lignans and diphyllin

Diphyllin glycosides (DG) are a type of arylnaphthalene lignans isolated from different plants, and their synthetic derivatives have shown effective antiviral, cytotoxic, hypotensive and diuretic effects at very low concentrations similar to standard drugs that are under clinical use. The biological activities of the DG interfere with signaling pathways of viral infection and cancer induction. The sugar moieties of DG enhance bioavailability and pharmacological activities. The promising results of DG at nanomolar concentrations under in vitro and in vivo conditions should be explored further with clinical trials to determine its toxic effects, pharmacokinetics and pharmacodynamics. This may help identify suitable antiviral and anticancer drugs in the near future. Considering all these activities, the present review is focused on the chemical aspects of DG with a detailed account of the mechanisms of action of DG. An attempt is also made to comment on the status of clinical trials involving DG along with the possible limitations in studies based on available literature till September 2020.

Topics: Antineoplastic Agents; Antiviral Agents; Benzodioxoles; Glycosides; Lignans

Lignans are widely produced by various plant species; they are a class of natural products that share structural similarity. They usually contain a core scaffold that is formed by two or more phenylpropanoid units. Lignans possess diverse pharmacological properties, including their antiviral activities that have been reported in recent years. This review discusses the distribution of lignans in nature according to their structural classification, and it provides a comprehensive summary of their antiviral activities. Among them, two types of antiviral lignans-podophyllotoxin and bicyclol, which are used to treat venereal warts and chronic hepatitis B (CHB) in clinical, serve as examples of using lignans for antivirals-are discussed in some detail. Prospects of lignans in antiviral drug discovery are also discussed.

Topics: Antiviral Agents; Benzodioxoles; Biological Products; Biphenyl Compounds; Drug Development; Furans; Lignans; Masoprocol; Plants; Podophyllotoxin

Cleistanthus collinus is an extremely toxic plant poison. We report a case of suicidal ingestion of boiled water decoction of C. collinus where the patient presented with abdominal pain and giddiness. There was persistent metabolic acidosis and fluctuation in the level of serum potassium. The ECG changes indicated a probable myocardial injury with conduction abnormality. At autopsy, the viscera were found to be congested. The toxins were detected in the viscera and blood by TLC and HPLC. Cleistanthin A and B, collinusin, and diphyllin are the principal toxic constituents of the plant. Consumption of a boiled decoction of leaves is highly toxic and, medical management of patients is mainly supportive because the molecular mechanisms of toxin action are unknown. In the recent years, C. collinus has created a considerable amount of interest because of its complex metabolites and their cytotoxic activities. Through this study, the authors have tried to highlight different properties pertaining to C. collinus.

Topics: Acidosis; Adult; Benzodioxoles; Euphorbiaceae; Female; Glycosides; Humans; Lignans; Naphthalenes; Plant Leaves; Suicide

Diphyllin is a natural arylnaphtalide lignan extracted from tropical plants of particular importance in traditional Chinese medicine. This compound has been described as a potent inhibitor of vacuolar (H

Topics: Animals; Antigens, Viral; Antiviral Agents; Cell Line; Cell Survival; Glucosides; Lignans; Vacuolar Proton-Translocating ATPases; Virus Replication; Viruses

Ebola virus (EBOV) is an aggressive filoviral pathogen that can induce severe hemorrhagic fever in humans with up to 90% fatality rate. To date, there are no clinically effective small-molecule drugs for postexposure therapies to treat filoviral infections. EBOV cellular entry and infection involve uptake via macropinocytosis, navigation through the endocytic pathway, and pH-dependent escape into the cytoplasm. We report the inhibition of EBOV cell entry via selective inhibition of vacuolar (V)-ATPase by a new series of phenol-substituted derivatives of the natural product scaffold diphyllin. In cells challenged with Ebola virus, the diphyllin derivatives inhibit viral entry dependent upon structural variations to low nanomolar potencies. Mechanistically, the diphyllin derivatives had no effect on uptake and colocalization of viral particles with endocytic marker LAMP1 but directly modulated endosomal pH. The most potent effects were reversible exhibiting higher selectivity than bafilomycin or the parent diphyllin. Unlike general lysosomotrophic agents, the diphyllin derivatives showed no major disruptions of endocytic populations or morphology when examined with Rab5 and LAMP1 markers. The dilated vacuole phenotype induced by apilimod treatment or in constitutively active Rab5 mutant Q79L-expressing cells was both blocked and reversed by the diphyllin derivatives. The results are consistent with the action of the diphyllin scaffold as a selective pH-dependent viral entry block in late endosomes. Overall, the compounds show improved selectivity and minimal cytotoxicity relative to classical endosomal acidification blocking agents.

