Anti-herpetic and anti-dengue activity of abietane ferruginol analogues synthesized from (+)-dehydroabietylamine

The Inhibitory Effect of Resveratrol from Reynoutria japonica on MNV-1, a Human Norovirus Surrogate

As a natural nonflavonoid polyphenol compound, resveratrol is the main functional component of Reynoutria japonica and has anti-inflammatory, antioxidant, antiviral, and other physiological activities. In this study, the effect of resveratrol on the viability of RAW264.7 cells was examined, and murine norovirus (MNV-1) was used as a surrogate for human norovirus to evaluate the inhibitory effect of resveratrol. The concentrations of resveratrol resulting in 50% cytotoxicity (CC50) for RAW264.7 cells were 21.32 and 24.97 μg/mL after 24 and 48 h of incubation, respectively, and resveratrol at a concentration lower than the half-effective inhibitory concentration (EC50) could not damage cell DNA. The EC50 of resveratrol on MNV-1 in infected RAW264.7 cells was determined to equal 5.496 μg/mL. After RAW264.7 cells, virus, and a fresh mixture of virus and RAW264.7 cells were treated with resveratrol solution for 1 h (denoted cell pre-treatment, virus pre-treatment, and mixture coprocessing), the RAW264.7 cells obtained after cell pre-treatment exhibited lower virus infection, and MNV-1 obtained after virus pre-treatment and mixture coprocessing showed a decreased infectious capacity. The inhibition ratio of resveratrol on MNV-1 did not significantly differ between the treatments at 4 and 25 °C or among the various pH values except for the lower acidic condition (pH 2). TEM revealed significant changes in the morphology of MNV-1 after treatment with resveratrol, and molecular docking indicated that resveratrol strongly binds to the viral capsid protein of MNV-1. In addition, resveratrol regulated the expression of cytokine that protects against MNV-1 infection. Therefore, at a lower concentration, resveratrol, a natural component from Reynoutria japonica, exerts an inhibitory effect on MNV-1 growth and could be used as a safe additive in food products to improve the nutritional status and control norovirus.

Marine-Derived Cytosine Arabinoside (Ara-C) Inhibits Biofilm Formation by Inhibiting PEL Operon Proteins (Pel A and Pel B) of Pseudomonas aeruginosa: An In Silico Approach

Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative biofilm-forming opportunistic human pathogen whose vital mechanism is biofilm formation for better survival. PelA and PelB proteins of the PEL operon are essential for bacterial-synthesized pellicle polysaccharide (PEL), which is a vital structural component of the biofilm. It helps in adherence of biofilm on the surface and maintenance of cell-to-cell interactions and with other matrix components. Here, in-silico molecular docking and simulation studies were performed against PelA and PelB using ten natural bioactive compounds, individually [podocarpic acids, ferruginol, scopadulcic acid B, pisiferic acid, metachromin A, Cytarabine (cytosine arabinoside; Ara-C), ursolic acid, oleanolic acid, maslinic acid, and betulinic acid], those have already been established as anti-infectious compounds. The results obtained from AutoDock and Glide-Schordinger stated that a marine-derived cytosine arabinoside (Ara-C) among the ten compounds binds active sites of PelA and PelB, exhibiting strong binding affinity [Trp224 (hydrogen), Ser219 (polar), Val234 (hydrophobic) for PelA; Leu365 and Glu389 (hydrogen), Gln366 (polar) for PelB] with high negative binding energy - 5.518 kcal/mol and - 6.056 kcal/mol, respectively. The molecular dynamic and simulation studies for 100 ns showed the MMGBSA binding energy scores are - 16.4 kcal/mol (Ara-C with PelA), and - 22.25 kcal/mol (Ara-C with PelB). Further, ADME/T studies indicate the IC50 values of AraC are 6.10 mM for PelA and 18.78 mM for PelB, which is a comparatively very low dose. The zero violation of Lipinski's Rule of Five further established that Ara-C is a good candidate for drug development. Thus, Ara-C could be considered a potent anti-biofilm compound against PEL operon-dependent biofilm formation of P. aeruginosa.

Synthesis and bioevaluation of water-soluble β-cyclodextrin-diterpene acid conjugates

A series of β-cyclodextrin (β-CD)-conjugates were prepared by combining three abietane-type diterpene acids with two azide-functionalized β-CDs via click chemistry, and the antiviral activity against wild-type and omicron SARS-CoV-2 spike pseudovirus as well as the antibacterial activity against Escherichia coli were investigated. All the synthesised conjugates exhibited no significant cytotoxicity to BHK-21-hACE2 cells with cell viability over 80% at concentration of 15 µM. Among the conjugates, the heptavalent β-CD-dehydroabietic acid conjugate 6b exhibited higher anti-SARS-CoV-2 activity against the omicron variant compared to the other conjugates. This study suggested that the multivalent diterpene acid derivatives may have potential application against coronaviruses as entry inhibitors.

Discovery of Dehydroabietylamine Derivatives as Antibacterial and Antifungal Agents

A diverse array of biologically active derivatives was derived by modifying the chemically active sites of dehydroabietylamine. Herein, we describe the synthesis of a new series of C-19-arylated dehydroabietylamine derivatives using a palladium-catalyzed C(sp3)-H activation reaction. Five analogues (3b, 3d, 3h, 3n, and 4a) exhibited antibacterial activity against Escherichia coli. Compound 4a exhibited strong inhibitory activity against DNA Topo II and Topo IV. Molecular docking modeling indicated that it can bind effectively to the target through interactions with amino acid residues. The synthesized compounds were tested in vitro for their antifungal activity against six common phytopathogenic fungi. The mechanism of action of compound 4c against Rhizoctorzia solani was investigated, revealing that it disrupts the morphology of the mycelium and enhances cell membrane permeability.

