Recent Advances Regarding Constituents and Bioactivities of Plants from the GenusHypericum

(±)-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.

Four new compounds from fruits of Hypericum patulum Thunb

A new naphthoquinone, patulumnaphthoquinone A (1) and three new glycosides, patulumside B (2), patulumside C (3) and patulumside D (4) were isolated from the 30% ethanol extract of the fresh ripe fruits of Hypericum patulum Thunb. using column chromatography techniques. The structures of these compounds including absolute configurations were elucidated on the basis of HRESIMS, NMR spectroscopic analyses, calculated electronic circular dichroism spectra and comparison with the literatures.

Meroterpenes and prenylated benzoylphloroglucinol from the flowers of Hypericum formosanum

Formohyperins A-F, previously undescribed meroterpenes, and grandone, a prenylated benzoylphloroglucinol being considered to be one of their biogenetic precursors, were isolated from the flowers of a Hypericaceous plant, Hypericum formosanum Maxim. Detailed spectroscopic analyses showed that formohyperins A-D were meroterpenes with an enolized 3-phenylpropane-1,3-dione moiety. Formohyperins E and F were elucidated as meroterpenes having a 4-benzoyl-5-hydroxycyclopent-4-ene-1,3-dione moiety. Formohyperins A-C and E were optically active, and their absolute configurations were deduced by comparison of the experimental and TDDFT calculated ECD spectra. In contrast, formohyperin D was concluded to be a racemate. Formohyperins A-F and grandone were found to show inhibitory activities against LPS-stimulated IL-1β production from murine microglial cells with EC50 values of 13.2, 6.6, 8.5, 24.3, 4.1, 10.9, and 3.0 μM, respectively.

Antidepressant polyprenylated acylphloroglucinols from Hypericum ascyron

Phytochemical investigation on the 90% EtOH extract of the air-dried aerial parts of Hypericum ascyron resulted in the isolation of three new polycyclic polyprenylated derivatives ascyronines A-C (1-3). Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. All the polycyclic polyprenylated acylphloroglucinols were evaluated for their antidepressant activity by inhibiting the reuptake of tritiated serotonin ([3H]-5-HT) and noradrenalinet ([3H]-NE) in rat brain synaptosomes. Compounds 2 and 3 exhibited weak antidepressant activities in the [3H]-5-HT mode.

Hyperelatolides A-D, Antineuroinflammatory Constituents with Unusual Carbon Skeletons from Hypericum elatoides

Four new δ- and γ-lactone derivatives, hyperelatolides A-D (1-4, respectively), were discovered from the aerial portions of Hypericum elatoides R. Keller. Their structures were elucidated by analysis of NMR spectra, HRESIMS, quantum chemical calculations of NMR and ECD spectra, and X-ray crystallographic data. Hyperelatolides A (1) and B (2) represent the first examples of δ-lactone derivatives characterized by a (Z)-(5,5-dimethyl-2-(2-oxopropyl)cyclohexylidene)methyl moiety and a benzoyloxy group attached to the β- and γ-positions of the δ-lactone core, respectively, while hyperelatolides C (3) and D (4) are unprecedented γ-lactone derivatives featuring substituents similar to those of 1 and 2. All compounds were tested for their inhibitory effects on NO production in LPS-activated BV-2 cells. Lactones 1 and 2 exhibited considerable antineuroinflammatory activity, with IC50 values of 5.74 ± 0.27 and 7.35 ± 0.26 μM, respectively. Moreover, the mechanistic study revealed that lactone 1 significantly suppressed nuclear factor kappa B signaling and downregulated the expression of inducible nitric oxide synthase and cyclooxygenase-2 in LPS-induced cells, which may contribute to its antineuroinflammatory activity.

Cytotoxic and Antibacterial Prenylated Acylphloroglucinols from Hypericum olympicum L

Two new bicyclo[3.3.1]nonane type bicyclic polyprenylated acylphloroglucinol derivatives (BPAPs), olympiforin A and B as well as three known prenylated phloroglucinols, were isolated from the aerial parts of Hypericum olympicum L. The structures of the isolated compounds were established by means of spectral techniques (HRESIMS and 1D and 2D NMR). All compounds were tested on a panel of human tumor (MDA-MB-231, EJ, K-562, HL-60 and HL-60/DOX) and non- tumorigenic (HEK-293 and EA.hy926) cell lines using the MTT assay. All tested compounds exerted significant in vitro cytotoxicity with IC₅₀ values ranging from 1.2 to 24.9 μM and from 0.9 to 34 μM on tumor and non-cancerous cell lines, respectively. Most of the compounds had good selectivity and were more cytotoxic to the tumor cell lines than to the normal ones. A degradation of the precursor caspase 9 for some of the compounds was observed; therefore, the intrinsic pathway of apoptosis is the most likely mechanism of cytotoxic activity. The BPAPs were examined for antibacterial and antibiofilm activity through the broth microdilution method and the protocol of Stepanović. They showed a moderate effect against Enterococcus faecalis and Streptococcus pyogenes but a very profound activity against Staphylococcus aureus with minimum inhibitory concentrations (MIC) in the range of 0.78-2 mg/L. Olympiforin B also had a great effect against methicillin-resistant S. aureus (MRSA) with an MIC value of 1 mg/L and a very significant antibiofilm activity on that strain with a minimum biofilm inhibition concentration (MBIC) value of 0.5 mg/L. The structures of the isolated compounds were in silico evaluated using ADME and drug likeness tests.

