Houttuynoids A–E, Anti-Herpes Simplex Virus Active Flavonoids with Novel Skeletons from Houttuynia cordata

Houttuynoids A–E (1–5), a new type of flavonoid with houttuynin tethered to hyperoside, and their presumed biosynthetic precursor hyperoside (6) were isolated from the whole plant of Houttuynia cordata. Their structures were elucidated by analysis of 1D and 2D NMR. A hypothetical biogenetic pathway for houttuynoids A–E was proposed. Compounds 1–5 exhibited potent anti-HSV (herpes simplex viruses) activity.