Synergistic In Vitro Antiviral Effect of Combinations of Ivermectin, Essential Oils, and 18-(Phthalimid-2-yl)ferruginol against Arboviruses and Herpesvirus

Combining antiviral drugs with different mechanisms of action can help prevent the development of resistance by attacking the infectious agent through multiple pathways. Additionally, by using faster and more economical screening methods, effective synergistic drug candidates can be rapidly identified, facilitating faster paths to clinical testing. In this work, a rapid method was standardized to identify possible synergisms from drug combinations. We analyzed the possible reduction in the antiviral effective concentration of drugs already approved by the FDA, such as ivermectin (IVM), ribavirin (RIBA), and acyclovir (ACV) against Zika virus (ZIKV), Chikungunya virus (CHIKV), and herpes virus type 2 (HHV-2). Essential oils (EOs) were also included in the study since they have been reported for more than a couple of decades to have broad-spectrum antiviral activity. We also continued studying the antiviral properties of one of our patented molecules with broad-spectrum antiviral activity, the ferruginol analog 18-(phthalimid-2-yl)ferruginol (phthFGL), which presented an IC99 of 25.6 μM for the three types of virus. In general, the combination of IVM, phthFGL, and oregano EO showed the greatest synergism potential against CHIKV, ZIKV, and HHV-2. For instance, this combination achieved reductions in the IC99 value of each component up to ~8-, ~27-, and ~12-fold for CHIKV, respectively. The ternary combination of RIBA, phthFGL, and oregano EO was slightly more efficient than the binary combination RIBA/phthFGL but much less efficient than IVM, phthFGL, and oregano EO, which indicates that IVM could contribute more to the differentiation of cell targets (for example via the inhibition of the host heterodimeric importin IMP α/β1 complex) than ribavirin. Statistical analysis showed significant differences among the combination groups tested, especially in the HHV-2 and CHIKV models, with p = 0.0098. Additionally, phthFGL showed a good pharmacokinetic profile that should encourage future optimization studies.

Anticoronavirus Evaluation of Antimicrobial Diterpenoids: Application of New Ferruginol Analogues

The abietane diterpene (+)-ferruginol (1), like other natural and semisynthetic abietanes, is distinguished for its interesting pharmacological properties such as antimicrobial activity, including antiviral. In this study, selected C18-functionalized semisynthetic abietanes prepared from the commercially available (+)-dehydroabietylamine or methyl dehydroabietate were tested in vitro against human coronavirus 229E (HCoV-229E). As a result, a new ferruginol analogue caused a relevant reduction in virus titer as well as the inhibition of a cytopathic effect. A toxicity prediction based on in silico analysis was also performed as well as an estimation of bioavailability. This work demonstrates the antimicrobial and specifically antiviral activity of two tested compounds, making these molecules interesting for the development of new antivirals.

Host Cell Targets for Unconventional Antivirals against RNA Viruses

The recent COVID-19 crisis has highlighted the importance of RNA-based viruses. The most prominent members of this group are SARS-CoV-2 (coronavirus), HIV (human immunodeficiency virus), EBOV (Ebola virus), DENV (dengue virus), HCV (hepatitis C virus), ZIKV (Zika virus), CHIKV (chikungunya virus), and influenza A virus. With the exception of retroviruses which produce reverse transcriptase, the majority of RNA viruses encode RNA-dependent RNA polymerases which do not include molecular proofreading tools, underlying the high mutation capacity of these viruses as they multiply in the host cells. Together with their ability to manipulate the immune system of the host in different ways, their high mutation frequency poses a challenge to develop effective and durable vaccination and/or treatments. Consequently, the use of antiviral targeting agents, while an important part of the therapeutic strategy against infection, may lead to the selection of drug-resistant variants. The crucial role of the host cell replicative and processing machinery is essential for the replicative cycle of the viruses and has driven attention to the potential use of drugs directed to the host machinery as therapeutic alternatives to treat viral infections. In this review, we discuss small molecules with antiviral effects that target cellular factors in different steps of the infectious cycle of many RNA viruses. We emphasize the repurposing of FDA-approved drugs with broad-spectrum antiviral activity. Finally, we postulate that the ferruginol analog (18-(phthalimide-2-yl) ferruginol) is a potential host-targeted antiviral.

Discovery of Novel Bioactive Tanshinones and Carnosol Analogues against Breast Cancer

The abietane diterpenoids ferruginol (1), tanshinone IIA (3), and carnosol (4) are well-known for their interesting pharmacological properties, including antitumor, similar to other natural and semisynthetic abietanes. In this study, a pair of semisynthetic C18-functionalized analogues of 3 and 4 were prepared from the commercially available (+)-dehydroabietylamine or readily obtained methyl dehydroabietate. Semisynthetic ferruginol (1) and some selected analogues, together with the synthesized analogues, were tested in vitro for the inhibition of proliferation in four breast cancer cell lines, SUM149, MDA-MB231, T47D, and MCF07. As a result, several tested abietane analogues decreased cell proliferation and enhanced cell death, with IC₅₀ in the range 1.3-18.7 μM. This work demonstrates the antitumor activities of two tested compounds, making these molecules interesting for the development of new anticancer agents.

