Analysis of the action of euxanthone, a plant-derived compound that stimulates neurite outgrowth

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.

Active components and molecular mechanisms of Sagacious Confucius' Pillow Elixir to treat cognitive impairment based on systems pharmacology

BACKGROUND

Sagacious Confucius' Pillow Elixir (SCPE) is a common clinical prescription to treat cognitive impairment (CI) in East Asia.

OBJECTIVE

To predict the active components of SCPE, identify the associated signaling pathway, and explore the molecular mechanism using systems pharmacology and an animal study.

METHODS

Systems pharmacology and Python programming language-based molecular docking were used to select and analyze the active components and targets. Senescence-accelerated prone 8 mice were used as a CI model. The molecular mechanism was evaluated using the water maze test, neuropathological observation, cerebrospinal fluid microdialysis, and Western blotting.

RESULTS

Thirty active components were revealed by screening relevant databases and performing topological analysis. Additionally, 376 differentially expressed genes for CI were identified. Pathway enrichment analysis, protein-protein interaction (PPI) network analysis and molecular docking indicated that SCPE played a crucial role in modulating the PI3K/Akt/mTOR signaling pathway, and 23 SCPE components interacted with it. In the CI model, SCPE improved cognitive function, increased the levels of the neurotransmitter 5-hydroxytryptamine (5-HT) and metabolite 5-hydroxyindole acetic acid (5-HIAA), ameliorated pathological damage and regulated the PI3K/AKT/mTOR signaling pathway. SCPE increased the LC3-II/LC3-I, p-PI3K p85/PI3K p85, p-AKT/AKT, and p-mTOR/mTOR protein expression ratios and inhibited P62 expression in the hippocampal tissue of the CI model.

CONCLUSION

Our study revealed that 23 active SCPE components improve CI by increasing the levels of the neurotransmitter 5-HT and metabolite 5-HIAA, suppressing pathological injury and regulating the PI3K/Akt/mTOR signaling pathway to improve cognitive function.

Modulatory effect of euxanthone in liver cancer-bearing obese mice: crosstalk between PPARγ and TIMP3 signalling axes

Liver cancer is one of the prominent cancer-associated fatal diseases with > 80% of cases befall in low-middle resource nations worldwide. In the current study, we studied the effect of euxanthone (EUX) on obesity-associated liver cancer using a high-fat diet-fed mouse model of diethylnitrosamine (DEN)-provoked hepatocellular carcinoma. Mice with 2 weeks of age were intraperitoneally injected with diethylnitrosamine (DEN) 25 mg/kg b.w. After 4 weeks, the mice were divided into four groups with low-fat diet (LFD), high-fat diet (HFD), and EUX treatment groups with or without PPARγ inhibitor (GW9662). We observed that TIMP3, E-cadherin, and Klotho expressions were downmodulated, while MMP9, ADAM17, and Wnt signalling biofactors (Wnt5a, Wnt3a and β-catenin) were upmodulated in the HFD groups. Nevertheless, these aberrations were reciprocated by the treatment with EUX; at the same time, co-administration of PPARγ inhibitor ablated the anti-cancer effects of EUX, indicating that PPARγ activation is a pivotal mechanism underpinning the negative regulation of oncogenic factors by EUX. Together, these results imply that EUX might be a viable therapeutic option in the treatment of obesity-associated hepatocarcinogenesis.

Euxanthone inhibits lipopolysaccharide-induced injury, inflammatory response, and MUC5AC hypersecretion in human airway epithelial cells by the TLR4/MyD88 pathway

