Evaluation of the antiviral activity of anthraquinones, anthrones and anthraquinone derivatives against human cytomegalovirus

New insights into the interaction of emodin with lipid membranes

Emodin is a natural anthraquinone derivative found in nature, widely known as an herbal medicine. Here, the partition, location, and interaction of emodin with lipid membranes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) are experimentally investigated with different techniques. Our studies have considered the neutral form of emodin (EMH) and its anionic/deprotonated form (EM-), and their interaction with a more and less packed lipid membrane, DMPC at the gel and fluid phases, respectively. Though DSC results indicate that the two species, EMH and EM-, similarly disrupt the packing of DMPC bilayers, spin labels clearly show that EMH causes a stronger bilayer disruption, both in gel and fluid DMPC. Fluorescence spectroscopy shows that both EMH and EM- have a high affinity for DMPC: the binding of EM- to both gel and fluid DMPC bilayers was found to be quite similar, and similar to that of EMH to gel DMPC, Kp = (1.4 ± 0.3)x103. However, EMH was found to bind twice more strongly to fluid DMPC bilayers, Kp = (3.2 ± 0.3)x103. Spin labels and optical absorption spectroscopy indicate that emodin is located close to the lipid bilayer surface, and suggest that EM- is closer to the lipid/water interface than EMH, as expected. The present studies present a relevant contribution to the current understanding of the effect the two species of emodin, EMH and EM-, present on different microregions of an organism, as local pH values can vary significantly, can cause in a neutral lipid membrane, either more or less packed, liked gel and fluid DMPC, respectively, and could be extended to lipid domains of biological membranes.

Construction of recombinant fluorescent LSDV for high-throughput screening of antiviral drugs

Lumpy skin disease virus (LSDV) infection is a major socio-economic issue that seriously threatens the global cattle-farming industry. Here, a recombinant virus LSDV-ΔTK/EGFP, expressing enhanced green fluorescent protein (EGFP), was constructed with a homologous recombination system and applied to the high-throughput screening of antiviral drugs. LSDV-ΔTK/EGFP replicates in various kidney cell lines, consistent with wild-type LSDV. The cytopathic effect, viral particle morphology, and growth performance of LSDV-ΔTK/EGFP are consistent with those of wild-type LSDV. High-throughput screening allowed to identify several molecules that inhibit LSDV-ΔTK/EGFP replication. The strong inhibitory effect of theaflavin on LSDV was identified when 100 antiviral drugs were screened in vitro. An infection time analysis showed that theaflavin plays a role in the entry of LSDV into cells and in subsequent viral replication stages. The development of this recombinant virus will contribute to the development of LSDV-directed antiviral drugs and the study of viral replication and mechanisms of action.

Current Advances in Japanese Encephalitis Virus Drug Development

Japanese encephalitis virus (JEV) belongs to the Flaviviridae family and is a representative mosquito-borne flavivirus responsible for acute encephalitis and meningitis in humans. Despite the availability of vaccines, JEV remains a major public health threat with the potential to spread globally. According to the World Health Organization (WHO), there are an estimated 69,000 cases of JE each year, and this figure is probably an underestimate. The majority of JE victims are children in endemic areas, and almost half of the surviving patients have motor or cognitive sequelae. Thus, the absence of a clinically approved drug for the treatment of JE defines an urgent medical need. Recently, several promising and potential drug candidates were reported through drug repurposing studies, high-throughput drug library screening, and de novo design. This review focuses on the historical aspects of JEV, the biology of JEV replication, targets for therapeutic strategies, a target product profile, and drug development initiatives.

Antiviral, antioxidant, and anti-inflammatory activities of rhein against white spot syndrome virus infection in red swamp crayfish (Procambarus clarkii)

IMPORTANCE

Aquaculture is essential for ensuring global food security by providing a significant source of animal protein. However, the spread of the white spot syndrome virus (WSSV) has resulted in considerable economic losses in crustacean industries. In this study, we evaluated the antiviral activity of rhein, the primary bioactive component of Rheum palmatum L., against WSSV infection, and many pathological aspects of WSSV were also described for the first time. Our mechanistic studies indicated that rhein effectively arrested the replication of WSSV in crayfish by modulating innate immunity to inhibit viral gene transcription. Furthermore, we observed that rhein attenuated WSSV-induced oxidative and inflammatory stresses by regulating the expression of antioxidant and anti-inflammatory-related genes while enhancing innate immunity by reducing total protein levels and increasing phosphatase activity. Our findings suggest that rhein holds great promise as a potent antiviral agent for the prevention and treatment of WSSV in aquaculture.

Synthesis of novel rhodamine type Anthrone Spiro-lactam (ASL) analogues and evaluation of antiviral activity against dengue and chikungunya viruses

A series of Rhodamine type Anthrone-Spirolactam (ASL) derivatives Benzylimin-Anthrone-Spirolactam (ASL-1 to ASL-10) and Benzamide-Anthrone-Spirolactam (ASL-11 and ASL-12) were synthesized via a simple condensation reaction between Anthrone Spiro-lactamine (2) and various aromatic aldehyde and acyl chlorides respectively. Since rhodamine-based compounds were reported to have antiviral activity, the ASL derivatives were examined for in vitro antiviral activity against dengue and chikungunya viruses. Among all the analogues, ASL-3, ASL-6, ASL-7, ASL-8, ASL-9 and ASL-10 were the most potent against dengue virus (DENV) and exerted around one log reduction in virus titre under post-treatment conditions. At the same time ASL-3 was effective under co-treatment conditions. Two analogues ASL-6 and ASL-12 exerted anti-chikungunya virus (CHIKV) activity under post-treatment conditions. In silico docking studies revealed that the ASL derivatives interacted with the proteins of DENV and CHIKV. Together, the results suggest the anti-DENV and CHIKV activity of ASL derivatives which may be exploited further for therapeutic purposes.

Thioxothiazolo[3,4-a]quinazoline derivatives inhibit the human cytomegalovirus alkaline nuclease

Human cytomegalovirus (HCMV, human herpesvirus 5) is an opportunistic pathogen responsible for serious disease in immunocompromised patients. Current antiviral therapies rely predominantly on drugs interfering with viral DNA replication and packaging. However, the serious side effects of existing drugs and the emergence of drug resistance indicate the need for new targets for anti-HCMV therapy. One such target is the viral alkaline nuclease (AN), an enzyme highly conserved among the Herpesviridae. In this study, we validated the HCMV AN, encoded by the viral UL98 open reading frame, as a drug target by demonstrating that a UL98-deficient HCMV mutant is severely attenuated and shows a reduced ability to spread in cell culture. We established a fluorescence-based enzyme assay suitable for high-throughput screening and used it on a small-molecule compound library. The most promising hit, a thioxothiazolo[3,4-a]quinazoline derivative, blocked AN activity in vitro and inhibited HCMV replication in plaque reduction (PRA) and fluorescence reduction assays (FRA). Several derivatives of the hit compound were tested, some of which had similar or better inhibitory activities. The most potent derivative of hit scaffold A, compound AD-51, inhibited HCMV replication with a 50% effective concentrations (EC50) of 0.9 μM in the FRA and 1.1 μM in the PRA. AD-51 was also active against ganciclovir, foscarnet, and letermovir-resistant HCMVs. Moreover, it inhibited herpes simplex virus, Kaposi's sarcoma-associated herpesvirus, and murine CMV, a mouse virus serving as a model for HCMV. These results suggest that thioxothiazolo[3,4-a]quinazoline derivatives are a new class of herpesvirus inhibitors targeting the viral AN.