Hyperhubeins A-I, Bioactive Sesquiterpenes with Diverse Skeletons from Hypericum hubeiense

Nine new sesquiterpenes, hyperhubeins A-I (1-9), and 14 known analogues (10-23) were isolated from the aerial portions of Hypericum hubeiense. Their structures and absolute configurations were determined unambiguously via spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compounds 1-3 possess an unprecedented sesquiterpene carbon skeleton. Further, a plausible biosynthetic pathway from farnesyl diphosphate (FPP) is proposed. The isolated phytochemicals were evaluated for neuroprotective and anti-neuroinflammatory properties in vitro. Compounds 1, 2, 5-8, 14, and 21 displayed notable neuroprotective activity against hydrogen peroxide (H₂O₂)-induced lesions in PC-12 cells at 10 μM. Additionally, compounds 1, 2, 12, and 13 exhibited inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cells, with their IC₅₀ values ranging from 4.92 to 6.81 μM. Possible interactions between these bioactive compounds and inducible nitric oxide synthase (iNOS) were predicted via molecular docking. Moreover, Western blotting indicated that compound 12 exerted anti-neuroinflammatory activity by suppressing LPS-stimulated expression of toll-like receptor-4 (TLR-4) and inhibiting consequent activation of nuclear factor-kappa-B (NF-κB) signaling.

Outstanding Antibacterial Activity of Hypericum rochelii-Comparison of the Antimicrobial Effects of Extracts and Fractions from Four Hypericum Species Growing in Bulgaria with a Focus on Prenylated Phloroglucinols

Microbial infections are by no means a health problem from a past era due to the increasing antimicrobial resistance of infectious strains. Medicine is in constant need of new drugs and, recently, plant products have had a deserved renaissance and garnered scientific recognition. The aim of this work was to assess the antimicrobial activity of ten active ingredients from four Hypericum species growing in Bulgaria, as well as to obtain preliminary data on the phytochemical composition of the most promising samples. Extracts and fractions from H. rochelii Griseb. ex Schenk, H. hirsutum L., H. barbatum Jacq. and H. rumeliacum Boiss. obtained with conventional or supercritical CO₂ extraction were tested on a panel of pathogenic microorganisms using broth microdilution, agar plates, dehydrogenase activity and biofilm assays. The panel of samples showed from weak to extraordinary antibacterial effects. Three of them (from H. rochelii and H. hirsutum) had minimum inhibitory concentrations as low as 0.625-78 mg/L and minimum bactericidal concentrations of 19.5-625 mg/L against Staphylococcus aureus and other Gram-positive bacteria. These values placed these samples among the best antibacterial extracts from the Hypericum genus. Some of the agents also demonstrated very high antibiofilm activity against methicillin-resistant S. aureus. Ultra-high-performance liquid chromatography-high-resolution mass spectrometry revealed the three most potent samples as rich sources of biologically active phloroglucinols. They were shown to be good drug or nutraceutical candidates, presumably without some of the side effects of conventional antibiotics.

Phytochemical Profiles and Biological Studies of Selected Botanical Dietary Supplements Used in the United States

Based on their current wide bioavailability, botanical dietary supplements have become an important component of the United States healthcare system, although most of these products have limited scientific evidence for their use. The most recent American Botanical Council Market Report estimated for 2020 a 17.3% increase in sales of these products when compared to 2019, for a total sales volume of $11,261 billion. The use of botanical dietary supplements products in the United States is guided by the Dietary Supplement Health and Education Act (DSHEA) from 1994, enacted by the U.S. Congress with the aim of providing more information to consumers and to facilitate access to a larger number of botanical dietary supplements available on the market than previously. Botanical dietary supplements may be formulated for and use only using crude plant samples (e.g., plant parts such as the bark, leaves, or roots) that can be processed by grinding into a dried powder. Plant parts can also be extracted with hot water to form an "herbal tea." Other preparations of botanical dietary supplements include capsules, essential oils, gummies, powders, tablets, and tinctures. Overall, botanical dietary supplements contain bioactive secondary metabolites with diverse chemotypes that typically are found at low concentration levels. These bioactive constituents usually occur in combination with inactive molecules that may induce synergy and potentiation of the effects observed when botanical dietary supplements are taken in their different forms. Most of the botanical dietary supplements available on the U.S. market have been used previously as herbal remedies or as part of traditional medicine systems from around the world. Their prior use in these systems also provides a certain level of assurance in regard to lower toxicity levels. This chapter will focus on the importance and diversity of the chemical features of bioactive secondary metabolites found in botanical dietary supplements that are responsible for their applications. Many of the active principles of botanical dietary substances are phenolics and isoprenoids, but glycosides and some alkaloids are also present. Biological studies on the active constituents of selected botanical dietary supplements will be discussed. Thus, the present chapter should be of interest for both members of the natural products scientific community, who may be performing development studies of the products available, as well as for healthcare professionals who are directly involved in the analysis of botanical interactions and evaluation of the suitability of botanical dietary supplements for human consumption.