Asthma progression is involved in airway epithelial dysfunction, airway inflammatory response, and mucus hypersecretion. Euxanthone has been found to exhibit cytotoxic activity on several human diseases, such as neurological disorders and cancers. Our study aimed to explore the influence of euxanthone on lipopolysaccharide (LPS)-induced injury, inflammatory response, and mucin 5AC (MUC5AC) hypersecretion in human airway epithelial cells (AECs). Network pharmacology analysis was carried out to analyze the drug targets and key pathways of euxanthone against asthma. Cell injury was evaluated by CCK-8, Lactate dehydrogenase (LDH) release assay, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. The production of interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and MUC5AC was measured using enzyme-linked immunosorbent assay (ELISA). MUC5AC mRNA expression was detected by qRT-PCR. Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) protein expression was examined by western blot analysis. Venn diagram showed 14 overlapping targets between euxanthone and asthma. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, we focused on TLR signaling pathway. LPS exposure evoked viability reduction, increased LDH release and apoptosis, and induced production of inflammatory cytokines (IL-6, IL-8, and MCP-1) and MUC5AC hypersecretion in human AECs, which were alleviated by euxanthone. Mechanistically, we validated that euxanthone attenuated LPS-induced activation of TLR4/MyD88 pathway in AECs. Moreover, inhibition of the TLR4/MyD88 pathway enhanced the inhibitory effect of euxanthone on LPS-induced cell injury, inflammatory response and MUC5AC expression. In conclusion, euxanthone attenuated LPS-induced cell injury, inflammatory response, and MUC5AC expression in AECs by inhibiting the activation of TLR4/MyD88 pathway.

Natural compounds modulate the autophagy with potential implication of stroke

Stroke is considered a leading cause of mortality and neurological disability, which puts a huge burden on individuals and the community. To date, effective therapy for stroke has been limited by its complex pathological mechanisms. Autophagy refers to an intracellular degrading process with the involvement of lysosomes. Autophagy plays a critical role in maintaining the homeostasis and survival of cells by eliminating damaged or non-essential cellular constituents. Increasing evidence support that autophagy protects neuronal cells from ischemic injury. However, under certain circumstances, autophagy activation induces cell death and aggravates ischemic brain injury. Diverse naturally derived compounds have been found to modulate autophagy and exert neuroprotection against stroke. In the present work, we have reviewed recent advances in naturally derived compounds that regulate autophagy and discussed their potential application in stroke treatment.

Euxanthone inhibits traumatic spinal cord injury via anti-oxidative stress and suppression of p38 and PI3K/Akt signaling pathway in a rat model

Background

Owing to neurite promoting, antioxidant and anti-inflammatory effects of Euxanthone (Eux), the investigation was aimed to probe the neuroprotective efficacy of Eux against traumatic spinal cord injury (t-SCI) in rats and whether Eux can improve neuropathic function in t-SCI.

Method

Sprague-Dawley (SD) rats were randomized in – Sham, t-SCI, Eux30, and Eux60 (t-SCI + 30 and 60 mg/kg respectively). Animals with compression force-induced t-SCI were subjected to estimation of locomotor functions. Spinal cord water content and Evans blue (EB) effusion were determined for quantifying edema and intactness of the spinal cord. Oxidative stress and immunochemical markers were quantified by ELISA and western blotting.

Results

Findings revealed that Eux60 group animals had greater Basso, Beattie, and Bresnahan (BBB) and (incline plane test) IPT score indicating improved locomotor functions. There was a reduction in the spinal edema and water content after Eux treatment, together with lowering of oxidative stress markers. The expression of IL-6, IL-12, IL-1β, caspase-3, RANKL, TLR4, NF-κB, p-38, PI3K, and Akt in spinal cord tissues of t-SCI-induced rats was lowered after Eux treatment.

Conclusion

Overall, the investigation advocates that Eux attenuates t-SCI and associated inflammation, oxidative damage, and resulting apoptosis via modulation of TLR4/NF-κB/p38 and PI3K/Akt signaling cascade.

