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.

Cell proliferation activity delineated by molecular docking of four new compounds isolated from the aerial parts of Suaeda monoica Forssk. ex. J.F. Gmel.

Using different chromatographic methods, four new compounds were isolated from the aerial parts of Suaeda monoica (Chenopodiaceae) along with 2-hydroxy-1-naphthoic acid (SCM-3). The structures of the new compounds were established as 6'-hydroxy-10'-geranilanyl naphtha-1-oate (SMC-1), 4,4,8ß,10ß-Tetramethyl-9ß-isobutanyl decalin-13-ol-13-O-ß-D-xylopyranoside (SCM-2), 6'-(2-hydroxynaphthalen-3-yl) hexanoic acid (SCM-4) and 1'-(2-Methoxy-3-naphthyl)-4'-(2''-methylbenzoyl)-n-butane (SMC-5) by IR, EIMS and NMR (1 & 2D) analyses. All compounds (50 µg/mL) were tested for cell proliferative potential on cultured human liver cell HepG2 cells by MTT assay. The results revealed a marked cell proliferative potential of all compounds (1.42-1.48 fold) as compared to untreated control. The results of molecular docking and binding with specific proteins such as PTEN (Phosphatase and Tensin homolog) and p53 also justify the cell proliferative potential of the isolated compounds. Glide program with Schrodinger suit 2018 was used to evaluate the binding between SMC compounds and proteins (PTEN and p53). The binding affinity of all compounds was in order of 104-105 M-1 towards both PTEN and p53. All the SMC compounds have been found to bind at the active site of PTEN, thereby may prevent the binding of phosphatidylinositiol 3,4,5-triphosphate (PI3P). In the locked position, PTEN would not be able to hydrolyze PI3P and hence the PI3P regulated signaling pathway remains active. Similarly, SMC molecules were found to interact with the amino acid residues (Ser99, Thr170, Gly199, and Asp224) which are critically involved in the formation of tetrameric p53. The blockage of p53 to attain its active conformation thus may prevent the recruitment of p53 on DNA and hence may promote cell proliferation.

Hepatoprotective effect of Solanum surattense leaf extract against chemical- induced oxidative and apoptotic injury in rats.

BACKGROUND: Of over 35 Saudi plants traditionally used to treat liver disorders, majority still lack scientific validations. We therefore, evaluated the anti-oxidative, anti-apoptotic and hepatoprotective potential of Solanum surattense leaves total ethanol-extract (SSEE). METHODS: The cytoprotective (4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide/ MTT assay) and anti-apoptotic (caspase-3/7) potential of SSEE (25-200 µg/mL) were assessed in cultured HepG2 cells against dichlorofluorescein (DCFH)-induced toxicity. The hepatoprotective salutation of SSEE (100 and 200 mg/kg.bw/day) in carbon tetrachloride (CCl4)-intoxicated rats was evaluated by serum biochemistry and histopathology. The anti-oxidative activity of SSEE (31.25-500 µg/mL) was tested by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and linoleic acid bleaching assays. Also, SSEE was subjected to qualitative phytochemical analysis, and standardized by validated high-performance liquid chromatography (HPTLC). RESULTS: SSEE at doses 50, 100 and 200 µg/mL showed HepG2 cell proliferative and protective potential by about 61.0, 67.2 and 95%, respectively through inhibition of caspase-3/7 against DCFH-toxicity. In CCl4-injured rats, SSEE (200 mg/kg) significantly (P < 0.001) normalized serum transaminases, alkaline phosphatase, bilirubin, cholesterol, triglycerides, and total protein, including tissue malondialdehyde and nonprotein sulfhydryls levels, supported by the liver histopathology. SSEE further showed strong in vitro anti-oxidative and anti-lipid peroxidative activities, evidenced by the presence of alkaloids, flavonoids, tannins, sterols and saponins. Identification of ß-sitosterol (3.46 µg/mg) strongly supported the anti-oxidative and hepatoprotective salutation of SSEE. CONCLUSION: Our findings suggest the therapeutic potential of S. surattense against chemical-induced oxidative stress and liver damage. However, isolation of the active principles and elucidation of mechanism of action remain to be addressed.

The anti-hepatitis B virus therapeutic potential of anthraquinones derived from Aloe vera.

