Methotrexate, an anti-inflammatory drug, inhibits Hepatitis E viral replication.

Hepatitis E Virus (HEV) is a positively oriented RNA virus having a 7.2 kb genome. HEV consists of three open reading frames (ORF1-3). Of these, ORF1 codes for the enzymes Methyltransferase (Mtase), Papain-like cysteine protease (PCP), RNA helicase, and RNA-dependent RNA polymerase (RdRp). Unavailability of a vaccine or effective drug against HEV and considering the side effects associated with the off-label use of ribavirin (RBV) and pegylated interferons, an alternative approach is required by the modulation of specific enzymes to prevent the infection. HEV helicase is involved in unwinding the double-stranded RNA, RNA processing, transcriptional regulation, and pre-mRNA processing. Therefore, we screened FDA-approved compounds from the ZINC15 database against the modelled 3D structure of HEV helicase and found that methotrexate and compound A (Pubchem ID BTB07890) inhibit the NTPase and dsRNA unwinding activity leading to inhibition of HEV RNA replication. This may be further authenticated by in vivo study.

Deep-sea fungal metabolites as potential inhibitors of glucose-regulatory enzymes: In silico structure-activity analysis.

Chronic diabetes mellites related hyperglycemia is a major cause of mortality and morbidity due to further complications like retinopathy, hypertension and cardiovascular diseases. Though several synthetic anti-diabetes drugs specifically targeting glucose-metabolism enzymes are available, they have their own limitations, including adverse side-effects. Unlike other natural or marine-derived pharmacologically important molecules, deep-sea fungi metabolites still remain under-explored for their anti-diabetes potential. We performed structure-based virtual screening of deep-sea fungal compounds selected by their physiochemical properties, targeting crucial enzymes viz., α -amylase, α -glucosidase, pancreatic-lipoprotein lipase, hexokinase-II and protein tyrosine phosphatase-1B involved in glucose-metabolism pathway. Following molecular docking scores and MD simulation analyses, the selected top ten compounds for each enzyme, were subjected to pharmacokinetics prediction based on their AdmetSAR- and pharmacophore-based features. Of these, cladosporol C, tenellone F, ozazino-cyclo-(2,3-dihydroxyl-trp-tyr), penicillactam and circumdatin G were identified as potential inhibitors of α -amylase, α -glucosidase, pancreatic-lipoprotein lipase, hexokinase-II and protein tyrosine phosphatase-1B, respectively. Our in silico data therefore, warrants further experimental and pharmacological studies to validate their anti-diabetes therapeutic potential.

Isolation and Characterization of Two Chalcone Derivatives with Anti-Hepatitis B Virus Activity from the Endemic Socotraen Dracaena cinnabari (Dragon's Blood Tree).

Hepatitis B virus (HBV) infection is prevalent and continues to be a global health concern. In this study, we determined the anti-hepatitis B virus (HBV) potential of the Socotra-endemic medicinal plant Dracaena cinnabari and isolated and characterized the responsible constituents. A bioassay-guided fractionation using different chromatographic techniques of the methanolic extract of D. cinnabari led to the isolation of two chalcone derivatives. Using a variety of spectroscopic techniques, including 1H-, 13C-, and 2D-NMR, these derivatives were identified as 2,4'-dihydroxy-4-methoxydihydrochalcone (compound 1) and 2,4'-dihydroxy-4-methoxyhydrochalcone (compound 2). Both compounds were isolated for the first time from the red resin (dragon's blood) of D. cinnabari. The compounds were first evaluated for cytotoxicity on HepG2.2.15 cells and 50% cytotoxicity concentration (CC50) values were determined. They were then evaluated for anti-HBV activity against HepG2.2.15 cells by assessing the suppression of HBsAg and HBeAg production in the culture supernatants and their half maximum inhibitory concentration (IC50) and therapeutic index (TI) values were determined. Compounds 1 and 2 indicated inhibition of HBsAg production in a dose- and time-dependent manner with IC50 values of 20.56 and 6.36 µg/mL, respectively.

The anti-hepatitis B virus and anti-hepatotoxic efficacies of solanopubamine, a rare alkaloid from Solanum schimperianum.

