St. John’s wort extract and hyperforin inhibit multiple phosphorylation steps of cytokine signaling and prevent inflammatory and apoptotic gene induction in pancreatic β cells

Cellular neurobiology of hyperforin

Hyperforin is a phloroglucinol derivative isolated from the medicinal plant Hypericum perforatum (St John's wort, SJW). This lipophilic biomolecule displays antibacterial, pro-apoptotic, antiproliferative, and anti-inflammatory activities. In addition, in vitro and in vivo data showed that hyperforin is a promising molecule with potential applications in neurology and psychiatry. For instance, hyperforin possesses antidepressant properties, impairs the uptake of neurotransmitters, and stimulates the brain derived neurotrophic factor (BDNF)/TrkB neurotrophic signaling pathway, the adult hippocampal neurogenesis, and the brain homeostasis of zinc. In fact, hyperforin is a multi-target biomolecule with a complex neuropharmacological profile. However, one prominent pharmacological feature of hyperforin is its ability to influence the homeostasis of cations such as Ca2+ , Na+ , Zn2+ , and H+ . So far, the pathophysiological relevance of these actions is currently unknown. The main objective of the present work is to provide an overview of the cellular neurobiology of hyperforin, with a special focus on its effects on neuronal membranes and the movement of cations.

Hyperforin modulates MAPK/CCL11 signaling to reduce the inflammatory response of nasal mucosal epithelial cells caused by allergic rhinitis by targeting BCL6

Hyperforin is a type of bicyclic tetraketone with four isoprenoid chains extracted from Hypericum perforatum L. that has multiple biological activities such as anti-diabetes, antitumor and anti-inflammation. However, the role and potential mechanism of hyperforin in allergic rhinitis (AR) remains to be clarified. In the present study, cell viability was analyzed using Cell Counting Kit-8 assay, while inflammation was detected using ELISA and reverse transcription-quantitative PCR. Epithelial cell barrier damage was measured using western blotting and immunofluorescence staining. The expression levels of B-cell lymphoma 6 (BCL6) and the p38 MAPK/C-C motif chemokine 11 (CCL11) pathway were detected using western blotting. In addition, the association between hyperforin and BCL6 was analyzed by SWISS TargetPrediction, DisGeNET, Gene Ontology and Pathway databases. Molecular docking was performed using AutoDockTools 1.5.6 and Discovery Studio 4.5 software. The data demonstrated that there were 16 interlinking target genes of hyperforin with AR, in which BCL6 was the most relevant one with hyperforin in AR. The binding between hyperforin and BCL6 was verified, and molecular docking was modeled. The results revealed that hyperforin inhibited IL-13-induced nasal epithelial inflammatory cytokine release and repressed the damage to the cellular barrier from IL-13 stimulation. In addition, hyperforin activated BCL6 expression and significantly suppressed the expression of p38 MAPK/CCL11. Silencing of BCL6 reversed the effects of hyperforin on IL-13-induced inflammation and barrier damage. In summary, the present results revealed that hyperforin suppressed IL-13-induced nasal epithelial cell inflammation and barrier damage by targeting BCL6/p38 MAPK/CCL11, which may provide promising therapeutic targets for AR.

Hyperforin: A natural lead compound with multiple pharmacological activities

Hypericum perforatum L. (Clusiaceae), commonly known as St. John's wort, has a rich historical background as one of the oldest and most widely studied herbal medicines. Hyperforin is the main antidepressant active ingredient of St. John's wort. In recent years, hyperforin has attached increasing attention due to its multiple pharmacological activities. In this review, the information on hyperforin was systematically summarized. Hyperforin is considered to be a lead compound with diverse pharmacological activities including anti-depression, anti-tumor, anti-dementia, anti-diabetes and others. It can be obtained by extraction and synthesis. Further pharmacological studies and more precise detection methods will help develop a value for hyperforin. In addition, structural modification and pharmaceutical preparation technology will be beneficial to promoting the research progress of hyperforin based innovative drugs. Although these works are full of known and unknown challenges, researchers are still expected to make hyperforin play a greater value.