Six New Constituents from the Fruit of Hypericum patulum and Their Anti-Inflammatory Activity

Four new xanthone glucosides, 3-hydroxy-2-methoxyxanthone-4-O-β-D-glucopyranoside (1), 4,8-dihydroxy-2-methoxyxanthone-3-O-β-D-glucopyranoside (2), 2-methoxyxanthone-5-O-β-D-glucopyranoside (3), 4-hydroxy-2-methoxyxanthone-3-O-β-D-glucopyranoside (4), a new phenolic acid, 4,4'-dihydroxy-3,3'-imino-di-benzoic acid monomethyl ester (5), and a new isoquinoline, methyl 6-hydroxy-1-oxo-1,2,3,4-tetrahydroisoquinoline-4-carboxylate (6) were isolated from the fruit of Hypericum patulum. The structural elucidation of the isolated compounds was primarily based on HR-ESI-MS, UV, IR, 1D and 2D NMR. All compounds were evaluated for their inhibitory effect against LPS-induced NO production in RAW 264.7 cells. Compound 2, 3 exhibited moderate inhibitory activity against NO production.

Hyperpatone A, a polycyclic polyprenylated acylphloroglucinol with a rare 8/6/5/6/5 pentacyclic skeleton from Hypericum patulum

Hyperpatone A (1), a highly oxidated polycyclic polyprenylated acylphloroglucinol (PPAP), along with a biosynthesized related PPAP (2) was isolated from Hypericum patulum under the guidance of LC-MS investigation. Architecturally, compound 1 represents the first PPAP with an unprecedented 8/6/5/6/5 pentacyclic skeleton and an intramolecular peroxy bridge, which might be derived from the [3.3.1]-type bicyclic polyprenylated acylphloroglucinol via the critical Baeyer-Villiger oxidation, decarboxylation, and intramolecular cyclization. The structures were established by extensive spectroscopic analysis, ACD software calculation, and quantum chemical computations. A plausible biogenetic pathway of 1 and 2 was also proposed. Importantly, both compounds exhibited moderate cytotoxic activities against the HEL cell line with the IC₅₀ values ranging from 10.2 to 19.2 μM. Moreover, compound 1 showed an inhibitory effect on NO production in lipopolysaccharide-stimulated RAW264.7 cells at a lower concentration of 5 or 1 μM.

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.

Bioactive Potential: A Pharmacognostic Definition through the Screening of Four Hypericum Species from the Canary Islands

In this work, we propose a general methodology to assess the bioactive potential (BP) of extracts in the quest of vegetable-based drugs. To exemplify the method, we studied the anticancer potential (AP) of four endemic species of genus Hypericum (Hypericum canariense L, Hypericum glandulosum Aiton, Hypericum grandifolium Choisy and Hypericum reflexum L.f) from the Canary Islands. Microextracts were obtained from the aerial parts of these species and were tested against six human tumor cell lines, A549 (non-small-cell lung), HBL-100 (breast), HeLa (cervix), SW1573 (non-small-cell lung), T-47D (breast) and WiDr (colon). The methanol–water microextracts were evaluated further for cell migration, autophagy and cell death. The most promising bioactive polar microextracts were analyzed by UHPLC–DAD–MS. The extraction yield, the bioactivity evaluation and the chemical profiling by LC–MS suggested that H. grandifolium was the species with the highest AP. Label-free live-cell imaging studies on HeLa cells exposed to the methanol–water microextract of H. grandifolium enabled observing cell death and several apoptotic hallmarks. Overall, this study allows us to select Hypericum grandifolium Choisy as a source of new chemical entities with a potential interest for cancer treatment.

A comparison of artificial intelligence techniques for predicting hyperforin content in Hypericum perforatum L. in different ecological habitats

Hyperforin, a major bioactive constituent of Hypericum concentration, is impacted by various phenological phases and soil characteristics. We aimed to design a model predicting hyperforin content in Hypericum perforatum based on different ecological and phenological conditions. We employed artificial intelligence modeling techniques including multilayer perceptron (MLP), radial basis function (RBF), and support vector machine (SVM) to examine the factors critical in predicting hyperforin content. We found that the MLP model (R 2 = .9) is the most suitable and precise model compared with RBF (R 2 = .81) and SVM (R 2 = .74) in predicting hyperforin in H. perforatum based on ecological conditions, plant growth, and soil features. Moreover, phenological stages, organic carbon, altitude, and total N are detected in sensitivity analysis as the main factors that have a considerable impact on hyperforin content. We also report that the developed graphical user interface would be adaptable for key stakeholders including producers, manufacturers, analytical laboratory managers, and pharmacognosists.