Topics: Benzodioxoles; Ebolavirus; Hemorrhagic Fever, Ebola; Humans; Lignans; Phenol; Virus Internalization

Diphyllin and its natural derivatives were identified as potent vacuolar H

Topics: Antineoplastic Agents; Benzodioxoles; Cell Line, Tumor; Drug Screening Assays, Antitumor; Lignans; Molecular Docking Simulation; Molecular Structure; Structure-Activity Relationship; Vacuolar Proton-Translocating ATPases

Diphyllin, an arylnaphthalene lignan lactone, isolated from many traditional medicinal plants, has been reported to possess anticancer and antiviral activities. Natural diphyllin and its glycosides were identified as potent vacuolar H+-ATPase (V-ATPase) inhibitors.. The aim of this study was to design and synthesize a series of heterocyclic derivatives of diphyllin as novel anticancer agents.. The targeted heterocyclic derivatives of diphyllin were synthesized from diphyllin employing etherification reaction and N-substitution reaction. Cytotoxicity of these compounds on four cancer cells was assessed by MTT assay. The inhibitory activity of V-ATPase of compound 3n was measured on MGC-803 cells. Anti-migration and anti-invasion abilities were assessed by transwell invasion assay and scratch wound assay.. Most of these derivatives displayed potent cytotoxicity on four cancer cells at submicromolar concentrations. The most potent derivative 3n has been shown to inhibit V-ATPase activity, migration and invasion abilities on MGC-803 cells at 0.75 μM.. The collective results clearly indicate that heterocyclic derivatives of diphyllin inhibit the viability, V-ATPase activity, migration and invasion of the MGC803 cells. The current findings provide valuable insights for the future development of novel diphyllin derivatives as anticancer agents.

Topics: Antineoplastic Agents; Benzodioxoles; Cell Line, Tumor; Humans; Lignans; Vacuolar Proton-Translocating ATPases

Annihilation of biofilm forming bacterial pathogens is a challenging aspect in seafood and aquaculture industries. Microbes growing as biofilms cause deleterious effects on food products leading to food spoilage or loss of shelf life. As a measure to fight biofilms, agents that prevent/disrupt biofilms are recurrently screened. The study exemplifies the bactericidal and biofilm disruption potentials of a plant derived compound, diphyllin, against fish pathogens that colonizes Oreochromis mossambicus and Oreochromis niloticus. Precisely, diphyllin disrupted Salmonella typhi biofilms by triggering reactive oxidative species (ROS). Diphyllin-induced ROS had satisfactory correlation with S. typhi cell membrane damage and intracellular DNA degradation profiles providing a putative mechanistic model. In conclusion, the study identifies diphyllin as a therapeutic and dispersal agent aimed at biofilms formed by food-borne pathogens that persistently plague food processing and aquaculture settings.

Topics: Animals; Anti-Bacterial Agents; Benzodioxoles; Biofilms; Lignans; Microbial Sensitivity Tests; Salmonella typhi

Flaviviruses such as Zika cause sporadic pandemic outbreaks worldwide. There is an urgent need for anti-Zika virus (ZIKV) drugs to prevent mother-to-child transmission of ZIKV, new infections in high-risk populations, and the infection of medical personnel in ZIKV-affected areas.. These investigations revealed that DGP inhibits ZIKV infection in vitro and in vivo.. The small molecule DGP has great potential for preclinical studies and the ability to inhibit ZIKV infection in humans.

Topics: Animals; Antiviral Agents; Benzodioxoles; Chlorocebus aethiops; Disease Models, Animal; Dose-Response Relationship, Drug; Endosomes; Flavivirus; Glycosylation; Humans; Lignans; Mice; Mice, Knockout; Microbial Sensitivity Tests; Molecular Structure; Molecular Weight; Receptor, Interferon alpha-beta; Vero Cells; Zika Virus; Zika Virus Infection

Topics: Antineoplastic Agents; Benzodioxoles; Cell Line, Tumor; Drug Screening Assays, Antitumor; Glycosides; Humans; Lignans; Molecular Structure

Diphyllin is a natural component of traditional Chinese medicine, which effectively inhibits V-ATPase activity and affects the progression of cancer. However, few studies have been conducted on esophageal cancer, and the mechanisms remain to be elucidated. The present study revealedthat diphyllin inhibited proliferation and induced S arrest in esophageal cancer cell lines TE-1 and ECA-109. Further experiments revealed that diphyllin inhibited V-ATPase activity and decreased the mRNA expression of mammalian target of rapamycin complex 1 (mTORC1), hypoxia-inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF). The present study also revealed that diphyllin inhibited proliferation and reduced the formation of new blood vessels. Diphyllin inhibited blood metastasis by regulating the mTORC1/HIF-1α-/VEGF pathway, therefore it could be considered as a new V-ATPase inhibitor to treat esophageal cancer.