Emodin and rhapontigenin inhibit the replication of African swine fever virus by interfering with virus entry

Africa swine fever (ASF) is a highly pathogenic contagion caused by African swine fever virus (ASFV), which not only affects the development of domestic pig industry, but also causes huge losses to the world agricultural economy. Vaccine development targeting ASFV remains elusive, which leads to severe difficulties in disease prevention and control. Emodin (EM) and rhapontigenin (RHAG), which are extracted from the dried rhizome of Polygonum knotweed, have various biological properties such as anti-neoplastic and anti-bacterial activities, but no studies have reported that they have anti-ASFV effects. This study discovered that EM and RHAG at different concentrations had a significant dose-dependent inhibitory effect on the ASFV GZ201801 strain in porcine alveolar macrophages (PAMs), and at the specified concentration, EM and RHAG showed continuous inhibition at 24 h, 48 h and 72 h. Not only did they strongly impact virion attachment and internalization, but also inhibit the early stages of ASFV replication. Further research proved that the expression level of Rab 7 protein was reduced by EM and RHAG, and treatments with EM and RHAG induced the accumulation of free cholesterol in endosomes and inhibited endosomal acidification, which prevented the virus from escaping and shelling from late endosomes. This study summarized the application of EM and RHAG in inhibiting ASFV replication in-vitro. Similarly, EM and RHAG targeted Rab 7 in the viral endocytosis pathway, inhibited viral infection, and induced the accumulation of cholesterol in the endosomes and the acidification of the endosomes to inhibit uncoating. A reference could be made to the results of this study when developing antiviral drugs and vaccines.

Identification of natural compounds as SARS-CoV-2 inhibitors via molecular docking and molecular dynamic simulation

Background

Base mutations increase the contagiousness and transmissibility of the Delta and Lambda strains and lead to the severity of the COVID-19 pandemic. Molecular docking and molecular dynamics (MD) simulations are frequently used for drug discovery and relocation. Small molecular compounds from Chinese herbs have an inhibitory effect on the virus. Therefore, this study used computational simulations to investigate the effects of small molecular compounds on the spike (S) protein and the binding between them and angiotensin-converting enzyme 2 (ACE2) receptors.

Methods

In this study, molecular docking, MD simulation, and protein-protein analysis were used to explore the medicinal target inhibition of Chinese herbal medicinal plant chemicals on SARS-CoV-2. 12,978 phytochemicals were screened against S proteins of SARS-CoV-2 Lambda and Delta mutants.

Results

Molecular docking showed that 65.61% and 65.28% of the compounds had the relatively stable binding ability to the S protein of Lambda and Delta mutants (docking score ≤ -6). The top five compounds with binding energy with Lambda and Delta mutants were clematichinenoside AR2 (-9.7), atratoglaucoside,b (-9.5), physalin b (-9.5), atratoglaucoside, a (-9.4), Ochnaflavone (-9.3) and neo-przewaquinone a (-10), Wikstrosin (-9.7), xilingsaponin A (-9.6), ardisianoside G (-9.6), and 23-epi-26-deoxyactein (-9.6), respectively. Four compounds (Casuarictin, Heterophylliin D, Protohypericin, and Glansrin B) could interact with S protein mutation sites of Lambda and Delta mutants, respectively, and MD simulation results showed that four plant chemicals and spike protein have good energy stable complex formation ability. In addition, protein-protein docking was carried out to evaluate the changes in ACE2 binding ability caused by the formation of four plant chemicals and S protein complexes. The analysis showed that the binding of four plant chemicals to the S protein could reduce the stability of the binding to ACE2, thereby reducing the replication ability of the virus.

Conclusion

To sum up, the study concluded that four phytochemicals (Casuarictin, Heterophylliin D, Protohypericin, and Glansrin B) had significant effects on the binding sites of the SARS-CoV-2 S protein. This study needs further in vitro and in vivo experimental validation of these major phytochemicals to assess their potential anti-SARS-CoV-2. Graphical abstract.

Comparative Analysis of the Efficiency of Medicinal Plants for the Treatment and Prevention of COVID-19

The COVID-19 pandemic has once again prompted people to resort to the remedies of folk and alternative medicine. Medicinal plants, because of their chemical composition, pharmacological properties, and the action of biologically active substances, can stop and relieve the symptoms of the disease. The purpose of the work is a comparative flora analysis of medicinal plants to identify the most prospective plant and further production of a remedy for the avoidance, treatment, and rehabilitation of COVID-19. The search for prospective medicinal plants was performed by analyzing the literature in online databases: Web of Science, Scopus, Google Scholar, and PubMed, including official WHO media sites. According to recent studies related to COVID-19, a significant number of medicinal plants with anti-inflammatory, antiviral, and immunostimulatory effects have been identified. A comparative study of nine medicinal plants was conducted to determine the most suitable medicinal plant to treat coronavirus infection. According to the results of the comparative analysis, Chamaenerion angustifolium Seg. showed itself as the most prospective medicinal plant with the greatest pharmacological effect compared with other types of medicinal plants. Its therapeutic properties allow physiological relief of 18 symptoms of coronavirus infection. It is advisable to conduct further clinical trials for the treatment and rehabilitation of COVID-19 using preparations from this plant.

Microbial Biosynthesis of Chrysazin Derivatives in Recombinant Escherichia coli and Their Biological Activities

Anthraquinone and its derivatives show remarkable biological properties such as anticancer, antibacterial, antifungal, and antiviral activities. Hence, anthraquinones derivatives have been of prime interest in drug development. This study developed a recombinant Escherichia coli strain to modify chrysazin to chrysazin-8-O-α-l-rhamnoside (CR) and chrysazin-8-O-α-l-2′-O-methylrhamnoside (CRM) using rhamnosyl transferase and sugar-O-methyltransferase. Biosynthesized CR and CRM were structurally characterized using HPLC, high-resolution mass spectrometry, and various nuclear magnetic resonance analyses. Antimicrobial effects of chrysazin, CR, and CRM against 18 superbugs, including 14 Gram-positive and 4 Gram-negative pathogens, were investigated. CR and CRM exhibited antimicrobial activities against nine pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) in a disk diffusion assay at a concentration of 40 µg per disk. There were MIC and MBC values of 7.81−31.25 µg/mL for CR and CRM against methicillin-sensitive S. aureus CCARM 0205 (MSSA) for which the parent chrysazin is more than >1000 µg/mL. Furthermore, the anti-proliferative properties of chrysazin, CR, and CRM were assayed using AGS, Huh7, HL60, and HaCaT cell lines. CR and CRM showed higher antibacterial and anticancer properties than chrysazin.