Discovery of bioactive polycyclic polyprenylated acylphloroglucinols from Hypericum wilsonii

Eleven new polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperwilsones A-K (1-11), along with five known PPAPs (12-16), were isolated from Hypericum wilsonii. Their structures were established via spectroscopic methods, the careful analysis of calculated and experimental electronic circular dichroism (ECD) spectra, single-crystal X-ray diffraction, the modified Mosher's method, and [Rh₂(OCOCF₃)₄]-induced ECD. Hyperwilsone A (1) and hyperwilsone B (2) possessed the unique acetal functionality. Hyperwilsone C (3) was a rare example of [3.3.1]-type PPAP possessing a 3-isopropylfuran moiety. In bioassay, compounds 9 and 10 showed potent anti-inflammatory activity against LPS-induced NO production by inhibiting the nuclear translocation of NF-κB p65 and thus reducing the production of proinflammatory cytokines. Compounds 5, 8, 11, and 14 exhibited moderate inhibitory activity against SUDHL-4 and HL60 cancer cells with IC₅₀ values in the range of 5.74-19.82 μM.

(±)-hyperzewalsins A-D, four pairs of nor-monocyclic polyprenylated acylphloroglucinols with immunosuppressive activity from hypericum przewalskii maxim

Three pairs of previously undescribed 2,3-nor-monocyclic polyprenylated acylphloroglucinols (MPAPs), (±)-hyperzewalsins A-C, a pair of 1,2,3,4-nor-MPAPs, (±)-hyperzewalsins D, along with one undescribed precursor, hyperzewalsin E, were isolated and identified from the aerial parts of Hypericum przewalskii Maxim. (Hypericaceae), and their structures were confirmed by extensive spectroscopic analyses, and quantum-chemical calculations including electronic circular dichroism calculations and NMR calculations with a DP4+ analysis. Significantly, (±)-hyperzewalsins A-D represented the first nor-MPAPs bearing carbon chain constitutions based on diverse highly degraded phloroglucinols. (±)-Hyperzewalsins A-C were the rare nor-MPAPs characterized by degradations of C-2 and C-3 in the core decorated by scissions of C-3/C-4 and C-1/C-2 bonds through Retro-Claisen reactions. (±)-Hyperzewalsins D were the first examples of naturally occurring MPAPs with the loss of C-1/2/3/4 in the phloroglucinol ring formed by cleavages of C-3/C-4 and C-1/C-6 bonds via Retro-Claisen and decarboxylation reactions. Plausible biogenetic pathways for the isolates were proposed. The isolates were evaluated for their immunosuppressive activity in lipopolysaccharide-stimulated murine splenocytes.

Hyperdioxanes, dibenzo-1,4-dioxane derivatives from the roots of Hypericum ascyron

Six dibenzo-1,4-dioxane derivatives (1-6) were isolated from the roots of a Hypericaceous plant Hypericum ascyron. Spectroscopic analyses revealed 2 and 4-6 to be new compounds. The partial racemic natures of 1-3 were concluded by chiral HPLC analyses, while 5 was confirmed to be a racemate. The absolute configurations 1-4 were deduced on the basis of ECD calculations. Biological activity evaluation of the dibenzo-1,4-dioxane derivatives along with two related compounds: hyperdioxanes A (7) and B (8), previously isolated from the same plant material by our group demonstrated that 7 exhibit an anti-HIV activity (IC₅₀ 5.3 μM, TI 7.2) while 8 showed an inhibitory effect on IL-1β production (inhibition rate: 72.3% at 6.3 μM) from LPS-stimulated microglial cells.

Characteristic metabolites of Hypericum plants: their chemical structures and biological activities

Plants belonging to the genus Hypericum (Hypericaceae) are recognized as an abundant source of natural products with interesting chemical structures and intriguing biological activities. In the course of our continuing study on constituents of Hypericum plants, aiming at searching natural product-based lead compounds for therapeutic agents, we have isolated more than 100 new characteristic metabolites classified as prenylated acylphloroglucinols, meroterpenes, ketides, dibenzo-1,4-dioxane derivatives, and xanthones including prenylated xanthones, phenylxanthones, and xanthonolignoids from 11 Hypericum plants and one Triadenum plant collected in Japan, China, and Uzbekistan or cultivated in Japan. This review summarizes their chemical structures and biological activities.

Ethnopharmacology of Hypericum species in China: A comprehensive review on ethnobotany, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum species have been used traditionally as astringent, antipyretic, diuretic, antiphlogistic, analgesic, and antidepressant in Europe, America, Africa, and Asia. One of the most extensively investigated medicinal herbs, H. perforatum L. (St. John's wort), is widely used in many countries to treat mild to moderate mental depression. Hypericum species are abundant throughout China, including 30 used as ethnomedicines. There are limited publications describing the ethnobotanical uses and biological activities associated with Hypericum species in China. Some reported activities include the treatment of wounds and bruises, irregular menstruation, dysentery, hepatitis, mastitis, jaundice, hemoptysis, and epistaxis.

AIM OF THE REVIEW

This review aims to critically examine how Hypericum species are used ethnomedicinally in China, to see if the ethnobotanical data may be useful to help prioritize Hypericum species and certain phytochemical constituents that may be new drug leads, and consider the focus and lack of the phytopharmacological study on Hypericum species in China.

MATERIALS AND METHODS

Classic medicinal books and ethnomedicinal publications were reviewed for the genus Hypericum (called jin si tao in Chinese). In addition, relevant information about ethnobotany, phytochemistry, and pharmacology were from online databases including SciFinder, Science Direct, PubMed, Google Scholar, and China National Knowledge Infrastructure (CNKI). "Hypericum", "", "ethnobotany", "traditional use", "ethnomedicine", "phytochemistry", "pharmacology" and "bioactivity" were used as keywords when searching the databases. Thus, available articles from 1959 to 2019 were collected and analyzed.

