Comprehensive Summary Hyperlanins A ( 1 ) and B ( 2 ), two highly rearranged polycyclic polyprenylated acylphloroglucinol (PPAP)‐related meroterpenoids based on different new carbon skeletons, were isolated from Hypericum lancasteri . Compound 1 incorporates an unprecedented 5/6/7/5 ring system featuring a 3,13‐dioxatetracyclo[9.2.1.1 2,5 .0 1,8 ]pentadecane core. Compound 2 possesses a unique compact 6/6/5/6/6/5/6 ring system with a caged tetracyclo[6.2.1.1 3,8 .0 5,11 ]dodecane motif. Their structures were established by spectroscopic data, X‐ray diffraction, and computational approaches. Both compounds showed anti‐inflammatory activity in vitro . Compounds 1 and 2 could decrease the lipopolysaccharide (LPS)‐/nigericin‐induced IL‐1 β release in THP‐1 cells. Both compounds also showed inhibition in hypoxia‐inducible factor‐1 α (HIF‐1 α ) pathway luciferase reporter assay.