Stability and antiviral activity against human cytomegalovirus of artemisinin derivatives

Antiviral, virucidal and antioxidant properties of Artemisia annua against SARS-CoV-2

Natural products are a rich source of bioactive molecules that have potential pharmacotherapeutic applications. In this study, we focused on Artemisia annua (A. annua) and its enriched extracts which were biologically evaluated in vitro as virucidal, antiviral, and antioxidant agents, with a potential application against the COVID-19 infection. The crude extract showed virucidal, antiviral and antioxidant effects in concentrations that did not affect cell viability. Scopoletin, arteannuin B and artemisinic acid (single fractions isolated from A. annua) exerted a considerable virucidal and antiviral effect in vitro starting from a concentration of 50 µg/mL. Data from Surface Plasmon Resonance (SPR) showed that the inhibition of the viral infection was due to the interaction of these compounds with the 3CLpro and Spike proteins of SARS-CoV-2, suggesting that the main interaction of compounds may interfere with the viral pathways during the insertion and the replication process. The present study suggests that natural extract of A. annua and its components could have a key role as antioxidants and antiviral agents and support the fight against SARS-CoV-2 variants and other possible emerging Coronaviruses.

Dihydroartemisinin synergistically enhances the cytotoxic effects of oxaliplatin in colon cancer by targeting the PHB2-RCHY1 mediated signaling pathway

Dihydroartemisinin (DHA) has recently attracted increasing attention for its low toxicity and high antitumor activity. DHA has been reported to have synergistic anticancer effects with a variety of drugs in the clinic; however, the molecular mechanism by which DHA inhibits tumorigenesis and improves oxaliplatin cytotoxicity in colon cancer cells is still not well understood. In this study, we found that DHA can inhibit cell proliferation and colony formation in a dose-dependent manner. Prohibitin 2 (PHB2) is a potential target by which DHA exerts its antitumor and cytotoxic effects. The function and molecular mechanism of PHB2 in colon cancer tumorigenesis were fully studied to determine the regulatory mechanism between DHA and PHB2. We found that PHB2, a mitochondrial inner membrane scaffold protein, has a higher expression level in colon cancer tissues than in adjacent nontumor tissues and is mainly localized in mitochondria. Overexpression of PHB2 can promote cell proliferation and colony formation in vitro and accelerate tumor growth in vivo. We also found that the expression level of PHB2 was inversely related to the cytotoxicity of DHA and oxaliplatin in colon cancer cells. The molecular mechanism of PHB2 in tumorigenesis and cancer therapy was further studied. The results showed that 20 μM DHA can downregulate PHB2 expression in a ubiquitylation-dependent manner and subsequently block PHB2-induced RCHY1 upregulation and p53 and p21 downregulation. In this process, RCHY1 is necessary for PHB2 to play a tumor-promoting role. Thus, PHB2 and RCHY1 are effective targets for colon cancer therapy, and DHA has synergistic anticancer effects with oxaliplatin via promoting PHB2 degradation in colon cancer cells.

Artesunate: A review of its therapeutic insights in respiratory diseases

BACKGROUND

Artesunate, as a semi-synthetic artemisinin derivative of sesquiterpene lactone, is widely used in clinical antimalarial treatment due to its endoperoxide group. Recent studies have found that artesunate may have multiple pharmacological effects, indicating its significant therapeutic potential in multiple respiratory diseases.

PURPOSE

This review aims to summarize proven and potential therapeutic effects of artesunate in common respiratory disorders.

STUDY DESIGN

This review summarizes the pharmacological properties of artesunate and then interprets the function of artesunate in various respiratory diseases in detail, such as bronchial asthma, chronic obstructive pulmonary disease, lung injury, lung cancer, pulmonary fibrosis, coronavirus disease 2019, etc., on different target cells and receptors according to completed and ongoing in silico, in vitro, and in vivo studies (including clinical trials).

METHODS

Literature was searched in electronic databases, including Pubmed, Web of Science and CNKI with the primary keywords of 'artesunate', 'pharmacology', 'pharmacokinetics', 'respiratory disorders', 'lung', 'pulmonary', and secondary search terms of 'Artemisia annua L.', 'artemisinin', 'asthma', 'chronic obstructive lung disease', 'lung injury', 'lung cancer', 'pulmonary fibrosis', 'COVID-19' and 'virus' in English and Chinese. All experiments were included. Reviews and irrelevant studies to the therapeutic effects of artesunate on respiratory diseases were excluded. Information was sort out according to study design, subject, intervention, and outcome.

RESULTS

Artesunate is promising to treat multiple common respiratory disorders via various mechanisms, such as anti-inflammation, anti-oxidative stress, anti-hyperresponsiveness, anti-proliferation, airway remodeling reverse, induction of cell death, cell cycle arrest, etc. CONCLUSION: Artesunate has great potential to treat various respiratory diseases.

Artemisia Extracts and Artemisinin-Based Antimalarials for COVID-19 Management: Could These Be Effective Antivirals for COVID-19 Treatment?

As the world desperately searches for ways to treat the coronavirus disease 2019 (COVID-19) pandemic, a growing number of people are turning to herbal remedies. The Artemisia species, such as A. annua and A. afra, in particular, exhibit positive effects against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and COVID-19 related symptoms. A. annua is a source of artemisinin, which is active against malaria, and also exhibits potential for other diseases. This has increased interest in artemisinin's potential for drug repurposing. Artemisinin-based combination therapies, so-called ACTs, have already been recognized as first-line treatments against malaria. Artemisia extract, as well as ACTs, have demonstrated inhibition of SARS-CoV-2. Artemisinin and its derivatives have also shown anti-inflammatory effects, including inhibition of interleukin-6 (IL-6) that plays a key role in the development of severe COVID-19. There is now sufficient evidence in the literature to suggest the effectiveness of Artemisia, its constituents and/or artemisinin derivatives, to fight against the SARS-CoV-2 infection by inhibiting its invasion, and replication, as well as reducing oxidative stress and inflammation, and mitigating lung damage.