RESULTS

Among 64 Hypericum species recorded in China, 30 have been used as ethnomedicines by 15 linguistic groups such as Dai, Dong, Han, Miao, and Mongolian people. Hypericum species in China possess traditional uses which are also mirrored in Europe, America, Africa, and other countries in Asia. However, there are some unique ethnomedicinal uses in China. For example, several Hypericum species are used as a local remedy in southwest China, and H. attenuatum Fisch. ex Choisy is used to treat cardiac disorders in northeast China. Antitumor, anti-inflammatory, antimicrobial, neuroprotective, antidepressant, hepatoprotective, cardioprotective, and antiviral activities have been reported in numerous biological studies. The main phytochemical constituents in Hypericum consist of phloroglucinols, naphthodianthrones, xanthones, flavonoids, and terpenoids.

CONCLUSIONS

There is a rich traditional knowledge regarding the ethnomedicinal uses of Hypericum species in China. Through phytochemical and pharmacological studies, several medicinal Hypericum from China have yielded many bioactive phytochemicals, possessing antitumor, anti-inflammatory, antimicrobial, and neuroprotective properties. Hypericum species from China are potential sources of drugs to fight cancer and other chronic diseases. Remarkably, nearly half of Hypericum species in China have rarely been studied, and their ethnomedicinal potential have not been scientifically evaluated. Thus, in vitro mechanistic studies, in vivo pharmacology, and clinical efficacy are all needed, prioritizing those studies that relate most closely with their traditional uses. In addition, a comprehensive plant-resource evaluation, quality control, and toxicology studies are needed.

Antimicrobial Photoinactivation Using Visible Light Plus Water-Filtered Infrared-A (VIS + wIRA) and Hypericum Perforatum Modifies In Situ Oral Biofilms

Due to increasing antibiotic resistance, the application of antimicrobial photodynamic therapy (aPDT) is gaining increasing popularity in dentistry. The aim of this study was to investigate the antimicrobial effects of aPDT using visible light (VIS) and water-filtered infrared-A (wIRA) in combination with a Hypericum perforatum extract on in situ oral biofilms. The chemical composition of H. perforatum extract was analyzed using ultra-high-performance liquid chromatography coupled with high resolution mass spectrometry (UPLC-HRMS). To obtain initial and mature oral biofilms in situ, intraoral devices with fixed bovine enamel slabs (BES) were carried by six healthy volunteers for two hours and three days, respectively. The ex situ exposure of biofilms to VIS + wIRA (200 mWcm^-2) and H. perforatum (32 mg ml^-1, non-rinsed or rinsed prior to aPDT after 2-min preincubation) lasted for five minutes. Biofilm treatment with 0.2% chlorhexidine gluconate solution (CHX) served as a positive control, while untreated biofilms served as a negative control. The colony-forming units (CFU) of the aPDT-treated biofilms were quantified, and the surviving microorganisms were identified using MALDI-TOF biochemical tests as well as 16 S rDNA-sequencing. We could show that the H. perforatum extract had significant photoactivation potential at a concentration of 32 mg ml^-1. When aPDT was carried out in the presence of H. perforatum, all biofilms (100%) were completely eradicated (p = 0.0001). When H. perforatum was rinsed off prior to aPDT, more than 92% of the initial viable bacterial count and 13% of the mature oral biofilm were killed. Overall, the microbial composition in initial and mature biofilms was substantially altered after aPDT, inducing a shift in the synthesis of the microbial community. In conclusion, H. perforatum-mediated aPDT using VIS + wIRA interferes with oral biofilms, resulting in their elimination or the substantial alteration of microbial diversity and richness. The present results support the evaluation of H. perforatum-mediated aPDT for the adjunctive treatment of biofilm-associated oral diseases.

Three new prenyloxy chromanones from aerial parts of Hypericum aucheri

Three new prenyloxy chromanone derivatives, aucherine A-C (6, 7 and 9) as well as six known prenylated phloroglucinols (1-5 and 8) were isolated from the aerial parts of Hypericum aucheri Jaub. Et Spach. The structures of the isolated compounds were established by means of spectral techniques (HRESIMS, 1D and 2D NMR). The new compounds were tested on а panel of human tumor cell line using MTT assay. All tested compounds exerted moderate cytotoxicity with IC₅₀ values ranging from 19.6 to 57.8 μM. The influence of the new compounds on some key signaling molecules (procaspase-9 and Bcl-xL), implicated in the regulation of programmed cell death was assessed by Western blot analysis.