Euxanthone represses the proliferation, migration, and invasion of glioblastoma cells by modulating STAT3/SHP-1 signaling

Glioblastoma is one of the most prevalent primary malignant brain tumors. Glioblastoma often develops resistance to conventional chemoradiotherapy, and thus, new ways to treat glioblastoma are urgently required. The aim of this study was to investigate the effect of euxanthone on the anticancer activities of glioblastoma and its potential mechanism. The U87 and U251 glioblastoma cell lines were cultured in media containing different concentrations of euxanthone. CCK-8 and colony formation assay were used to evaluate the cell proliferation. Cell migration and invasion were evaluated by wound healing and Transwell assays. Flow cytometry was used to assess the cell cycle and apoptosis rate. TUNEL assay was also employed to evaluate the apoptosis rate. Gene and protein expressions were determined by RT-qPCR and western blotting, respectively. A xenograft model was established to evaluate the efficacy of euxanthone in vivo. Euxanthone significantly repressed cell viability, migration, invasion, and epithelial-to-mesenchymal transition of U87 and U251 cells; and increased the rate of apoptosis. Western blotting results revealed that the levels of p21, p27, cleaved caspase-3, Bax, TIMP-3, and E-cadherin were upregulated while, the levels of CDK4, CDK6, pro-caspase-3, Bcl-2, MMP-2, MMP-9, N-cadherin, and Vimentin were downregulated by euxanthone. In addition, the expression of p-STAT3 was decreased, while the expression of SHP-1 was upregulated by euxanthone. We proposed that euxanthone could repress the malignant behavior of glioblastoma cells through suppression of STAT3 phosphorylation and activation of SHP-1. Further, in vivo data demonstrated that euxanthone repressed tumor growth and promoted apoptosis.

Cytoprotective effects of euxanthone against ox-LDL-induced endothelial cell injury is mediated via Nrf2

AIM

Atherosclerosis (AS) is a chronic condition of the arterial vessels and a risk factor for myocardial infarction and stroke. Euxanthone is a xanthone compound extracted from Polygala caudata, and shows vasodilatory action. The aim of this study was to determine the potential pharmacological effects of euxanthone against oxidized low-density lipoprotein (ox-LDL)-induced endothelial cell injury.

MATERIAL AND METHODS

Human umbilical vein endothelial cells (HUVECs) were exposed to ox-LDL, following pre-treatment with different concentrations of euxanthone. Viability, apoptosis and DNA fragmentation were respectively assessed by CCK-8 assay, Annexin-V/PI staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) assay. The cellular levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were analyzed by enzyme linked immune-sorbent assays (ELISA), and reactive oxygen species (ROS) levels using dichlorodihydrofluorescin diacetate (DCFH) staining. Quantitative RT-PCR and Western blotting were respectively used to analyze the expression levels of specific mRNAs and proteins. HUVECs were transfected with Nrf2 siRNA to induce knockdown of the latter.

KEY FINDINGS

Euxanthone pre-treatment rescued the HUVECs from ox-LDL-induced cytotoxicity, apoptosis and DNA fragmentation in a dose-dependent manner. In addition, euxanthone also significantly reversed ox-LDL-triggered loss of mitochondrial membrane potential (MMP), cytochrome C release from mitochondria to cytosol, cleavage of caspase-3 and PARP, and increase in Bax/Bcl-2 ratio. Pre-treatment with euxanthone markedly suppressed ox-LDL-induced ROS generation and inhibition of antioxidant enzymes, as well as the up-regulation of pro-inflammatory factors like MCP-1, IL-1β and TNF-α in the HUVECs. Euxanthone up-regulated and activated Nrf2 by repressing Keap1, and increased the expression of its downstream genes HO-1 and NQO-1. Nrf2 knockdown abrogated the cyto-protective, anti-apoptotic, anti-oxidant and anti-inflammatory effects of euxanthone in ox-LDL-treated HUVECs. Finally, euxanthone activated Nrf2 via the MAPK pathway and blocking the latter likewise negated the protective effects of euxanthone against cell ox-LDL.

SIGNIFICANCE

Euxanthone protected HUVECs against the oxidative and inflammatory damage induced by ox-LDL, indicating its potential as a novel therapeutic agent for AS.