Topics: Apoptosis; Benzodioxoles; Biomarkers, Tumor; Carcinoma, Squamous Cell; Cell Cycle; Cell Movement; Cell Proliferation; Cells, Cultured; Esophageal Neoplasms; Human Umbilical Vein Endothelial Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lignans; Mechanistic Target of Rapamycin Complex 1; Signal Transduction; Vacuolar Proton-Translocating ATPases; Vascular Endothelial Growth Factor A

A series of arylnaphthalene lignan lactones based on the structure of the phyllanthusmins, a class of potent natural products possessing diphyllin as the aglycone, has been synthesized and screened for activity against multiple cancer cell lines. SAR exploration was performed on both the carbohydrate and lactone moieties of this structural class. These studies have revealed the importance of functionalization of the carbohydrate hydroxy groups with both acetylated and methylated analogues showing increased potency relative to those with unsubstituted sugar moieties. In addition, the requirement for the presence and position of the C-ring lactone has been demonstrated through reduction and selective re-oxidation of the lactone ring. The most potent compound in this study displayed an IC

Topics: Antineoplastic Agents; Benzodioxoles; Cell Line, Tumor; Drug Screening Assays, Antitumor; Etoposide; Glycosides; Humans; Lactones; Lignans; Molecular Structure; Naphthalenes; Stereoisomerism; Structure-Activity Relationship; Topoisomerase II Inhibitors

Many viruses use endosomal pathways to gain entry into cells and propagate infection. Sensing of endosomal acidification is a trigger for the release of many virus cores into the cell cytosol. Previous efforts with inhibitors of vacuolar ATPase have been shown to block endosomal acidification and affect viral entry, albeit with limited potential for therapeutic selectivity. In this study, four novel series of derivatives of the vacuolar ATPase inhibitor diphyllin were synthesized to assess their potential for enhancing potency and anti-filoviral activity over cytotoxicity. Derivatives that suitably blocked cellular entry of Ebola pseudotyped virus were further evaluated as inhibitors of endosomal acidification and isolated human vacuolar ATPase activity. Several compounds with significant increases in potency over diphyllin in these assays also separated from cytotoxic doses in human cell models by >100-fold. Finally, three derivatives were shown to be inhibitors of replication-competent Ebola viral entry into primary macrophages with similar potencies and enhanced selectivity toward antiviral activity.

Topics: Antiviral Agents; Benzodioxoles; Cell Survival; Ebolavirus; HEK293 Cells; Humans; Hydrogen-Ion Concentration; Lignans; Structure-Activity Relationship; Vacuolar Proton-Translocating ATPases; Virus Internalization

Influenza virus infections are a major public health concern worldwide. Conventional treatments against the disease are designed to target viral proteins. However, the emergence of viral variants carrying drug-resistant mutations can outpace the development of pathogen-targeting antivirals. Diphyllin and bafilomycin are potent vacuolar ATPase (V-ATPase) inhibitors previously shown to have broad-spectrum antiviral activity. However, their poor water solubility and potential off-target effect limit their clinical application.. In this study, we report that nanoparticle encapsulation of diphyllin and bafilomycin improves the drugs' anti-influenza applicability.. Using PEG-PLGA diblock copolymers, sub-200 nm diphyllin and bafilomycin nanoparticles were prepared, with encapsulation efficiency of 42% and 100%, respectively. The drug-loaded nanoparticles have sustained drug release kinetics beyond 72 hours and facilitate intracellular drug delivery to two different influenza virus-permissive cell lines. As compared to free drugs, the nanoparticulate V-ATPase inhibitors exhibited lower cytotoxicity and greater. These results demonstrate the potential of the nanoparticulate V-ATPase inhibitors for host-targeted treatment against influenza.

Topics: Animals; Antiviral Agents; Benzodioxoles; Cell Line; Dogs; Drug Liberation; Enzyme Inhibitors; Humans; Influenza, Human; Inhibitory Concentration 50; Kinetics; Lignans; Macrolides; Mice; Nanoparticles; Orthomyxoviridae; Orthomyxoviridae Infections; Vacuolar Proton-Translocating ATPases; Viral Proteins; Virus Replication

