Negative regulation of thyroid adenoma-associated protein (THADA) in the cardiac glycoside-induced anti-cancer effect.

Cardiac glycosides, known as inhibitors of Na+,K+-ATPase, have anti-cancer effects such as suppression of cancer cell proliferation and induction of cancer cell death. Here, we examined the signaling pathway elicited by cardiac glycosides in the human hepatocellular carcinoma HepG2 cells and human epidermoid carcinoma KB cells. Three kinds of cardiac glycosides (ouabain, oleandrin, and digoxin) inhibited the cancer cell proliferation and decreased the expression level of thyroid adenoma-associated protein (THADA). Interestingly, the knockdown of THADA inhibited cancer cell proliferation, and the proliferation was significantly rescued by re-expression of THADA in the THADA-knockdown cells. In addition, the THADA-knockdown markedly decreased the expression level of L-type amino acid transporter LAT1. Cardiac glycosides also reduced the LAT1 expression. The LAT1 inhibitor, JPH203, significantly weakened the cancer cell proliferation. These results suggest that the binding of cardiac glycosides to Na+,K+-ATPase negatively regulates the THADA-LAT1 pathway, exerting the anti-proliferative effect in cancer cells.

Synthesis of 4'-Thionucleoside Analogues Bearing a C2' Stereogenic All-Carbon Quaternary Center.

The design of novel 4'-thionucleoside analogues bearing a C2' stereogenic all-carbon quaternary center is described. The synthesis involves a highly diastereoselective Mukaiyama aldol reaction, and a diastereoselective radical-based vinyl group transfer to generate the all-carbon stereogenic C2' center, along with different approaches to control the selectivity of the N-glycosidic bond. Intramolecular SN2-like cyclization of a mixture of acyclic thioaminals provided analogues with a pyrimidine nucleobase. A kinetic bias favoring cyclization of the 1',2'-anti thioaminal furnished the desired ß-D-4'-thionucleoside analogue in a 7:1 ratio. DFT calculations suggest that this kinetic resolution originates from additional steric clash in the SN2-like transition state for 1',4'-trans isomers, causing a significant decrease in their reaction rate relative to 1',4'-cis counterparts. N-glycosylation of cyclic glycosyl donors with a purine nucleobase enabled the formation of novel 2-chloroadenine 4'-thionucleoside analogues. These proprietary molecules and other derivatives are currently being evaluated both in vitro and in vivo to establish their biological profiles.

In Silico Approach Triterpene Glycoside of H. atra Targeting Orotidine 5-Monophosphate Decarboxylase Protein (PfOMPDC) in P. falciparum Infection Mechanism.

This study accessed the potential antimalarial activity of triterpene glycoside of H. atra through targeting orotidine 5-monophosphate decarboxylase protein (PfOMPDC) in P. falciparum by molecular docking. Nine triterpene glycosides from H. atra extract modeled the structure by the Corina web server and interacted with PfOMPDC protein by using Hex 8.0.0. The docking results were visualized and analyzed by Discovery Studio version 21.1.1. 17-Hydroxyfuscocineroside B showed the lowest binding energy in PfOMPDC interaction, which was -1,098.13 kJ/mol. Holothurin A3, echinoside A, and fuscocineroside C showed low binding energy. Nine triterpene glycosides of H. atra performed interaction with PfOMPDC protein at the same region. Holothurin A1 posed interaction with PfOMPDC protein by 8 hydrogen bonds, 3 hydrophobic interactions, and 8 unfavorable bonds. Several residues were detected in the same active sites of other triterpene glycosides. Residue TYR111 was identified in all triterpene glycoside complexes, except holothurin A3 and calcigeroside B. In summary, the triterpene glycoside of H. atra is potentially a drug candidate for malaria therapeutic agents. In vitro and in vivo studies were required for further investigation.

Cardiac glycosides inhibit early and late vaccinia virus protein expression.