Chronic liver disease caused by hepatitis B virus (HBV) remains an important health issue. Though there are effective HBV-polymerase inhibitors (e.g., lamivudine), their prolonged use leads to emergence of drug-resistant (polymerase mutant) strains. Several herbal formulations and phytochemicals have been therefore, reported as potential anti-HBV agents with no sign of resistance in experimental and clinical settings. In this study, we assessed the anti-HBV as well as hepatoprotective salutations of solanopubamine, a rare alkaloid isolated from S. schimperianum. In cultured HepG2.2.15 cells, solanopubamine showed marked anti-HBV activity in a time and dose-dependent manner. Solanopubamine (30 µM) efficiently inhibited HBsAg and HBeAg expressions by 66.5%, 70.5%, respectively as compared to 82.5% and 86.5% respective inhibition by lamivudine (2 µM) at day 5. Molecular docking analyses of solanopubamine revealed formations of stable complexes with lamivudine-sensitive as well as lamivudine-resistant polymerase through interactions of catalytic 'YMDD/YIDD' motif residues. Moreover, solanopubamine attenuated DCFH-induced oxidative and apoptotic damage and restored HepG2 cell viability by 28.5%, and downregulated caspase-3/7 activations by 33%. Further docking analyses of solanopubamine showed formation of stable complexes with caspase-3/7. Taken together, our data demonstrates promising anti-HBV and anti-hepatotoxic therapeutic potential of solanopubamine, and warrants further molecular and pharmacological studies.

Structural exploration of Y-domain reveals its essentiality in HEV pathogenesis.

Hepatitis E virus (HEV) is a major causative agent of hepatitis E infections across the globe. Although the essentiality of HEV nonstructural polyprotein (pORF1) putative Y-domain (Yd) has been established in viral pathogenesis, its structural-functional role remains elusive. The current research discusses the novel exploration on Yd protein expression, purification, biophysical characterization and structure-based docking analysis. The codon optimized synthetic gene and optimized expression parameters i.e., 5 h induction with 0.25 mM IPTG at 37 °C, resulted in efficient production of Yd protein (~40 kDa) in E. coli BL21(DE3) cells. Majority of the recombinant Yd (rYd) protein expressed as inclusion bodies was solubilized in 0.5% N-lauroylsarcosine and purified using Ni-NTA chromatography. Circular dichroism (CD) and UV visible absorption spectroscopic studies on Yd revealed both secondary and tertiary structure stability in alkaline range (pH 8.0-10.0), suggesting correlation with its physiological activity. Thus, loss in structure at low pH perhaps play crucial role in cytoplasmic-membrane interaction. The biophysical data were in good agreement with insilico structural analyses, which suggested mixed α/ß fold, non-random and basic nature of Yd protein. Furthermore, due to Yd protein essentiality in HEV replication and pathogenesis, it was considered as a template for docking and drug-likeness analyses. The 3D modeling of Yd protein and structure-based screening and drug-likeness of inhibitory compounds, including established antiviral drugs led to the identification of top nine promising candidates. Nonetheless, in vitro studies on the predicted interaction of Yd with intracellular-membrane towards establishing replication-complexes as well as validations of the proposed therapeutic agents are warranted.

New terpenic and phenolic compounds from Suaeda monoica reverse oxidative and apoptotic damages in human endothelial cells.

Elevation in hyperglycemia-associated methylglyoxal level can trigger vascular endothelial cells oxidative stress and apoptosis. The present work assesses the cell proliferative, anti-oxidative and anti-apoptotic potential of Suaeda monoica derived four new terpenes: a norsesquaterpenol (normonisesquaterpenol), a monocyclic triterpenoid (suaedanortriterpene dione), an aromatic monoterpenic ester and a labdane-type norditerpenic xyloside as well as two new phenols: an alkylated ß-naphthol and a ß-methoxy naphthalene in cultured human umbilical vein endothelial cells (HUVEC). Of these, suaedanortriterpenedione (53.7%), normonisesquaterpenol (51.4%) and norditerpenic xyloside (48%) showed the most promising cell proliferative activities compared to others. Moreover, normonisesquaterpenol, norditerpenic xyloside and suaedanortriterpenedione efficiently reversed the oxidative and apoptotic cell damage via downregulation of capase-3/7 by 44.3%, 42.2% and 39.4%, respectively against dichlorofluorescin, whereas by 46.2%, 43.5% and 42.5%, respectively against methylglyoxal. Aminoguanidine, the reference drug inhibited caspase-3/7 activity by 56.2% and 54.7% through attenuation of dichlorofluorescin and methylglyoxal, respectively. Further in silico molecular docking analysis revealed formation of stable complexes between the tested compounds and caspase-3/7. Conclusively, we for the first time demonstrate the growth stimulatory, anti-oxidative and anti-apoptotic salutations of S. monoica derived novel compounds in human endothelial cells. This warrants their further assessment as vascular cell protective and rejuvenating therapeutics, especially in hyperglycemic conditions.

Corrigendum to "New terpenic and phenolic compounds from Suaeda monoica reverse oxidative and apoptotic damages in human endothelial cells". [Saudi Pharm. J. 29(10) (2021) 1102-1111].

[This corrects the article DOI: 10.1016/j.jsps.2021.08.007.].