Feline infectious peritonitis (FIP), caused by a mutated feline coronavirus, is one of the most serious and fatal viral diseases in cats. The disease remains incurable, and there is no effective vaccine available. In light of the pathogenic mechanism of feline coronavirus that relies on endosomal acidification for cytoplasmic entry, a novel vacuolar ATPase blocker, diphyllin, and its nanoformulation are herein investigated for their antiviral activity against the type II feline infectious peritonitis virus (FIPV). Experimental results show that diphyllin dose-dependently inhibits endosomal acidification in fcwf-4 cells, alters the cellular susceptibility to FIPV, and inhibits the downstream virus replication. In addition, diphyllin delivered by polymeric nanoparticles consisting of poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PEG-PLGA) further demonstrates an improved safety profile and enhanced inhibitory activity against FIPV. In an in vitro model of antibody-dependent enhancement of FIPV infection, diphyllin nanoparticles showed a prominent antiviral effect against the feline coronavirus. In addition, the diphyllin nanoparticles were well tolerated in mice following high-dose intravenous administration. This study highlights the therapeutic potential of diphyllin and its nanoformulation for the treatment of FIP.

Topics: Animals; Antiviral Agents; Benzodioxoles; Cats; Cell Line; Coronavirus, Feline; Disease Models, Animal; Endosomes; Enzyme Inhibitors; Feline Infectious Peritonitis; Host-Pathogen Interactions; Lignans; Nanoparticles; Polyethylene Glycols; Vacuolar Proton-Translocating ATPases

In a search for new anti-HIV active leads from over several thousands of plant extracts, we have identified a potent plant lead. The active plant is determined as Justicia gendarussa (Acanthaceae), a medicinal plant that has been used for the treatment of injury, arthritis and rheumatism in Asia including China. Our bioassay-guided fractionation of the methanol extract of the stems and barks of the plant led to the isolation of two anti-HIV compounds, justiprocumins A and B. The compounds are identified as new arylnaphthalide lignans (ANL) glycosides. We further determined that the ANL glycosides are the chemical constituents that contribute to the anti-HIV activity of this plant. Justiprocumin B displayed potent activity against a broad spectrum of HIV strains with IC

Topics: Anti-HIV Agents; Benzodioxoles; Drugs, Chinese Herbal; Glycosides; HIV-1; Inhibitory Concentration 50; Justicia; Lignans; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular

During the process of exploring bioactive lead compounds from Phyllanthus species, two new glycosides including an arylnaphthalene lignan, diphyllin 4-O-α-L-arabinopyranosyl-(1 → 3)-α-L-arabinopyranoside (1), and a phenolic compound, 3,4,5-trimethoxybenzyl alcohol 7-O-α-L-arabinofuranosyl-(1 → 6)-β-D-glucopyranoside (2), were isolated from the methanol extract of the whole plants of Phyllanthus glaucus Wall. ex Müll. Arg. In addition, 31 known compounds, including 19 lignan derivatives (3-21), four phenylpropanoids (22-25), seven simple phenolics (26-32) and one monoterpenoid (33) were obtained. Their structures were determined on the basis of the HR-ESI-MS, 1D and 2D NMR spectroscopic analysis, and pre-column derivative/chiral HPLC analysis in case of 1 for the absolute configurations. All these compounds were obtained from P. glaucus for the first time. Moreover, the known lignan glycoside, phyllanthusmin C (5) showed in vitro cytotoxicities against HL-60, MCF-7 and SW480 cells with IC50 values of 9.2 ± 0.2, 19.2 ± 1.7 and 20.5 ± 0.9, respectively.

Topics: Antineoplastic Agents, Phytogenic; Benzodioxoles; Cell Line, Tumor; Chromatography, High Pressure Liquid; Disaccharides; Glycosides; Humans; Lignans; Magnetic Resonance Spectroscopy; Monoterpenes; Phenols; Phyllanthus; Plant Extracts; Spectrometry, Mass, Electrospray Ionization

A novel route has been developed for regioselective synthesis of highly substituted α-naphthols, binaphthols, and anthracenol through silver(I) catalyzed C(sp(3))-H/C(sp)-H, C(sp(2))-H/C(sp)-H functionalization of β-ketoesters and alkynes, respectively, in a single step using water as a solvent. This protocol exhibited broad substrate scope and paved the way for synthesis of anticancer arylnaphthalene lignan natural products such as diphyllin, taiwanin E, and justicidin A with excellent selectivity.