Influence of seasonal and geographic variation on the anti-HSV-1 properties and chlorogenic acids content of Helichrysum aureonitens Sch. Bip

Pharmacological studies conducted in the past revealed the potential source of medicinal plants in the development of novel medicines. The phenolic contents of medicinal plants containing chlorogenic acids (CGA) have been linked to a variety of therapeutic effects, especially antiviral activity. Helichrysum aureonitens is a medicinal plant which has been reported to contain chlorogenic acids compounds and has also shown antiviral activities against a number of virus species including Herpes Simplex Virus-1 (HSV-1). In this study, the aim was to determine both the influence of seasonal variation and locality on the antiviral properties of H. aureonitens. Since chlorogenic acids have been reported as potent antiviral compounds, these compounds were targeted to determine the effects of locality and seasonal change on the chlorogenic acid profile, and subsequent antiviral activity. The ultra-performance liquid chromatography-quadrupole time-of-flight mass spectroscopy (UPLC-qTOF-MS) was employed to determine the metabolic profile variations of three derivatives of chlorogenic acids-caffeoylquinic acid (CQA), dicaffeoylquinic acid (DCQA) and tricaffeoylquinic acid (TCQA) in the harvested plants growing in two diverse geographical climates and two different seasons (spring and autumn). Using the cytopathic effect (CPE) reduction approach, twenty-six samples of the plants’ leaves and stems collected during spring and autumn at Telperion nature reserve in Mpumalanga and Wakefield farm, Midlands in KwaZulu-Natal region of South Africa were evaluated for anti-HSV activity. The MTT assay was used for the cytotoxicity evaluation of the extracts prior to antiviral determination. Seventeen (mostly spring collections) of the twenty-six extracts examined were found to have considerable anti-HSV activity as measured by a reduction in tissue culture infectious dose (TCID₅₀) of less than 10⁵. The UPLC-qTOF-MS result revealed that dicaffeoylquinic acid (DCQA) is the most abundant, with higher concentrations in both regions and seasons. 3-CQA was also shown to be the most abundant isomer of caffeoylquinic acid in this investigation.

Promising Role of Emodin as Therapeutics to Against Viral Infections

Emodin is an anthraquinone derivative that is widely present in natural plants and has a wide spectrum of pharmacological effects, such as antibacterial, anti-inflammatory, anti-fibrotic and anticancer and so on. Through reviewing studies on antiviral effect of emodin in the past decades, we found that emodin exhibits ability of inhibiting the infection and replication of more than 10 viruses in vitro and in vivo, including herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), coxsackievirus B (CVB), hepatitis B virus (HBV), influenza A virus (IAV), SARS-CoV, viral haemorrhagic septicaemia rhabdovirus (VHSV), enterovirus 71 (EV71), dengue virus serotype 2 (DENV-2) and Zika virus (ZIKV). Therefore, this review aims to summarize the antiviral effect of emodin, in order to provide reference and hopes to support the further investigations.

Crystal structure, Hirshfeld surface and computational study of 1-(9,10-dioxo-9,10-dihydroanthracen-1-yl)-3-propanoylthiourea

In the title compound, the thio­urea chromophore is planar to an r.m.s deviation of 0.032 Å with the thiol­ate sulfur atom being the most deviated. Bifurcated N—H⋯O intra­molecular hydrogen bonds result in an S(6) supra­molecular synthon. In the crystal, mol­ecules are linked by N—H⋯O inter­molecular hydrogen-bonding inter­actions and stabilized by C—H⋯π and π–π inter­actions.

The title compound, C₁₈H₁₄N₂O₃S, crystallizes in the ortho­rhom­bic crystal system and Pbca space group. The thio­urea chromophore is planar to an r.m.s deviation of 0.032 Å with the thiol­ate sulfur atom being the most deviated. Bifurcated N—H⋯O intra­molecular hydrogen bonds result in an S(6) supra­molecular synthon. In the crystal, mol­ecules are linked by N—H⋯O inter­molecular hydrogen-bonding inter­actions and stabilized by C—H⋯π and π–π inter­actions. Hirshfeld surface analysis and fingerprint plot indicate the H⋯H inter­molecular contacts as the highest contributor to the overall surface contacts (38%) and this is supported by the high dispersive and electrostatic inter­action energies.

Preparation and Characterization of ACE2 Receptor Inhibitor-Loaded Chitosan Hydrogels for Nasal Formulation to Reduce the Risk of COVID-19 Viral Infection

The COVID-19 virus is spread by pulmonary droplets. Its high infectivity is caused by the high-affinity binding of the viral spike protein to the ACE2 receptors on the surface of respiratory epithelial cell membranes. The proper hydration of nasal mucosa plays an essential role in defense of bacterial and viral infections. Therefore, a nasal formulation, which can moisture the nasal mucosa and contains the ACE2 receptor inhibitor, can reduce the risk of COVID-19 infection. This article presents a systematic study of the preparation of chitosan hydrogels with dicarboxylic acids (malic and glutaric acid) and their detailed characterization (Fourier transform infrared spectroscopy, determination of cross-linking efficiency, rheological studies, thermal analysis, and swelling kinetics). The results confirm that chemically cross-linked chitosan hydrogels can be synthesized using malic or glutaric acid without additives or catalysts. The adsorption capacity of hydrogels for three different ACE2 inhibitors, as APIs, has also been investigated. The API content of hydrogels and their mucoadhesive property can provide an excellent basis to use the hydrogels for the development of a nasal formulation in order to reduce the risk of SARS-CoV 2 infection.

Naturally occurring anthraquinones as potential inhibitors of SARS-CoV-2 main protease: an integrated computational study

The novel coronavirus disease (COVID-19) has spread throughout the globe, affecting millions of people. The World Health Organization (WHO) has declared this infectious disease a pandemic. At present, several clinical trials are going on to identify possible drugs for treating this infection. SARS-CoV-2 M^pro is one of the most critical drug targets for the blockage of viral replication. The aim of this study was to identify potential natural anthraquinones that could bind to the active site of SARS-CoV-2 main protease and stop the viral replication. Blind molecular docking studies of 13 anthraquinones and one control drug (Boceprevir) with SARS-CoV-2 M^pro were carried out using the SwissDOCK server, and alterporriol-Q that showed the highest binding affinity towards M^pro were subjected to molecular dynamics simulation studies. This study indicated that several antiviral anthraquinones could prove to be effective inhibitors for SARS-CoV-2 M^pro of COVID-19 as they bind near the active site having the catalytic dyad, HIS41 and CYS145 through non-covalent forces. The anthraquinones showed less inhibitory potential as compared to the FDA-approved drug, boceprevir. Among the anthraquinones studied, alterporriol-Q was found to be the most potent inhibitor of SARS-CoV-2 M^pro. Further, MD simulation studies for M^pro- alterporriol-Q system suggested that alterporriol-Q does not alter the structure of M^pro to a significant extent. Considering the impact of COVID-19, identification of alternate compounds like alterporriol-Q that could inhibit the viral infection will help in accelerating the process of drug discovery.

In Vitro Anticancer Screening and Preliminary Mechanistic Study of A-Ring Substituted Anthraquinone Derivatives

Anthraquinone derivatives exhibit various biological activities, e.g., antifungal, antibacterial and in vitro antiviral activities. They are naturally produced in many fungal and plant families such as Rhamnaceae or Fabaceae. Furthermore, they were found to have anticancer activity, exemplified by mitoxantrone and pixantrone, and many are well known redox-active compounds. In this study, various nature inspired synthetic anthraquinone derivatives were tested against colon, prostate, liver and cervical cancer cell lines. Most of the compounds exhibit anticancer effects against all cell lines, therefore the compounds were further studied to determine their IC₅₀-values. Of these compounds, 1,4-bis(benzyloxy)-2,3-bis(hydroxymethyl)anthracene-9,10-dione (4) exhibited the highest cytotoxicity against PC3 cells and was chosen for a deeper look into its mechanism of action. Based on flow cytometry, the compound was proven to induce apoptosis through the activation of caspases and to demolish the ROS/RNS and NO equilibrium in the PC3 cell line. It trapped cells in the G2/M phase. Western blotting was performed for several proteins related to the effects observed. Compound 4 enhanced the production of PARP and caspase-3. Moreover, it activated the conversion of LC3A/B-I to LC3A/B-II showing that also autophagy plays a role in its mechanism of action, and it caused the phosphorylation of p70 s6 kinase.