Cardiac glycosides (CGs) are natural steroid glycosides, which act as inhibitors of the cellular sodium-potassium ATPase pump. Although traditionally considered toxic to human cells, CGs are widely used as drugs for the treatment of cardiovascular-related medical conditions. More recently, CGs have been explored as potential anti-viral drugs and inhibit replication of a range of RNA and DNA viruses. Previously, a compound screen identified CGs that inhibited vaccinia virus (VACV) infection. However, no further investigation of the inhibitory potential of these compounds was performed, nor was there investigation of the stage(s) of the poxvirus lifecycle they impacted. Here, we investigated the anti-poxvirus activity of a broad panel of CGs. We found that all CGs tested were potent inhibitors of VACV replication. Our virological experiments showed that CGs did not impact virus infectivity, binding, or entry. Rather, experiments using recombinant viruses expressing reporter proteins controlled by VACV promoters and arabinoside release assays demonstrated that CGs inhibited early and late VACV protein expression at different concentrations. Lack of virus assembly in the presence of CGs was confirmed using electron microscopy. Thus, we expand our understanding of compounds with anti-poxvirus activity and highlight a yet unrecognized mechanism by which poxvirus replication can be inhibited.

Expeditious Synthesis of Gwanakoside A and the Chloronaphthol Glycoside Congeners.

The synthesis of gwanakoside A, a chlorinated naphthol bis-glycoside, and its analogues was achieved through stepwise chlorination and donor-equivalent controlled regioselective phenol glycosylation with glycosyl N-phenyltrifluoroacetimidates as donors. Gwanakoside A displayed considerable inhibitory effects against various cancer cells and Staphylococcus aureus strains.

[A new benzopyran glycoside from Gentiana macrophylla].

Thirteen compounds were isolated and identified from 70% ethanol extract of the roots of Gentiana macrophylla by multi-chromatographic methods, including microporous resin, silica gel, and C_(18) reversed-phase column chromatography, as well as HPLC as follows: macrophylloside G(1), macrophylloside D(2), 5-formyl-2,3-dihydroisocoumarin(3),(+)-medicarpin(4),(+)-syringaresinol(5), liquiritigenin(6),(3R)-sativanone(7),(3R)-3'-O-methylviolanone(8), 4,2',4'-trihydroxychalcone(9), latifolin(10), gentioxepine(11), 6α-hydroxycyclonerolidol(12), and ethyl linoleate(13). Compound 1 was a new benzopyran glycoside. Compounds 4, 6-10, 12, and 13 were isolated for the first time from Gentiana plants. Compounds 1 and 2 showed promising hepatoprotective activity against D-GalN-induced AML12 cell damage at the concentration of 10 µmol·L~(-1), and compound 2 exhibited more significant activity than silybin at the same concentration.

New phenylbutenoids and terpene glycosides from Ginkgo biloba leaves.

Our continued works on the chemical constituents of Ginkgo biloba (G. biloba) leaves has led to the isolation of two novel phenylbutenoids (1, 2), along with five previously unidentified terpene glycosides (3-7). Among them, compounds 1 and 2 represent unique (Z)-phenylbutenoids, 3-6 are megastigmane glycosides, and 7 is identified as a rare bilobanone glycoside (Fig. 1). This study marks the first reported isolation of phenylbutenoid and bilobanone glycoside from G. biloba. The chemical structures of these compounds were elucidated through extensive spectroscopic analysis, including HR-ESI-MS and various 1D and 2D NMR experiments. Furthermore, the absolute configurations of these molecules were determined using Mosher's method, ECD experiments, and Cu-Kα X-ray crystallographic analyses.

Cardiac glycosides from Streblus asper with potential antiviral activity.

Ten undescribed cardiac glycosides, strasperosides A-J, together with twelve known analogues, were isolated from Streblus asper Lour. Their structures were elucidated on the basis of spectroscopic analysis, electronic circular dichroism data, and chemical methods. These cardiac glycosides showed diversity in steroid skeleton and sugar moiety. Strasperosides A and B are a pair of unusual stereoisomers featuring different orientation of the lactone motif. Ten cardiac glycosides demonstrated potent antiviral effects on HSV-1 in vitro with the IC50 values from 0.19 ± 0.08 to 1.03 ± 0.25 µM and the therapeutic indices from 66.61 ± 5.08 to 326.75 ± 11.75.

Effects of Cardiac Glycoside Digoxin on Dendritic Spines and Motor Learning Performance in Mice.