Hypascyrins A-E, Prenylated Acylphloroglucinols from Hypericum ascyron

Six new prenylated acylphloroglucinols with menthane moieties, hypascyrins A-E (1-5) and ent-hyphenrone J (6), together with four known analogues, were isolated from Hypericum ascyron roots. Detailed spectroscopic data analyses resulted in the assignment of their structures. The absolute configuration of 1 was deduced by experimental and calculated ECD data, while those of 2-6 were assigned by ECD data analyses as well as chemical conversions. Hypascyrins A (1), C (3), and E (5) and ent-hyphenrone J (6) exhibited antimicrobial activity against MRSA (MIC₅₀ values of 4.0, 8.0, 2.0, and 4.0 μM, respectively) and Bacillus subtilis (MIC values of 4.0, 4.0, 2.0, and 4.0 μM, respectively).

Hypericum species: An analysis on the patent technologies

Hypericum (Hypericaceae) is a genus that comprises approximately 500 species around the world. The industrial relevance of these plants is based on the occurence of specialized metabolites that exhibit a range of pharmaceutical potential. Besides that, several species are relevant due to their ornamental value. Taking to account the vast market worth of products and processes involving Hypericum, the present study aims to provide a comprehensive overview of patents concerning this subject between 2007and 2017. For this purpose, a survey was performed in free databases (Espacenet®, PatentScope® and Google Patents®) using the keyword Hypericum in the patents title or title plus abstract. The documents were then organized by groups (medicinal and non-medicinal approaches), subgroups, type of applicants and countries. Espacenet® was chosen to data analysis, and a total of 174 patents were found. The majority of the applicants are from China and companies appear as the principal owners of patents. Several technologies are not intended for medicinal purposes, being mainly related to the development of new cultivars for ornamental uses. Concerning the medicinal approaches, the chief subject is related to extraction and incorporation into formulations. The main species cited in the documents is H. perforatum and the therapeutic use is for central nervous system diseases. In general, this study covers the patents published in recent years hoping to boost the scientists and companies that invest in Hypericum researches to visualize the state of art, opportunities and challenges for innovation in this area.

Me2AlSEt-Promoted Domino Dieckmann Cyclization Enables the Total Synthesis of Polycyclic Polyprenylated Acylphloroglucinols

A bioinspired, Me₂AlSEt-promoted domino Dieckmann cyclization via an 8-membered ring intermediate to construct bicyclo[3.3.1]nonanes was developed, and the divergent syntheses of nine complex polycyclic polyprenylated acylphloroglucinols were achieved. This novel domino cyclization tolerates a series of congested substrates, providing a very efficient way to construct diverse polycyclic structures. The selectivity and the advantages of the domino cyclization were studied. Moreover, the structure-activity relationship study leads to the identification of three simplified potent antitumor agents.

Diverse Polyphenols from Hypericum faberi

Six new polyphenols with different isoprenylated xanthones, isoprenylated acylphloroglucinols, and chromone architectures, hyperfaberols A-F (1-6), were isolated from the whole plants of Hypericum faberi along with seven other related known compounds. In which hyperfaberols A/B (1/2) and 12-13 were isoprenylated xanthones, hyperfaberols C-E (3-5) and 8-11 were seven isoprenylated acylphloroglucinol derivatives, while 6-7 were two chromones. Their structures were elucidated by comprehensive analysis of their spectroscopic data as well as detailed comparison with the literature data. Compounds 1 and 11 showed cytotoxities against the human esophageal cancer cell line (ECA-109) and the pancreatic tumor cell line (PANC-1) in vitro, respectively.

Polycyclic polyprenylated acylphloroglucinol and phenolic metabolites from the aerial parts of Hypericum elatoides and their neuroprotective and anti-neuroinflammatory activities

A phytochemical study on the aerial parts of Hypericum elatoides led to the isolation of a previously undescribed polycyclic polyprenylated acylphloroglucinol derivative, hyperelatone A, seven previously undescribed phenolic metabolites, hyperelatones B-H, along with ten known analogues. The structures of hyperelatones A-H were elucidated by 1D and 2D NMR spectroscopy, HRESIMS experiment, single-crystal X-ray diffraction and comparison of experimental and calculated ECD spectra, as well as chemical derivatization. All compounds were evaluated for their neuroprotective activity against hydrogen peroxide (H₂O₂)-induced cell injury in rat pheochromocytoma PC-12 cells and inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cells. Hyperelatones B-D and H, cinchonain Ib, and tenuiside A showed noticeable neuroprotection at concentrations of 1.0-100.0 μM. Hyperelatones D, G, and H, (-)-epicatechin, tenuiside A, and (Z)-3-hexenyl-β-D-glucopyranoside exhibited significant anti-neuroinflammatory activity with IC₅₀ values ranging from 0.75 ± 0.02 to 5.83 ± 0.23 μM.

Hyperbeanols F-Q, diverse monoterpenoid polyprenylated acylphloroglucinols from the flowers of Hypericum beanii

Hyperbeanols F-Q, which are twelve undescribed monoterpenoid polyprenylated acylphloroglucinols, and four known analogues were isolated from the dried flowers of Hypericum beanii. Their structures were elucidated by detailed HRESIMS and 1D and 2D NMR data analyses. The absolute configurations of hyperbeanols FH were established by the circular dichroism (CD) exciton chirality method. The plausible biosynthetic pathway speculation of hyperbeanols F-Q indicated that diverse reactions, including prenylation, 1,6-ene reaction, rearrangement, epoxidation and dehydration, contributed to their diverse skeletons. Hyperbeanols FI, O and hypercalin B exhibited moderate nitric oxide (NO) inhibitory activities in LPS-induced RAW 264.7 macrophages, with IC₅₀ values in the range of 17.11-28.74 μM.