Euxanthone Impairs the Metastatic Potential of Osteosarcoma by Reducing COX-2 Expression

Osteosarcoma (OS) is one of the most common malignancies of bone. This study was aimed to explore the anti-metastatic effect of euxanthone on OS. Adhesion assay and Transwell assay were used to examine the effect of euxanthone on adhesion, migration and invasion of OS cells. COX-2-over-expressing plasmid was applied to transfect OS cells to assess whether COX-2 affects the anti-metastatic function of euxanthone. PDCD4 knockdown and miR-21 mimic were applied to assess whether euxanthone suppresses the transactivation of c-jun via modulating miR-21-PDCD4 signaling. The effect of euxanthone in vivo was also examined by lung metastasis assay. Euxanthone, a xanthone derivative extracted from Polygala caudata, has been found to exhibit anti-neoplastic activities. In present study, our results showed that euxanthone suppressed cell adhesion, migration, and invasion in OS cells. Our experimental data also showed that repression of COX-2 by euxanthone mediated its anti-metastatic activities. Moreover, our findings revealed that euxanthone modulated the COX-2 expression through the miR-21/PDCD4/c-jun signaling pathway. The anti-metastatic activities of euxanthone were also validated in a pulmonary metastasis model. Taken together, our results highlighted the potential of euxanthone to be used in the treatment of OS. Anat Rec, 302:1399-1408, 2019. © 2018 Wiley Periodicals, Inc.

Euxanthone suppresses tumor growth and metastasis in colorectal cancer via targeting CIP2A/PP2A pathway

AIM

Colorectal cancer (CRC) accounts for over 600,000 deaths annually worldwide. Euxanthone is a flavonoid compound extracted from Polygala caudata, with documented anti-neoplastic actions. The current study aimed to determine the therapeutic potential of euxanthone in CRC.

METHODS AND MATERIALS

Cell Counting Kit-8 (CCK-8) assay was used to analyze the effect of euxanthone on the cell viability, and apoptosis was detected by the TUNEL assay. The in vitro migratory capacity was determined by wound healing and the invasiveness was assessed by Transwell assay. Western blotting was used to determine the level of relevant proteins. Furthermore, a CRC xenograft murine model was used to analyze the therapeutic efficacy of euxanthone in vivo. Isobaric tags for relative and absolute quantification (iTRAQ) was then performed to identify the potential targets of euxanthone. To validate the role of cancerous inhibitor of PP2A (CIP2A) in the anti-cancer effects of euxanthone, plasmid overexpressing CIP2A and shRNA targeting CIP2A were used in in vitro assays.

KEY FINDINGS

Euxanthone decreased cell viability and increased apoptosis in CRC cells, in addition to restraining migration, invasion and EMT. Similarly, euxanthone also effectively suppressed tumor growth and pulmonary metastasis in vivo. iTRAQ analysis identified CIP2A as the primary target responsible for the anticancer effects of euxanthone. The mediatory role of CIP2A was validated when the anticancer activity of euxanthone was significantly blocked by CIP2A overexpression, while CIP2A knockdown sensitized the CRC cells to euxanthone.

SIGNIFICANCE

Euxanthone exerts anti-cancer effects in vitro and in vivo in CRC by targeting CIP2A/PP2A signaling.

Euxanthone inhibits glycolysis and triggers mitochondria-mediated apoptosis by targeting hexokinase 2 in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is one of the most prevalent gynaecological cancers. Euxanthone, an active ingredient of the medicinal plant Polygala caudata, exhibits a selective cytotoxic effect in tumour cells. The present study was aimed to determine whether euxanthone could suppress ovarian tumour growth, and to study the relevant mechanism. Two EOC cell lines, SKOV3 and A2780, were used as the in vitro model and treated with euxanthone. Cell viability and apoptosis were assayed using Cell Counting Kit-8 (CCK-8) and Annexin-V FITC/PI staining, respectively. Commercially available kits were used to measure the glucose consumption, lactate production, and intracellular ATP levels. Western blots assay was conducted to examine the level of apoptotic markers. To examine the roles of HK2 and STAT3 in the anti-tumour effect of euxanthone, cells were transfected with vectors overexpressing HK2 or STAT3, and assayed as above. Finally, SKOV3 cells were injected to mice models to appreciate the anti-neoplastic effect of euxanthone in vivo. We found that euxanthone impaired the cell viability and induced apoptosis via the intrinsic pathway in a concentration-dependent fashion in both SKOV3 and A2780 cells. Euxanthone also caused inhibition of glycolysis. Apoptosis and glycolysis inhibition was mediated by the downregulation of HK2, which in turn was a result of STAT3 inactivation. In vivo experiments also supported that euxanthone could exert anti-cancer activities without general toxicity. In conclusion, euxanthone triggered mitochondrial apoptosis and inhibited glycolysis in EOC cells.