Topics: Alkynes; Antineoplastic Agents; Benzodioxoles; Biological Products; Catalysis; Dioxolanes; Lignans; Molecular Structure; Naphthalenes; Naphthols; Silver; Stereoisomerism

Two new (1 and 2) and four known arylnaphthalene lignan lactones (3-6) were isolated from different plant parts of Phyllanthus poilanei collected in Vietnam, with two further known analogues (7 and 8) being prepared from phyllanthusmin C (4). The structures of the new compounds were determined by interpretation of their spectroscopic data and by chemical methods, and the structure of phyllanthusmin D (1) was confirmed by single-crystal X-ray diffraction analysis. Several of these arylnaphthalene lignan lactones were cytotoxic toward HT-29 human colon cancer cells, with compounds 1 and 7-O-[(2,3,4-tri-O-acetyl)-α-L-arabinopyranosyl)]diphyllin (7) found to be the most potent, exhibiting IC50 values of 170 and 110 nM, respectively. Compound 1 showed activity when tested in an in vivo hollow fiber assay using HT-29 cells implanted in immunodeficient NCr nu/nu mice. Mechanistic studies showed that this compound mediated its cytotoxic effects by inducing tumor cell apoptosis through activation of caspase-3, but it did not inhibit DNA topoisomerase IIα activity.

Topics: Animals; Antineoplastic Agents, Phytogenic; Benzodioxoles; Caspase 3; DNA Topoisomerases, Type I; Drug Screening Assays, Antitumor; Glycosides; HT29 Cells; Humans; Lactones; Lignans; Mice; Molecular Structure; Naphthalenes; Nuclear Magnetic Resonance, Biomolecular; Phyllanthus; Vietnam

An influenza pandemic poses a serious threat to humans and animals. Conventional treatments against influenza include two classes of pathogen-targeting antivirals: M2 ion channel blockers (such as amantadine) and neuraminidase inhibitors (such as oseltamivir). Examination of the mechanism of influenza viral infection has shown that endosomal acidification plays a major role in facilitating the fusion between viral and endosomal membranes. This pathway has led to investigations on vacuolar ATPase (v-ATPase) activity, whose role as a regulating factor on influenza virus replication has been verified in extensive genome-wide screenings. Blocking v-ATPase activity thus presents the opportunity to interfere with influenza viral infection by preventing the pH-dependent membrane fusion between endosomes and virions. This study aims to apply diphyllin, a natural compound shown to be as a novel v-ATPase inhibitor, as a potential antiviral for various influenza virus strains using cell-based assays. The results show that diphyllin alters cellular susceptibility to influenza viruses through the inhibition of endosomal acidification, thus interfering with downstream virus replication, including that of known drug-resistant strains. In addition, combinatorial treatment of the host-targeting diphyllin with pathogen-targeting therapeutics (oseltamivir and amantadine) demonstrates enhanced antiviral effects and cell protection in vitro.

Topics: Amantadine; Animals; Antiviral Agents; Benzodioxoles; Drug Therapy, Combination; Drugs, Chinese Herbal; Endosomes; Enzyme Inhibitors; Humans; Influenza, Human; Lignans; Magnoliopsida; Membrane Fusion; Orthomyxoviridae; Oseltamivir; Vacuolar Proton-Translocating ATPases; Virus Replication

Recently, a novel glycosylated diphyllin derivative 11 which exhibiting potent anticancer activity by targeting topoisomerase IIα was reported by our group. In order to provide more molecules for structure-activity relationship (SAR) studies, 12 new glycosylated diphyllin analogs have been designed, synthesized, and evaluated for their biological activities. The SAR analysis revealed that (i) the sugar moiety on the diphyllin is essential for the anticancer activity; (ii) equatorial C4'-OH on the sugar is superior to the axial one, and (iii) a proper cyclic lipophilic group at the C4' and C6' of sugar might enhance the anticancer activity.

Topics: Apoptosis; Benzodioxoles; Cell Cycle Checkpoints; Cell Line, Tumor; Dioxolanes; DNA Fragmentation; DNA Topoisomerases, Type II; Drug Design; Drug Resistance, Multiple; Glycosylation; Humans; Lignans; Structure-Activity Relationship; Topoisomerase II Inhibitors

A series of diphyllin glycosides were synthesized from diphyllin by phase transfer catalysis glycosylation, deprotection, and etherification, and the structures were established by (1) H NMR, (13) C NMR, and HRMS. These glycosides were evaluated for their in vitro cytotoxicity against HCT-116, A549, and A549T cancer cell lines by MTT assay, and most of them were cytotoxic at submicromolar concentrations. They were also effective against the paclitaxel-resistant cell line A549T. The kDNA decatenation assay indicated that most of these compounds inhibited topoisomerase IIα-mediated kDNA decatenation. In addition, the in vitro tubulin polymerization study showed that compounds 5 and 6 had antimicrotubule activity with a paclitaxel-like mode of action. Taken together, these results suggest that these diphyllin glycosides act on both TopoII and tubulin.

