New Polyprenylated Acylphloroglucinol Derivatives and Xanthones From Hypericum wilsonii

Hypericum Genus as a Natural Source for Biologically Active Compounds

Hypericum L. genus plants are distributed worldwide, with numerous species identified throughout all continents, except Antarctica. These plant species are currently used in various systems of traditional medicine to treat mild depression, wounds and burns, diarrhea, pain, fevers, and their secondary metabolites previously shown, and the in vitro and/or in vivo cytotoxic, antimicrobial, anti-inflammatory, antioxidant, antihyperglycemic, and hepatoprotective activities, as well as the acetylcholinesterase and monoamine oxidase inhibitory activities. We conducted a systematic bibliographic search according to the Cochrane Collaboration guidelines to answer the question: "What is known about plants of Hypericum genus as a source of natural products with potential clinical biological activity?" We documented 414 different natural products with confirmed in vitro/in vivo biological activities, and 58 different Hypericum plant species as sources for these natural products. Phloroglucinols, acylphloroglucinols, xanthones, and benzophenones were the main chemical classes identified. The selective cytotoxicity against tumor cells, cell protection, anti-inflammatory, antimicrobial, antidepressant, anti-Alzheimer's, and adipogenesis-inhibition biological activities are described. Acylphloroglucinols were the most frequent compounds with anticancer and cell-protection mechanisms. To date, no work has been published with a full descriptive list directly relating secondary metabolites to their species of origin, plant parts used, extraction methodologies, mechanisms of action, and biological activities.

Discovery of bicyclic polyprenylated acylphloroglucinols from Hypericum himalaicum with glucose transporter 4 translocation activity

Hyperhimatins A-P (1-16), sixteen new bicyclic polyprenylated acylphloroglucinols (BPAPs), were isolated and identified from Hypericum himalaicum. The planner structures of hyperhimatins A-P were confirmed via extensive NMR and careful HRESIMS data analysis. The absolute configurations of the new compounds were mainly determined by electronic circular dichroism (ECD) calculation, NMR calculation, and the circular dichroism data of the in situ formed [Rh₂(OCOCF₃)₄] complexes. All compounds were assessed for the glucose transporter 4 (GLUT-4) translocation and expression enhancing effects in L6 myotubes. Compounds 1-16 could promote the GLUT-4 expression by the range of 1.95-6.04 folds, and accelerate the GLUT-4 fusion with the plasma membrane ranged from 53.56% to 76.97% at a consistence of 30 μg/mL, among compound 10 displayed the strongest GLUT-4 translocation effect.

Four new polycyclic polyprenylated acylphloroglucinols from Hypericum wilsonii and their glucose uptake bioactivities

Wilsonglucinols H-K (1-4), four new polycyclic polyprenylated acylphloroglucinols (PPAPs), and eight known compounds (5-12) were isolated and identified from the aerial parts of Hypericum wilsonii. Their planner structures were confirmed via extensive NMR and HRESIMS data analysis. The absolute configurations of the new compounds were mainly determined by NMR calculation and electronic circular dichroism (ECD) calculation. Compounds 1, 6, 8, and 10 showed glucose uptake activities at 30 μg/mL, in which compound 6 showed the strongest effect and increased the glucose uptake by 2.73 folds.

Gerberdriasins A–F, six undescribed coumarin derivatives from Gerbera anandria (Linn) Sch-Bip and their protective effects on scopolamine-induced injury in PC12 cells

A chemical investigation on the herb Gerbera anandria (Linn) Sch-Bip led to the isolation and identification of six previously undescribed coumarin derivatives, named Gerberdriasins A–F (1–6). Structurally, their chemical structures and absolute configurations were determined by nuclear magnetic resonance (1D and 2D NMR), high resolution electrospray ionization mass spectroscopy (HR-ESI-MS), experimental and quantum mechanical nuclear magnetic resonance (QM-NMR) methods, Mosher's method and calculated electronic circular dichroism (ECD) experiments. The biological activity of the obtained compounds showed that they displayed significant neuroprotective effects against scopolamine-induced injury in PC12 cells at the concentrations 12.5, 25.0 and 50.0 nM. Further study demonstrated that 1 could inhibit cell apoptosis, decrease malondialdehyde (MDA) levels and increase superoxide dismutase (SOD) activity in scopolamine-treated PC12 cells.

A chemical investigation on Gerbera anandria (Linn) Sch-Bip led to the isolation and identification of six coumarin derivatives, named Gerberdriasins A–F (1–6). Their structures and absolute configurations were determined by NMR, HR-ESI-MS, QM-NMR, Mosher's method and ECD.