Impact of new cyclooxygenase 2 inhibitors on human cytomegalovirus replication in vitro

Background

Human cytomegalovirus (HCMV) is involved in complications on immunocompromised patients. Current therapeutics are associated with several drawbacks, such as nephrotoxicity.

Purpose:

As HCMV infection affects inflammation pathways, especially prostaglandin E2 (PGE2) production via cyclooxygenase 2 enzyme (COX-2), we designed 2'-hydroxychalcone compounds to inhibit human cytomegalovirus.

Study design

We first selected the most efficient new synthetic chalcones for their effect against COX-2-catalyzed PGE2.

Study sample

Among the selected compounds, we assessed the antiviral efficacy against different HCMV strains, such as the laboratory strain AD169 and clinical strains (naïve or multi-resistant to conventional drugs) and toxicity on human cells.

Results

The most efficient and less toxic compound (chalcone 7) was tested against HCMV in combination with other antiviral molecules: artesunate (ART), baicalein (BAI), maribavir (MBV), ganciclovir (GCV), and quercetin (QUER) using Compusyn software. Association of chalcone 7 with MBV and BAI is synergistic, antagonistic with QUER, and additive with GCV and ART.

Conclusion

These results provide a promising search path for potential bitherapies against HCMV.

DHA exhibits synergistic therapeutic efficacy with cisplatin to induce ferroptosis in pancreatic ductal adenocarcinoma via modulation of iron metabolism

Pancreatic ductal adenocarcinoma (PDAC) is an extremely lethal cancer with limited treatment options. Cisplatin (DDP) is used as a mainstay of chemotherapeutic agents in combination with other drugs or radiotherapy for PDAC therapy. However, DDP exhibits severe side-effects that can lead to discontinuation of therapy, and the acquired drug resistance of tumor cells presents serious clinical obstacles. Therefore, it is imperative to develop a more effective and less toxic therapeutic strategy. We and others have previously discovered that dihydroartemisinin (DHA) represents a safe and promising therapeutic agent to preferentially induce cancer cell ferroptosis. In the present study, we find that DHA could intensively strengthen the cytotoxicity of DDP and significantly reduce its effective concentrations both in vitro and in vivo. Combination of DHA and DDP synergistically inhibits the proliferation and induces DNA damage of PDAC cells. Mechanically, the combinative treatment impairs mitochondrial homeostasis, characterized by destroyed mitochondrial morphology, decreased respiratory capacity, reduced ATP production, and accumulated mitochondria-derived ROS. Further studies show that ferroptosis contributes to the cytotoxic effects in PDAC cells under the challenge of DHA and DDP, together with catastrophic accumulation of free iron and unrestricted lipid peroxidation. Moreover, pharmacologic depleting of the free iron reservoir or reconstituted expression of FTH contributes to the tolerance of DHA/DDP-induced ferroptosis, while iron addition accelerates the ferroptotic cell death. In summary, these results provide experimental evidence that DHA acts synergistically with DDP and renders PDAC cells vulnerable to ferroptosis, which may act as a promising therapeutic strategy.

Recent pharmacological advances in the repurposing of artemisinin drugs

Artemisinins are a family of sesquiterpene lactones originally derived from the sweet wormwood (Artemisia annua). Beyond their well-characterized role as frontline antimalarial drugs, artemisinins have also received increased attention for other potential pharmaceutical effects, which include antiviral, antiparsitic, antifungal, anti-inflammatory, and anticancer activities. With concerted efforts in further preclinical and clinical studies, artemisinin-based drugs have the potential to be viable treatments for a great variety of human diseases. Here, we provide a comprehensive update on recent reports of pharmacological actions and applications of artemisinins outside of their better-known antimalarial role and highlight their potential therapeutic viability for various diseases.

Antimalarial and anticancer properties of artesunate and other artemisinins: current development

This review provides a recent perspective of artesunate and other artemisinins as antimalarial drugs and their uses in cancer therapy. Artesunate is an artemisinin derivative. Artemisinin is extracted from the plant Artemisia annua. Artemisinin and its derivatives have been the most useful drug for malarial treatment in human history. The artesunate has an advantage of a hydrophilic group over other artemisinins which makes it a more potent drug. On the industrial scale, artemisinins are synthesized in semisynthetic ways. The 1,2,4-endoperoxide bridge of artemisinins is responsible for the drug's antimalarial activity. There is the emergence of artemisinin resistance on Plasmodium falciparum and pieces of evidence suggest that it is mainly due to the mutation at Kelch13 protein of P. falciparum. Clinical trial data show that the artesunate is more favorable than quinine and other artemisinins to treat patients with severe malaria. Pieces of evidence indicate that artemisinins can be developed as anticancer drugs. The mechanism of actions on how artemisinins act as an anticancer drug involves oxidative stress, DNA damage and repair, and various types of cell deaths.

From hydroxychloroquine to ivermectin: what are the anti-viral properties of anti-parasitic drugs to combat SARS-CoV-2?

BACKGROUND

Nearly a year into the COVID-19 pandemic, we still lack effective anti-SARS-CoV-2 drugs with substantial impact on mortality rates except for dexamethasone. As the search for effective antiviral agents continues, we aimed to review data on the potential of repurposing antiparasitic drugs against viruses in general, with an emphasis on coronaviruses.

METHODS

We performed a review by screening in vitro and in vivo studies that assessed the antiviral activity of several antiparasitic agents: chloroquine, hydroxychloroquine (HCQ), mefloquine, artemisinins, ivermectin, nitazoxanide (NTZ), niclosamide, atovaquone and albendazole.