SIGNIFICANCE OF THE STUDY

Euxanthone triggered mitochondrial apoptosis and inhibited glycolysis in EOC cells. Our findings provide preliminary experimental data that support further studies on the potential therapeutic role of euxanthone in ovarian cancer.

A Chinese Herbal Preparation, Xiao-Er-An-Shen Decoction, Exerts Neuron Protection by Modulation of Differentiation and Antioxidant Activity in Cultured PC12 Cells

Xiao-Er-An-Shen Decoction (XEASD), a Chinese herbal formula, has been used in clinic for treating insomnia and mental excitement in children and adolescents. However, less of scientific data supports its effectiveness in clinic. Here, we aim to study the role of XEASD in regulating neuron differentiation and antioxidant activity. An HPLC-MS was used to chemically standardize herbal extract of XEASD. The standardized herbal extracts of XEASD (0.3–3.0 mg/mL) were applied onto cultured PC12 cells for 48 hours. The treatment with XEASD extract induced neurite outgrowth of PC12 cells in a dose-dependent manner, having the highest response by ~50% of differentiated cells. Application of XEASD extract dose dependently stimulated expressions of NF68, NF160, and NF200 in cultured PC12 cells. Furthermore, XEASD activated the phosphorylation of cAMP responsive element binding protein on PC12 cells, the effect of which was blocked by H89, a protein kinase A inhibitor. Moreover, XEASD showed free radical scavenging activity and stimulated the transcriptional activity of ARE. These results supported the neurobeneficial effects of XEASD in the induction of neurite outgrowth and protection against oxidative stress and could be useful for neurological diseases, in which neurotrophin deficiency and oxidation insult are involved.

Autophagy is a pro-survival mechanism in ovarian cancer against the apoptotic effects of euxanthone

BACKGROUND

Ovarian cancer is one of the most prevalent gynecological malignancies and thus the development of novel therapeutic agents for managing ovarian cancer is imperative. Euxanthone, a xanthone derived from Polygala caudata, has been found to exert cytotoxic effects on cancerous cells. This study was designed to assess the role of euxanthone in ovarian cancer.

METHODS AND MATERIALS

Cell Counting Kit-8 (CCK-8) assay was utilized to assess the viability of human ovarian cancer SKOV3 and OVCAR3 cell lines. The population of apoptotic cells was measured by flow cytometry and TUNEL assay. Cell cycle analysis was carried out by flow cytometry. Autophagy was determined by western blotting to detect LC3-II, p62 degradation, and Beclin1 expression, by transfection with GFP-LC3B expressing plasmid and by flow cytometry. To examine the role of STAT3 in the induction of autophagy and apoptosis by euxanthone, STAT3 expression was suppressed using siRNA. Moreover, xenograft model was established to evaluate the therapeutic effect of euxanthone in vivo.

RESULTS

Euxanthone decreased cell viability and blocked cell cycle progression at G2/M phase. Euxanthone induced apoptotic cell death in a caspase-dependent manner in ovarian cancer cells. Euxanthone treatment also led to the accumulation of autophagosomes. We also found that inhibition of autophagy by 3-MA or Beclin1 siRNA enhanced the pro-apoptotic effect of euxanthonein ovarian cancer cells. Furthermore, our results revealed that euxanthone induced apoptosis and autophagy by modulating pSTAT3/Bcl-2 signaling. In vivo data also demonstrated that euxanthone exerted anti-tumor activities without harming healthy tissues.

CONCLUSION

Euxanthone induced cytoprotective autophagy in ovarian cancer cells, which negatively contributed to its anti-tumor activities. Our findings provide preliminary experimental data that support further investigation on the therapeutic efficacy of euxanthone in ovarian cancer.

