Novel Anti-Hepatitis B Virus Activity of Euphorbia schimperi and Its Quercetin and Kaempferol Derivatives
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ABSTRACT:
SUBMITTER: Parvez M
PROVIDER: S-EPMC8567387 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Dengue is a systemic viral infection that is transmitted to humans by Aedes mosquitoes. No vaccines or specific therapeutics are currently available for dengue. Lycorine, which is a natural plant alkaloid, has been shown to possess antiviral activities against flaviviruses. In this study, a series of novel lycorine derivatives were synthesized and assayed for their inhibition of dengue virus (DENV) in cell cultures. Among the lycorine analogues, 1-acetyllycorine exhibited the most potent anti-DENV activity (EC50 =0.4 μM) with a reduced cytotoxicity (CC50 >300 μM), which resulted in a selectivity index (CC50 /EC50 ) of more than 750. The ketones 1-acetyl-2-oxolycorine (EC50 =1.8 μM) and 2-oxolycorine (EC50 =0.5 μM) also exhibited excellent antiviral activities with low cytotoxicity. Structure-activity relationships for the lycorine derivatives against DENV are discussed. A three-dimensional quantitative structure-activity relationship model was established by using a comparative molecular-field analysis protocol in order to rationalize the experimental results. Further modifications of the hydroxy group at the C1 position with retention of a ketone at the C2 position could potentially lead to inhibitors with improved overall properties.
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Project description:BackgroundTwo important flavonoids, kaempferol and quercetin possess remarkably potent biological impacts on human health. However, their structural complexity and low abundance in nature make both bulk chemical synthesis and extraction from native plants difficult. Therefore microbial production via heterologous expression of plant enzymes can be a safe and sustainable route for their production. Despite several attempts reported in microbial hosts, the production levels of kaempferol and quercetin still stay far behind compared to many other microbial-produced flavonoids.ResultsIn this study, Saccharomyces cerevisiae was engineered for high production of kaempferol and quercetin in minimal media from glucose. First, the kaempferol biosynthetic pathway was reconstructed via screening various F3H and FLS enzymes. In addition, we demonstrated that amplification of the rate-limiting enzyme AtFLS could reduce the dihydrokaempferol accumulation and improve kaempferol production. Increasing the availability of precursor malonyl-CoA further improved the production of kaempferol and quercetin. Furthermore, the highest amount of 956 mg L- 1 of kaempferol and 930 mg L- 1 of quercetin in yeast was reached in fed-batch fermentations.ConclusionsDe novo biosynthesis of kaempferol and quercetin in yeast was improved through increasing the upstream naringenin biosynthesis and debugging the flux-limiting enzymes together with fed-batch fermentations, up to gram per liter level. Our work provides a promising platform for sustainable and scalable production of kaempferol, quercetin and compounds derived thereof.
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Project description:BackgroundDespite the great progress made in the last 10 years, alternative strategies might help improving definitive treatment options against hepatitis C virus infection.MethodsWith the aim of identifying novel inhibitors of the hepatitis C virus-1b replication targeting the viral NS3 helicase, the structures of previously reported symmetrical inhibitors of this enzyme were rationally modified, and according to docking-based studies, four novel scaffolds were selected for synthesis and evaluation in the hepatitis C virus-1b subgenomic replicon assay.ResultsAmong the newly designed compounds, one new structural family was found to inhibit the hepatitis C virus-1b replication in the micromolar range. This scaffold was chosen for further exploration and different novel analogues were synthesised and evaluated.ConclusionsDifferent new inhibitors of the hepatitis C virus genotype 1b replication were identified. Some of the new compounds show mild inhibition of the NS3 helicase enzyme.
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