RESULTS

For HCQ and chloroquine we found ample in vitro evidence of antiviral activity. Cohort studies that assessed the use of HCQ for COVID-19 reported conflicting results, but randomized controlled trials (RCTs) demonstrated no effect on mortality rates and no substantial clinical benefits of HCQ used either for prevention or treatment of COVID-19. We found two clinical studies of artemisinins and two studies of NTZ for treatment of viruses other than COVID-19, all of which showed mixed results. Ivermectin was evaluated in one RCT and few observational studies, demonstrating conflicting results. As the level of evidence of these data is low, the efficacy of ivermectin against COVID-19 remains to be proven. For chloroquine, HCQ, mefloquine, artemisinins, ivermectin, NTZ and niclosamide, we found in vitro studies showing some effects against a wide array of viruses. We found no relevant studies for atovaquone and albendazole.

CONCLUSIONS

As the search for an effective drug active against SARS-CoV-2 continues, we argue that pre-clinical research of possible antiviral effects of compounds that could have antiviral activity should be conducted. Clinical studies should be conducted when sufficient in vitro evidence exists, and drugs should be introduced into widespread clinical use only after being rigorously tested in RCTs. Such a search may prove beneficial in this pandemic or in outbreaks yet to come.

Dihydroartemisinin inhibits the tumorigenesis and invasion of gastric cancer by regulating STAT1/KDR/MMP9 and P53/BCL2L1/CASP3/7 pathways

Dihydroartemisinin (DHA), an effective antimalarial drug, has been widely investigated as an anti-tumor agent. Although previous studies have indicated the potential therapeutic effects of DHA on multiple malignancies, its detailed molecular mechanisms in gastric cancer (GC) are still undocumented. In the present study, we applied network pharmacology and bioinformatics (gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses) to obtain the collective targets of DHA and GC and analyzed their involvement in constructing a protein-protein interaction (PPI) network. The top 10% hub targets in this network were identified, and TCGA database was utilized for the single gene analysis of their correlation with the prognosis of GC. CCK8, EdU, Transwell, and flow cytometry analyses were conducted, and subcutaneous xenograft tumor models were constructed to assess the effects of DHA on the tumorigenesis and invasion of GC. Furthermore, the targets of DHA were verified by molecular docking, quantitative real-time PCR (qPCR) and western blot analyses in GC cells. The results indicated that the common targets of DHA and GC were enriched in multiple cancer-related pathways including KDR, STAT1 and apoptosis signaling pathways, where the core genes included KDR, MMP9, STAT1, TP53, CASP3/7 and BCL2L1. The lowered expression of KDR and increased expression of TP53 and CASP7 harbored a favorable survival for patients with GC patients. CASP7 showed a positive correlation with CASP3 but a negative correlation with KDR and could be regarded as an independent protective factor for overall survival in GC. Moreover, DHA treatment induced cell apoptosis and suppressed the cell proliferation, DNA synthesis, cycle progression and invasive capabilities both in vitro and in vivo. DHA also upregulated p53, CASP3, and cleaved-CASP3 and downregulated BCL2L1, MMP9, KDR, p-KDR, STAT1 and p-STAT1 in GC cell lines. In conclusion, DHA could suppress the tumorigenesis and invasion of GC by regulating STAT1/KDR/MMP9 and p53/BCL2L1/CASP3/7 pathways. Our findings might provide a novel approach for the treatment of GC.

Anti-SARS-CoV-2 Potential of Artemisinins In Vitro

The discovery of novel drug candidates with anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) potential is critical for the control of the global COVID-19 pandemic. Artemisinin, an old antimalarial drug derived from Chinese herbs, has saved millions of lives. Artemisinins are a cluster of artemisinin-related drugs developed for the treatment of malaria and have been reported to have multiple pharmacological activities, including anticancer, antiviral, and immune modulation. Considering the reported broad-spectrum antiviral potential of artemisinins, researchers are interested in whether they could be used to combat COVID-19. We systematically evaluated the anti-SARS-CoV-2 activities of nine artemisinin-related compounds in vitro and carried out a time-of-drug-addition assay to explore their antiviral mode of action. Finally, a pharmacokinetic prediction model was established to predict the therapeutic potential of selected compounds against COVID-19. Arteannuin B showed the highest anti-SARS-CoV-2 potential with an EC50 of 10.28 ± 1.12 μM. Artesunate and dihydroartemisinin showed similar EC50 values of 12.98 ± 5.30 μM and 13.31 ± 1.24 μM, respectively, which could be clinically achieved in plasma after intravenous administration. Interestingly, although an EC50 of 23.17 ± 3.22 μM was not prominent among the tested compounds, lumefantrine showed therapeutic promise due to high plasma and lung drug concentrations after multiple dosing. Further mode of action analysis revealed that arteannuin B and lumefantrine acted at the post-entry step of SARS-CoV-2 infection. This research highlights the anti-SARS-CoV-2 potential of artemisinins and provides leading candidates for anti-SARS-CoV-2 drug research and development.

A systematic review on COVID-19 pandemic with special emphasis on curative potentials of Nigeria based medicinal plants

Despite the frightening mortality rate associated with COVID-19, there is no known approved drug to effectively combat the pandemic. COVID-19 clinical manifestations include fever, fatigue, cough, shortness of breath, and other complications. At present, there is no known effective treatment or vaccine that can mitigate/inhibit SARS-CoV-2. Available clinical intervention for COVID-19 is only palliative and limited to support. Thus, there is an exigent need for effective and non-invasive treatment. This article evaluates the possible mechanism of actions of SARS-CoV-2 and present Nigeria based medicinal plants which have pharmacological and biological activities that can mitigate the hallmarks of the pathogenesis of COVID-19. SARS-CoV-2 mode of actions includes hyper-inflammation characterized by a severe and fatal hyper-cytokinaemia with multi-organ failure; immunosuppression; reduction of angiotensin-converting enzyme 2 (ACE2) to enhance pulmonary vascular permeability causing damage to the alveoli; and further activated by open reading frame (ORF)3a, ORF3b, and ORF7a via c-Jun N- terminal kinase (JNK) pathway which induces lung damage. These mechanisms of action of SARS-CoV-2 can be mitigated by a combination therapy of medicinal herbs based on their pharmacological activities. Since the clinical manifestations of COVID-19 are multifactorial with co-morbidities, we strongly recommend the use of combined therapy such that two or more herbs with specific therapeutic actions are administered to combat the mediators of the disease.

