To identify new potential anti-influenza compounds, we isolated six flavonoids, 2′-hydroxyl yokovanol (1), 2′-hydroxyl neophellamuretin (2), yokovanol (3), swertisin (4), spinosin (5), and 7-methyl-apigenin-6-C-β-glucopyranosyl 2″-O-β-d-xylopyranoside (6) from MeOH extractions of Ohwia caudata. We screened these compounds for antiviral activity using green fluorescent protein (GFP)-expressing H1N1 (A/PR/8/34) influenza A-infected RAW 264.7 cells. Compounds 1 and 3 exhibited significant inhibitory effects against influenza A viral infection in co-treatment conditions. In addition, compounds 1 and 3 reduced viral protein levels, including M1, M2, HA, and neuraminidase (NA), and suppressed neuraminidase (NA) activity in RAW 264.7 cells. These findings demonstrated that 2′-hydroxyl yokovanol and yokovanol, isolated from O. caudate, inhibit influenza A virus by suppressing NA activity. The moderate inhibitory activities of these flavonoids against influenza A virus suggest that they may be developed as novel anti-influenza drugs in the future.

中文翻译：

---

Ohwia caudata 黄酮类化合物对甲型流感病毒感染的保护作用

为了鉴定新的潜在抗流感化合物，我们分离了 6 种黄酮类化合物：2'-羟基 yokovanol (1)、2'-羟基新蛇麻素 (2)、yokovanol (3)、swertisin (4)、spinosin (5) 和 7-甲基-芹菜素-6-C-β-吡喃葡萄糖基 2″-O-β-d-吡喃木糖苷 (6) 来自 Ohwia caudata 的 MeOH 提取物。我们使用表达绿色荧光蛋白 (GFP) 的 H1N1 (A/PR/8/34) 感染 A 型流感的 RAW 264.7 细胞筛选这些化合物的抗病毒活性。化合物1和3在共同治疗条件下表现出对甲型流感病毒感染的显着抑制作用。此外，化合物 1 和 3 降低了病毒蛋白水平，包括 M1、M2、HA 和神经氨酸酶 (NA)，并抑制了 RAW 264.7 细胞中的神经氨酸酶 (NA) 活性。这些发现表明，从尾状核糖体中分离的 2'-羟基 yokovanol 和 yokovanol，通过抑制 NA 活性来抑制甲型流感病毒。这些黄酮类化合物对甲型流感病毒的中等抑制活性表明它们可能在未来被开发为新型抗流感药物。