Discovery of Diverse Polycyclic Polyprenylated Acylphloroglucinols from Hypericum kouytchense with Anti-Liver Fibrosis Potential

Abstract Hypercoretions A–C (1–3), three types of unprecedented polycyclic polyprenylated acylphloroglucinols (PPAPs), were isolated from Hypericum kouytchense using a combined FBMN and UV-guided isolation method. Notably, hypercoretion A (1) represents a unique nor-PPAP characterized by a rearranged 5/6/6/5 tetracyclic skeleton, while hypercoretion B (2) is the first example of a seco-nor-PPAP featuring an unusual 5/5/5 tricyclic skeleton. Their structures were established via spectroscopic analyses, X-ray diffraction, vibrational circular dichroism, and quantum chemical calculations. Biologically, the isolates were evaluated for their anti-liver fibrosis activities in TGF-β1-stimulated LX-2 hepatic stellate cells.