The Artemisinin-Derived Autofluorescent Compound BG95 Exerts Strong Anticytomegaloviral Activity Based on a Mitochondrial Targeting Mechanism

Human cytomegalovirus (HCMV) is a major human pathogen associated with severe pathology. Current options of antiviral therapy only partly satisfy the needs of a well-tolerated long-term treatment/prophylaxis free from drug-induced viral resistance. Recently, we reported the strong antiviral properties in vitro and in vivo of the broad-spectrum anti-infective drug artesunate and its optimized derivatives. NF-κB signaling was described as a targeting mechanism and additional target proteins have recently been identified. Here, we analyzed the autofluorescent hybrid compound BG95, which could be utilized for intracellular visualization by confocal imaging and a tracking analysis in virus-infected primary human fibroblasts. As an important finding, BG95 accumulated in mitochondria visualized by anti-prohibitin and MitoTracker staining, and induced statistically significant changes of mitochondrial morphology, distinct from those induced by HCMV infection. Notably, mitochondrial membrane potential was found substantially reduced by BG95, an effect apparently counteracting efficient HCMV replication, which requires active mitochondria and upregulated energy levels. This finding was consistent with binding properties of artesunate-like compounds to mitochondrial proteins and thereby suggested a new mechanistic aspect. Combined, the present study underlines an important role of mitochondria in the multifaceted, host-directed antiviral mechanism of this drug class, postulating a new mitochondria-specific mode of protein targeting.

Artemisia annua, a Traditional Plant Brought to Light

Traditional remedies have been used for thousand years for the prevention and treatment of infectious diseases, particularly in developing countries. Of growing interest, the plant Artemisia annua, known for its malarial properties, has been studied for its numerous biological activities including metabolic, anti-tumor, anti-microbial and immunomodulatory properties. Artemisia annua is very rich in secondary metabolites such as monoterpenes, sesquiterpenes and phenolic compounds, of which the biological properties have been extensively studied. The purpose of this review is to gather and describe the data concerning the main chemical components produced by Artemisia annua and to describe the state of the art about the biological activities reported for this plant and its compounds beyond malaria.

Artemisinin inhibits the replication of flaviviruses by promoting the type I interferon production

Flaviviruses are considered to be major emerging human pathogens globally. Currently available anti-flavivirus approaches are ineffective, thus there is a desperate need for broad-spectrum drugs that can be active against existing and emerging flaviviruses. Artemisinin has been found to cause an antiviral effect against several viruses; however, its antiviral effect against flaviviruses remains unexplored. Here the antiviral activity of artemisinin against flaviviruses such as JEV, DENV, and ZIKV was evaluated by measuring the hallmark features of virus replication both in vitro and in vivo. Mechanistically, the artemisinin-induced antiviral effect was associated with enhanced host type I interferon response. The blocking of interferon signaling inhibited the artemisinin-induced interferon-stimulated genes expression and rescued the artemisinin-suppressed virus replication. This study demonstrated for the first time the antiviral activity of artemisinin against flaviviruses with a novel antiviral mechanism. The therapeutic application of artemisinin may constitute a broad-spectrum approach to cure infections caused by flaviviruses.

The Use of Antimalarial Drugs against Viral Infection

In recent decades, drugs used to treat malaria infection have been shown to be beneficial for many other diseases, including viral infections. In particular, they have received special attention due to the lack of effective antiviral drugs against new emerging viruses (i.e., HIV, dengue virus, chikungunya virus, Ebola virus, etc.) or against classic infections due to drug-resistant viral strains (i.e., human cytomegalovirus). Here, we reviewed the in vitro/in vivo and clinical studies conducted to evaluate the antiviral activities of four classes of antimalarial drugs: Artemisinin derivatives, aryl-aminoalcohols, aminoquinolines, and antimicrobial drugs.

Synthesis, in vitro and in vivo biological evaluation of dihydroartemisinin derivatives with potential anti-Toxoplasma gondii agents

In this study, four series of dihydroartemisinin derivatives were designed, synthesized, and evaluated for anti-toxoplasma gondii activity, and calculated the selectivity index (SI). It was the higher the SI, the better the effect of this compound against Toxoplasma gondii. Our goal was to filter out compounds that were bigger SI than the lead compound. The compound with the highest SI was selected for the anti-toxoplasmosis test in mice in vivo. Among the synthesized compounds, the (3R,5aS,6R,8aS,9R,12R,12aR)-3,6,9-trimethyl-decahydro-12H-3,12-epoxy[1,2]di-oxepino[4,3 -i]isochromen-10-yl-(te-rt-butoxycarbonyl)-l-alaninate (A2) exhibited the most potent anti-T. gondii activity and low cytotoxicity (SI: 6.44), yielding better results than the lead compound DHA (SI: 1.00) and the clinically used positive-control drug spiramycin (SI: 0.72) in vitro. Furthermore, compound A2 had better growth inhibitory effects on T. gondii in vivo than spiramycin did and significantly reduced the number of tachyzoites in the peritoneal cavity of mice (P < 0.01). The evaluation of the data generated in the T. gondii mouse infection model indicates that compound A2 treatment was a good inhibitor of T. gondii in vivo and that it was effective in relieving the liver damage induced by T. gondii. In addition, the results of a docking study revealed that A2 could become a better T. gondii calcium-dependent protein kinase1 (TgCDPK1) inhibitor. For this reason, compound A2 has potential as an anti-parasitic drug. Further studies are required to elucidate the mechanism of the action of compound A2, as well as to develop drug delivery systems for patients.