Novel polycyclic pyrroloquinazoline alkaloids from Anisotes trisulcus and their biological activity.

Two new polycyclic pyrroloquinazoline alkaloids with unprecedented skeleton, anisulcusines A (1) and B (2), along with four known compounds (3-6), were identified from the aerial parts of Anisotes trisulcus (Forssk.) Nees. To our knowledge, anisulcusines A and B are the first polycyclic pyrroloquinazoline alkaloids that possess a unique N-methyl-1,2-dihydro-1'H-spiro[benzo[d][1,3]oxazine moiety. The chemical structures of the new compounds were elucidated through extensive spectroscopic analyses and high-resolution mass spectroscopy. Anisulcusine B (2) exerted moderate cytotoxic effect on cultured human hepatoma (HuH7) cells, whereas compounds 1 and 3-5 exhibited mild cell proliferative or growth stimulatory activity. HIGHLIGHTS Two new polycyclic pyrroloquinazoline alkaloids from Anisotes trisulcus. Structures were elucidated on the basis of 1D- and 2D-NMR and HR-ESI-MS spectra. Compound (2) exerted moderate cytotoxic effect against human hepatoma (HuH7) cells. Compounds (1, 3-5) exhibited mild cell proliferative or growth stimulatory activity.

Oncoglabrinol C, a new flavan from Oncocalyx glabratus protects endothelial cells against oxidative stress and apoptosis, and modulates hepatic CYP3A4 activity.

Active herbal or natural compounds have high chemical diversity and specificity than synthetic drugs. Recently, we have validated the hypoglycemic salutation of Oncocalyx glabratus in rodent model, and demonstrated the activation of PPARα/γ by its newly ioslated flavan derivative Oncoglabrinol C (5,3'-Dihydroxyflavan 7-4'-O-digallate) in liver cells (HepG2). Here we evaluated the potential of Oncoglabrinol C against Dichlorofluorescin (DCFH) and Methylglyoxal (MGO) induced endothelial cells (HUVEC) oxidative and apoptotic damage, including activation of PXR-mediated hepatic CYP3A4. Our MTT assay showed protection of ~57% and ~63.5% HUVEC cells by 10 and 20 µg/ml doses of Oncoglabrinol C, respectively through attenuating DCFH triggered free-radicals. Also, the two doses effectively protected ~53% and ~65.5% cells, respectively by reversing MGO toxicity. In DCFH and MGO treated cells, Oncoglabrinol C (20 µg/ml) effectively downregulated caspase 3/7 activity by ~33% and ~43.5%, respectively. Moreover, in reporter gene (dual-luciferase) assay, Oncoglabrinol C (20 µg/ml) moderately activated hepatic CYP3A4. Molecular docking of Oncoglabrinol C indicated its strong interactions with cellular caspase 3/7, PPARα/γ and PXR proteins, which supported its anti-apoptotic (antagonistic) as well as pro-hypoglycemic and PXR/CYP activating (agonistic) activities. Taken together, our findings demonstrated the potential of Oncoglabrinol C in reversing the endothelial oxidative and apoptotic damage as well as in the activation of hepatic CYP3A4. This warrants further evaluations of Oncoglabrinol C and related compounds towards developing effective and safe drugs against diabetes associated cardiovascular disorders.

Bioassay-guided isolation of anti-hepatitis B virus flavonoid myricetin-3-O-rhamnoside along with quercetin from Guiera senegalensis leaves.

Recently, we have shown in vitro anti-hepatitis B virus (HBV) activity of G. senegalensis J.F. Gmel leaves, and Identified quercetin and other flavonoids by HPTLC. Here we report bioassay-directed fractionation of G. senegalensis leaves using column chromatography and isolation of two flavonoinds from the n-butanol fraction, their structure determination (1H NMR, 13C NMR and 2D-NMR) and assessment of antiviral activities (HBsAg and HBeAg assay) in HBV-reporter HepG2.2.2.15 cells. Further molecular docking was performed against HBV polymerase (Pol/RT) and capsid (Core) proteins as well as host-receptor sodium taurocholate co-transporting polypeptide (NTCP). The two isolated bioactive compounds were identified as quercetin and myricetin-3-O-rhamnoside. Quercetin significantly inhibited synthesis of HBsAg and HBeAg by about 60% and 62%, respectively as compared to myricetin-3-O-rhamnoside by 44% and 35%, respectively. Molecular docking of the two anti-HBV flavonoids revealed their higher binding affinities towards Pol/RT than Core and NTCP. In conclusion, this is the first report on anti-HBV active myricetin-3-O-rhamnoside along with quercetin isolated from G. senegalensis leaves. Their possible mode of anti-HBV activities are suggested through binding with viral Pol/RT and Core as well as host NTCP proteins.