Topics: Animals; Antineoplastic Agents; Benzodioxoles; Brain; Cell Line, Tumor; Dioxolanes; Drug Screening Assays, Antitumor; Glycosides; Humans; Inhibitory Concentration 50; Lignans; Molecular Structure; Structure-Activity Relationship; Topoisomerase II Inhibitors; Tubulin

Glycosylated natural products are reliable platforms for the development of anticancer drugs, simply due to the important features added by sugar appendages to the shape and the stereoelectronic properties of natural scaffolds. Herein, we indentified D11, a novel diphyllin glycoside with acetylated D-quinovose sugar moiety, as a potent topoisomerase IIα (Topo IIα) inhibitior. This peculiar sugar moiety endows D11 an optimal conformation with a high binding affinity for Topo IIα via hydrogen bonding to the entrance of ATPase pocket, thereby helping achieve more potent Topo II inhibition activity compared to the aglycon diphyllin. Further biochemical insights manifested that D11 significantly inhibited Topo IIα ATPase-catalyzed ATP hydrolysis in an ATP-dependent, but a DNA-independent manner. All these underlie the consequent superiority of D11 in the in vitro proliferation inhibition, apoptosis induction and the in vivo remarkable antitumor potency in xenograft mouse model. Moreover, D11 treatment also displayed no obvious body weight loss and other apparent toxicities, indicative of the restricted side effects by the virtue of sugar attachment. Taken together, a defined glycosylated manipulation of diphyllin may be a promising alternative approach in the development of novel Topo II inhibitors.

Topics: Adenosine Triphosphatases; Adenosine Triphosphate; Animals; Antigens, Neoplasm; Antineoplastic Agents; Apoptosis; Benzodioxoles; Biocatalysis; Cell Line, Tumor; Dioxolanes; DNA; DNA Topoisomerases, Type I; DNA Topoisomerases, Type II; DNA-Binding Proteins; Female; Glucosides; Glycosylation; Humans; Hydrolysis; Lignans; Mice; Mice, Inbred BALB C; Topoisomerase II Inhibitors; Xenograft Model Antitumor Assays

The natural compound diphyllin, a cytostatic lignan isolated from Cleistanthus collinus, can dramatically inhibit the proliferation and induce the apoptosis of human gastric cancer cells, SGC7901. Our study found that diphyllin can inhibit the expression of V-ATPases in a dose-dependent manner, decrease the internal pH (pHi) and reverse the transmembrane pH gradient in SGC7901 cells. Changes of the pH gradient were positively correlated with diphyllin concentration. Further study found that diphyllin treatment caused a decrease in phospho-LRP6, but not in LRP6. β-catenin in Wnt/β-catenin signaling and its target genes, c-myc and cyclin-D1, were also decreased with the inhibition of V-ATPases. Therefore, diphyllin could be characterized as a new V-ATPase inhibitor in treating gastric cancer and inhibiting the phosphorylation of LRP6 in Wnt/β-catenin signaling.

Topics: Adenocarcinoma; Animals; Apoptosis; Benzodioxoles; Cell Line, Tumor; Cell Proliferation; Dioxolanes; Enzyme Inhibitors; Extracellular Space; Humans; Hydrogen-Ion Concentration; Intracellular Space; Lignans; Low Density Lipoprotein Receptor-Related Protein-6; Mice; Mice, Inbred BALB C; Neoplasm Invasiveness; Stomach Neoplasms; Vacuolar Proton-Translocating ATPases; Xenograft Model Antitumor Assays

Lignans are natural phytochemicals which exhibit multiple pharmacological effects such as anti-inflammation, antivirus and anti-tumor activities. Whether they have effects on neural tissues and ion channels is still unknown. The effects of several arylnaphathalene lignans purified from Taiwania cryptomerioides on voltage-gated K(+) (Kv) channels in mouse neuroblastoma N2A cells were examined. These lignans included Taiwanin E, helioxanthin (HXT) and diphyllin. All lignans showed inhibitory effects on Kv channels and HXT was the most potent compound (IC(50)=1.7 μM). The mechanism of HXT block was further investigated. Its action was found to be extracellular but not intracellular. HXT accelerated current decay, caused a left-shift in steady-state inactivation curve but had no effect on voltage-dependence of activation. HXT block was unaffected by intracellular K(+) concentrations. Further, it did not affect ATP-sensitive K(+) channels. Our data therefore suggest that HXT is a potent and specific blocker of Kv channels, possibly with an inhibitory mechanism involving acceleration of slow inactivation.