Synthesis and Anti-Inflammatory Activities of Phloroglucinol-Based Derivatives

The natural product phloroglucinol-based derivatives representing monoacyl-, diacyl-, dimeric acyl-, alkylated monoacyl-, and the nitrogen-containing alkylated monoacylphloro- glucinols were synthesized and evaluated for inhibitory activities against the inflammatory mediators such as inducible nitric oxide synthase (iNOS) and nuclear factor kappaB (NF-κB). The diacylphloroglucinol compound 2 and the alkylated acylphloroglucinol compound 4 inhibited iNOS with IC₅₀ values of 19.0 and 19.5 µM, respectively, and NF-κB with IC₅₀ values of 34.0 and 37.5 µM, respectively. These compounds may serve as leads for the synthesis of more potent anti-inflammatory compounds for future drug discovery.

Structural diversity and biological activities of phloroglucinol derivatives from Hypericum species

Plants of the genus Hypericum (Hypericaceae) are used in folk medicine all over the world, H. perforatum being the most well-known species. Standardized extracts of this plant are commercially-available to treat mild to moderate depression cases. The present review summarizes the literature published up to 2016 concerning the phloroglucinol derivatives isolated from Hypericum species, together with their structural features and biological activities. These phytochemical studies led to the isolation of 101 prenylated phloroglucinols, chromanes and chromenes, 35 dimeric acylphloroglucinols, 235 polycyclic polyprenylated acylphloroglucinols, 25 simple benzophenones and 33 phloroglucinol-terpene adducts. These compounds show a diverse range of biological activities, such as antimicrobial, cytotoxic, antinociceptive and antidepressant-like effects.

Hyperdioxane A, a Conjugate of Dibenzo-1,4-dioxane and Sesquiterpene from Hypericum ascyron

Two new dibenzo-1,4-dioxane derivatives, hyperdioxanes A (1) and B (2), were isolated from the roots of a Hypericaceous plant, Hypericum ascyron. Hyperdioxane A (1) is a conjugate of dibenzo-1,4-dioxane and sesquiterpene with an unprecedented heptacyclic ring system. The structures of 1 and 2 were assigned by detailed spectroscopic analyses, including application of a modified Mosher's method. A possible biogenetic pathway of hyperdioxane A (1) from hyperdioxane B (2) and a sesquiterpene, eremophil-9,11(13)-dien-8β,12-olide (3), is presented.

Hyperelatosides A-E, biphenyl ether glycosides from Hypericum elatoides, with neurotrophic activity

Five new biphenyl ether glycosides, hyperelatosides A-E (1-5), one new benzoate glycoside, hyperelatoside F (6), along with nine known phenolic compounds (7-15), were isolated from the aerial parts of Hypericum elatoides. Their structures were elucidated by 1D and 2D NMR spectroscopy and HRESIMS, as well as chemical derivatization. This is the first report of the identification of biphenyl ether glycosides as plant metabolites and their possible biosynthetic pathway is proposed. Except for 3, the new phenolic metabolites exhibited significant neurotrophic activities to enhance nerve growth factor-induced neurite outgrowth in PC12 cells. In addition, the anti-neuroinflammatory and antioxidant activities of compounds 1-15 were preliminarily evaluated in vitro.

Integration of in vitro and in silico perspectives to explain chemical characterization, biological potential and anticancer effects of Hypericum salsugineum: A pharmacologically active source for functional drug formulations

The genus Hypericum is one of the most popular genera in both traditional medicine and scientific platform. This study is designed to provide conceptual insights on the biological potential and chemical characterization of H. salsugineum, which is endemic to Turkey. The qualitative and quantitative phenolic content of the extracts was characterized by HPLC-ESI-MSn. Biological efficiency was investigated by enzyme inhibitory assays (cholinesterases, tyrosinase, amylase, and glucosidase) and anti-cancer efficacy tests (anti-proliferative activities with the iCELLigence technology, colony formation and wound healing scratch assays). Phenolic acids (3-O-caffeoylquinic, 5-O-caffeoylquinic, and 4-O-caffeoylquinic acids) were the predominant group in the studied extracts, although several flavonoids were also detected and quantified. The extracts exhibited good inhibitory effects on tyrosinase and glucosidase, while they had weak ability against cholinesterases and amylase. Computational studies were also performed to explain the interactions between the major phenolics and these enzymes. The extracts displayed significant anti-cancer effects on breast carcinoma cell lines. Our findings suggest that Hypericum salsugineum could be valued as a potential source of biologically-active compounds for designing novel products.