Hyperforin Elicits Cytostatic/Cytotoxic Activity in Human Melanoma Cell Lines, Inhibiting Pro-Survival NF-κB, STAT3, AP1 Transcription Factors and the Expression of Functional Proteins Involved in Mitochondrial and Cytosolic Metabolism

Hyperforin (HPF), the main component responsible for the antidepressant action of Hypericum perforatum, displays additional beneficial properties including anti-inflammatory, antimicrobic, and antitumor activities. Among its antitumor effects, HPF activity on melanoma is poorly documented. Melanoma, especially BRAF-mutated melanoma, is still a high-mortality tumor type and the currently available therapies do not provide solutions. We investigated HPF's antimelanoma effectiveness in A375, FO1 and SK-Mel-28 human BRAF-mutated cell lines. Cell viability assays documented that all melanoma cells were affected by low HPF concentrations (EC50% 2-4 µM) in a time-dependent manner. A Br-deoxy-uridine incorporation assay attested a significant reduction of cell proliferation accompanied by decreased expression of cyclin D1 and A2, CDK4 and of the Rb protein phosphorylation, as assessed by immunoblots. In addition, the expression of P21/waf1 and the activated form of P53 were increased in A375 and SK-Mel-28 cells. Furthermore, HPF exerts cytotoxic effects. Apoptosis is induced 24 h after HPF administration, documented by an increase of cleaved-PARP1 and a decrease of both Bcl2 and Bcl-xL expression levels. Autophagy is induced, attested by an augmented LC3B expression and augmentation of the activated form of AMPK. Moreover, HPF lowers GPX4 enzyme expression, suggesting ferroptosis induction. HPF has been reported to activate the TRPC6 Ca⁺⁺ channel and/or Ca⁺⁺ and Zn⁺⁺ release from mitochondria stores, increasing cytosolic Ca⁺⁺ and Zn⁺⁺ concentrations. Our data highlighted that HPF affects many cell-signaling pathways, including signaling induced by Ca⁺⁺, such as FRA1, pcJun and pCREB, the expression or activity of which are increased shortly after treatment. However, the blockage of the TRPC6 Ca⁺⁺ channel or the use of Ca⁺⁺ and Zn⁺⁺ chelators do not hinder HPF cytostatic/cytotoxic activity, suggesting that damages induced in melanoma cells may pass through other pathways. Remarkably, 24 h after HPF treatment, the expression of activated forms of the transcription factors NF-κB P65 subunit and STAT3 are significantly lowered. Several cytosolic (PGM2, LDHA and pPKM2) and mitochondrial (UQCRC1, COX4 and ATP5B) enzymes are downregulated by HPF treatment, suggesting a generalized reduction of vital functions in melanoma cells. In line with these results is the recognized ability of HPF to affect mitochondrial membrane potential by acting as a protonophore. Finally, HPF can hinder both melanoma cell migration and colony formation in soft agar. In conclusion, we provide evidence of the pleiotropic antitumor effects induced by HPF in melanoma cells.

In vitro screening of anti-viral and virucidal effects against SARS-CoV-2 by Hypericum perforatum and Echinacea

Hypericum perforatum and Echinacea are reported to have antiviral activities against several viral infections. In this study, H. perforatum (St. John's Wort) and Echinacea were tested in vitro using Vero E6 cells for their anti-viral effects against the newly identified Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) through its infectious cycle from 0 to 48 h post infection. The hypericin of H. perforatum and the different parts (roots, seeds, aerial) of two types of Echinacea species (Echinacea purpurea and Echinacea angustifolia) were tested for their anti-viral activities to measure the inhibition of viral load using quantitative real-time polymerase chain reaction (qRT-PCR) on cell culture assay. Interestingly, the H. perforatum-Echinacea mixture (1:1 ratio) of H. perforatum and Echinacea was tested as well on SARS-CoV-2 and showed crucial anti-viral activity competing H. perforatum then Echinacea effects as anti-viral treatment. Therefore, the results H. perforatum and Echinacea species, applied in this study showed significant anti-viral and virucidal effects in the following order of potency: H. perforatum, H. perforatum-Echinacea mixture, and Echinacea on SARS-CoV-2 infectious cycle. Additionally, molecular simulation analysis of the compounds with essential proteins (Mpro and RdRp) of the SARS-CoV-2 revealed the most potent bioactive compounds such as Echinacin, Echinacoside, Cyanin, Cyanidin 3-(6''-alonylglucoside, Quercetin-3-O-glucuronide, Proanthocyanidins, Rutin, Kaempferol-3-O-rutinoside, and Quercetin-3-O-xyloside. Thus, based on the outcome of this study, it is demanding the setup of clinical trial with specific therapeutic protocol.

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.

