Hyperforatins L-U: Prenylated acylphloroglucinols with a terminal double bond from Hypericum perforatum L. (St John's Wort)

Hyperguanyes A and B, two new PPAPs from the branches and leaves of Hypericum perforatum L. with anti-cholinesterase activities

Two new polycyclic polyprenylated acylphloroglucinols, hyperguanyes A and B (1-2) together with eight known compounds (3-10), were isolated from Hypericum perforatum L. Their structures were determined by using comprehensive spectroscopic techniques and quantum chemical calculation. The in vitro anti-cholinesterase activity of all compounds were studied. Among them, compounds 1-4, 8 and 9 exhibited anti-AchE and anti-BchE effects with IC50 ranging from 0.34 ± 0.04 to 15.68 ± 0.54 μM.

Hyperatins A-D, highly oxidized polycyclic polyprenylated acylphloroglucinols from Hypericum perforatum L. with hypoglycemic potential in liver cells

Hyperatins A-D (1-4), four previously undescribed polycyclic polyprenylated acylphloroglucinols, were isolated from Hypericum perforatum L. (St. John's wort). Compound 1 possessed a unique octahydroindeno[1,7a-b]oxirene ring system with a rare 2,7-dioxabicyclo[2.2.1]heptane fragment. Compounds 2-4 had an uncommon decahydrospiro[furan-3,7'-indeno[7,1-bc]furan] ring system. Their structures were established by spectroscopic analyses and X-ray crystallography. Plausible biosynthetic pathways of 1-4 were also proposed. Compounds 1 and 2 exerted promising hypoglycemic activity by inhibiting glycogen synthase kinase 3 expression in liver cells.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Hyperipersions A-C, three new acylphloroglucinols from the branches and leaves of Hypericum perforatum L. with antiangiogenic activities

Three new acylphloroglucinols were isolated from the branches and leaves of Hypericum perforatum L., named as hyperipersions A-C (1-3), together with three known compounds which were identified as elegaphenone (4), 2,6-dihydroxy-3,4-dimethylbenzoic acid methyl ester (5) and 2,3-methylenedioxyxanthone (6), respectively. The structures of isolated compounds were determined by UV, IR, HR-ESI-MS, NMR analysis. Their antiangiogenic activities were studied against HUVECs. The IC50 value of compound 3 was 2.39 ± 0.21 μM against HUVECs, which was stronger than vatalanib, and other compounds had moderate antiangiogenic activity.

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.

(±)-Hyperpyran A: Terpenoid-based bicyclic dihydropyran enantiomers with hypoglycemic activity from Hypericum perforatum (St. John's wort)

(±)-Hyperpyran A (1a/1b), a pair of new terpenoid-based bicyclic dihydropyran enantiomers, were isolated from the aerial parts of Hypericum perforatum (St. John's wort). Their structures and absolute configurations were elucidated by NMR spectroscopic analyses, ECD comparison, and X-ray crystal diffraction. Compounds 1a/1b possess hexahydrocyclopenta[c]pyran ring system and a plausible biosynthetic pathway was also proposed. In addition, compound 1a exhibited a moderate promotion of glucose uptake activity in hepatocytes.

Hypericum spp.—An Overview of the Extraction Methods and Analysis of Compounds

The Hypericum genus contains one of the few genera of flowering plants that contains a species with authorization for marketing as a traditional medicine, H. perforatum. Due to the fact that this is a large genus, comprising numerous species, a large amount of interest has been shown over the years in the study of its various pharmacological activities. The chemical composition of these species is quite similar, containing compounds belonging to the class of phloroglucinol derivatives, naphthodianthrones, phenols, flavonoids and essential oils. Taking all of this into consideration, the present study aims to offer an overview of the species of the genus from the point of view of their extraction techniques and analysis methods. An extensive study on the scientific literature was performed, and it revealed a wide range of solvents and extraction methods, among which ethanol and methanol, together with maceration and ultrasonication, are the most frequent. Regarding analysis methods, separation and spectral techniques are the most employed. Therefore, the present study provides necessary data for future studies on the species of the genus, offering a complete overview and a possible basis for their development.

Discovery of 13,15-nor-Polycyclic Polyprenylated Acylphloroglucinols from Hypericum longistylum with Anti-Inflammatory Activity

Spihyperglucinols A (1) and B (2), the first 13,15-nor-polycyclic polyprenylated acylphloroglucinols (PPAPs) featuring a 7/6/5 tricyclic ring system based on an unexpected bicyclo[3.2.2]nonane core, along with three new congeners, spihyperglucinols...