Synapse formation following the generation of postsynaptic dendritic spines is essential for motor learning and functional recovery after brain injury. The C-terminal fragment of agrin cleaved by neurotrypsin induces dendritic spine formation in the adult hippocampus. Since the α3 subunit of sodium-potassium ATPase (Na/K ATPase) is a neuronal receptor for agrin in the central nervous system, cardiac glycosides might facilitate dendritic spine formation and subsequent improvements in learning. This study investigated the effects of cardiac glycoside digoxin on dendritic spine turnover and learning performance in mice. Golgi-Cox staining revealed that intraperitoneal injection of digoxin less than its IC50 in the brain significantly increased the density of long spines (≥2 µm) in the cerebral cortex in wild-type mice and neurotrypsin-knockout (NT-KO) mice showing impairment of activity-dependent spine formation. Although the motor learning performance of NT-KO mice was significantly lower than control wild-type mice under the control condition, low doses of digoxin enhanced performance to a similar degree in both strains. In NT-KO mice, lower digoxin doses equivalent to clinical doses also significantly improved motor learning performance. These data suggest that lower doses of digoxin could modify dendritic spine formation or recycling and facilitate motor learning in compensation for the disruption of neurotrypsin-agrin pathway.

Iridoid Glycosides and Coumarin Glycoside Derivatives from the Roots of Nymphoides peltata and Their In Vitro Wound Healing Properties.

Nymphoides peltata has been used as a medicinal herb in traditional medicines to treat strangury, polyuria, and swelling. The phytochemical investigation of the MeOH extract of N. peltata roots led to the isolation of three iridoid glycosides and three coumarin glycoside derivatives, which were characterized as menthiafolin (1), threoninosecologanin (2), callicoside C (3), and scopolin (4), as well as two undescribed peltatamarins A (5) and B (6). The chemical structures of the undescribed compounds were determined by analyzing their 1 dimensional (D) and 2D nuclear magnetic resonance (NMR) spectra and using high-resolution (HR)-electrospray ionization mass spectroscopy (ESI-MS), along with the chemical reaction of acid hydrolysis. The wound healing activities of the isolated compounds 1-6 were evaluated using a HaCaT cell scratch test. Among the isolates, scopolin (4) and peltatamarin A (5) promoted HaCaT cell migration over scratch wounds, and compound 5 was the most effective. Furthermore, compound 5 significantly promoted cell migration without adversely affecting cell proliferation, even when treated at a high dose (100 µM). Our results demonstrate that peltatamarin A (5), isolated from N. peltata roots, has the potential for wound healing effects.

Glycoside constituents of Camellia amplexicaulis and their α-glucosidase inhibitory activity.

Four new glycosides, named amplexicosides A-D (1-4), and five known compounds: benzyl 2-[ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyloxy]-benzoate (5), benzyl 2-neohesperidosyloxy-6-hydroxybenzoate (6), chrysandroside A (7), chrysandroside B (8) and camelliquercetiside C (9) were isolated from the branches and leaves of Camellia amplexicaulis (Pit.) Cohen-Stuart. Their structures were elucidated using HR-ESI-MS and 1D- and 2D-NMR spectra and compared to reported NMR data. All of the isolated compounds were screened in an α-glucosidase assay. Compounds 4, 8, and 9 significantly inhibited α-glucosidase with respective IC50 values of 254.9 ± 4.2, 304.8 ± 11.9 and 228.1 ± 16.4 µM.

Antioxidant isolation and characterization from the plant Tradescantia spathacea Sw. of the Commelinaceae family.

A novel bioactive flavan glycoside was isolated by solvent extraction method with the help of Soxhlet apparatus from the methanolic extract of Tradescantia spathacea Sw. Flavan glycoside having molecular formula C20H22O10, melting point 175-1780C, molecular weight by ESI-MS m/z (M + H]+ 423, optical rotation was[α]21D-45.1(c 0.20 methanol). Its structure was determined (-)-epicatechin 7-O-alpha-L-arabinopyranoside. Various color reactions, chemical degradation (like acid hydrolysis, permethylation, and enzymatic hydrolysis), UV-Visible spectrophotometry, Fourier transforms infrared spectroscopy, electrospray ionization mass spectrometry, and nuclear magnetic resonance spectroscopy were used to establish the structure of compound (-)-(-)-epicatechin 7-O-alpha-L-arabinopyranoside.. A flavan glycoside was also tested with a DPPH assay method for antioxidant activity by using Ascorbic acid as standard. DPPH radical scavenging test data demonstrate that a flavan glycoside possesses potent antioxidant activity so this flavan glycoside can be utilized as a potent antioxidant agent.