Synthesis of rhein and diacerein: a chemoenzymatic approach using anthrol reductase of Talaromyces islandicus

Herein, we report two methods for the synthesis of the osteoarthritis drug rhein and its prodrug diacerein using a chemoenzymatic approach. The strategy relies on the use of an NADPH-dependent anthrol reductase of Talaromyces islandicus (ARti-2), which mediates the regioselective and reductive deoxygenation of anthraquinones. The work further implies similar biosynthesis of rhein in fungi.

Antiviral Activities of Halogenated Emodin Derivatives against Human Coronavirus NL63

The current COVID-19 outbreak has highlighted the need for the development of new vaccines and drugs to combat Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2). Recently, various drugs have been proposed as potentially effective against COVID-19, such as remdesivir, infliximab and imatinib. Natural plants have been used as an alternative source of drugs for thousands of years, and some of them are effective for the treatment of various viral diseases. Emodin (1,3,8-trihydroxy-6-methylanthracene-9,10-dione) is a biologically active anthraquinone with antiviral activity that is found in various plants. We studied the selectivity of electrophilic aromatic substitution reactions on an emodin core (halogenation, nitration and sulfonation), which resulted in a library of emodin derivatives. The main aim of this work was to carry out an initial evaluation of the potential to improve the activity of emodin against human coronavirus NL63 (HCoV-NL63) and also to generate a set of initial SAR guidelines. We have prepared emodin derivatives which displayed significant anti-HCoV-NL63 activity. We observed that halogenation of emodin can improve its antiviral activity. The most active compound in this study was the iodinated emodin analogue E_3I, whose anti-HCoV-NL63 activity was comparable to that of remdesivir. Evaluation of the emodin analogues also revealed some unwanted toxicity to Vero cells. Since new synthetic routes are now available that allow modification of the emodin structure, it is reasonable to expect that analogues with significantly improved anti-HCoV-NL63 activity and lowered toxicity may thus be generated.

Natural Products and Their Derivatives against Human Herpesvirus Infection

Herpesviruses establish long-term latent infection for the life of the host and are known to cause numerous diseases. The prevalence of viral infection is significantly increased and causes a worldwide challenge in terms of health issues due to drug resistance. Prolonged treatment with conventional antiviral drugs is more likely to develop drug-resistant strains due to mutations of thymidine nucleoside kinase or DNA polymerase. Hence, the development of alternative treatments is clearly required. Natural products and their derivatives have played a significant role in treating herpesvirus infection rather than nucleoside analogs in drug-resistant strains with minimal undesirable effects and different mechanisms of action. Numerous plants, animals, fungi, and bacteria-derived compounds have been proved to be efficient and safe for treating human herpesvirus infection. This review covers the natural antiherpetic agents with the chemical structural class of alkaloids, flavonoids, terpenoids, polyphenols, anthraquinones, anthracyclines, and miscellaneous compounds, and their antiviral mechanisms have been summarized. This review would be helpful to get a better grasp of anti-herpesvirus activity of natural products and their derivatives, and to evaluate the feasibility of natural compounds as an alternative therapy against herpesvirus infections in humans.

Glycan-Lectin Interactions in Cancer and Viral Infections and How to Disrupt Them

Glycan-lectin interactions play an essential role in different cellular processes. One of their main functions is involvement in the immune response to pathogens or inflammation. However, cancer cells and viruses have adapted to avail themselves of these interactions. By displaying specific glycosylation structures, they are able to bind to lectins, thus promoting pathogenesis. While glycan-lectin interactions promote tumor progression, metastasis, and/or chemoresistance in cancer, in viral infections they are important for viral entry, release, and/or immune escape. For several years now, a growing number of investigations have been devoted to clarifying the role of glycan-lectin interactions in cancer and viral infections. Various overviews have already summarized and highlighted their findings. In this review, we consider the interactions of the lectins MGL, DC-SIGN, selectins, and galectins in both cancer and viral infections together. A possible transfer of ways to target and disrupt them might lead to new therapeutic approaches in different pathological backgrounds.

Anthraquinones as Potential Antibiofilm Agents Against Methicillin-Resistant Staphylococcus aureus

Biofilms formed by methicillin-resistant Staphylococcus aureus (MRSA) are one of the contributing factors to recurrent nosocomial infection in humans. There is currently no specific treatment targeting on biofilms in clinical trials approved by FDA, and antibiotics remain the primary therapeutic strategy. In this study, two anthraquinone compounds isolated from a rare actinobacterial strain Kitasatospora albolonga R62, 3,8-dihydroxy-l-methylanthraquinon-2-carboxylic acid (1) and 3,6,8-trihydroxy-1-methylanthraquinone-2-carboxylic acid (2), together with their 10 commercial analogs 3–12 were evaluated for antibacterial and antibiofilm activities against MRSA, which led to the discovery of two potential antibiofilm anthraquinone compounds anthraquinone-2-carboxlic acid (6) and rhein (12). The structure-activity relationship analysis of these anthraquinones indicated that the hydroxyl group at the C-2 position of the anthraquinone skeleton played an important role in inhibiting biofilm formation at high concentrations, while the carboxyl group at the same C-2 position had a great influence on the antibacterial activity and biofilm eradication activity. The results of crystal violet and methyl thiazolyl tetrazolium staining assays, as well as scanning electron microscope and confocal scanning laser microscopy imaging of compounds 6 and 12 treatment groups showed that both compounds could disrupt preformed MRSA biofilms possibly by killing or dispersing biofilm cells. RNA-Seq was subsequently used for the preliminary elucidation of the mechanism of biofilm eradication, and the results showed upregulation of phosphate transport-related genes in the overlapping differentially expressed genes of both compound treatment groups. Herein, we propose that anthraquinone compounds 6 and 12 could be considered promising candidates for the development of antibiofilm agents.

nCOV-19 peptides mass fingerprinting identification, binding, and blocking of inhibitors flavonoids and anthraquinone of Moringa oleifera and hydroxychloroquine

An rare pandemic of viral pneumonia occurs in December 2019 in Wuhan, China, which is now recognized internationally as Corona Virus Disease 2019 (COVID-19), the etiological agent classified as Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2). According to the World Health Organization (WHO), it has so far expanded to more than 213 countries/territories worldwide. Our study aims to find the viral peptides of SARS-COV-2 by peptide mass fingerprinting (PMF) in order to predict its novel structure and find an inhibitor for each viral peptide. For this reason, we calculated the mass of amino acid sequences translated from the SARS-CoV2 whole genome and identify the peptides that may be a target for inhibition. Molecular peptide docking with Moringa oleifera, phytochemicals (aqueous and ethanolic) leaf extracts of flavonoids (3.56 ± 0.03), (3.83 ± 0.02), anthraquinone (11.68 ± 0.04), (10.86 ± 0.06) and hydroxychloroquine present therapy of COVID-19 in Pakistan for comparative study. Results indicate that 15 peptides of SARS-CoV2 have been identified from PMF, which is then used as a selective inhibitor. The maximum energy obtained from AutoDock Vina for hydroxychloroquine is -5.1 kcal/mol, kaempferol (flavonoid) is -6.2 kcal/mol, and for anthraquinone -6 kcal/mol. Visualization of docking complex, important effects are observed regarding the binding of peptides to drug compounds. In conclusion, it is proposed that these compounds are effective antiviral agents against COVID-19 and can be used in clinical trials.Communicated by Ramaswamy H. Sarma.