A new host-targeted antiviral cyclolignan (SAU-22.107) for Dengue Virus infection in cell cultures. Potential action mechanisms based on cell imaging

Dengue virus (DENV) infection is the most arbovirosis in the world. However, medications have not been approved for its treatment. Drug discovery based on the host-targeted antiviral (HTA) constitutes a new promising strategy, considering their high genetic barrier to resistance and the low probability of selecting drug resistance strains. In this study, we have tested fifty-seven podophyllotoxin-related cyclolignans on DENV-2 infected cells and found the most promising compound was S.71. Using cellular and molecular biology experiments, we have discovered that the new lignan altered the distribution of microtubules, induced changes in cell morphology, and caused retraction of the rough endoplasmic reticulum. In addition, the compound alters the viral envelope protein and the double-stranded RNA, while there is a decrease in negative-strand RNA synthesis; especially when the compound was added between 6- and 12-hours post-infection. Altogether, S.71 decreases the viral yield through an HTA-related mechanism of action, possibly altering the DENV genome replication and/or polyprotein translation, through the alteration of microtubule distribution and endoplasmic reticulum deterioration. Finally, pharmacokinetic predictors show that S.71 falls within the standard ranges established for drugs.

The Colombian Zika Virus Isolate (COL345Si) Replicates in Prostate Adenocarcinoma Cells and Modulates the Antiviral Response

Zika virus (ZIKV), a flavivirus that is mainly transmitted by A. aegypti and A. albopictus and sexual transmission, has been documented and described. The ZIKV RNA detection in the semen of vasectomized men indicates that accessory glands such as the prostate could be a site of virus replication. In this study, we characterized the ZIKV infection, evaluated the antiviral profile, and demonstrated the AXL and TIM-1 expression on the PC3 prostate cell line. It was also determined that PC3 cells are susceptible and permissive to ZIKV infection without altering the cell viability or causing a cytopathic effect. The antiviral profile suggests that the PC3 cells modulate the antiviral response through the suppressor molecule expression, SOCS-1, during a ZIKV infection.

Phytochemical Compound Profile and the Estimation of the Ferruginol Compound in Different Parts (Roots, Leaves, and Seeds) of Juniperus procera

Secondary plant metabolites and their derivatives play a significant role in human health. Ferruginol is a diterpene phenol that has recently received attention for its pharmacological properties, including antibacterial, antitumor, antimalarial, and cardioprotective effects. Recently, we detected the ferruginol compound in the leaf and seed extracts of Juniperus procera using different analytical approaches. The present work aims at detecting phytochemical compounds in a root extract of J. procera and estimating the amount of ferruginol compound in different parts of Juniperus procera. To screen the phytochemical compounds present in the root extract of J. procera, Gas chromatography/mass spectrometry (GC/MS) was performed. For ferruginol identification and estimation, high-performance liquid chromatography (HPLC) with the ferruginol reference standard and high-resolution direct analysis in real-time (DART) time-of-flight mass spectrometry (TOFMS) (DART-TOF-MS) analysis were used. GC/MS analysis revealed more than 20 bioactive compounds related to secondary plant metabolites in the root extract of J. procera with biological activity. The DART-TOF-MS result showed the typical positive ion spectra of ferruginol, and the HPLC result confirmed that the root extract of J. procera contains the ferruginol compound. In contrast, the root extract of J. procera contained a significant amount of ferruginol compared to that in the leaf and seed extracts. All parts of the J. procera contained the ferruginol compound and proved that ferruginol might be accumulated in the roots, leaves, and seeds of J. procera.

Synthesis and Biological Evaluation of Cassane Diterpene (5α)-Vuacapane-8(14), 9(11)-Diene and of Some Related Compounds

A set of thirteen cassane-type diterpenes was synthesized and an expedient synthetic route was used to evaluate 14-desmethyl analogs of the most active tested cassane. The anti-inflammatory activities of these 13 compounds were evaluated on a lipopolysaccharide (LPS)-activated RAW 264.7 cell line by inhibition of nitric oxide (NO) production, some of them reaching 100% NO inhibition after 72 h of treatment. The greatest anti-inflammatory effect was observed for compounds 16 and 20 with an IC_{50 NO} of 2.98 ± 0.04 μg/mL and 5.71 ± 0.14 μg/mL, respectively. Flow-cytometry analysis was used to determine the cell cycle distribution and showed that the inhibition in NO release was accompanied by a reversion of the differentiation processes. Moreover, the anti-cancer potential of these 13 compounds were evaluated in three tumor cell lines (B16-F10, HT29, and Hep G2). The strongest cytotoxic effect was achieved by salicylaldehyde 20, and pterolobirin G (6), with IC₅₀ values around 3 μg/mL in HT29 cells, with total apoptosis rates 80% at IC₈₀ concentrations, producing a significant cell-cycle arrest in the G0/G1 phase, and a possible activation of the extrinsic apoptotic pathway. Additionally, initial SAR data analysis showed that the methyl group at the C-14 positions of cassane diterpenoids is not always important for their cytotoxic and anti-inflammatory activities.

Antiviral Profiling of C-18- or C-19-Functionalized Semisynthetic Abietane Diterpenoids

Viral infections affect several million patients annually. Although hundreds of viruses are known to be pathogenic, only a few can be treated in the clinic with available antiviral drugs. Naturally based pharmacotherapy may be a proper alternative for treating viral diseases. Several natural and semisynthetic abietane-type diterpenoids have shown important antiviral activities. In this study, a biological evaluation of a number of either C-18- or C-19-functionalized known semisynthetic abietanes against Zika virus, Dengue virus, Herpes virus simplex type 1, and Chikungunya virus are reported. Semisynthetic abietane ferruginol and its analogue 18-(phthalimid-2-yl)ferruginol displayed broad-spectrum antiviral properties. The scale-up synthesis of this analogue has been optimized for further studies and development. This molecule displayed an EC₅₀ between 5.0 and 10.0 μM against Colombian Zika virus strains and EC₅₀ = 9.8 μM against Chikungunya virus. Knowing that this ferruginol analogue is also active against Dengue virus type 2 (EC₅₀ = 1.4 μM, DENV-2), we can conclude that this compound is a promising broad-spectrum antiviral agent paving the way for the development of novel antivirals.