Kai-Xin-San, a traditional Chinese medicine formula, induces neuronal differentiation of cultured PC12 cells: Modulating neurotransmitter regulation enzymes and potentiating NGF inducing neurite outgrowth

ETHNOPHARMACOLOGICAL RELEVANCE

Kai-Xin-San, an ancient formula composed of Ginseng Radix et Rhizoma, Polygalae Radix, Acori Tatarinowii Rhizoma and Poria, was frequently applied for major depression disorders for thousands of years. However, its molecular mechanism has not clearly been investigated.

AIM OF THE STUDY

We aimed to reveal the action mechanism of KXS on anti-depression on inducing neuronal differentiation on PC12 cells.

MATERIALS AND METHODS

A chemically standardized water extract of KXS was applied onto cultured PC12 cells in determining its effect on neurotransmitter regulation enzymes and neurite outgrowth.

RESULTS

Single KXS treatment showed obvious changes in the expression of neurofilament and neurotransmitter regulation enzymes, which in parallel to treatment of nerve growth factor (NGF). Although KXS by itself did not show significant inductive effect on neurite outgrowth of PC12 cells, KXS could potentiate the NGF induced neurite outgrowth. Among the three ratios, K-652 showed the most powerful effect and cAMP-dependent pathway might play the major role.

CONCLUSIONS

KXS might exert the anti-depressant-like action of be inducing neuronal differentiation, which supported the clinically usage of this decoction.

Peptides derived from the solvent-exposed loops 3 and 4 of BDNF bind TrkB and p75(NTR) receptors and stimulate neurite outgrowth and survival

Brain-derived neurotrophic factor (BDNF) is critically involved in modeling the developing nervous system and is an important regulator of a variety of crucial functions in the mature CNS. BDNF exerts its action through interactions with two transmembrane receptors, either separately or in concert. BDNF has been implicated in several neurological disorders, and irregularities in BDNF function may have severe consequences. Administration of BDNF as a drug has thus far yielded few practicable results, and the potential side effects when using a multifunctional protein are substantial. In an effort to produce more specific compounds without side effects, small peptides mimicking protein function have been developed. The present study characterized two mimetic peptides, Betrofin 3 and Betrofin 4, derived from the BDNF sequence. Both Betrofins bound the cognate BDNF receptors, TrkB and p75(NTR), and induced neurite outgrowth and enhanced neuronal survival, probably by inducing signaling through tha Akt and MAPK pathways. Distinct, charged residues within the Betrofin sequences were identified as important for generating the neuritogenic response, which was also inhibited when BDNF was added together with either Betrofin, indicating partial agonistic effects of the peptides. Thus, two peptides derived from BDNF induced neurite outgrowth and enhanced neuronal survival, probably through binding to BDNF receptors.

In-vitro effects of brain-derived neurotrophic factor on neural progenitor/stem cells from rat hippocampus

Mounting evidences from in-vivo studies showed that brain-derived neurotrophic factor (BDNF) plays an important role in the neurogenesis, but the effects of BDNF are controversial because of neurogenesis affected by many factors in vivo. In this study, we investigated the effects of BDNF on the survival, proliferation, and differentiation of the neural progenitor/stem cells (NPCs) in vitro. The results showed that 40 ng/ml of BDNF significantly increased the number and diameter of neurospheres formed by NPCs; meanwhile, the TUNEL rates and lactate dehydrogenase release of NPCs were also inhibited. Tuj-1+ immunostaining showed that BDNF obviously induced the NPCs to differentiate into neurons and elongated the neurite. Our results implied that BDNF promotes the proliferation of NPCs and induces them to differentiate into neurons, and enhancement of the survival of NPCs probably is one of the mechanisms.

Quinones as key intermediates in natural products Synthesis. Syntheses of bioactive xanthones from Hypericum perforatum

Two bioactive xanthones from Hypericum perforatum have been synthesized by direct routes. Benzo[c]xanthone 5 can be prepared from intermediate 4.