Effect of Substitution of Hydrogen Atoms in the Molecules of Anthrone and Anthraquinone

The geometry of anthrone and anthraquinone-natural substances of plant origin-was investigated under the substitution of hydrogen atoms in side aromatic ring and, for anthrone, also in the central ring. A significant influence of substitution on geometry expressed by the angle between the side rings was shown. The geometry changes are connected with the changes of electron density and aromaticity of the anthrone and anthraquinone rings. The flexibility of the investigated compounds was confirmed by comparison of the optimized molecules and the molecules in the crystal state where the packing forces can influence the molecular geometry.

Anthraquinone: a promising scaffold for the discovery and development of therapeutic agents in cancer therapy

Cancer, characterized by uncontrolled malignant neoplasm, is a leading cause of death in both advanced and emerging countries. Although, ample drugs are accessible in the market to intervene with tumor progression, none are totally effective and safe. Natural anthraquinone (AQ) equivalents such as emodin, aloe-emodin, alchemix and many synthetic analogs extend their antitumor activity on different targets including telomerase, topoisomerases, kinases, matrix metalloproteinases, DNA and different phases of cell lines. Nano drug delivery strategies are advanced tools which deliver drugs into tumor cells with minimum drug leakage to normal cells. This review delineates the way AQ derivatives are binding on these targets by abolishing tumor cells to produce anticancer activity and purview of nanoformulations related to AQ analogs.

Effect of cassic acid on immunity and immune-reproductive genes transcription in Clarias gariepinus against Edwardsiella tarda

The present study was investigated the dietary administration of cassic acid (CA) on growth, innate immunity, transcription profiles of estrogen and follicle-stimulating hormones as well as lysozyme enzyme determined in Clarias gariepinus against Edwardsiella tarda. The weight gain (WG), protein efficacy ratio (PER), and feed conversion ratio (FCR) were significantly improved in infected fish fed dietary administration with CA at 5 and 10 mg kg^-1 diets. The survival is higher (96.7% and 98.3%) in the infected groups fed at 5 and 10 mg kg^-1 CA diets. The red (RBC) and white (WBC) blood cells, hemoglobin (Hb), and packed cell volume (PCV) was found significantly high in the infected fish feeding at 5 and 10 mg kg^-1 CA diets. Total protein and albumin were significantly increased with 5 and 10 mg kg^-1 CA diets among weeks 1-4 while the globulin and albumin: globulin ratio increased of these diet only after week 2. The phagocytic and respiratory burst activities were enhanced statistically the infected fish fed at 10 mg kg^-1 CA diet group whereas the production of superoxide anion (SOA) and nitric oxide (NO) were significantly increased at 5 and 10 mg kg^-1 CA diets. The lymphocyte proliferation and myeloperoxidase (MPO) activity were significantly high the infected fish when fed at 5 and 10 mg kg^-1 CA diets after 2nd week whereas the alternate complement activity (ACP), generation of reactive oxygen species (ROS), and lysozyme activity (Lyz) were observed at 5 and 10 mg kg^-1 CA diets among weeks 1-4. The accumulative mortality was 10% in infected fish fed at 1 and 5 mg kg^-1 CA diets whereas 15% mortality found with 10 mg kg^-1 CA diet. The highest levels of estrogen receptor alpha (ERα) mRNA expression found in gonad while the highest levels of follicle stimulating hormone-beta subunit (FSH-β) mRNA expression found in testis of the infected fish given at 5 and 10 mg kg^-1 CA diets. The up-regulation of chick-type lysozyme (c-Lyz) mRNA was observed at 5 and 10 mg kg^-1 CA diets after 2nd week while goose-type lysozyme (g-Lyz) mRNA was up-regulation amongst weeks 1-4 of these diets. The present study suggested that E. tarda challenged fish after feeding with 5 and 10 mg kg^-1 CA diets did not affect growth and hemato-biochemical parameter, but it enhanced nonspecific immune system and improving ERα, FSH-β, c-Lyz, and g-Lyz mRNA expression in C. gariepinus against E. tarda.

A novel β-cyclodextrin-rhein conjugate for improving the water solubility and bioavailability of rhein

Rhein is a potential antitumor agent, but the poor water-solubility restricts its clinical applicability. β-cyclodextrin-drug conjugates provide a possibility to improve the water-solubility of rhein and thereby enhance its bioavailability. A novel β-cyclodextrin-rhein conjugate (β-CD-RH) was synthesized by covalently link β-cyclodextrin with rhein through a 1,8-diamino-3,6-dioxaoctane linker. The structure of β-CD-RH was characterized by ¹H NMR, FT-IR, Maldi-tof MS etc. The inclusion style of β-CD-RH in water was detected by 2D NMR. The 2D ROESY spectrum provided details of the rhein moiety encapsulated in the β-CD cavity. The water-solubility of β-CD-RH is up to 3.24 μmol/mL β-CD-RH exhibited higher cytotoxicity than rhein and rhein/β-CD mixture against Hela cells. Our work provides a new way for the preparation of novel β-CD-drug conjugate.

Apoptotic effects of rhein through the mitochondrial pathways, two death receptor pathways, and reducing autophagy in human liver L02 cells

Rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid) is a major component of many medicinal herbs such as Rheum palmatum L. and Polygonum multiflorum. Despite being widely used, intoxication cases associated with rhein-containing herbs are often reported. Currently, there are no available reports addressing the effects of rhein on apoptosis in human liver L02 cells. Thus, the aim of this study is to determine the cytotoxic effects and the underlying mechanism of rhein on human normal liver L02 cells. In the present study, the methyl thiazolyl tetrazolium assay demonstrated that rhein decreased the viability of L02 cells in dose-dependent and time-dependent ways. Rhein was found to trigger apoptosis in L02 cells as shown by Annexin V-fluoresceine isothiocyanate (FITC) apoptosis detection kit and cell mitochondrial membrane potential (MMP) assay, with nuclear morphological changes demonstrated by Hoechst 33258 staining. Detection of intracellular superoxide dismutase activity, lipid oxidation (malondialdehyde) content, and reactive oxygen species (ROS) levels showed that apoptosis was associated with oxidative stress. Moreover, it was observed that the mechanism implicated in rhein-induced apoptosis was presumably via the death receptor pathway and the mitochondrial pathway, as illustrated by upregulation of TNF-α, TNFR1, TRADD, and cleaved caspase-3, and downregulation of procaspase-8, and it is suggested that rhein may increase hepatocyte apoptosis by activating the increase of TNF-α level. Meanwhile, rhein upregulates the expression of Bax and downregulates the expression of procaspase-9 and -3, and it is suggested that the mitochondrial pathway is activated and rhein-induced apoptosis may be involved. In addition, we also want to explore whether rhein-induced apoptosis is related to the autophagic changes induced by rhein. The results showed that rhein treatment increased P62 and decreased LC3-II and beclin-1, which means that autophagy was weakened. The results of our studies indicated that rhein induced caspase-dependent apoptosis via both the Fas death pathway and the mitochondrial pathway by generating ROS, and meanwhile the autophagy tended to weaken.

