGT 可以重新分为四个等级。此外，鉴定出 8 种代谢物，并显示了 LGGT 的与等级相关的生物标志物，分别为没食子酸、儿茶素、表儿茶素、水杨酸、特儿茶素 B、特儿茶素 C、山奈酚 3-（6''-鼠李糖苷）和 l-芳樟醇 3-[木糖基-（1->6）-葡萄糖苷]。定量分析进一步证实，没食子酸、儿茶素、表儿茶素和水杨酸是明显的与等级相关的代谢物。体外和体内数据表明，较高等级的 LGGT 的甲醇提取物比较低等级的提取物具有更强的α-淀粉酶和α-葡萄糖苷酶抑制活性和降血糖作用。