Syntheses and high selective cytotoxicity of dehydroabietylamine C-ring nitration derivatives

To find more effective anticancer agents, a series of novel dehydroabietylamine (DA) derivatives were synthesized, focusing on C-ring nitro modifications and C-18 imide introduction. Their cytotoxic activities against human tumor cell line HeLa (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver), and nonmalignant cell line HUVEC (umbilical vein) in vitro were screened. The C-18 imide heterocyclic compounds 1, 2, and C-ring 14-nitro substituted 14 exhibited moderate to good cytotoxic activities and significant selectivity towards malignant cell lines. More importantly, they were significantly less cytotoxic to nonmalignant cells (HUVEC) than the parent compound and positive control doxorubicin hydrochloride (DOX). Meantime the mechanism of cytotoxicity of DA derivatives was studied. Annexin V-FITC/PI double-staining analysis suggested that cytotoxicity of compounds 2 and 14 was associated with early apoptosis induction. The interaction between compounds and DNA (herring sperm DNA) was studied using absorption spectral analysis and ethidium bromide (EB) fluorescence displacement experiments, the results exhibited that the binding of the compound to DNA was in the intercalative mode. The structure-activity relationship discussion implied that introduction of the nitro-group, especially the 14-nitro group, can significantly improve the cytotoxicity of dehydroabietylimide compounds. The relatively high cytotoxicity and significant high selectivity of compounds 2 and 14 indicated that they were particularly noteworthy. NO released amounts indicated that the amounts of NO released by the compounds bearing nitro-group were quite well associated positive correlation with their cytotoxic activity, which provide a new strategy for structure design of DA anticancer agents in the future.

Computer aided identification of potential SARS CoV-2 main protease inhibitors from diterpenoids and biflavonoids of Torreya nucifera leaves

SARS CoV-2 is the causative agent of the pandemic disease COVID-19. There is an urgent need for effective drugs or vaccines which can effectively combat this outbreak. The main protease (Mpro), a key component for the SARS CoV-2 replication, is considered to be one of the important drug targets for developing anti-COVID-19 drugs. This SARS CoV-2 Mpro/cysteine protease has high sequence similarity with the same protease from SARS CoV-1. Previously, it has been shown experimentally that eight diterpenoids and four biflavonoids derived from the leaf of Torreya nucifera show inhibitory effect on the cleavage/catalytic activity of the SARS CoV-1 Mpro. But whether these phytochemicals exhibit any inhibitory effect on SARS CoV-2 Mpro is unclear. To understand this fact, here, we have adopted various in-silico approaches. Diterpenoids and biflavonoids those qualified pharmacological test (hinokiol, amentoflavone, bilobetin and ginkgetin) and two well-known Mpro inhibitors (N3 and lopinavir) were subjected for molecular docking studies. Only three biflavonoids (amentoflavone, bilobetin and ginkgetin) were selected by comparing their binding affinities with N3 and lopinavir. They interacted with two most important catalytic residues of Mpro (His41 and Cys145). Molecular dynamics studies further revealed that these three Mpro-biflavonoid complexes are highly stable and share a similar degree of compactness. Besides, these complexes experience less conformational fluctuations and more expansion than Mpro-N3 and/or Mpro-lopinavir complex. MM-GBSA and H-bond analysis further corroborated these findings. Altogether, our study suggested that these three biflavonoids could possibly inhibit the proteolytic/catalytic activity of SARS CoV-2 Mpro and might be useful for COVID-19 treatment.Communicated by Ramaswamy H. Sarma.

Phthalimide analogs for antimalarial drug discovery

Malaria remains one of the world's most life-threatening diseases and, thus, it is a major public health concern all around the world. The disease can become devastating if not treated with proper medication in a timely manner. Currently, the number of viable treatment therapies is in continuous decline due to compromised effectiveness, probably owing to the complex life cycle of Plasmodium falciparum. The factors responsible for the unclear status of malaria eradication programmes include ever-developing parasite resistance to the most effective treatments used on the frontline (i.e., artemisinin derivatives) and the paucity of new effective therapeutics. Due to these circumstances, the development of novel effective drug candidates with unique modes of action is essential for overcoming the listed obstacles. As such, the discovery of novel chemical compounds based on validated pharmacophores remains an unmet need in the field of medicinal chemistry. In this area, functionalized phthalimide (Pht) analogs have been explored as potential candidates against various diseases, including malaria. Pht presents a promising bioactive scaffold that can be easily functionalized and thus utilized as a starting point for the development of new antimalarial candidates suitable for preclinical and clinical studies. In this short review, we highlight a wide range of Pht analogs that have been investigated for their activity against various strains of Plasmodium falciparum.

Abietane Diterpenoids from the Hairy Roots of Salvia corrugata

Salvia corrugata Vahl. is an interesting source of abietane and abeo-abietane compounds that showed antibacterial, antitumor, and cytotoxic activities. The aim of the study was to obtain transformed roots of S. corrugata and to evaluate the production of terpenoids in comparison with in vivo root production. Hairy roots were initiated from leaf explants by infection with ATCC 15834 Agrobacterium rhizogenes onto hormone-free Murashige and Skoog (MS) solid medium. Transformation was confirmed by polymerase chain reaction analysis of rolC and virC1 genes. The biomass production was obtained in hormone-free liquid MS medium using Temporary Immersion System bioreactor RITA®. The chromatographic separation of the methanolic extract of the untransformed roots afforded horminone, ferruginol, 7-O-acetylhorminone and 7-O-methylhorminone. Agastol and ferruginol were isolated and quantified from the hairy roots. The amount of these metabolites indicated that the hairy roots of S. corrugata can be considered a source of these compounds.

