Diphyllin (1) 和 justicidin B (2) 是具有抗病毒和抗增殖效果的芳基萘丙烷木脂素。化合物1也被称为严重急性呼吸综合症冠状病毒2（SARS-CoV-2）的有效抑制剂。为评估这两个木脂素在SARS-CoV-2感染的细胞和各种癌细胞系中的体外抗病毒和细胞毒性效力，分别从奥地利亚麻（Linum austriacum）和多年生亚麻（Linum perenne）的地下器官中分离出1和2。还分离并鉴定了两种先前未描述的芳基萘丙烷木脂素，分别称为linadiacin A和B（3和4）。在酸性介质中，3经两步反应转化为中间体4，再转化为2。通过一步制备高效液相色谱（HPLC）确定最佳酸处理条件以分离木脂素。转化、HPLC串联质谱、核磁共振光谱和分子模拟研究的结果允许了完整的结构分析。化合物1和2对SARS-CoV-2最有效，在12.5μM浓度下病毒拷贝数降低3个数量级。十个人类癌细胞系对至少一种分离的木脂素敏感。

Diphyllin (1) and justicidin B (2) are arylnaphthalene lignans with antiviral and antiproliferative effects. Compound 1 is also known as an effective inhibitor of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). To evaluate the in vitro antiviral and cytotoxic potency of both lignans in SARS-CoV-2 -infected cells and various cancer cell lines, respectively, 1 and 2 were isolated from the underground organs of Linum austriacum and Linum perenne. Two previously undescribed arylnaphthalene lignans, denominated linadiacin A and B (3 and 4), were also isolated and identified. In acidic media, 3 was converted by a two-step reaction into 2 via the intermediate 4. Optimum acid treatment conditions were determined to isolate lignans by one-step preparative high-performance liquid chromatography (HPLC). The results of the conversion, HPLC-tandem mass spectrometry, nuclear magnetic resonance spectroscopy, and molecular modeling studies allowed complete structure analysis. Compounds 1 and 2 were the most effective against SARS-CoV-2 with a 3-log reduction in the viral copy number at a 12.5 μM concentration. Ten human cancer cell lines showed sensitivity to at least one of the isolated lignans.