Anti-viral activity of culinary and medicinal mushroom extracts against dengue virus serotype 2: an in-vitro study

BACKGROUND

Dengue is a mosquito-borne viral infection that has become a major public health concern worldwide. Presently, there is no specific vaccine or treatment available for dengue viral infection.

METHODS

Lignosus rhinocerotis, Pleurotus giganteus, Hericium erinaceus, Schizophyllum commune and Ganoderma lucidium were selected for evaluation of their in-vitro anti-dengue virus serotype 2 (DENV-2) activities. Hot aqueous extracts (HAEs), ethanol extracts (EEs), hexane soluble extracts (HSEs), ethyl acetate soluble extracts (ESEs) and aqueous soluble extracts (ASEs) were prepared from the selected mushrooms. The cytotoxic effects of the extracts were evaluated by the MTT assay. The anti-DENV-2 activities of the extracts were evaluated in three different assays: simultaneous, attachment and penetration assays were perfomed using plaque reduction assays and RT-qPCR assays. The effect of the addition time on viral replication was assessed by the time of addition assay, and a virucidal assay was carried out to evaluate the direct effect of each mushroom extract on DENV-2. The chemical composition of glucans, and the protein and phenolic acid contents in the extracts were estimated.

RESULTS

We found that the HAEs and ASEs of L. rhinocerotis, P. giganteus, H. erinaceus and S. commune were the least toxic to Vero cells and showed very prominent anti-DENV2 activity. The 50% inhibitory concentration (IC₅₀) values of the ASEs ranged between 399.2-637.9 μg/ml, while for the HAEs the range was 312.9-680.6 μg/ml during simultaneous treatment. Significant anti-dengue activity was also detected in the penetration assay of ASEs (IC₅₀: 226.3-315.4 μg/ml) and HAEs (IC₅₀: 943.1-2080.2 μg/ml). Similarly, we observed a marked reduction in the expression levels of the ENV and NS5 genes in the simultaneous and penetration assays of the ASEs and HAEs. Time-of-addition experiments showed that the highest percent of anti-DENV2 activity was observed when the mushroom extracts were added immediately after virus adsorption. None of the extracts exhibited virucidal effect. Chemical composition analysis showed that the major components in the mushroom HAEs and ASEs were glucan (beta D-glucan) and proteins, however, there was no significant correlation between the anti-dengue activity and the concentration of glucans and proteins.

CONCLUSION

These findings demonstrated the potential of mushroom extracts as anti-dengue therapeutic agents with less toxic effects.

Anthraquinones and autophagy - Three rings to rule them all?

In order to overcome therapy resistance in cancer, scientists search in nature for novel lead structures for the development of improved chemotherapeutics. Anthraquinones belong to a class of tricyclic organic natural compounds with promising anti-cancer effects. Anthraquinone derivatives are rich in structural diversity, and exhibit pleiotropic properties, among which the modulation of autophagy seems promising in the context of overcoming cancer-therapy resistance. Among the most promising derivatives in this regard are emodin, aloe emodin, rhein, physcion, chrysophanol and altersolanol A. On the molecular level, these compounds target autophagy via different upstream pathways including the AKT/mTOR-axis and transcription of autophagy-related proteins. The role of autophagy is pro-survival as well as cell death-promoting, depending on derivatives and their cell type specificity. This review summarizes observed effects of anthraquinone derivatives on autophagy and discusses targeted pathways and crosstalks. A cumulative knowledge about this topic paves the way for further research on modes of action, and aids to find a therapeutic window of anthraquinones in cancer-therapy.

The Importance of Anthraquinone and Its Analogues and Molecular Docking Calculation

In drug-delivery systems containing nano-drug structures, targeting the tumorous tissue by anthraquinone molecules with high biological activity, and reaching and destroying tumors by their tumor-killing effect reveals remarkable results for the treatment of tumors. The various biological activities of anthraquinones and their derivatives depend on molecular conformation; hence, their intra-cell interaction mechanisms including deoxyribonucleic acid (DNA), ribonucleic acid (RNA), enzymes, and hormones. Computer-based drug design plays an important role in the design of drugs and the determination of goals for them. Molecular docking has been widely used in structure-based drug design. The effects of anthraquinone analogues in tumor cells as a result of their interaction with DNA strand has increased the number of studies done on them, and they have been shown to have a wide range of applications in chemistry, medicine, pharmacy, materials, and especially in the field of biomolecules.

Photodynamic Inactivation of Herpes Simplex Viruses

Herpes simplex virus (HSV) infections can be treated with direct acting antivirals like acyclovir and foscarnet, but long-term use can lead to drug resistance, which motivates research into broadly-acting antivirals that can provide a greater genetic barrier to resistance. Photodynamic inactivation (PDI) employs a photosensitizer, light, and oxygen to create a local burst of reactive oxygen species that inactivate microorganisms. The botanical plant extract Orthoquin^TM is a powerful photosensitizer with antimicrobial properties. Here we report that Orthoquin also has antiviral properties. Photoactivated Orthoquin inhibited herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) infection of target cells in a dose-dependent manner across a broad range of sub-cytotoxic concentrations. HSV inactivation required direct contact between Orthoquin and the inoculum, whereas pre-treatment of target cells had no effect. Orthoquin did not cause appreciable damage to viral capsids or premature release of viral genomes, as measured by qPCR for the HSV-1 genome. By contrast, immunoblotting for HSV-1 antigens in purified virion preparations suggested that higher doses of Orthoquin had a physical impact on certain HSV-1 proteins that altered protein mobility or antigen detection. Orthoquin PDI also inhibited the non-enveloped adenovirus (AdV) in a dose-dependent manner, whereas Orthoquin-mediated inhibition of the enveloped vesicular stomatitis virus (VSV) was light-independent. Together, these findings suggest that the broad antiviral effects of Orthoquin-mediated PDI may stem from damage to viral attachment proteins.

Secondary Metabolites from Escovopsis weberi and Their Role in Attacking the Garden Fungus of Leaf-Cutting Ants

The specialized, fungal pathogen Escovopsis weberi threatens the mutualistic symbiosis between leaf-cutting ants and their garden fungus (Leucoagaricus gongylophorus). Because E. weberi can overwhelm L. gongylophorus without direct contact, it was suspected to secrete toxins. Using NMR and mass spectrometry, we identified several secondary metabolites produced by E. weberi. E. weberi produces five shearinine-type indole triterpenoids including two novel derivatives, shearinine L and shearinine M, as well as the polyketides, emodin and cycloarthropsone. Cycloarthropsone and emodin strongly inhibited the growth of the garden fungus L. gongylophorous at 0.8 and 0.7 μmol, respectively. Emodin was also active against Streptomyces microbial symbionts (0.3 μmol) of leaf-cutting ants. Shearinine L instead did not affect the growth of L. gongylophorus in agar diffusion assays. However, in dual choice behavioral assays Acromyrmex octospinosus ants clearly avoided substrate treated with shearinine L for the garden fungus after a 2 d learning period, indicating that the ants quickly learn to avoid shearinine L.