ATP1A1/BCL2L1 predicts the response of myelomonocytic and monocytic acute myeloid leukemia to cardiac glycosides.

Myelomonocytic and monocytic acute myeloid leukemia (AML) subtypes are intrinsically resistant to venetoclax-based regimens. Identifying targetable vulnerabilities would limit resistance and relapse. We previously documented the synergism of venetoclax and cardiac glycoside (CG) combination in AML. Despite preclinical evidence, the repurposing of cardiac glycosides (CGs) in cancer therapy remained unsuccessful due to a lack of predictive biomarkers. We report that the ex vivo response of AML patient blasts and the in vitro sensitivity of established cell lines to the hemi-synthetic CG UNBS1450 correlates with the ATPase Na+/K+ transporting subunit alpha 1 (ATP1A1)/BCL2 like 1 (BCL2L1) expression ratio. Publicly available AML datasets identify myelomonocytic/monocytic differentiation as the most robust prognostic feature, along with core-binding factor subunit beta (CBFB), lysine methyltransferase 2A (KMT2A) rearrangements, and missense Fms-related receptor tyrosine kinase 3 (FLT3) mutations. Mechanistically, BCL2L1 protects from cell death commitment induced by the CG-mediated stepwise triggering of ionic perturbation, protein synthesis inhibition, and MCL1 downregulation. In vivo, CGs showed an overall tolerable profile while impacting tumor growth with an effect ranging from tumor growth inhibition to regression. These findings suggest a predictive marker for CG repurposing in specific AML subtypes.

Involvement of cardiac glycosides targeting Na/K-ATPase in their inhibitory effects on c-Myc expression via its transcription, translation and proteasomal degradation.

Cardiac glycosides (CGs) have been used for decades to treat heart failure and arrhythmic diseases. Recent non-clinical and epidemiological findings have suggested that CGs exhibit anti-tumor activities. Therefore, CGs may be repositioned as drugs for the treatment of cancer. A detailed understanding of the anti-cancer mechanisms of CGs is essential for their application to the treatment of targetable cancer types. To elucidate the factors associated with the anti-tumor effects of CGs, we performed transcriptome profiling on human multiple myeloma AMO1 cells treated with periplocin, one of the CGs. Periplocin significantly down-regulated the transcription of MYC (c-Myc), a well-established oncogene. Periplocin also suppressed c-Myc expression at the protein levels. This repression of c-Myc was also observed in several cell lines. To identify target proteins for the inhibition of c-Myc, we generated CG-resistant (C9) cells using a sustained treatment with digoxin. We confirmed that C9 cells acquired resistance to the inhibition of c-Myc expression and cell proliferation by CGs. Moreover, the sequencing of genomic DNA in C9 cells revealed the mutation of D128N in α1-Na/K-ATPase, indicating the target protein. These results suggest that CGs suppress c-Myc expression in cancer cells via α1-Na/K-ATPase, which provides further support for the anti-tumor activities of CGs.

Three new phenolic glycosides and a new lignan glycoside from Gaultheria leucocarpa var. yunnanensis.

Three new phenolic glycosides (1-3) and a new lignan glycoside (4), together with five known compounds (5-9) were isolated from the ethanol extract of the aerial part of Gaultheria leucocarpa var. yunnanensis (Franch.) T.Z.Hsu & R.C.Fang. Their structures were determined on the basis of spectroscopic techniques, experimental and calculated ECD spectra, acid hydrolysis, and enzymatic hydrolysis experiments. All the isolates were evaluated for their anti-inflammatory and antioxidant activities. Compounds 7 and 8 exhibited inhibitory effects against the LPS-induced production of NO with IC50 of 63.71 and 10.66 µM, respectively, compared to L-NMMA having an IC50 of 6.95 µM. Besides, compound 7 also represented significant DPPH radical scavenging activity with EC50 of 18.75 µM, comparable with vitamin C (EC50 = 15.77 µM).

Zika virus: Antiviral immune response, inflammation, and cardiotonic steroids as antiviral agents.