Plant Metabolites as Antiviral Preparations Against Coronaviruses

In 2019-2020, the Coronavirus (CoV) disease 2019 pandemic created a serious challenge for health care systems in several countries worldwide. A cure has not been developed yet and currently used treatment protocols are aimed at relieving clinical symptoms of the disease. This article presents a retrospective review of biologically active compounds of plant origin that can inhibit the reproduction of CoVs, which makes them potential candidates for creating medicinal antiviral preparations against severe acute respiratory syndrome CoV-2 infections. A literature review of articles from highly rated journals was performed using public databases. The search was carried out using keywords related to CoVs, targets for therapy, and plant as antiviral agents. Although inhibition of viral replication is often considered the common mechanism of antiviral activity exerted by most natural products, several plant-derived compounds show specific activity for particular target viruses. In this context, certain classes of plant preparations can serve as a basis for designing modern antiviral agents. In addition, a large number of plant compounds that are potentially active against CoVs are the main components of certain common dietary supplements that can be used to improve the resistance of a population against certain respiratory infections. In this review, we have attempted to characterize the main groups of biologically active plant compounds that have the potential to disrupt the key stages of CoV replication. It has been shown that the use of certain herbal preparations can change the course of infection.

Ameliorative effect of ferruginol on isoprenaline hydrochloride-induced myocardial infarction in rats

Cardiovascular-related diseases continue to be a leading cause of death globally. Among ischemic-induced cardiac diseases, myocardial infarction (MI) is reported to be of an alarming value. Despite numerous improvements in the medical intrusions, still this armamentarium fails to be effective in managing the illness without setbacks. Ferruginol (FGL) is a major polyphenols and terpenoids with numerous pharmacological activities including antioxidant and anti-inflammatory. Following, this work was aimed to explore the cardio protective effect of FGL (50 mg/kg) in isoprenaline hydrochloride (ISO)-induced MI in experimental rats. After treatment with FGL in ISO-induced MI in rats, noticeable changes were observed in the experimental rats. Injection of ISO to rats resulted in the augmented cardiac weight, serum cardiac markers (creatine kinase, creatine kinase-MB, cardiac troponin T, and Cardiac troponin I), lipid peroxidation end products (thiobarbituric acid-reactive substance and lipid hydroperoxides), reduced endogenous antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione), reduced ATPase activity, and escalated pro-inflammatory cytokines (interleukin-6, tumor necrosis factor-α, and nuclear factor-κB) levels. Interestingly, the FGL supplementation to the ISO-treated rats revealed the diminished heart weight, reduced cardiac markers, and lipid peroxidation. FGL also possessed the improved antioxidants status and diminished pro-inflammatory mediator levels. The outcomes of histological analysis also evidenced the cardio protective role of FGL. Treatment with FGL reduced the cardiac damage biomarkers maintained to near normal levels in ISO-induced rats. These study findings disclose the prospective capability of FGL in the treatment of MI in the future.

Anti-Zika virus activity of several abietane-type ferruginol analogues

Abietane diterpenoids are naturally occurring plant metabolites with a broad spectrum of biological effects including antibacterial, antileishmanial, antitumor, antioxidant, as well as antiinflammatory activities. Recently, we found that some analogues of natural ferruginol ( 2 ) actively inhibited dengue virus 2 (DENV-2) replication. Due to the similarity with DENV, we envisaged that abietane diterpenoids would also be active against Zika virus (ZIKV). Six selected semi-synthetic abietane derivatives of (+)-dehydroabietylamine ( 3 ) were tested. Cytotoxicity was determined by MTT assay in Vero cells. In vitro anti-ZIKV (clinical isolate, IMT17) activity was evaluated by plaque assay. Interestingly, these molecules showed potential as anti-ZIKV agents, with EC₅₀ values ranging from 0.67 to 18.57 µM, and cytotoxicity (CC₅₀ values) from 2.56 to 35.09 µM. The 18-Oxoferruginol (8) (EC₅₀ = 2.60 µM, SI = 13.51) and 12-nitro-N-benzoyldehydroabietylamine (9) (EC₅₀= 0.67 µM, SI = 3.82) were the most active compounds, followed by 12-hydroxy-N-tosyldehydroabietylamine ( 7 ) (EC₅₀ = 3.58 µM, SI = 3.20) and 12-hydroxy-N,N-phthaloyldehydroabietylamine ( 5 ) (EC₅₀ = 7.76 µM, SI = 1.23). To the best of our knowledge, this is the first report on anti-Zika virus properties of abietanes.

Discovery of sclareol and sclareolide as filovirus entry inhibitors

Filoviruses cause severe hemorrhagic fever in humans. Ebola virus (EBOV) is the most contagious filovirus. Although compassionate treatments have been used during the latest Ebola outbreak, novel anti-EBOV agents are still urgently needed. In this study, sclareol and sclareolide, two natural products in Salvia sclarea, were identified as EBOV entry inhibitors with EC₅₀s of 2.4 μmol/L and 8.0 μmol/L, respectively, through blocking the viral fusion process. Moreover, both compounds exhibited inhibitory effects on all tested filoviruses' entry, indicating their wide-spectrum activities against filoviruses. This study provides insights into the two natural products and their applications against filovirus infectious diseases.