Experimental and theoretical studies of emodin interacting with a lipid bilayer of DMPC

Emodin is one of the most abundant anthraquinone derivatives found in nature. It is the active principle of some traditional herbal medicines with known biological activities. In this work, we combined experimental and theoretical studies to reveal information about location, orientation, interaction and perturbing effects of Emodin on lipid bilayers, where we have taken into account the neutral form of the Emodin (EMH) and its anionic/deprotonated form (EM^-). Using both UV/Visible spectrophotometric techniques and molecular dynamics (MD) simulations, we showed that both EMH and EM^- are located in a lipid membrane. Additionally, using MD simulations, we revealed that both forms of Emodin are very close to glycerol groups of the lipid molecules, with the EMH inserted more deeply into the bilayer and more disoriented relative to the normal of the membrane when compared with the EM^-, which is more exposed to interfacial water. Analysis of several structural properties of acyl chains of the lipids in a hydrated pure DMPC bilayer and in the presence of Emodin revealed that both EMH and EM^- affect the lipid bilayer, resulting in a remarkable disorder of the bilayer in the vicinity of the Emodin. However, the disorder caused by EMH is weaker than that caused by EM^-. Our results suggest that these disorders caused by Emodin might lead to distinct effects on lipid bilayers including its disruption which are reported in the literature.

Rhein Induces Oxidative Stress and Apoptosis in Mouse Blastocysts and Has Immunotoxic Effects during Embryonic Development

Rhein, a glucoside chemical compound found in a traditional Chinese medicine derived from the roots of rhubarb, induces cell apoptosis and is considered to have high potential as an antitumor drug. Several previous studies showed that rhein can inhibit cell proliferation and trigger mitochondria-related or endoplasmic reticulum (ER) stress-dependent apoptotic processes. However, the side effects of rhein on pre- and post-implantation embryonic development remain unclear. Here, we show that rhein has cytotoxic effects on blastocyst-stage mouse embryos and induces oxidative stress and immunotoxicity in mouse fetuses. Blastocysts incubated with 5-20 μM rhein showed significant cell apoptosis, as well as decreases in their inner cell mass cell numbers and total cell numbers. An in vitro development assay showed that rhein affected the developmental potentials of both pre- and post-implantation embryos. Incubation of blastocysts with 5-20 μM rhein was associated with increased resorption of post-implantation embryos and decreased fetal weight in an embryo transfer assay. Importantly, in an in vivo model, intravenous injection of dams with rhein (1, 3, and 5 mg/kg body weight/day) for four days resulted in apoptosis of blastocyst-stage embryos, early embryonic developmental injury, and decreased fetal weight. Intravenous injection of dams with 5 mg/kg body weight/day rhein significantly increased the total reactive oxygen species (ROS) content of fetuses and the transcription levels of antioxidant proteins in fetal livers. Additional work showed that rhein induced apoptosis through ROS generation, and that prevention of apoptotic processes effectively rescued the rhein-induced injury effects on embryonic development. Finally, the transcription levels of the innate-immunity related genes, CXCL1, IL-1β and IL-8, were down-regulated in the fetuses of dams that received intravenous injections of rhein. These results collectively show that rhein has the potential to induce embryonic cytotoxicity and induce oxidative stress and immunotoxicity during the development of mouse embryos.

Application of HPLC-LTQ Orbitrap MS for metabolic profiles of Polygonum multiflora extract in rats

The root of Polygonum multiflorum (PM) is an important Chinese herbal medicine for treatment of various diseases. Extensive pharmacological studies have been conducted and demonstrated that it shows a wide range of bioactivities. Meanwhile, a considerable number of hepatotoxicity cases owing to oral administration of PM have been reported and have attracted great attention. However, the limited knowledge regarding the metabolism of PM restricts the deeper studies on its pharmacological/toxicological mechanism and therapeutic material basis. The present study aimed to develop a high-performance liquid chromatography coupled with a linear ion trap-Orbitrap hybrid mass spectrometry method for separation and identification of metabolites in rat urine and plasma after oral administration of PM. Based on the proposed strategy, metabolism profiles of PM in rats were proposed for the first time and 43 metabolites were characterized or tentatively identified. Phase II metabolism, such as glucuronidation and sulfation, are the principal pathways of the main components. These findings will be beneficial to further understanding of the pharmacological mechanism and pharmacodynamic material basis of PM.

Selective inhibition of monoamine oxidase A by purpurin, an anthraquinone

Monoamine oxidase (MAO) catalyzes the oxidation of monoamines that act as neurotransmitters. During a target-based screening of natural products using two isoforms of recombinant human MAO-A and MAO-B, purpurin (an anthraquinone derivative) was found to potently and selectively inhibit MAO-A, with an IC50 value of 2.50μM, and not to inhibit MAO-B. Alizarin (also an anthraquinone) inhibited MAO-A less potently with an IC50 value of 30.1μM. Furthermore, purpurin was a reversible and competitive inhibitor of MAO-A with a Ki value of 0.422μM. A comparison of their chemical structures suggested the 4-hydroxy group of purpurin might play an important role in its inhibition of MAO-A. Molecular docking simulation showed that the binding affinity of purpurin for MAO-A (-40.0kcal/mol) was higher than its affinity for MAO-B (-33.9kcal/mol), and that Ile 207 and Gly 443 of MAO-A were key residues for hydrogen bonding with purpurin. The findings of this study suggest purpurin is a potent, selective, reversible inhibitor of MAO-A, and that it be considered a new potential lead compound for development of novel reversible inhibitors of MAO-A (RIMAs).

Sennoside A, derived from the traditional chinese medicine plant Rheum L., is a new dual HIV-1 inhibitor effective on HIV-1 replication

BACKGROUND

Despite the availability of effective antiretroviral therapies, drugs for HIV-1 treatment with new mode of action are still needed. An innovative approach is aimed to identify dual HIV-1 inhibitors, small molecules that can inhibit two viral functions at the same time. Rhubarb, originated from Rheum palmatum L. and Rheum officinale Baill., is one of the earliest and most commonly used medicinal plants in Traditional Chinese Medicine (TCM) practice. We wanted to explore TCM for the identification of new chemical scaffolds with dual action abilities against HIV-1.

METHODS

R. palmatum L. and R. officinale Baill. extracts along with their main single isolated constituents anthraquinone derivatives were tested on both HIV-1 Reverse Transcriptase (RT)-associated DNA Polymerase (RDDP) and Ribonuclease H (RNase H) activities in biochemical assays. Active compounds were then assayed for their effects on HIV-1 mutated RTs, integrase (IN) and viral replication.

RESULTS

Both R. palmatum L. and R. officinale Baill. extracts inhibited the HIV-1 RT-associated RNase H activity. Among the isolated constituents, Sennoside A and B were effective on both RDDP and RNase H RT-associated functions in biochemical assays. Sennoside A was less potent when tested on K103N, Y181C, Y188L, N474A and Q475A mutated RTs, suggesting the involvement of two RT binding sites for its antiviral activity. Sennoside A affected also HIV-1 IN activity in vitro and HIV-1 replication in cell-based assays. Viral DNA production and time of addition studies showed that Sennoside A targets the HIV-1 reverse transcription process.

CONCLUSION

Sennoside A is a new scaffold for the development of HIV-1 dual RT inhibitors.

