Hyperacmoses A–C, Three Seco-Norpolyprenylated Acylphloroglucinols from Hypericum acmosepalum with Lipid-Lowering Activity

Hyperacmoses A–C, three seco-norpolyprenylated acylphloroglucinols (PPAPs) (1–3), along with two processors (4 and 5), were purified from Hypericum acmosepalum. Structurally, compounds 1 and 2 represent the first seco-norPPAP with an unprecedented 5/6/5/6/5 pentacyclic framework, while compound 3 is the first seco-norPPAP with a 5/5/6/6 tetracyclic core. Three rare PPAPs had the same biosynthetic precursor, and Baeyer–Villiger oxidation of this precursor at different positions could finally give different types of PPAPs (1–3). Four compounds (1, 2, 4, and 5) exhibited a better triglyceride (TG) inhibitory effect than atorvastatin in oleic acid-induced HepG2 cells. The compound with the highest potential, compound 1, could prohibit the expression of lipid synthesis proteins, FASN and ACACA, by targeting ACSS2.