Efficiency of hypericum perforatum, povidone iodine, tincture benzoin and tretinoin on wound healing

Different topical agents have been used to accelerate wound healing. The purpose of this study is to compare the safety and efficacy of topical application of the extract of Hypericum perforatum (HPE), povidone iodine (PI), tincture benzoin (TB) and tretinoin (T) on surgical wound healing. Ten adult female, Wistar albino rats were included in the study. HPE, PI, TB and T solutions were applied on the wounds. After seven days, tissue samples were collected and inflammatory cells, re-epithelialization, granulation tissue, angiogenesis, collagen accumulation, hemorrhage and lysis of cells were investigated histopathologically. No dermal toxicity was noted. HPE, TB, PI have all showed good epithelialization and granulation, but HPE showed the most advanced stage of healing within a short period of time. HPE had significantly higher values of re-epithelialization and collagen accumulation, but lower inflammatory cell count and granulation tissue. TB had the second best in re-epithelialization, collagen accumulation and the highest granulation tissue. PI induced better reepithelialization and granulation than the control group with remarkable cell lysis. As a result, HPE can be a safe, effective, and cheap agent that can be used for surgical wounds.

Comparative assessment of proliferation and immunomodulatory potential of Hypericum perforatum plant and callus extracts on mesenchymal stem cells derived adipose tissue from multiple sclerosis patients

BACKGROUND

Mesenchymal stem cells-derived adipose tissue (AT-MSCs) are recognized for the treatment of inflammatory diseases including multiple sclerosis (MS). Hypericum perforatum (HP) is an anti-inflammatory pharmaceutical plant with bioactive compounds. Plant tissue culture is a technique to improve desired pharmacological potential. The aim of this study was to compare the anti-inflammatory and proliferative effects of callus with field-growing plant extracts of HP on AT-MSCs derived from MS patients.

MATERIALS AND METHODS

AT-MSCs were isolated and characterized. HP callus was prepared and exposure to light spectrum (blue, red, blue-red, and control). Total phenols, flavonoids, and hypericin of HP callus and plant extracts were measured. The effects of HP extracts concentrations on proliferation were evaluated by MTT assay. Co-culture of AT-MSCs: PBMCs were challenged by HP plant and callus extracts, and Tregs percentage was assessed by flow cytometry.

RESULTS

Identification of MSCs was performed. Data showed that blue light could stimulate total phenols, flavonoids, and hypericin. MTT test demonstrated that plant extract in concentrations (0.03, 1.2, 2.5 and 10 μg/ml) and HP callus extract in 10 μg/ml significantly increased. Both HP extracts lead to an increase in Tregs percentage in all concentrations. In particular, a comparison between HP plant and callus extracts revealed that Tregs enhanced 3-fold more than control groups in the concentration of 10 μg/ml callus.

CONCLUSIONS

High concentrations of HP extracts showed effectiveness on AT-MSCs proliferation and immunomodulatory properties with a certain consequence in callus extract. HP extracts may be considered as supplementary treatments for the patients who receiving MSCs transplantation.

Polycyclic polyprenylated acylphloroglucinol derivatives from Hypericum pseudohenryi

Seven previously unidentified polycyclic polyprenylated acylphloroglucinol (PPAP) derivatives hypseudohenrins A-G, along with six known analogs, were isolated from the aerial portion of Hypericum pseudohenryi. Their structures were determined by NMR, ECD and X-ray crystallographic spectroscopy. These compounds were screened for anti-inflammatory activity, and hypseudohenrins B and G (at the concentration of 10 μM) showed NO production inhibition ratios of 52.56% and 54.01%, respectively, which imply good anti-inflammatory activity. In particular, uraloidin A exhibited an NO inhibition ratio of 90.61%, while that ratio of the positive control compound dexamethasone was 94.88%. Additionally, anti-cancer and neural-protective activities were screened, but none of these compounds showed desirable activity.

Hypseudohenrins I - K: three new polycyclic polyprenylated acylphloroglucinol derivatives from Hypericum pseudohenryi

Three previously unidentified polycyclic polyprenylated acylphloroglucinols (PPAPs) derivatives, hypseudohenrins I-K (1-3), along with a known analogue hyphenrone X (4), were isolated from the aerial part of Hypericum pseudohenryi. The structures of the new compounds were elucidated by NMR spectroscopy and ECD calculation. The anti-inflammatory activity of the compounds was evaluated. Compounds 1-3 showed mild anti-inflammatory activity while hyphenrone X showed prominent anti-inflammatory activity.[Formula: see text].