Artemisone demonstrates synergistic antiviral activity in combination with approved and experimental drugs active against human cytomegalovirus

We have recently shown that the artemisinin derivative artemisone, which was screened against malaria in human clinical studies, is a potent inhibitor of human cytomegalovirus (HCMV). Here we evaluated the antiviral effect of artemisone when employed in 2-drug combinations with approved and experimental anti-HCMV agents. Using the Chou-Talalay method, we found that in-vitro combination of artemisone with cidofovir, brincidofovir, or with the HCMV UL97 inhibitor maribavir resulted in antiviral synergism and the combination of artemisone with ganciclovir or with the viral terminase inhibitors letermovir and BDCRB resulted in moderate synergism. Importantly, the combination of artemisone with maribavir demonstrated synergistic antiviral activity ex-vivo, in a clinically-relevant multicellular model of human placental tissues maintained in organ culture. Our findings provide the basis for the use of artemisone in synergistically acting drug combinations, to enhance viral control and reduce antiviral drug toxicities.

Combination Anthelmintic/Antioxidant Activity Against Schistosoma Mansoni

Schistosomiasis is a major neglected tropical disease. Treatment for schistosomiasis with praziquantel (PZQ), which is effective against the parasite, by itself is not capable to counteract infection-associated disease lesions including hepatic fibrosis. There is a pressing need for novel therapies. Due to their biological properties, antioxidant biomolecules might be useful in treating and reverting associated pathological sequelae. Here, we investigated a novel therapy approach based on a combination of anthelmintic drugs with antioxidant biomolecules. We used a host-parasite model involving Bioamphalaria glabrata and newly transformed schistosomula (NTS) of Schistosoma mansoni. For in vitro drug screening assays, was selected several antioxidants and evaluated not only antischistosomal activity but also ability to enhance activity of the anthelmintic drugs praziquantel (PZQ) and artesunate (AS). The morphological alterations induced by compounds alone/combined were assessed on daily basis using an inverted and automated microscope to quantify NTS viability by a fluorometric-based method. The findings indicated that not only do some antioxidants improve antischistosomal activity of the two anthelmintics, but they exhibit activity per se, leading to high mortality of NTS post-exposure. The combination index (CI) of PZQ + Mel (CI = 0.80), PZQ + Resv (CI = 0.74), AS + Resv (CI = 0.34), AS + NAC (CI = 0.89), VDT + Flav (CI = 1.03) and VDT + Resv (CI = 1.06) reveal that they display moderate to strong synergism. The combination of compounds with discrete mechanisms of action might provide a valuable adjunct to contribution for treatment of schistosomiasis-associated disease.

Nanostructured Dihydroartemisinin Plus Epirubicin Liposomes Enhance Treatment Efficacy of Breast Cancer by Inducing Autophagy and Apoptosis

The heterogeneity of breast cancer and the development of drug resistance are the relapse reasons of disease after chemotherapy. To address this issue, a combined therapeutic strategy was developed by building the nanostructured dihydroartemisinin plus epirubicin liposomes. Investigations were performed on human breast cancer cells in vitro and xenografts in nude mice. The results indicated that dihydroartemisinin could significantly enhance the efficacy of epirubicin in killing different breast cancer cells in vitro and in vivo. We found that the combined use of dihydroartemisinin with epirubicin could efficiently inhibit the activity of Bcl-2, facilitate release of Beclin 1, and further activate Bax. Besides, Bax activated apoptosis which led to the type I programmed death of breast cancer cells while Beclin 1 initiated the excessive autophagy that resulted in the type II programmed death of breast cancer cells. In addition, the nanostructured dihydroartemisinin plus epirubicin liposomes prolonged circulation of drugs, and were beneficial for simultaneously delivering drugs into breast cancer tissues. Hence, the nanostructured dihydroartemisinin plus epirubicin liposomes could provide a new therapeutic strategy for treatment of breast cancer.

The Artemisinin Derivative Artemisone Is a Potent Inhibitor of Human Cytomegalovirus Replication

Human cytomegalovirus (HCMV) is a major cause of disease in immunocompromised individuals and the most common cause of congenital infection and neurosensorial disease. The expanding target populations for HCMV antiviral treatment along with the limitations of the currently available HCMV DNA polymerase inhibitors underscore the need for new antiviral agents with alternative modes of action. The antimalarial artemisinin derivative artesunate was shown to inhibit HCMV in vitro yet has demonstrated limited antiviral efficacy in vivo, prompting our search for more potent anti-HCMV artemisinin derivatives. Here we show that the innovative artemisinin derivative artemisone, which has been screened for its activity against malaria parasites in human clinical studies, is a potent and noncytotoxic inhibitor of HCMV. Artemisone exhibited an antiviral efficacy comparable to that of ganciclovir (50% effective concentration, 1.20 ± 0.46 μM) in human foreskin fibroblasts, with enhanced relative potency in lung fibroblasts and epithelial cells. Significantly, the antiviral efficacy of artemisone was consistently ≥10-fold superior to that of artesunate in all cells. Artemisone effectively inhibited both laboratory-adapted and low-passage-number clinical strains, as well as drug-resistant HCMV strains. By using quantitative viral kinetics and gene expression studies, we show that artemisone is a reversible inhibitor targeting an earlier phase of the viral replication cycle than ganciclovir. Importantly, artemisone most effectively inhibited HCMV infection ex vivo in a clinically relevant multicellular model of integral human placental tissues maintained in organ culture. Our promising findings encourage preclinical and clinical studies of artemisone as a new inhibitor against HCMV.