Research Progress of Polycyclic Polyprenylated Acylphloroglucinols

Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of hybrid natural products sharing the mevalonate/methylerythritol phosphate and polyketide biosynthetic pathways and showing considerable structure and bioactivity diversity. This review discusses the progress of research into the chemistry and biological activity of 421 natural PPAPs in the past 11 years as well as in-depth studies of biological activities and total synthesis of some PPAPs isolated before 2006. We created an online database of all PPAPs known to date at http://www.chem.uky.edu/research/grossman/PPAPs . Two subclasses of biosynthetically related metabolites, spirocyclic PPAPs with octahydrospiro[cyclohexan-1,5'-indene]-2,4,6-trione core and complicated PPAPs produced by intramolecular [4 + 2] cycloadditions of MPAPs, are brought into the PPAP family. Some PPAPs' relative or absolute configurations are reassigned or critically discussed, and the confusing trivial names in PPAPs investigations are clarified. Pharmacologic studies have revealed a new molecular mechanism whereby hyperforin and its derivatives regulate neurotransmitter levels by activating TRPC6 as well as the antitumor mechanism of garcinol and its analogues. The antineoplastic potential of some type B PPAPs such as oblongifolin C and guttiferone K has increased significantly. As a result of the recent appearances of innovative synthetic methods and strategies, the total syntheses of 22 natural PPAPs including hyperforin, garcinol, and plukenetione A have been accomplished.

Environmental Factors do not Affect the Phenolic Profile of Hypericum perforatum Growing Wild in Bosnia and Herzegovina

Using appropriate isolation and fractionation procedure, and UHPLC-MS/MS as powerful analytical tool, comprehensive phenolic acid profile of leaves and flowers of Hypericum perforatum L., growing wild in Bosnia and Herzegovina, has been analyzed for the first time. The phenolic acids were isolated from plant tissue, liberated from esters and glycosidic bonds, and then analyzed as free acids. Results show that free forms of caffeic and chlorogenic acid were the most abundant. Generally, the content of acids is higher in flowers than in leaves, but environmental factors do not significantly influence chemical composition of this medicinal plant.

Dual/multitargeted xanthone derivatives for Alzheimer's disease: where do we stand?

To date, the current therapy for Alzheimer's disease (AD) based on acetylcholinesterase inhibitors is only symptomatic, being its efficacy limited. Hence, the recent research has been focused in the development of different pharmacological approaches. Here we discuss the potential of xanthone derivatives as new anti-Alzheimer agents. The interference of xanthone derivatives with acetylcholinesterase and other molecular targets and cellular mechanisms associated with AD have been recently systematically reported. Therefore, we report xanthones with anticholinesterase, monoamine oxidase and amyloid β aggregation inhibitory activities as well as antioxidant properties, emphasizing xanthone derivatives with dual/multitarget activity as potential agents to treat AD. We also propose the structural features for these activities that may guide the design of new, more effective xanthone derivatives. [Formula: see text].

Biotechnological production of hyperforin for pharmaceutical formulation

Hyperforin is a major active constituent of Hypericum perforatum (St. John's wort). It has amazing pharmacological activities, such as antidepressant properties, but it is labile and difficult to synthesize. Its sensitivity and lipophilicity are challenges for processing and formulation. Its chemical complexity provokes approaches of biotechnological production and modification. Dedifferentiated H. perforatum cell cultures lack appropriate storage sites and hence appreciable hyperforin levels. Shoot cultures are capable of forming hyperforin but less suitable for biomass up-scaling in bioreactors. Roots commonly lack hyperforin but a recently established adventitious root line has been demonstrated to produce hyperforin and derivatives at promising levels. The roots also contained lupulones, the typical constituents of hop (Humulus lupulus). Although shear-sensitive, these root cultures provide a potential production platform for both individual compounds and extracts with novel combinations of constituents and pharmacological activities. Besides in vitro cultivation techniques, the reconstruction of hyperforin biosynthesis in microorganisms is a promising alternative for biotechnological production. The biosynthetic pathway is under study, with omics-technologies being increasingly implemented. These biotechnological approaches may not only yield hyperforin at reasonable productivity but also allow for modifications of its chemical structure and pharmacological profile.

Selective syntheses of diversely substituted 2-hydroxy-4′-hydroxybenzophenones through [4 + 2] or [3 + 3] annulation of penta-3,4-dien-2-ones with 3-formylchromones

A selective synthesis of 2-hydroxy-4′-hydroxybenzophenones or their 3′-acylated counterparts via the cascade reactions of 3-formylchromones with diversely substituted penta-3,4-dien-2-ones is presented.

Polyprenylated Tetraoxygenated Xanthones from the Roots of Hypericum monogynum and Their Neuroprotective Activities

Ten new polyprenylated tetraoxygenated xanthones, monogxanthones A-J (1-10), together with eight known analogues (4b, 11-17) were identified from the roots of Hypericum monogynum. The structures of these new polyprenylated xanthones (1-10), a class of compounds rarely found in plants of the genus Hypericum, were elucidated by the interpretation of their HRESIMS, 1D and 2D NMR, and electronic circular dichroism data. Compounds 1 and 2 exhibited neuroprotective effects against corticosterone (Cort)-induced lesions of PC12 cells at concentrations of 6.25, 12.50, and 25.00 μM, with cell viability greater than 75%, as well as inhibitory effects on nitric oxide production in lipopolysaccharide-induced BV2 microglia cells, with IC50 values of 7.47 ± 0.65 and 9.60 ± 0.12 μM, respectively. Collectively, these results shed new light on the potential of polyprenylated xanthones from the genus Hypericum in the development of antidepression therapies.