Hyperforin Ameliorates Imiquimod-Induced Psoriasis-Like Murine Skin Inflammation by Modulating IL-17A-Producing γδ T Cells

Hyperforin is a major active constituent of Hypericum perforatum L. extract, which is widely used for the treatment of depressive disorders. Recent studies have reported that hyperforin reduced inflammation in stroke and suppressed proliferation and differentiation in keratinocytes. Psoriasis is a chronic immune-mediated inflammatory skin disease in which the IL-23/IL-17 axis plays an important role. To investigate the underlying inflammatory mechanisms and response of hyperforin in psoriasis, we use imiquimod (IMQ)-induced mice model, in vitro cultured murine splenic γδ T cells, and HaCaT cells in this study. Data showed that hyperforin reduced epidermal thickness and decreased IMQ-induced pathological scores of cutaneous skin lesions in mice. Meanwhile we proved that hyperforin suppressed infiltration of CD3+ T cells and downregulated expression of Il1, Il6, Il23, Il17a, Il22, antimicrobial peptides (AMPs) in the skin lesion. Hyperforin significantly inhibited imiquimod-induced splenomegaly, reduced serum levels of TNF-α and IL-6, and IL-17A in splenocytes and draining lymph nodes. Our study also suggested that hyperforin lessened the infiltration of γδ T cell and CCR6+ γδ T cells in spleen and lymph nodes. Hyperforin also suppressed the typical psoriasis-like inflammatory responses and the infiltration of IL-17A+ cells in dermal γδ T cells of IMQ treated Tcrd-/- mice transferred with γδ T cells. In vitro studies, hyperforin reduced the expression and secretion of IL-17A in γδ T cells, and suppressed the activation of MAPK/STAT3 pathways in human keratinocyte HaCaT cells and γδ T cells. In conclusion, hyperforin alleviates IMQ-induced inflammation in psoriasis through suppressing the immune responses exerted by IL-17 A-producing γδ T cells and related cytokines by modulating MAPK/STAT3 pathways. Our study provided a novel therapeutic tragedy for psoriasis by which hyperforin attenuates psoriasis-related inflammatory responses.

Selective beta-cell toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin on isolated pancreatic islets

An association between exposure to environmental pollutants and diabetes risk has been repeatedly shown by epidemiological studies. However, the biological basis of this association still need to be clarified. In this research we explored the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure on isolated pancreatic islets. After 1, 6 and 24 h exposure of isolated islets to different concentrations (1-50 nM) of TCDD we assayed: i) cell survival; ii) ultrastructure; iii) glucose-stimulated insulin secretion (GSIS); iv) expression of selected genes. A significant, dose-related increase of both necrosis and apoptosis was observed isolated rat islets after 24 h exposure to TCDD. The electron microscopic analysis revealed, at the same time point, the presence of several ultrastructural alterations (mitochondrial swelling, increased mitophagy, dilation of the endoplasmic reticulum) that, very interestingly, were exclusively observed in beta cells and not in other endocrine cells. Similar results were obtained in isolated human islets. GSIS was rapidly (1 h) and persistently (6 and 24 h) decreased by TCDD exposure even at the smallest concentration (1 nM). TCDD exposure significantly affected gene expression in isolated islets: Glut2, Gck, Bcl-xL, MafA, Pdx1 FoxO1 and IRE1 gene expression was significantly decreased, whereas Puma, DP5, iNOS and Chop gene expression was significantly increased after 6 h exposure to TCDD. In conclusion, our results clearly indicated that pancreatic beta cells represent not only a sensitive but also a specific target of the toxic action of dioxin.

Anti-Tumor Activity of Hypericum perforatum L. and Hyperforin through Modulation of Inflammatory Signaling, ROS Generation and Proton Dynamics

In this paper we review the mechanisms of the antitumor effects of Hypericum perforatum L. (St. John's wort, SJW) and its main active component hyperforin (HPF). SJW extract is commonly employed as antidepressant due to its ability to inhibit monoamine neurotransmitters re-uptake. Moreover, further biological properties make this vegetal extract very suitable for both prevention and treatment of several diseases, including cancer. Regular use of SJW reduces colorectal cancer risk in humans and prevents genotoxic effects of carcinogens in animal models. In established cancer, SJW and HPF can still exert therapeutic effects by their ability to downregulate inflammatory mediators and inhibit pro-survival kinases, angiogenic factors and extracellular matrix proteases, thereby counteracting tumor growth and spread. Remarkably, the mechanisms of action of SJW and HPF include their ability to decrease ROS production and restore pH imbalance in tumor cells. The SJW component HPF, due to its high lipophilicity and mild acidity, accumulates in membranes and acts as a protonophore that hinders inner mitochondrial membrane hyperpolarization, inhibiting mitochondrial ROS generation and consequently tumor cell proliferation. At the plasma membrane level, HPF prevents cytosol alkalization and extracellular acidification by allowing protons to re-enter the cells. These effects can revert or at least attenuate cancer cell phenotype, contributing to hamper proliferation, neo-angiogenesis and metastatic dissemination. Furthermore, several studies report that in tumor cells SJW and HPF, mainly at high concentrations, induce the mitochondrial apoptosis pathway, likely by collapsing the mitochondrial membrane potential. Based on these mechanisms, we highlight the SJW/HPF remarkable potentiality in cancer prevention and treatment.