Synthesis of Artemisinin-Derived Dimers, Trimers and Dendrimers: Investigation of Their Antimalarial and Antiviral Activities Including Putative Mechanisms of Action

Generation of dimers, trimers and dendrimers of bioactive compounds is an approach that has recently been developed for the discovery of new potent drug candidates. Herein, we present the synthesis of new artemisinin-derived dimers and dendrimers and investigate their action against malaria parasite Plasmodium falciparum 3D7 strain and human cytomegalovirus (HCMV). Dimer 7 was the most active compound (EC₅₀ 1.4 nm) in terms of antimalarial efficacy and was even more effective than the standard drugs dihydroartemisinin (EC₅₀ 2.4 nm), artesunic acid (EC₅₀ 8.9 nm) and chloroquine (EC₅₀ 9.8 nm). Trimer 4 stood out as the most active agent against HCMV in vitro replication and exerted an EC₅₀ value of 0.026 μm, representing an even higher activity than the two reference drugs ganciclovir (EC₅₀ 2.60 μm) and artesunic acid (EC₅₀ 5.41 μm). In addition, artemisinin-derived dimer 13 and trimer 15 were for the first time both immobilized on TOYOPEARL AF-Amino-650M beads and used for mass spectrometry-based target identification experiments using total lysates of HCMV-infected primary human fibroblasts. Two major groups of novel target candidates, namely cytoskeletal and mitochondrial proteins were obtained. Two putatively compound-binding viral proteins, namely major capsid protein (MCP) and envelope glycoprotein pUL132, which are both essential for HCMV replication, were identified.

Artesunate-derived monomeric, dimeric and trimeric experimental drugs - Their unique mechanistic basis and pronounced antiherpesviral activity

Human cytomegalovirus (HCMV) is a major human pathogen and is associated with severe pathology, such as life-threatening courses of infection in immunocompromised individuals and neonates. Currently, antiviral therapy is still hampered by a considerable toxicity of the available drugs and induction of viral resistance. Recently, we and others reported the very potent antiviral activity of the broad antiinfective drug artesunate in vitro and in vivo. Here, we investigated further optimized analogs including monomeric, dimeric and trimeric derivatives belonging to this highly interesting chemical group of experimental drugs (sesquiterpenes/trioxanes) and compared these to the previously identified trimeric artesunate compound TF27. We could demonstrate that (i) seven of the eight investigated monomeric, dimeric and trimeric artesunate derivatives, i.e. TF79, TF85, TF87, TF93.2.4, TF111, TF57a and TF57ab, exerted a strong anti-HCMV activity in primary human fibroblasts, (ii) the EC₅₀ values ranged in the low to sub-micromolar concentrations and indicated a higher antiviral potency than the recently described artesunate analogs, (iii) one trimeric compound, TF79, showed a very promising EC₅₀ of 0.03 ± 0.00 μM, which even exceled the antiviral potency of TF27 (EC₅₀ 0.04 ± 0.01 μM), (iv) levels of cytotoxicity (quantitative measurement of lactate dehydrogenase release) were low in a range between 100 and 30 μM and thus different from antiviral concentrations, (v) an analysis of protein expression levels indicated a potent block of viral protein expression, and (vi) data from a NF-κB reporter cell system strongly suggested that these compounds share the same antiviral mechanism. Taken together, our data on these novel compounds strongly encourages our earlier concept on the oligomerization and hybridization of artesunate analogs, providing an excellent platform for the generation of antiherpesviral drugs.

Peroxides with Anthelmintic, Antiprotozoal, Fungicidal and Antiviral Bioactivity: Properties, Synthesis and Reactions

The biological activity of organic peroxides is usually associated with the antimalarial properties of artemisinin and its derivatives. However, the analysis of published data indicates that organic peroxides exhibit a variety of biological activity, which is still being given insufficient attention. In the present review, we deal with natural, semi-synthetic and synthetic peroxides exhibiting anthelmintic, antiprotozoal, fungicidal, antiviral and other activities that have not been described in detail earlier. The review is mainly concerned with the development of methods for the synthesis of biologically active natural peroxides, as well as its isolation from natural sources and the modification of natural peroxides. In addition, much attention is paid to the substantially cheaper biologically active synthetic peroxides. The present review summarizes 217 publications mainly from 2000 onwards.

Rheum emodin inhibits enterovirus 71 viral replication and affects the host cell cycle environment

Human enterovirus 71 (EV71) is the primary causative agent of recent large-scale outbreaks of hand, foot, and mouth disease (HFMD) in Asia. Currently, there are no drugs available for the prevention and treatment of HFMD. In this study, we compared the anti-EV71 activities of three natural compounds, rheum emodin, artemisinin and astragaloside extracted from Chinese herbs Chinese rhubarb, Artemisia carvifolia and Astragalus, respectively, which have been traditionally used for the treatment and prevention of epidemic diseases. Human lung fibroblast cell line MRC5 was mock-infected or infected with EV71, and treated with drugs. The cytotoxicity of the drugs was detected with MTT assay. The cytopathic effects such as cell death and condensed nuclei were morphologically observed. The VP1-coding sequence required for EV71 genome replication was assayed with qRT-PCR. Viral protein expression was analyzed with Western blotting. Viral TCID50 was determined to evaluate EV71 virulence. Flow cytometry analysis of propidium iodide staining was performed to analyze the cell cycle distribution of MRC5 cells. Rheum emodin (29.6 μmol/L) effectively protected MRC5 cells from EV71-induced cytopathic effects, which resulted from the inhibiting viral replication: rheum emodin treatment decreased viral genomic levels by 5.34-fold, viral protein expression by less than 30-fold and EV71 virulence by 0.33107-fold. The fact that inhibition of rheum emodin on viral virulence was much stronger than its effects on genomic levels and viral protein expression suggested that rheum emodin inhibited viral maturation. Furthermore, rheum emodin treatment markedly diminished cell cycle arrest at S phase in MRC5 cells, which was induced by EV71 infection and favored the viral replication. In contrast, neither astragaloside (50 μmol/L) nor artemisinin (50 μmol/L) showed similar anti-EV71 activities. Among the three natural compounds tested, rheum emodin effectively suppressed EV71 viral replication, thus is a candidate anti-HFMD drug.

