Unprecedented Monoterpenoid Polyprenylated Acylphloroglucinols with a Rare 6/6/5/4 Tetracyclic Core, Enhanced MCF-7 Cells' Sensitivity to Camptothecin by Inhibiting the DNA Damage Response

(±)-hypermonanones A-G, seven pairs of monoterpenoid polyprenylated acylphloroglucinol enantiomers from Hypericum monanthemum

Seven pairs of undescribed monoterpenoid polyprenylated acylphloroglucinol enantiomers [(±)-hypermonanones A-G (1-7)], together with three known analogues, were identified from the whole plant of Hypericum monanthemum Hook. The structures of these compounds were determined by analyses of their UV, HRESIMS, 1D/2D NMR spectroscopic data, and NMR calculations. The absolute configurations of these compounds were assigned by ECD calculations after chiral HPLC separation. Diverse monoterpene moieties were fused at C-3/C-4 of the dearomatized acylphloroglucinol core, which led to 3,4-dihydro-2H-pyran-integrated angular or linear type 6/6/6 tricyclic skeletons in 1-7. Compounds (-)-2 and (+)-2 exhibited significant NO inhibitory activity against LPS induced RAW264.7 cells with the IC50 values of 7.07 ± 1.02 μM and 11.39 ± 0.24 μM, respectively.

Monoterpenoid acylphloroglucinols from Hypericum hengshanense W. T. Wang with antiproliferative activities

Hypericum species (Hypericaceae) are a group of important plants with medicinal, edible, and ornamental values. A phytochemical study on the whole plants of H. hengshanense W. T. Wang, a species endemic to China, led to the isolation and elucidation of 25 monoterpenoid acylphloroglucinols (MAPs). Among them, 10 are undescribed compounds, namely hyphengshanols A-D, (+)-empetrilatinol A, (-)-empetrilatinol B, (-)-hyperjovinol A, (9S,2'S)-dauphinol F, and (8R,2'S)-empetrikathiforin. In addition, the absolute configurations of other six compounds were firstly determined in the current study. The structures were established by ultraviolet (UV), high resolution electrospray ionization mass spectrum (HR-ESI-MS), and nuclear magnetic resonance spectroscopy (NMR) data. The absolute configurations were determined by experimental and calculated electronic circular dichroism (ECD) data analyses. Cytotoxicity assays on five human cell lines HL-60, A549, SMMC-7721, MDA-MB-231, and SW480 revealed that 16 compounds exhibited broad-spectrum antiproliferative activities with IC₅₀ ranging from 7.54 to 45.70 μM.

Seco-polyprenylated acylphloroglucinols from Hypericum elodeoides induced cell cycle arrest and apoptosis in MCF-7 cells via oxidative DNA damage

Four undescribed seco-polyprenylated acylphloroglucinols (seco-PAPs), elodeoidesones A-D (1-4), were characterized from Hypericum elodeoides. Compound 1 represents the 1,6-seco-PAPs with fascinating 5/5 fused ring, while 2-4 possess a 1,2-seco-PAPs skeleton with a five-membered lactone core. Their structures including absolute configurations were established by spectroscopic analyses and quantum chemical computations. A possible biosynthetic pathway of 1-4 from normal PAPs was proposed. All the isolates were investigated for their cytotoxicity against tumor cells. Notably, 1 inhibited the proliferation of MCF-7 cells with the IC₅₀ value of 7.34 μM. Mechanism investigation indicated that 1 induced MCF-7 cells apoptosis by blocking cell cycle at S phase via inducing oxidative DNA damage.