Protective Role of St. John's Wort and Its Components Hyperforin and Hypericin against Diabetes through Inhibition of Inflammatory Signaling: Evidence from In Vitro and In Vivo Studies

Diabetes mellitus is a very common chronic disease with progressively increasing prevalence. Besides the well-known autoimmune and inflammatory pathogenesis of type 1 diabetes, in many people, metabolic changes and inappropriate lifestyle favor a subtle chronic inflammatory state that contributes to development of insulin resistance and progressive loss of β-cell function and mass, eventually resulting in metabolic syndrome or overt type 2 diabetes. In this paper, we review the anti-inflammatory effects of the extract of Hypericum perforatum L. (St. John's wort, SJW) and its main active ingredients firstly in representative pathological situations on inflammatory basis and then in pancreatic β cells and in obese or diabetic animal models. The simultaneous and long-lasting inhibition of signal transducer and activator of transcription (STAT)-1, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinases (MAPKs)/c-jun N-terminal kinase (JNK) signaling pathways involved in pro-inflammatory cytokine-induced β-cell dysfunction/death and insulin resistance make SJW particularly suitable for both preventive and therapeutic use in metabolic diseases. Hindrance of inflammatory cytokine signaling is likely dependent on the hyperforin content of SJW extract, but recent data reveal that hypericin can also exert relevant protective effects, mediated by activation of the cyclic adenosine monophosphate (cAMP)/protein kinase cAMP-dependent (PKA)/adenosine monophosphate activated protein kinase (AMPK) pathway, against high-fat-diet-induced metabolic abnormalities. Actually, the mechanisms of action of the two main components of SJW appear complementary, strengthening the efficacy of the plant extract. Careful quantitative analysis of SJW components and suitable dosage, with monitoring of possible drug-drug interaction in a context of remarkable tolerability, are easily achievable pre-requisites for forthcoming clinical applications.

Protective and therapeutic effects of natural products against diabetes mellitus via regenerating pancreatic β-cells and restoring their dysfunction

Diabetes mellitus is a growing public health concern and an increasing interest has been raised to search for new compounds with therapeutic effects on β-cells. There are chronic insulin resistance and loss of β-cell mass in the case of type-2 diabetes which covers about 90% of total diabetic patients. This work aims to critically review the protective and regenerative effects of various antidiabetic natural products on pancreatic β-cells. A thorough literature survey was conducted on the natural molecules and extracts having a protective, regenerative, and repairing effect on β-cells. The primary source of the literature was online scientific databases such as PubMed, Scopus, and Google Scholar. Besides, selected relevant textbooks were also consulted. Various natural molecules including berberine, curcumin, mangiferin, stevioside and capsaicin, and extracts obtained from the plants like Capsicum annum, Gymnema sylvestre, Stevia rebaudiana and Nymphaea stellate, were found to produce regenerative and anti-apoptosis effects on β-cells. These natural products were also found to increase insulin secretion by stimulating β-cells. The present review concluded that a large number of molecules and extracts, abundantly found in nature, possess antidiabetic effect via targeting β-cells. Further research is warranted to use these agents as a drug against diabetes.

Bicyclic polyprenylated acylphloroglucinols and their derivatives: structural modification, structure-activity relationship, biological activity and mechanism of action

Bicyclic polyprenylated acylphloroglucinols (BPAPs), the principal bioactive benzophenone products isolated from plants of genera Garcinia and Hypericum, have attracted noticeable attention from the synthetic and biological communities due to their fascinating chemical structures and promising biological activities. However, the potential drug interaction, undesired physiochemical properties and toxicity have limited their potential use and development. In the last decade, pharmaceutical research on the structural modifications, structure-activity relationships (SARs) and mechanisms of action of BPAPs has been greatly developed to overcome the challenges. A comprehensive review of these scientific literature is extremely needed to give an overview of the rapidly emerging area and facilitate research related to BPAPs. This review, containing over 226 references, covers the progress made in the chemical synthesis-based structure modifications, SARs and the mechanism of action of BPAPs in vivo and vitro. The most relevant articles will focus on the discovery of lead compounds via synthetic modifications and the important BPAPs for which the direct targets have been deciphered. From this review, several key points of the SARs and mode of actions of this novel class of compounds have been summarized. The perspective and future direction of the research on BPAPs are concluded. This review would be helpful to get a better grasp of medicinal research of BPAPs and become a compelling guide for chemists dedicated to the synthesis of these compounds.