Although the approved hepatitis B virus (HBV)-polymerase inhibitors (e.g., lamivudine) often lead to drug-resistance, several natural products have shown promising efficacies. Though Aloe vera (AV) gel and its constituents are shown inhibitors of many viruses, their anti-HBV activity still remains elusive. We therefore, tested the anti-HBV potential of AV extract and its anthraquinones in hepatoma cells, including molecular docking, high-performance thin layer chromatography (HPTLC), and cytochrome P450 (CYP3A4) activation analyses. Our anti-HBV assays (HBsAg/HBeAg Elisa) showed maximal inhibition of viral antigens production by aloe-emodin (~83%) > chrysophanol (~62%) > aloin B (~61%) > AV extract (~37%) in HepG2.2.15 cells. Interestingly, the effect of aloe-emodin was comparable with lamivudine (~86%). Moreover, sequential treatment with lamivudine (pulse) followed by aloe-emodin (chase) enhanced the efficacy of monotherapy by ~12%. Docking (AutoDock Vina) of the anthraquinones indicated strong interactions with HBV-polymerase residues that formed stable complexes with high Gibbs's free energy. Further, identification of aloe-emodin and aloin B by validated HPTLC in AV extract strongly endorsed its anti-HBV potential. In addition, our luciferase-reporter gene assay of transfected HepG2 cells showed moderate induction of CYP3A4 by aloe-emodin. In conclusion, this is the first report on anti-HBV potential of AV-derived anthraquinones, possibly via HBV-polymerase inhibition. Of these, although aloin B exhibits novel antiviral effect, aloe-emodin appears as the most promising anti-HBV natural drug with CYP3A4 activating property towards its enhanced therapeutic efficacy.

The in vitro and in vivo anti-hepatotoxic, anti-hepatitis B virus and hepatic CYP450 modulating potential of Cyperus rotundus.

In the present study we investigated the hepatotoprotective, hepatitis B virus (HBV) inhibitory and hepatic CYP450 enzyme (CYP3A4) modulatory potential of Cyperus rotundus rhizome fractions. The crude ethanol-extract, including different organic and aqueous fractions were tested for in vitro cytoprotection on HepG2 cells (MTT assay), followed by in vivo evaluation in Wistar rats (serum biochemistry and lipid profile). The in vitro anti-HBV activity was tested on HepG2.2.15 cells (HBsAg and HBeAg Elisa). Of these, the n-butanol and aqueous fractions showed the most promising, dose-dependent hepatoprotection in DCFH-injured HepG2 cells. Further, in CCl4-injured rats, oral administration of C. rotundus (100 and 200 mg/kg·bw/day) significantly normalized serum markers of healthy liver function (SGOT, SGPT, GGT, ALP and bilirubin) and lipid profile (cholesterol, HDL, LDL, VLDL, TG and MDA), including tissue NP-SH and TP levels. Compared to other fractions, the ethyl acetate, n-butanol and aqueous fractions exhibited the best inhibitory effects on viral HBsAg and HBeAg secretions in dose- and time-dependent manner. In addition, reporter gene assay (Dual-luciferase) of transfected HepG2 cells showed mild activation of nuclear PXR-mediated CYP3A4 gene by the three active fractions. Taken together, C. rotundus showed very promising hepatoprotective and anti-HBV potential in experimental settings. In addition, this is the first report on modulation of CYP3A4 by C. rotundus that suggests its safe consumption in relation to drug metabolism and efficacy. Our data could therefore, provide the basis for the ethnobotanical medicinal use of C. rotundus in metabolic liver disorder and hepatitis B patients.

Plant-derived antiviral drugs as novel hepatitis B virus inhibitors: Cell culture and molecular docking study.

