Antigenic mismatch can cause influenza vaccines to be ineffective, and influenza viruses resistant to antiviral drugs are rising. Thus, development of antiviral agents against these viruses is an immediate need. Rhus verniciflua (RVS) has long been used in herbal medicine and as a nutritional supplement. The effect of RVS and its components on influenza virus has not, however, been reported. We found that RVS treatment significantly reduced viral replication when evaluated with green fluorescent protein- (GFP-) tagged virus (influenza A virus, A/PR/8/34-GFP) in Madin–Darby canine kidney (MDCK) cells. RVS showed significant inhibition of neuraminidase from A/PR/8/34. Subsequently, three fractions were prepared from an ethanolic crude extract of RVS. In vitro assays indicated that an ethyl acetate fraction (RVSE) was more potent than H₂O and CHCl₃ fractions. RVSE significantly suppressed influenza virus infection in MDCK cells via neuraminidase inhibition. Additionally, RVSE treatment inhibited expression of several virus proteins and decreased mortality of mice exposed to influenza A/PR/8/34 by 50% and reduced weight loss by 11.5%. Active components in RVSE were isolated, and 5-deoxyluteolin (5) and sulfuretin (7) demonstrate the highest neuraminidase inhibitory activity against influenza A virus. RVS, RVSE, and their constituents may be useful for the development of anti-influenza agents.

中文翻译：

---

神经氨酸酶抑制剂对黑疣猴乙醇提取物中乙酸乙酯部分的抗流感活性

抗原不匹配会导致流感疫苗无效，并且抗病毒药物耐药的流感病毒正在上升。因此，迫切需要开发针对这些病毒的抗病毒剂。长期存在的黑鼠李（RVS）已用于草药和作为营养补品。然而，尚未报道RVS及其组分对流感病毒的作用。我们发现，在Madin-Darby犬肾（MDCK）细胞中，用绿色荧光蛋白（GFP-）标记的病毒（甲型流感病毒，A / PR / 8 / 34-GFP）进行评估时，RVS治疗显着降低了病毒复制。RVS显示出对来自A / PR / 8/34的神经氨酸酶的显着抑制。随后，从RVS的乙醇粗提物中制备了三部分。体外分析表明，乙酸乙酯馏分（RVSE）比H ₂ O和CHCl ₃馏分更有效。RVSE通过抑制神经氨酸酶显着抑制MDCK细胞中的流感病毒感染。此外，RVSE处理可抑制几种病毒蛋白的表达，并使暴露于A / PR / 8/34流感的小鼠的死亡率降低50％，体重减轻减少11.5％。分离出RVSE中的活性成分，并且5-deoxyluteolin（5）和sulfetin（7）表现出对甲型流感病毒最高的神经氨酸酶抑制活性。RVS，RVSE及其成分可能对开发抗流感药物有用。