Hypericum spp.: An Update on the Biological Activities and Metabolic Profiles

Plants from the genus Hypericum, one genus of the Hypericaceae family, have attracted a lot of attention for their potential pharmaceutical applications. Most of the studies in the literature focus on H. perforatum L. (common St. John's wort), whose complex spectrum of bioactive compounds makes this species one of the top herbal remedies and supplements in the world. It is also important to compare the studies on other Hypericum species, both from the phytochemical and biological point of view. The aim of this review was to provide an update of most recent studies about biological investigations of plants belonging to Hypericum genus. The metabolic profiles of Hypericum spp. were also discussed in order to present a spectrum of secondary metabolites not previously identified in this genus.

Evaluation of the Effect of Topical Hypericum perforatum Oil on Excisional Palatal Wound Healing in Rabbits

Aim: The aim of this study was to evaluate the effect of Hypericum perforatum (HP) oil on wound-healing process in rabbit palatal mucosa. Materials and Methods: Thirty-six New Zealand albino rabbits were randomly allocated to following groups; (1) HP oil (test, n = 18) and (2) olive oil (control, n = 18). Palatinal excisional wounds were created and the oils were topically applied (0.1 ml, 30 s, twice a day). Gingival biopsies were excised, and analyzed for re-epithelialization (RE) and granulation tissue maturation (GTM) on days 3, 7, and 14 after surgery. Levels of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2) were assessed using the immunohistochemical method. Apoptotic cells (ACs) were evaluated using TUNEL staining. Enzyme-linked immunosorbent assay was used to assess tissue catalase (CAT) and malondialdehyde (MDA) levels. Results: RE and GTM were completed earlier in the HP oil group than in the control group. The number of positively stained cells/vessels was higher in olive oil than in the test group on day 3 for FGF-2 and on days 3 and 7 for VEGF (p < 0.05). In contrast, on day 14, a higher number of vessels was observed in the HP oil group than in the control group. HP oil treatment reduced the number of ACs compared to olive oil (p < 0.05), but the difference during the healing period did not reach significance. Tissue CAT and MDA levels between groups were not different, and also the results were the same when the levels were analyzed by the evaluated time periods (p > 0.05). Conclusions: The results of this study demonstrated that topical HP oil treatment did not provide an additional benefit to its base, olive oil, in the early phase of secondary wound healing.

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.

Persistence of STAT-1 inhibition and induction of cytokine resistance in pancreatic β cells treated with St John's wort and its component hyperforin

OBJECTIVES

St John's wort extract (SJW) and its component hyperforin (HPF) were shown to potently inhibit cytokine-induced STAT-1 and NF-κB activation in pancreatic β cells and protect them against injury. This study aimed at exploring the time course of STAT-1 inhibition afforded by these natural compounds in the β-cell line INS-1E.

METHODS

INS-1E cells were pre-incubated with SJW extract (2-5 μg/ml) or HPF (0.5-2 μm) and then exposed to a cytokine mixture. In some experiments, these compounds were added after or removed before cytokine exposure. STAT-1 activation was assessed by electrophoretic mobility shift assay, apoptosis by caspase-3 activity assay, mRNA gene expression by RT-qPCR.

KEY FINDINGS

Pre-incubation with SJW/HPF for 1-2 h exerted a remarkable STAT-1 downregulation, which was maintained upon removal of the compounds before early or delayed cytokine addition. When the protective compounds were added after cell exposure to cytokines, between 15 and 90 min, STAT-1 inhibition also occurred at a progressively decreasing extent. Upon 24-h incubation, SJW and HPF counteracted cytokine-induced β-cell dysfunction, apoptosis and target gene expression.

CONCLUSIONS

SJW and HPF confer to β cells a state of 'cytokine resistance', which can be elicited both before and after cytokine exposure and safeguards these cells from deleterious cytokine effects.