Synthesis and anticancer evaluation of novel 1H-benzo[d]imidazole derivatives of dehydroabietic acid as PI3Kα inhibitors

Phosphatidylinositol 3-kinase (PI3K) is one of the most attractive therapeutic targets for cancer treatment. In this study, a series of new 2-arylthio- and 2-arylamino-1H-benzo[d]imidazole derivatives of dehydroabietic acid were designed, synthesized and characterized by ¹H NMR, ¹³C NMR, IR and MS spectra analyses. In the in vitro anticancer assay, some title compounds showed significant inhibitory activities against four cancer cell lines (HCT-116, MCF-7, HeLa and HepG2). Among them, compound 9g exhibited the most potent activity with IC₅₀ values of 0.18 ± 0.03, 0.43 ± 0.05, 0.71 ± 0.08 and 0.63 ± 0.09 μM against four cancer cell lines, and considerably lower cytotoxicity to human gastric mucosal cell line Ges-1 (IC₅₀: 21.95 ± 0.73 μM). Besides, compound 9g displayed a certain selective activity to PI3Kα (IC₅₀ = 0.012 ± 0.002 μM) over PI3Kβ, γ and δ, and meanwhile, it can remarkably decrease the expression level of p-Akt (Ser473). In addition, compound 9g could increase intracellular reactive oxygen species level, decrease mitochondrial membrane potential, upregulate Bax and cleaved caspase-3/9 levels, downregulate Bcl-2 level and thus induce the apoptosis of HCT-116 cells in a dose-dependent manner. The results suggested that compound 9g could be considered as a promising PI3Kα inhibitor.

Synthesis, antitumor and DNA cleavage activities of a novel class of dehydroabietylamine derivatives

Previous studies have reported higher biological activity of dehydrorosinamine derivatives. In order to further synthesize novel compounds with higher biological activity, a series of novel compounds containing benzo-azepine structures were synthesized from dehydroabietylamine in good yields in this study. The structures of synthesized compounds were identified by infra red (IR), ¹H-NMR, ¹³C-NMR, and mass spectra (MS) analysis. The antitumor activities of the target compounds against L02 and HepG2 cells were studied. Furthermore, the dehydroabietylamine derivatives were studied on plasmid DNA cleavage activities. The results showed that the synthesized target compound exhibit antitumor and DNA cleavage activities against plasmid DNA (Escherichia coli). Our results further demonstrate the relationship between the chemical structure and biological function of the synthesized compounds.

Synthesis and biological evaluation of novel N-(piperazin-1-yl)alkyl-1H-dibenzo[a,c]carbazole derivatives of dehydroabietic acid as potential MEK inhibitors

In this paper, a series of novel 1H-dibenzo[a,c]carbazole derivatives of dehydroabietic acid bearing different N-(piperazin-1-yl)alkyl side chains were designed, synthesised and evaluated for their in vitro anticancer activities against three human hepatocarcinoma cell lines (SMMC-7721, HepG2 and Hep3B). Among them, compound 10g exhibited the most potent activity against three cancer cell lines with IC₅₀ values of 1.39 ± 0.13, 0.51 ± 0.09 and 0.73 ± 0.08 µM, respectively. In the kinase inhibition assay, compound 10g could significantly inhibit MEK1 kinase activity with IC₅₀ of 0.11 ± 0.02 µM, which was confirmed by western blot analysis and molecular docking study. In addition, compound 10g could elevate the intracellular ROS levels, decrease mitochondrial membrane potential, destroy the cell membrane integrity, and finally lead to the oncosis and apoptosis of HepG2 cells. Therefore, compound 10g could be a potent MEK inhibitor and a promising anticancer agent worthy of further investigations.

Synthesis and Antiproliferative Evaluation of Novel Hybrids of Dehydroabietic Acid Bearing 1,2,3-Triazole Moiety

To discover novel potent cytotoxic diterpenoids, a series of hybrids of dehydroabietic acid containing 1,2,3-triazole moiety were designed and synthesized. The target compounds were characterized by means of FT-IR, ¹H NMR, ¹³C NMR, ESI-MS and elemental analysis techniques. The in vitro cytotoxicity of these compounds was evaluated by standard MTT (methyl thiazolytetrazolium) assay against CNE-2 (nasopharynx), HepG2 (liver), HeLa (epithelial cervical), BEL-7402 (liver) human carcinoma cell lines and human normal liver cell (HL-7702). The screening results revealed that most of the hybrids showed significantly improved cytotoxicity over parent compound DHAA. Among them, [1-(3-fluorobenzyl)-1H-1,2,3-triazole-4-yl]dehydroabietic acid methyl ester (3c), and [1-(2-nitrobenzyl)-1H-1,2,3-triazole-4-yl]dehydroabietic acid methyl ester (3k) displayed better antiproliferative activity with IC₅₀ (50% inhibitory concentration) values of 5.90 ± 0.41 and 6.25 ± 0.37 µM toward HepG2 cells compared to cisplatin, while they exhibited lower cytotoxicity against HL-7702. Therefore, the 1,2,3-triazole-hybrids could be a promising strategy for the synthesis of antitumor diterpenoids and it also proved the essential role of 1,2,3-triazole moiety of DHAA in the biological activity.

La pérdida de función de la quinasa dependiente de ciclina 5 (CDK5) altera el citoesqueleto y reduce la infección in vitro por el virus del dengue 2

La quinasa dependiente de ciclina 5 (CDK5) regula diversas funciones en neuronas, células endoteliales y epiteliales, entre ellas la dinámica del citoesqueleto. Así mismo, se ha reportado que componentes del citoesqueleto, tales como, filamentos de actina y microtúbulos juegan un rol importante durante la infección por el virus dengue (DENV). El objetivo del presente trabajo fue evaluar por dos métodos, inhibición química y silenciamiento génico, la participación de CDK5 durante la infección por DENV-2. La actividad antiviral de roscovitina fue evaluada usando ensayos de Unidades Formadoras de Placa (PFU). La eficiencia de transfección y el silenciamiento de CDK5, empleando miARNs artificiales, se determinó por citometría de flujo. El efecto sobre la proteína de envoltura viral y elementos del citoesqueleto se evidenció mediante microscopia avanzada de fluorescencia y análisis de imágenes. Roscovitina mostró actividad antiviral en etapas pre y post-infectivas en una forma dependiente de la dosis. El tratamiento con roscovitina y miRCDK5 mostró ser efectivo reduciendo la cantidad de CDK5 en células no infectadas. En células infectadas y transfectadas con miRCDK5, así como tratadas con el inhibidor, se observó una reducción significativa de la proteína de envoltura viral; sin embargo, no se encontró reducción significativa de CDK5. Además, el tratamiento con roscovitina indujo cambios celulares morfológicos evidentes en células infectadas. Los resultados indican la potencial participación de CDK5 durante la infección por DENV-2, posiblemente mediando la traducción proteica o la replicación del genoma viral a través de la regulación de la dinámica del citoesqueleto. Se requieren datos adicionales para esclarecer la mecanística del fenómeno usando métodos alternativos.