Despite high anti-HBV efficacies, while the nucleoside analogs (e.g., lamivudine) lead to the emergence of drug-resistance, interferons (e.g., IFN-α causes adverse side-effects. Comparatively, various natural or plant products have shown similar or even better efficacy. Hence, new antiviral strategies must focus not only on synthetic molecules but also on potential natural compounds. In this report, we have combined the in vitro cell culture and in silico molecular docking methods to assess the novel anti-HBV activity and delineate the inhibitory mechanism of selected plant-derived pure compounds of different classes. Of the tested (2.5-50 µg/ml) twelve non-cytotoxic compounds, ten (10 µg/ml) were found to maximally inhibit HBsAg production at day 5. Compared to quercetin (73%), baccatin III (71%), psoralen (67%), embelin (65%), menisdaurin (64%) and azadirachtin (62%) that showed high inhibition of HBeAg synthesis, lupeol (52%), rutin (47%), ß-sitosterol (43%) and hesperidin (41%) had moderate efficacies against HBV replication. Further assessment of quercetin in combination with the highly active compounds, enhanced its anti-HBV activity up to 10%. Being the most important drug target, a 3-D structure of HBV polymerase (Pol/RT) was modeled and docked with the active compounds, including lamivudine as standard. Docking of lamivudine indicated strong interaction with the modeled HBV Pol active-site residues that formed stable complex (∆G = -5.2 kcal/mol). Similarly, all the docked antiviral compounds formed very stable complexes with HBV Pol (∆G = -6.1 to -9.3 kcal/mol). Taken together, our data suggest the anti-HBV potential of the tested natural compounds as novel viral Pol/RT inhibitors.

Novel plant inducers of PXR-dependent cytochrome P450 3A4 expression in HepG2 cells.

The cytochrome P450 3A4 (CYP3A4) is the most abundant CYP450 enzyme involved in the metabolism of endogenous products and xenobiotics, including prescription drugs and herbals. Modulation of hepatic CYP3A4 gene expression via nuclear receptors, like pregnane X receptor (PXR), is a major cause of adverse effects like drug-unresponsiveness and toxicity. In the present study, ethanol extracts of 58 medicinal plants, belonging to 27 families, were evaluated for potential activities in CYP3A4 induction in HepG2 cells by reporter gene assay. For PXR-mediated CYP3A4 induction, a 50 µg/ml concentration was used for all non-cytotoxic plants extracts. Rifampicin (10 µM) and DMSO (0.1%) were used as standard inducer and untreated (negative) control, respectively. The comparative fold-induction of CYP34A by the plant extracts in relation to the untreated control was determined. As a result, Dodonaea angustifolia (2.62 fold; P < 0.0001) was found to be the most promising inducer of CYP3A4, followed by Euphorbia tirucalli (1.95 fold; P = 0.0004), Alternanthera pungens (1.74 fold, P = 0.0035), and Ficus palmata (1.65 fold; P = 0.0097). Further phytochemical characterizations of the active plants are therefore, warranted.

Analysis of antioxidative and antiviral biomarkers ß-amyrin, ß-sitosterol, lupeol, ursolic acid in Guiera senegalensis leaves extract by validated HPTLC methods.

Guiera senegalensis J.F. Gmel is a broad-spectrum African folk- medicinal plant, having activities against fowlpox and herpes viruses. Very recently, we have shown the anti-hepatitis B vius (HBV) potential of G. senegalensis leaves extract (GSLE). Here, we report the antioxidative and hepatoprotective efficacy of GSLE, including HPTLC quantification of four biomarkers of known antioxidative and antiviral activities. In cultured liver cells (HuH7) GSLE attenuated DCFH-induced oxidative stress and cytotoxicity. This was supported by in vitro DPPH radical-scavenging and ß-carotene-linoleic acid bleaching assays that showed strong antioxidant activity of GSLE. Further, two simple and sensitive HPTLC methods (I and II) were developed and validated to quantify ß-amyrin, ß- sitosterol, lupeol, ursolic acid in GSLE. While HPTLC-I (hexane: ethylacetate; 75:25; v/v) enabled quantification of ß-amyrin (Rf = 0.39; 20.64 µg/mg) and ß-sitosterol (Rf = 0.25; 18.56 µg/mg), HPTLC-II (chloroform: methanol; 97:3; v/v) allowed estimation of lupeol (Rf = 0.47; 6.72 µg/mg) and ursolic acid (Rf = 0.23; 5.81 µg/mg) in GSLE. Taken together, the identified biomarkers strongly supported the antioxidant and anti-HBV potential of GSLE, suggesting its activity via abating the oxidative stress. To our knowledge, this is the first report on HPTLC analysis of these biomarkers in G. senegalensis that could be adopted for standardization and quality-control of herbal-formulations.

Evolution and Emergence of Pathogenic Viruses: Past, Present, and Future.