Topics: Animals; Benzodioxoles; Cell Line, Tumor; Cupressaceae; Dioxolanes; Lignans; Mice; Neuroblastoma; Plant Extracts; Potassium Channel Blockers; Potassium Channels, Voltage-Gated

Dissolution of the inorganic phase of bone by the osteoclasts mediated by V-ATPase and ClC-7 is a prerequisite for bone resorption. Inhibitors of osteoclastic V-ATPase or ClC-7 are novel approaches for inhibition of osteoclastic bone resorption. By testing natural compounds in acidification assays, diphyllin was identified. We characterized diphyllin with respect to the pharmacological effects on osteoclasts.. Osteoclastic acidification of the resorption lacuna and bone resorption requires activity of both V-ATPase and the chloride channel ClC-7. Inhibition of these processes represents a novel approach for treatment of bone metabolic disorders. We identified diphyllin, a novel inhibitor of V-ATPase, and characterized this natural compound with respect to activity in human osteoclasts.. Diphyllin was tested in the acid influx assay and V-ATPase assay using bovine chromaffin granules. Human osteoclasts were generated from CD14+ monocytes cultured with macrophage-colony stimulating factor (M-CSF) and RANKL. The effect of diphyllin on lysosomal acidification in human osteoclasts was studied using acridine orange. The effect of diphyllin on bone resorption by osteoclasts was measured as release of C-terminal cross-linked telopeptide of type I collagen (CTX-I) and calcium into the supernatants and by scoring pit area. Osteoclast number, TRACP activity, and cell viability were measured. Furthermore, the effect of diphyllin on bone nodule formation was tested using the mouse osteoblast cell line MC3T3-E1.. In the acid influx assay, diphyllin potently inhibited the acid influx (IC50 = 0.6 nM). We found that diphyllin inhibited V-ATPase with an IC50 value of 17 nM, compared with 4 nM for bafilomycin A1. Moreover, diphyllin dose-dependently inhibited lysosomal acidification in human osteoclasts. Furthermore, we found that diphyllin inhibited human osteoclastic bone resorption measured by CTX-I (IC50 = 14 nM), calcium release, and pit area, despite increasing TRACP activity, numbers of osteoclasts, and cell viability. Finally, diphyllin showed no effect on bone formation in vitro, whereas bafilomycin A1 was toxic.. We identified a natural compound that potently inhibits V-ATPase and thereby lysosomal acidification in osteoclasts, which leads to abrogation of bone resorption. Because recent studies indicate that inhibition of the osteoclastic acidification leads to inhibition of resorption without inhibiting formation, we speculate that diphyllin is a potential novel treatment for bone disorders involving excessive resorption.

Topics: Acids; Adrenal Medulla; Animals; Benzodioxoles; Biological Transport; Bone Resorption; Cattle; Cell Survival; Cells, Cultured; Dioxolanes; Enzyme Inhibitors; Humans; Hydrogen-Ion Concentration; Lignans; Molecular Structure; Osteoclasts; Vacuolar Proton-Translocating ATPases

The present study focuses on eudesmin (bicyclic lignan, 0.15 % of dry leaves) and diphyllin (arylnaphthalene lignan, 0.1 % of dry roots), both isolated from H. perforatum Kar. et Kir, a Rutaceae species endemic to Uzbekistan. We first compared their specificity for cancer cells with those of etoposide and podophyllotoxin by screening their cytotoxicity on 3 healthy cell-lines and 7 sensitive or resistant human solid cancer lines. We then tested their capacity to reverse P-glycoprotein-mediated multidrug resistance (MDR) by assaying dye and drug uptake in MDR1-transfected Madin-Darby canine kidney (MDCK-MDR1) and doxorubicine-resistant human breast carcinoma cells (MCF7/Dox). Eudesmin displays IC (50) values > 100 microM on all tested lines. Our data provide the first demonstration that this non-toxic lignan reverses Pgp-mediated drug efflux and supports the hypothesis that it may inhibit resistance mediated by MDR1 and MRP proteins. Even if its reversal activity is insufficient for clinical application, its capacity to accumulate [(3)H]-vinblastine in MDCK/MDR1 and MCF7/Dox cells suggests that eudesmin may positively affect the bioavailability and, thereby, the therapeutic potency of anticancer drugs in Pgp-overexpressing cells. Diphyllin exhibits IC (50) values ranging from 10 (- 6) to 10 (- 4) M. It is markedly less toxic than podophyllotoxin (IC (50) : 13 - 61 nM), but exhibits tumoricidal effects close to those of etoposide. Unfortunatly, it is 65-fold more toxic than etoposide on human primary fibroblasts. Consequently, it has no value as an anticancer drug. Its value as raw material for the hemisynthesis of anticancer drugs is discussed.