Application of the Triazolization Reaction to Afford Dihydroartemisinin Derivatives with Anti-HIV Activity

Artemisinin and synthetic derivatives of dihydroartemisinin are known to possess various biological activities. Post-functionalization of dihydroartemisinin with triazole heterocycles has been proven to lead to enhanced therapeutic potential. By using our newly developed triazolization strategy, a library of unexplored fused and 1,5-disubstituted 1,2,3-triazole derivatives of dihydroartemisinin were synthesized in a single step. All these newly synthesized compounds were characterized and evaluated for their anti-HIV (Human Immunodeficiency Virus) potential in MT-4 cells. Interestingly; three of the synthesized triazole derivatives of dihydroartemisinin showed activities with half maximal inhibitory concentration (IC₅₀) values ranging from 1.34 to 2.65 µM.

Dihydroartemisinin as a Putative STAT3 Inhibitor, Suppresses the Growth of Head and Neck Squamous Cell Carcinoma by Targeting Jak2/STAT3 Signaling

Developing drugs that can effectively block STAT3 activation may serve as one of the most promising strategy for cancer treatment. Currently, there is no putative STAT3 inhibitor that can be safely and effectively used in clinic. In the present study, we investigated the potential of dihydroartemisinin (DHA) as a putative STAT3 inhibitor and its antitumor activities in head and neck squamous cell carcinoma (HNSCC). The inhibitory effects of DHA on STAT3 activation along with its underlying mechanisms were studied in HNSCC cells. The antitumor effects of DHA against HNSCC cells were explored both in vitro and in vivo. An investigation on cooperative effects of DHA with cisplatin in killing HNSCC cells was also implemented. DHA exhibited remarkable and specific inhibitory effects on STAT3 activation via selectively blocking Jak2/STAT3 signaling. Besides, DHA significantly inhibited HNSCC growth both in vitro and in vivo possibly through induction of apoptosis and attenuation of cell migration. DHA also synergized with cisplatin in tumor inhibition in HNSCC cells. Our findings demonstrate that DHA is a putative STAT3 inhibitor that may represent a new and effective drug for cancer treatment and therapeutic sensitization in HNSCC patients.

The broad-spectrum antiinfective drug artesunate interferes with the canonical nuclear factor kappa B (NF-κB) pathway by targeting RelA/p65

Infection with human cytomegalovirus (HCMV) is a serious medical problem, particularly in immunocompromised individuals and neonates. The success of standard antiviral therapy is hampered by low drug compatibility and induction of viral resistance. A novel strategy is based on the exploitation of cell-directed signaling inhibitors. The broad antiinfective drug artesunate (ART) offers additional therapeutic options such as oral bioavailability and low levels of toxic side-effects. Here, novel ART-derived compounds including dimers and trimers were synthesized showing further improvements over the parental drug. Antiviral activity and mechanistic aspects were determined leading to the following statements: (i) ART exerts antiviral activity towards human and animal herpesviruses, (ii) no induction of ART-resistant HCMV mutants occurred in vitro, (iii) chemically modified derivatives of ART showed strongly enhanced anti-HCMV efficacy, (iv) NF-κB reporter constructs, upregulated during HCMV replication, could be partially blocked by ART treatment, (v) ART activity analyzed in stable reporter cell clones indicated an inhibition of stimulated NF-κB but not CREB pathway, (vi) solid-phase immobilized ART was able to bind to NF-κB RelA/p65, and (vii) peptides within NF-κB RelA/p65 represent candidates of ART binding as analyzed by in silico docking and mass spectrometry. These novel findings open new prospects for the future medical use of ART and ART-related drug candidates.

Some popular medicinal plants and diseases of the Upper Palaeolithic in Western Georgia

ETHNOPHARMACOLOGICAL RELEVANCE

Palynological studies of cultural layers of cave sediments have been used in order to better understand traditional practices. The Upper Palaeolithic in Georgia (36,000-11,000 cal. BP) provides a rich source of such material. However, up to day from such sediments the identification of medicinal plants has hardly been achieved. Large quantities of pollen most notably from entomophilous taxa in fossil spectra can serve as a tool to identify traditionally important species. As these plants are used in modern popular medicine on the territory of Georgia (like Achillea millefolium L., Artemisia annua L., Artemisia absinthium L., Centaurea jacea L., Urtica dioica L.) can be served as an indirect evidence for their medicinal relevance from the Palaeolithic Period up to days. Their modern uses may point that the main diseases during the Upper Palaeolithic were the same as today.

MATERIALS AND METHODS

The Upper Palaeolithic sediments were studied palynologically come from four caves: Dzudzuana, Satsurblia, Kotias Klde and Bondi. Modern sediments were investigated from 6 caves. Fossil and modern samples were taken according to the standard procedure in palynology. The laboratory treatment was carried out as follows: first, 50g of the sample was boiled in 10% KOH. At the second stage, centrifuging of the material in cadmium liquid was performed. At the final stage, acetolysis treatment was used.

RESULTS

Pollen of A. absinthium L. (Asteraceae), A. annua L. (Asteraceae), A. millefolium L. (Asteraceae), C. jacea L. (Asteraceae), and U. dioica L. (Urticaceae) are identified to species level. This species are not edible and are popular in present-day folk medicine. In the Upper Palaeolithic layers, significant amounts of studies species pollen were recorded in the cave, likely due to their flowering branches being brought in by humans for use. Detailed consideration of the pharmacological characteristics of the examined species showed that almost all of them have anti-inflammatory, antibacterial, antimicrobial and antipyretic activity.