Anti-Herpetic, Anti-Dengue and Antineoplastic Activities of Simple and Heterocycle-Fused Derivatives of Terpenyl-1,4-Naphthoquinone and 1,4-Anthraquinone

Quinones are secondary metabolites of higher plants associated with many biological activities, including antiviral effects and cytotoxicity. In this study, the anti-herpetic and anti-dengue evaluation of 27 terpenyl-1,4-naphthoquinone (NQ), 1,4-anthraquinone (AQ) and heterocycle-fused quinone (HetQ) derivatives was done in vitro against Human Herpesvirus (HHV) type 1 and 2, and Dengue virus serotype 2 (DENV-2). The cytotoxicity on HeLa and Jurkat tumor cell lines was also tested. Using plaque forming unit assays, cell viability assays and molecular docking, we found that NQ 4 was the best antiviral compound, while AQ 11 was the most active and selective molecule on the tested tumor cells. NQ 4 showed a fair antiviral activity against Herpesviruses (EC₅₀: <0.4 µg/mL, <1.28 µM) and DENV-2 (1.6 µg/mL, 5.1 µM) on pre-infective stages. Additionally, NQ 4 disrupted the viral attachment of HHV-1 to Vero cells (EC₅₀: 0.12 µg/mL, 0.38 µM) with a very high selectivity index (SI = 1728). The in silico analysis predicted that this quinone could bind to the prefusion form of the E glycoprotein of DENV-2. These findings demonstrate that NQ 4 is a potent and highly selective antiviral compound, while suggesting its ability to prevent Herpes and Dengue infections. Additionally, AQ 11 can be considered of interest as a leader for the design of new anticancer agents.

Pharmacokinetics and Tissue Distribution Study of Ferruginol in Wistar Rat by High-performance Liquid Chromatography

Background:

Ferruginol (FRGN) exhibits a broad range of pharmacological properties which make it a promising candidate for chemoprevention. However, little is known about its absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties.

Methods:

A rapid, sensitive and specific HPLC-DAD method was established to quantify FRGN in the plasma and tissues of Wistar rats. After extraction of FRGN with ethyl acetate (EtOAc), chromatographic separation was performed on a YMC ODS C18 column (250 × 4.6 mm I.D., 5 µm) with a mobile phase consisting of methanol-water (92:8, v/v) at a flow rate of 0.9 mL/min. Detection was conducted with a wavelength of 273 nm at 25 °C.

Results:

The calibration curves for FRGN were linear in the concentration range of 0.5-20 µg/mL for plasma, 0.5-10 µg/mL for heart, liver, spleen, lung, kidney, stomach, intestine, brain and muscle. After three cycles of freezing and thawing, the concentration variations were within ± 7% of nominal concentrations, indicating no significant substance loss during repeated thawing and freezing. The assay was applied to pharmacokinetic and tissue distribution study in rats. Results suggested that lung, heart, liver, spleen and kidney were the major distribution tissues of FRGN in rats, and FRGN could permeate the blood-brain barrier to distribute in the brain of rats.

Conclusion:

The information provided by this research is very useful for gaining knowledge of the pharmacokinetic process and tissue distribution of FRGN.

Ferruginol induced apoptosis on SK-Mel-28 human malignant melanoma cells mediated through P-p38 and NF-κB

In the present investigation, the antitumor effect of ferruginol (FGL) in SK-Mel-28 human malignant melanoma cells was studied. To investigate the cytotoxic property of FGL, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used. Results revealed that prolonged treatment duration decreases the IC25, IC50, and IC75 concentrations of FGL. The cytotoxicity was further confirmed by lactate dehydrogenase assay. As evident from comet assay, FGL induces DNA damage in a dose-dependent manner. Annexin V and 7-ADD assays showed that FGL-induced DNA damage triggers apoptosis-mediated cell death as confirmed by caspase-3 activity assay. As seen through Western blotting, FGL increases phosphorylation of p38 and nuclear translocation of NF-κB. Further, it was observed that p38 phosphorylation is responsible for NF-κB translocation to the nucleus. Further, inhibition of p38 phosphorylation and translocation of NF-κB decrease caspase-3 activity. The above finding confirms that caspase-3 activation is mediated through P-p38 and nuclear translocation of NF-κB. The present findings indicate that FGL significantly suppresses the proliferation of SK-Mel-28 cells in a dose- and time-dependent manner through induction of apoptosis. Furthermore, FGL executes apoptosis through phosphorylation of key protein such as p38 and translocation of NF-κB into the nucleus.

The Current Status of the Pharmaceutical Potential of Juniperus L. Metabolites

Background: Plants and their derived natural compounds possess various biological and therapeutic properties, which turns them into an increasing topic of interest and research. Juniperus genus is diverse in species, with several traditional medicines reported, and rich in natural compounds with potential for development of new drugs. Methods: The research for this review were based in the Scopus and Web of Science databases using terms combining Juniperus, secondary metabolites names, and biological activities. This is not an exhaustive review of Juniperus compounds with biological activities, but rather a critical selection taking into account the following criteria: (i) studies involving the most recent methodologies for quantitative evaluation of biological activities; and (ii) the compounds with the highest number of studies published in the last four years. Results: From Juniperus species, several diterpenes, flavonoids, and one lignan were emphasized taking into account their level of activity against several targets. Antitumor activity is by far the most studied, being followed by antibacterial and antiviral activities. Deoxypodophyllotoxin and one dehydroabietic acid derivative appears to be the most promising lead compounds. Conclusions: This review demonstrates the Juniperus species value as a source of secondary metabolites with relevant pharmaceutical potential.

