ABSTRACT
In this work, nine previous undescribed polycyclic polyprenylated acylphloroglucinols with adamantine/homoadamantane skeletons, cumilcinols A-I (1-9), along with six known analogues, were isolated and identified from the stems, leaves and flowers of Hypericum wilsonii. Their structures were determined by HRESIMS, NMR spectroscopic analysis, single-crystal X-ray crystallography as well as electronic circular dichroism calculations and comparisons. Compound 2 formed a unique furan ring bearing a rare acetal functionality. In bioassays, hyperacmosin G (13) could significantly inhibit the production of NO in LPS-stimulated RAW264.7 cell (IC50 = 4.350 ± 1.146 µM), and increased expression of related transcription factors at the gene level, inhibit the nuclear translocation of NF-κBp65, and reduce the protein expression of COX-2. Additionally, compound 5 showed significant inhibitory activity on Con A-induced T-lymphocyte proliferation (IC50 = 4.803 ± 3.149 µM), and treatment of 5 could reduce the increased ratio of CD4 and CD8 subpopulations induced by Con A in vitro. Those results indicated 13 possesses potential anti-inflammatory activity, and 5 exhibits a certain degree of immunosuppressive activity.
Subject(s)
Hypericum , Hypericum/chemistry , Phloroglucinol , Molecular Structure , Magnetic Resonance Spectroscopy , Circular DichroismABSTRACT
A chemical investigation on an endophytic fungus Penicillium expansum isolated from the medicinal plant Plantago depressa Willd. (Plantaginaceae) afforded one new diketopiperazine-type alkaloid, namely penicimine A (1), as well as two known congeners (2 and 3). Their structures were elucidated by widespread spectroscopic data, and the absolute configurations of 1 and 2 were further confirmed by single-crystal X-ray diffraction analyses. Compound 1 represented the first example of benzyl-containing diketopiperazine-type alkaloid bearing a methyl group attached at C-15 position. Compound 1 showed anti-inflammatory activity against LPS-induced nitric oxide (NO) production in RAW264.7 mouse macrophages with an IC50 value of 25.65 µM.
ABSTRACT
Longisglucinol A (1), a polycyclic polyprenylated acylphloroglucinol (PPAP) with a new skeleton, along with two new congeners, longisglucinols B (2) and C (3), were isolated from Hypericum longistylum. Compound 1 features an unparalleled 6/6/6/5 fused ring skeleton based on a unique 8-oxa-tetracyclo-[8.3.3.01,9.03,7]cetane core. Longisglucinol A showed remarkable anti-inflammatory activity by inducing macrophage M2 polarization through the suppression of NF-κB.