Stealth, biocompatible monoolein-based lyotropic liquid crystalline nanoparticles for enhanced aloe-emodin delivery to breast cancer cells: in vitro and in vivo studies

Recently, research has progressively highlighted on clues from conventional use of herbal medicines to introduce new anticancer drugs. Aloe-emodin (AE) is a herbal drug with promising anticancer activity. Nevertheless, its clinical utility is handicapped by its low solubility. For the first time, this study aims to the fabrication of surface-functionalized polyethylene glycol liquid crystalline nanoparticles (PEG-LCNPs) of AE to enhance its water solubility and enable its anticancer use. Developed AE-PEG-LCNPs were optimized via particle size and zeta potential measurements. Phase behavior, solid state characteristics, hemocompatibility, and serum stability of LCNPs were assessed. Sterile formulations were developed using various sterilization technologies. Furthermore, the potential of the formulations was investigated using cell culture, pharmacokinetics, biodistribution, and toxicity studies. AE-PEG-LCNPs showed particle size of 190 nm and zeta potential of −49.9, and PEGylation approach reduced the monoolein hemolytic tendency to 3% and increased the serum stability of the nanoparticles. Sterilization of liquid and lyophilized AE-PEG-LCNPs via autoclaving and γ-radiations, respectively, insignificantly affected the physicochemical properties of the nanoparticles. Half maximal inhibitory concentration of AE-PEG-LCNPs was 3.6-fold lower than free AE after 48 hours and their cellular uptake was threefold higher than free AE after 24-hour incubation. AE-PEG-LCNPs presented 5.4-fold increase in t_1/2 compared with free AE. Biodistribution and toxicity studies showed reduced AE-PEG-LCNP uptake by reticuloendothelial system organs and good safety profile. PEGylated LCNPs could serve as a promising nanocarrier for efficient delivery of AE to cancerous cells.

The Antiviral Agent Hypericin has in vitro Activity against HSV-1 Through Non-Specific Association with Viral and Cellular Membranes

The antiviral and virucidal compound, hypericin, was studied regarding its activity and possible mechanism against herpes simplex virus (HSV-1). It was determined that hypericin caused slight inhibition of viral adsorption to and penetration of Vero cells. Additionally, yield reduction assays suggested that hypericin was most effective against HSV-1 as a virucidal agent rather than as an intracellular antiviral agent. Fluorescence microscopy revealed that hypericin initially associated with cytoplasmic membranes and that over the course of time it became concentrated in intracellular membranous regions, probably the Golgi apparatus or endoplasmic reticulum (ER). These concentration events failed to inhibit glycosylation of either viral or cellular proteins and were effectively blocked by compounds which inhibit endocytosis or membrane cycling between the ER and Golgi. Based on fluorescence studies, it was determined that hypericin had non-specific affinity for protein and higher affinity for detergent and lipid. The evidence suggested that strong, non-specific association with membranes, both viral and cellular, are probably the basis of hypericin's virucidal and antiviral activity.

Transcriptomic analysis reveals distinct resistant response by physcion and chrysophanol against cucumber powdery mildew

Physcion and chrysophanol induce defense responses against powdery mildew in cucumbers. The combination of these two compounds has synergistic interaction against the disease. We performed RNA-seq on cucumber leaf samples treated with physcion and chrysophanol alone and with their combination. We generated 17.6 Gb of high-quality sequencing data (∼2 Gb per sample) and catalogued the expressions profiles of 12,293 annotated cucumber genes in each sample. We identified numerous differentially expressed genes that exhibited distinct expression patterns among the three treatments. The gene expression patterns of the Chr and Phy treatments were more similar to each other than to the Phy × Chr treatment. The Phy × Chr treatment induced the highest number of differentially expressed genes. This dramatic transcriptional change after Phy × Chr treatment leaves reflects that physcion combined with chrysophanol treatment was most closely associated with induction of disease resistance. The analysis showed that the combination treatment caused expression changes of numerous defense-related genes. These genes have known or potential roles in structural, chemical and signaling defense responses and were enriched in functional gene categories potentially responsible for cucumber resistance. These results clearly demonstrated that disease resistance in cucumber leaves was significantly influenced by the combined physcion and chrysophanol treatment. Thus, physcion and chrysophanol are appealing candidates for further investigation of the gene expression and associated regulatory mechanisms related to the defense response.

Anthraquinones and Derivatives from Marine-Derived Fungi: Structural Diversity and Selected Biological Activities

Anthraquinones and their derivatives constitute a large group of quinoid compounds with about 700 molecules described. They are widespread in fungi and their chemical diversity and biological activities recently attracted attention of industries in such fields as pharmaceuticals, clothes dyeing, and food colorants. Their positive and/or negative effect(s) due to the 9,10-anthracenedione structure and its substituents are still not clearly understood and their potential roles or effects on human health are today strongly discussed among scientists. As marine microorganisms recently appeared as producers of an astonishing variety of structurally unique secondary metabolites, they may represent a promising resource for identifying new candidates for therapeutic drugs or daily additives. Within this review, we investigate the present knowledge about the anthraquinones and derivatives listed to date from marine-derived filamentous fungi's productions. This overview highlights the molecules which have been identified in microorganisms for the first time. The structures and colors of the anthraquinoid compounds come along with the known roles of some molecules in the life of the organisms. Some specific biological activities are also described. This may help to open doors towards innovative natural substances.

Rhubarb decreased the systemic exposure of cyclosporine, a probe substrate of P-glycoprotein and CYP 3A

1. Rhubarb, rhizome of Rheum palmatum L. (RP), is an important herb in clinical Chinese medicine. 2. Cyclosporine (CSP) is an immunosuppressant with narrow therapeutic window. The oral bioavailability of CSP was associated with P-glycoprotein (P-gp) and CYP 3A4. CSP was used as a probe substrate to investigate the in vivo modulation effects of RP on P-gp and CYP 3A. 3. Rats were orally administered 2.5 mg/kg of CSP with and without 0.25 and 1.0 g/kg of RP. The blood CSP concentration was determined by a specific monoclonal fluorescence polarization immunoassay. 4. Both dosages of RP significantly decreased the Cmax and AUC0-t of CSP in rats. Mechanism studies indicated that RP activated the functions of P-gp and CYP 3A. 5. RP ingestion reduced the systemic exposure of CSP through activating P-gp and CYP 3A.

The Selectivity of CK2 Inhibitor Quinalizarin: A Reevaluation

Many polyphenolic compounds have been reported to inhibit protein kinases, with special reference to CK2, a pleiotropic serine/threonine kinase, implicated in neoplasia, neurodegenerative disease, and viral infections. In general however these compounds are not endowed with stringent selectivity. Among them quinalizarin (1,2,5,8-tetrahydroxyanthraquinone) turned out to be particularly potent (Ki = 0.058 μM) and quite selective as judged by profiling it on a small panel of 70 protein kinases. Here, by profiling quinalizarin on a larger panel of 140 kinases we reach the conclusion that quinalizarin is one of the most selective inhibitors of CK2, superior to the first-in-class CK2 inhibitor, CX-4945, now in clinical trials for the treatment of cancer. Moreover here we show that quinalizarin is able to discriminate between the isolated CK2 catalytic subunit (CK2α) and CK2 holoenzyme (CK2α2 β2), consistent with in silico and in vitro analyses.