Synthesis and biological evaluation of 2-aryl-benzimidazole derivatives of dehydroabietic acid as novel tubulin polymerization inhibitors

A series of novel 2-aryl-benzimidazole derivatives of dehydroabietic acid were synthesized and characterized by IR, 1H NMR, 13C NMR, MS and elemental analyses. All the target compounds were evaluated for their in vitro cytotoxic activity against SMMC-7721, MDA-MB-231, HeLa and CT-26 cancer cell lines and the normal hepatocyte cell line QSG-7701 through MTT assays. Among them, compound 6j displayed the most potent cytotoxic activity with IC50 values of 0.08 ± 0.01, 0.19 ± 0.04, 0.23 ± 0.05 and 0.42 ± 0.07 μM, respectively, and substantially reduced cytotoxicity against QSG-7701 cells (5.82 ± 0.38 μM). The treatment of SMMC-7721 cells with compound 6j led to considerable inhibition of cell migration ability. The influence of compound 6j on cell cycle distribution was assessed on SMMC-7721 cells, exhibiting a cell cycle arrest at the G2/M phase. Moreover, tubulin polymerization assays and immunofluorescence assays elucidated that compound 6j could significantly inhibit tubulin polymerization and disrupt the intracellular microtubule network. A molecular docking study provided insight into the binding mode of compound 6j in the colchicine site of tubulin. In addition, compound 6j was found to induce apoptosis of SMMC-7721 cells, an increase of intracellular ROS level and a loss of mitochondrial membrane potential in a dose-dependent manner. These findings provided new molecular scaffolds for the further development of novel antitumor agents targeting tubulin polymerization.

Synthesis and Evaluation of New Quinoxaline Derivatives of Dehydroabietic Acid as Potential Antitumor Agents

A series of new quinoxaline derivatives of dehydroabietic acid (DAA) were designed and synthesized as potential antitumor agents. Their structures were characterized by IR, ¹H-NMR, ¹³C-NMR, and MS spectra and elemental analyses. All the new compounds were screened for their in vitro antiproliferative activities against three human cancer cell lines (MCF-7, SMMC-7721 and HeLa) and noncancerous human hepatocyte cells (LO2). A cytotoxic assay manifested that compound 4b showed the most potent cytotoxic activity against the three cancer cell lines, with IC₅₀ values of 1.78 ± 0.36, 0.72 ± 0.09 and 1.08 ± 0.12 μM, respectively, and a substantially lower cytotoxicity to LO2 cells (IC₅₀: 11.09 ± 0.57 μM). Moreover, the cell cycle analysis suggested that compound 4b caused cell cycle arrest of SMMC-7721 cells at the G0/G1 phase. In a Hoechst 33258 staining assay, compound 4b caused considerable morphological changes of the nuclei of SMMC-7721 cells, correlated with cell apoptosis. In addition, an Annexin V-FITC/PI dual staining assay confirmed that compound 4b could induce the apoptosis of SMMC-7721 cells in a dose-dependent manner.

Synthesis and in vitro cytotoxic evaluation of new 1H-benzo[d]imidazole derivatives of dehydroabietic acid

A series of new 1H-benzo[d]imidazole derivatives of dehydroabietic acid were designed and synthesized as potent antitumor agents. Structures of the target molecules were characterized using MS, IR, ¹H NMR, ¹³C NMR and elemental analyses. In the in vitro cytotoxic assay, most compounds showed significant cytotoxic activities against two hepatocarcinoma cells (SMMC-7721 and HepG2) and reduced cytotoxicity against noncancerous human hepatocyte (LO2). Among them, compound 7b exhibited the best cytotoxicity against SMMC-7721 cells (IC₅₀: 0.36±0.13μM), while 7e was most potent to HepG2 cells (IC₅₀: 0.12±0.03μM). The cell cycle analysis indicated that compound 7b caused cell cycle arrest of SMMC-7721 cells at G2/M phase. Further, compound 7b also induced the apoptosis of SMMC-7721 cells in Annexin V-APC/7-AAD binding assay.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes labdanes, clerodanes, abietanes, pimaranes, kauranes, cembranes and their cyclization products. The literature from January to December, 2016 is reviewed.

Diterpenes as lead molecules against neglected tropical diseases

Nowadays, neglected tropical diseases (NTDs) are reported to be present everywhere. Poor and developing areas in the world have received great attention to NTDs. Drug resistance, safety profile, and various challenges stimulate the search for alternative medications. Plant-based drugs are viewed with great interest, as they are believed to be devoid of side effects. Diterpenes, a family of essential oils, have showed attractive biological effects. A systematic review of the literature was carried out to summarize available evidences of diterpenes against NTDs. For this, databases were searched using specific search terms. Among the 2338 collected reports, a total of 181 articles were included in this review. Of them, 148 dealt with investigations using single organisms, and 33 used multiple organisms. No mechanisms of action were reported in the case of 164 reports. A total of 93.92% were related to nonclinical studies, and 4.42% and 1.66% dealt with preclinical and clinical studies, respectively. The review displays that many diterpenes are effective upon Chagas disease, chikungunya, echinococcosis, dengue, leishmaniasis, leprosy, lymphatic filariasis, malaria, schistosomiasis, and tuberculosis. Indeed, diterpenes are amazing drug candidates against NTDs. Copyright © 2016 John Wiley & Sons, Ltd.