Zika virus (ZIKV) is a mosquito-borne virus first reported from humans in Nigeria in 1954. The first outbreak occurred in Micronesia followed by an outbreak in French Polynesia and another in Brazil when the virus was associated with numerous cases of severe neurological manifestations such as Guillain-Barre syndrome in adults and congenital zika syndrome in fetuses, particularly congenital microcephaly. Innate immunity is the first line of defense against ZIKV through triggering an antiviral immune response. Along with innate immune responses, a sufficient balance between anti- and pro-inflammatory cytokines and the amount of these cytokines are triggered to enhance the antiviral responses. Here, we reviewed the complex interplay between the mediators and signal pathways that coordinate antiviral immune response and inflammation as a key to understanding the development of the underlying diseases triggered by ZIKV. In addition, we summarize current and new therapeutic strategies for ZIKV infection, highlighting cardiotonic steroids as antiviral drugs for the development of this agent.

Lepiginosides A-D: three new triterpenoid saponins and a new farnesyl glycoside from the stembarks of Lepisanthes rubiginosa (roxb.) leenh.

Phytochemical investigation of methanolic extract of L. rubiginosa using modern chromatographic techniques has led to the isolation of three new triterpenoid saponins, lepiginosides A-C (1-3), a new farnesyl glycoside, lepiginoside D (4), together with lepisantheside B (5) and gleditsoside C (6). The characterization and structural elucidation of the isolated compounds were established by extensive spectroscopic data analysis and comparison with literature data. Moreover, the antibacterial activity against seven bacteria, but none is active.

Isolation and structural characterization of phytoconstituents from leaves of Bignonia binata.

Phytochemical investigation of Bignonia binata leaves led to the isolation of three new compounds: including a glycoside of simple alcohol, namely binatoside (2), 3,4-dihydroxy-N-methyl piperidin-2-one (7), and a phenyl ethanoid glycoside, namely bignanoside C (8), alongside with five known compounds; including a glycoside of simple alcohol; (2S) propane-1,2-diol 1-O-(6-O-caffeoy1)-ß-D-glucopyranoside (1), phenyl ethanoids; leucosceptoside A (3) and plantainoside C (4), and iridoids; ipolamiide (5) and strictoloside (6). The structure of the isolated compounds was elucidated by various spectroscopic methods, including 1 D and 2 D NMR experiments, HR-ESI-MS as well as by comparison with the literature.

A new megastigmane glycoside, a new organic acid glycoside and other constituents with anticomplementary activity from Artemisia halodendron.

A new megastigmane glycoside, (1R,5R,6S,7E)-megastigman-3,9-dione-7-en-6,11-diol 11-O-ß-D-glucopyranoside (1), and a new organic acid glycoside, methyl (4 R)-4-O-ß-D-glucopyranosyl-decanoate (2), together with eight known compounds (3-10), were isolated from the aerial parts of Artemisia halodendron Turcz. ex Bess. (Asteraceae). Their chemical structures were elucidated by 1 D and 2 D NMR and HR-ESI-MS spectra and DP4+ probability analysis. Among the identified compounds, compounds 5, 6 and 10 were isolated from the family Asteraceae, and compounds 3, 4 and 7-9 were identified from the genus Artemisia for the first time. All of the compounds were evaluated for their anticomplementary activity against the classical pathway (CP) and the alternative pathway (AP). Compounds 7 and 9 showed anticomplementary activity with the CH50 values of 0.31 ± 0.08 and 0.50 ± 0.09 mM, respectively.

Broad spectrum post-entry inhibitors of coronavirus replication: Cardiotonic steroids and monensin.

A small molecule screen identified several cardiotonic steroids (digitoxin and ouabain) and the ionophore monensin as potent inhibitors of HCoV-229E, HCoV-OC43, and SARS-CoV-2 replication with EC50s in the low nM range. Subsequent tests confirmed antiviral activity in primary cell models including human nasal epithelial cells and lung organoids. Addition of digitoxin, ouabain, or monensin strongly reduced viral gene expression as measured by both viral protein and RNA accumulation. Furthermore, the compounds acted post virus entry. While the antiviral activity of digitoxin was dependent upon activation of the MEK and JNK signaling pathways but not signaling through GPCRs, the antiviral effect of monensin was reversed upon inhibition of several signaling pathways. Together, the data demonstrates the potent anti-coronavirus properties of two classes of FDA approved drugs that function by altering the properties of the infected cell, rendering it unable to support virus replication.