Topics: Antineoplastic Agents, Phytogenic; ATP Binding Cassette Transporter, Subfamily B, Member 1; Benzodioxoles; Cell Line, Tumor; Dioxolanes; Drug Resistance, Neoplasm; Etoposide; Furans; Humans; Lignans; Phytotherapy; Plant Extracts; Plant Leaves; Plant Roots; Podophyllotoxin; Rutaceae

Diphyllin isolated from Haplophyllum bucharicum Litv. (Rutaceae), an endemic plant of Uzbekistan, displayed a moderate antiproliferative activity towards human monocytes (IC50 = 35.2 microM) and Leishmania promastigotes (IC50 = 14.4 microM), by a mechanism of action that involved interaction with macromolecules and resulted in cell cycle arrest in the S-phase and inhibition of protein synthesis. In the intracellular amastigote form of the parasite, diphyllin exerted a strong specific inhibitory activity (IC50 = 0.2 microM) resulting from the inhibition of parasite internalization within macrophages. This property was mainly due to modulation of macrophage phagocytosis and, to a lesser extent, it also involved interference with surface molecules of the promastigote membrane.

Topics: Animals; Antiprotozoal Agents; Benzodioxoles; Cell Cycle; Dioxolanes; Leishmania; Leishmaniasis; Lignans; Macrophages; Parasitic Sensitivity Tests; Phytotherapy; Plant Components, Aerial; Plant Extracts; Rutaceae

Chemical examination of the aerial parts of Cleistanthus collinus afforded the arylanphthalide lignans, cleistanone (1), diphyllin (2), cleistanthins A (3), C (4) and D (5), and 4-O-(3"-O-methyl-beta-D-glucopyranosyl)-diphyllin (6). The first compound is a new member of the rare group of arylnaphthalide lignans containing an alkoxy group on the lactone ring. The structure of the compound was determined from its spectral data, chemical transformations and partial synthesis from diphyllin (2). The new lignan, 1 and its acetyl derivative, 7 were found to exhibit cytotoxicity against MT(2) cell lines.

Topics: Acetylation; Antineoplastic Agents, Phytogenic; Benzodioxoles; Cell Line, Tumor; Chromatography, Thin Layer; Dioxolanes; Euphorbiaceae; Humans; Lignans; Magnetic Resonance Spectroscopy; Spectrometry, Mass, Electrospray Ionization; Spectrophotometry, Ultraviolet

A new lignan glycoside, 4-O-alpha-L-arabinopyranosyl-(1' "-->2' ')-beta-D-apiofuranosyldiphyllin (2), named procumbenoside A, and 11 known compounds were isolated from the whole plant of Justicia procumbens. The structure of 2 was established by spectral analysis and chemical methods. The known compounds justicidin A (1), diphyllin (3), and tuberculatin (4) showed potent cytotoxic effects against a number of cancer cells in vitro. Compounds 1 and 4 also strongly enhanced tumor-necrosis factor-alpha (TNF-alpha) generation from mouse macrophage-like RAW 264.7 cells stimulated with lipopolysaccharide (LPS).

Topics: Animals; Antineoplastic Agents, Phytogenic; Benzodioxoles; Cell Line, Transformed; Dioxolanes; Drug Screening Assays, Antitumor; Glycosides; Inhibitory Concentration 50; Lignans; Lipopolysaccharides; Macrophage Activation; Macrophages; Mice; Mice, Inbred Strains; Nitric Oxide; Nuclear Magnetic Resonance, Biomolecular; Plants, Medicinal; Spectrophotometry, Ultraviolet; Taiwan; Tumor Necrosis Factor-alpha

Ten antiviral lignans, seven known (justicidins A, B, C and D, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate) and three new compounds, justicidinosides A (justicidin C 6'-O-glucoside), B (justicidin A 6'-O-glucoside) and C (justicidin B 6'-O-glucoside), were isolated from a methanolic extract of the aerial parts of Justicia procumbens var. leucantha. Justicidins A and B, diphyllin, diphyllin apioside and diphyllin apioside-5-acetate showed strong antiviral activity (the MIC were less than 0.25 microgram ml-1, respectively) against vesicular stomatitis virus and low cytotoxicity (the MTC were larger than 31 micrograms ml-1, respectively) against cultured rabbit lung cells (RL-33).

Topics: Animals; Antiviral Agents; Benzodioxoles; Cell Line; Cell Survival; China; Dioxolanes; Glycosides; Lignans; Lung; Molecular Structure; Plants, Medicinal; Rabbits; Spectrometry, Mass, Fast Atom Bombardment; Vesicular stomatitis Indiana virus

Topics: Benzodioxoles; Chromatography, Thin Layer; Densitometry; Dioxolanes; Dioxoles; Growth Inhibitors; Lignans; Plants, Toxic; Spectrometry, Fluorescence