CONCLUSION

The fossil pollen complex of medicinal herbs, dominated by A. millefolium and Artemisia (A. annua and A. absinthium), suggests that the ancient population living in the studied caves could have been prone to malaria, rheumatism and gastrointestinal diseases. In the Upper Palaeolithic, the population inhabiting cave sites might have suffered from gout and callouses.

Inhibition of human cytomegalovirus replication by artemisinins: effects mediated through cell cycle modulation

Artemisinin-derived monomers and dimers inhibit human cytomegalovirus (CMV) replication in human foreskin fibroblasts (HFFs). The monomer artesunate (AS) inhibits CMV at micromolar concentrations, while dimers inhibit CMV replication at nanomolar concentrations, without increased toxicity in HFFs. We report on the variable anti-CMV activity of AS compared to the consistent and reproducible CMV inhibition by dimer 606 and ganciclovir (GCV). Investigation of this phenomenon revealed that the anti-CMV activity of AS correlated with HFFs synchronized to the G0/G1 stage of the cell cycle. In contact-inhibited serum-starved HFFs or cells arrested at early/late G1 with specific checkpoint regulators, AS and dimer 606 efficiently inhibited CMV replication. However, in cycling HFFs, in which CMV replication was productive, virus inhibition by AS was significantly reduced, but inhibition by dimer 606 and GCV was maintained. Cell cycle analysis in noninfected HFFs revealed that AS induced early G1 arrest, while dimer 606 partially blocked cell cycle progression. In infected HFFs, AS and dimer 606 prevented the progression of cell cycle toward the G1/S checkpoint. AS reduced the expression of cyclin-dependent kinases (CDK) 2, 4, and 6 in noninfected cycling HFFs, while the effect of dimer 606 on these CDKs was moderate. Neither compound affected CDK expression in noninfected contact-inhibited HFFs. In CMV-infected cells, AS activity correlated with reduced CDK2 levels. CMV inhibition by AS and dimer 606 also correlated with hypophosphorylation (activity) of the retinoblastoma protein (pRb). AS activity was strongly associated with pRb hypophosphorylation, while its reduced anti-CMV activity was marked by pRb phosphorylation. Roscovitine, a CDK2 inhibitor, antagonized the anti-CMV activities of AS and dimer 606. These data suggest that cell cycle modulation through CDKs and pRb might play a role in the anti-CMV activities of artemisinins. Proteins involved in this modulation may be identified and targeted for CMV inhibition.

Therapeutics to prevent congenital cytomegalovirus during pregnancy: what is available now and in the future?

Human cytomegalovirus (CMV) is the leading non-genetic cause of fetal malformation in developed countries. Congenital CMV infection can cause serious clinical sequelae, and in severe cases result in fetal or neonatal death. Despite the clinical and social importance of congenital CMV there is currently no standardised management strategy to prevent or treat maternal/fetal CMV infection during pregnancy and no evidence-based therapeutic for prenatally diagnosed CMV infection or disease. For pregnant women with a primary CMV infection during pregnancy, standard medical practise remains to offer no treatment at all or the option to terminate pregnancy. If intervention is requested, pregnant women may be offered a narrow range of medical therapies with limited evidence for efficacy and some with high risks of toxicity. However, there are several experimental and novel anti-CMV therapeutics currently being investigated that may provide a safe and effective therapeutic for use during pregnancy to prevent both fetal infection and reduce the risk of congenital CMV disease developing in the fetus once infected in utero.

Synthesis, characterization, and in vitro evaluation of artesunate-β-cyclodextrin conjugates as novel anti-cancer prodrugs

A novel series of artesunate-β-cyclodextrin (ATS-β-CD) conjugates, in which artesunate (ATS) was coupled covalently to one of the primary hydroxyl groups of β-cyclodextrin (β-CD) through amino bond formation, were synthesized and characterized by (1)H NMR, HRMS, 2D NMR (ROESY), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that the aqueous solubility of ATS-β-CD conjugates was 26-45 times better than that of free ATS. The cytotoxicity of the ATS-β-CD conjugates was evaluated on human colon cancer cell lines HCT116, LOVO, SW480, and HT-29, and the results indicated that ATS-2NβCD exhibited a very high cytotoxicity against HCT116, LOVO, and HT-29 with IC50 values of 0.58, 1.62, and 5.18μmol/L, respectively. In addition, the supposition of better cytotoxicity was further supported by the control experiment of fluorescent cyclodextrin.

Antiviral effects of artesunate on JC polyomavirus replication in COS-7 cells

The human JC polyomavirus (JCPyV) causes the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). A growing number of patients with induced or acquired immunosuppression are at risk for infection, and no effective antiviral therapy is presently available. The widely used antimalarial drug artesunate has shown broad antiviral activity in vitro but limited clinical success. The aim of this study was to investigate the effect of artesunate on JCPyV replication in vitro. The permissivity for JCPyV MAD-4 was first compared in four cell lines, and the monkey kidney cell line COS-7 was selected. Artesunate caused a concentration-dependent decrease in the extracellular JCPyV DNA load 96 h postinfection, with a 50% effective concentration (EC50) of 2.9 μM. This effect correlated with a decreased expression of capsid protein VP1 and a reduced release of infectious viral progeny. For concentrations of <20 μM, transient reductions in cellular DNA replication and proliferation were seen, while for higher concentrations, some cytotoxicity was detected. A selective index of 16.6 was found when cytotoxicity was calculated based on cellular DNA replication in the mock-infected cells, but interestingly, cellular DNA replication in the JCPyV-infected cells was more strongly affected. In conclusion, artesunate is efficacious in inhibiting JCPyV replication at micromolar concentrations, which are achievable in plasma. The inhibition at EC50 probably reflects an effect on cellular proteins and involves transient cytostatic effects. Our results, together with the favorable distribution of the active metabolite dihydroartemisinin to the central nervous system, suggest a potential use for artesunate in patients with PML.