Tricyclic Polyprenylated Acylphloroglucinols from St John’s Wort, <i>Hypericum perforatum</i>

The new polyprenylated acylphloroglucinol
derivatives 1–15 and the known furohyperforin
(16) were isolated from the stems and leaves of Hypericum perforatum. Their structures were determined by
analyses of NMR and HRESIMS
data. Their absolute configurations were elucidated by a combination
of electronic circular dichroism (ECD) and Rh2(OCOCF3)4-induced ECD, as well as X-ray diffraction crystallography.
The new hyperforatin F (9) contains a unique acetyl functionality
at C-1 of the bicyclo[3.3.1]­nonane core. Hyperforatins G (10) and H (11) are similarly the first examples of naturally
occurring [3.3.1]-type polycyclic prenylated acylphloroglucinols possessing
a carbonyl functionality at C-32. The compounds were tested for their
acetylcholinesterase (AChE) inhibitory activities and cytotoxic activities
against a panel of human tumor cell lines. Compounds 3, 5, 6, 8, and 9 exerted moderate inhibitory activities (IC50 3.98–9.13
μM) against AChE.