南岳云雾茶的品质评价及其方法学研究

目的:建立茶叶中茶氨酸、5种儿茶素类(+C、EC、EGC、EGCG、ECG)、总黄酮和咖啡因含量测定的HPLC法,并对南岳云雾茶的品质进行评价。方法:茶叶中有效成分的提取参照GB/T 8303-2018,分析采用安捷伦Eclipse XDB-C18色谱柱(4.6 mm×250 mm,5μm),流动相为2%乙酸水(A)-2%乙酸乙腈(B),流速0.8 mL/min^(-1),柱温25℃,检测波长为203 nm、278 nm、360 nm。结果:方法学结果显示+C、EC、EGC、EGCG、ECG、咖啡因、L-茶氨酸及芦丁分别在50.00μg∙mL^(-1)~150.00μg∙mL^(-1),50.00μg∙mL^(-1)~150.00μg∙mL^(-1),50.00μg∙mL^(-1)~150.00μg∙mL^(-1),100.00μg∙mL^(-1)~250.00μg∙mL^(-1),100.00μg∙mL^(-1)~300.00μg∙mL^(-1),10.00μg∙mL^(-1)~100.00μg∙mL^(-1),100.00μg∙mL^(-1)~400.00μg∙mL^(-1)及10.00μg∙mL^(-1)~100.00μg∙mL^(-1)浓度范围内线性关系良好,加样回收率为92.49%-105.56%。在上述条件下,测得南岳云雾茶中茶氨酸、儿茶素类、总黄酮和咖啡因的含量分别为67.32 mg/g、260.42mg/g、3.712 mg/g和34.05 mg/g。结论:南岳云雾茶中茶氨酸、儿茶素类及总黄酮的含量相对较高。该方法简便、准确、快速、重现性好,可为茶叶的质量控制提供科学的依据。

Macrocyclic trichothecenes from Myrothecium verrucaria PA 57 and their cytotoxic activity

Four novel macrocyclic trichothecenes,termed mytoxins D-G(1-4),along with four known analogs(5-8),were isolated from the ethyl acetate extract of fermented rice inoculated with the fungus Myrothecium verrucaria PA57.Each compound features a tricyclic 12,13-epoxytrichothec-9-ene(EPT)core.Notably,mytoxin G(4)represents the first instance of a macrocyclic trichothecene incorporating a glucosyl unit within the trichothecene structure.The structures of the newly identified compounds were elucidated through comprehensive spectroscopic analysis combined with quantum chemical calculations.All isolated compounds demonstrated cytotoxic activity against the CAL27 and HCT116 cell lines,which are models for human oral squamous cell carcinoma and colorectal cancer,respectively.Specifically,mytoxin D(1)and mytoxin F(3)exhibited pronounced cytotoxic effects against both cancer cell lines,with IC_(50)values ranging from 3 to 6 nmol·L~(-1).Moreover,compounds 1 and 3 were found to induce apoptosis in HCT116 cells by activating caspase-3.