Incidences of emerging/re-emerging deadly viral infections have significantly affected human health despite extraordinary progress in the area of biomedical knowledge. The best examples are the recurring outbreaks of dengue and chikungunya fever in tropical and sub-tropical regions, the recent epidemic of Zika in the Americas and the Caribbean, and the SARS, MERS, and influenza A outbreaks across the globe. The established natural reservoirs of human viruses are mainly farm animals, and, to a lesser extent, wild animals and arthropods. The intricate "host-pathogen-environment" relationship remains the key to understanding the emergence/re-emergence of pathogenic viruses. High population density, rampant constructions, poor sanitation, changing climate, and the introduction of anthropophilic vectors create selective pressure on host-pathogen reservoirs. Nevertheless, the knowledge and understanding of such zoonoses and pathogen diversity in their known non-human reservoirs are very limited. Prevention of arboviral infections using vector control methods has not been very successful. Currently, new approaches to protect against food-borne infections, such as consuming only properly cooked meats and animal products, are the most effective control measures. Though significant progress in controlling human immunodeficiency virus and hepatitis viruses has been achieved, the unpredictable nature of evolving viruses and the rare occasions of outbreaks severely hamper control and preventive modalities.

New Cytotoxic Seco-Type Triterpene and Labdane-Type Diterpenes from Nuxia oppositifolia.

Chromatographic purification of the n-hexane and dichloromethane extracts of Nuxia oppositifolia aerial parts, growing in Saudi Arabia, resulted in the isolation and characterization of three new labdane-type diterpene acids, 2ß-acetoxy-labda-7-en-15-oic acid (1), 2ß-acetoxy-7-oxolabda-8-en-15-oic acid (2), 2ß-acetoxy-6-oxolabda-7-en-15-oic acid (3), and one new seco-triterpene, 3,4-seco olean-12-en-3,30 dioic acid (4), together with 10 known lupane, oleanane and ursane-type triterpenes, as well as the common phytosterols, ß-sitosterol and stigmasterol (5-16). Their structures have been assigned on the basis of different spectroscopic techniques including 1D and 2D NMR. Moreover, 13 of the isolated compounds were tested on the human cancer cell lines HeLa (cervical), A549 (lung) and MDA (breast), and most of the compounds showed potent cytotoxic activities in vitro.

Quantitative analysis of rutin, quercetin, naringenin, and gallic acid by validated RP- and NP-HPTLC methods for quality control of anti-HBV active extract of Guiera senegalensis.

CONTEXT: Guiera senegalensis J.F. Gmel (Combretaceae) is a folk medicinal plant used in various metabolic and infectious diseases. In addition to its antiviral activities against herpes and fowlpox, the anti-HBV efficacy is very recently reported. OBJECTIVE: To develop and validate simple, sensitive RP-/NP-HPTLC methods for quantitative determination of biomarkers rutin, quercetin, naringenin, and gallic acid in the anti-HBV active G. senegalensis leaves ethanol-extract. MATERIALS AND METHODS: RP-HPTLC (rutin & quercetin; phase- acetonitrile:water, 4:6) and NP-HPTLC (naringenin & gallic acid; phase- toluene:ethyl acetate:formic acid, 6:4:0.8) were performed on glass-backed silica gel plates 60F254-RP18 and 60F254, respectively. The methods were validated according to the ICH guidelines. RESULTS: Well-separated and compact spots (Rf) of rutin (0.52 ± 0.006), quercetin (0.23 ± 0.005), naringenin (0.56 ± 0.009) and gallic acid (0.28 ± 0.006) were detected. The regression equations (Y) were 12.434x + 443.49, 10.08x + 216.85, 11.253x + 973.52 and 11.082x + 446.41 whereas the coefficient correlations (r2) were 0.997 ± 0.0004, 0.9982 ± 0.0001, 0.9974 ± 0.0004 and 0.9981 ± 0.0001, respectively. The linearity ranges (ng/spot) were 200-1400 (RP-HPTLC) and 100-1200 (NP-HPTLC). The LOD/LOQ (ng/band) were 33.03/100.1 (rutin), 9.67/29.31 (quercetin), 35.574/107.8 (naringenin), and 12.32/37.35 (gallic acid). Gallic acid (7.01 µg/mg) was the most abundant biomarker compared to rutin (2.42 µg/mg), quercetin (1.53 µg/mg) and naringenin (0.14 µg/mg) in the extract. CONCLUSION: The validated NP-/RP-HPTLC methods were simple, accurate, and sensitive for separating and quantifying antiviral biomarkers in G. senegalensis, and endorsed its anti-HBV activity. The developed methods could be further employed in the standardization and quality-control of herbal formulations.