An ultra-sensitive SARS-CoV-2 antigen optical biosensor based on angiotensin converting enzyme 2 (ACE-2) functionalized magnetic-fluorescent silica nanoparticles

This work reports on the design and synthesis of an angiotensin-converting enzyme 2 (ACE-2) functionalized magnetic fluorescent silica nanoparticles (Fe-FSNP) as a biosensing platform to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen. Iron oxide (Fe3O4) nanoparticles were synthesized via ultrasonic-assisted coprecipitation and then coated with fluorescent silica nanoparticles (FSNP) through thesol-gelmethod forming the Fe-FSNP samples. Silica obtained from local geothermal powerplant was used in this work and Rhodamine B was chosen as the incorporated fluorescent dye, hence this reports for the first time ACE-2 was immobilized on the natural silica surface. The Fe-FSNP nanoparticle consists of a 18-25 nm magnetic core and a silica shell with a thickness of 30 nm as confirmed from the transmission electron microscopy image. Successful surface functionalization of the Fe-FSNP with ACE-2 as bioreceptor was conducted through hydrosylilation reaction and confirmed through the Fourier transform infrared spectroscopy. The detection of SARS-Cov-2 antigen by Fe-FSNP/ACE2 was measured through the change in its maximum fluorescence intensity at 588 nm where fluorescence- quenching had occurred. The biosensing platform showed a rapid response at 30 min with a linear range of 10-6to 10-2μg ml-1. The magnetic-fluorescent properties of the nanoparticle enables an ultra-sensitive detection of SARS-Cov-2 antigen with the limit of detection as low as 2 fg ml-1.

The SARS-CoV-2 Mpro Dimer-Based Screening System: A Synthetic Biology Tool for Identifying Compounds with Dimerization Inhibitory Potential

The COVID-19 endemic remains a global concern. The search for effective antiviral candidates is still needed to reduce disease risk. However, the availability of high biosafety level laboratory facilities for drug screening is limited in number. To address this issue, a screening system that could be utilized at lower biosafety levels remains essential. This study aimed to develop a novel SARS-CoV-2 main protease (Mpro) dimer-based screening system (DBSS) utilizing synthetic biology in Escherichia coli BL21(DE3). We linked the SARS-CoV-2 Mpro with the DNA-binding domain of AraC regulatory protein, which regulates the reporter gene expression. Protein modeling and molecular docking showed that saquinavir could bind to AraC-Mpro both in its monomer and dimer forms. The constructed DBSS assay indicated the screening system could detect saquinavir inhibitory activity at a concentration range of 4-10 μg/mL compared to the untreated control (P ≤ 0.05). The Vero E6 cell assay validated the DBSS result that saquinavir at 4-10 μg/mL exhibited antiviral activity against SARS-CoV-2. Our DBSS could be used for preliminary screening of numerous drug candidates that possess a dimerization inhibitor activity of SARS-CoV-2 Mpro and also minimize the use of a high biosafety level laboratory.

Porphyrin-derived carbon dots for an enhanced antiviral activity targeting the CTD of SARS-CoV-2 nucleocapsid

BACKGROUND

Since effective antiviral drugs for COVID-19 are still limited in number, the exploration of compounds that have antiviral activity against SARS-CoV-2 is in high demand. Porphyrin is potentially developed as a COVID-19 antiviral drug. However, its low solubility in water restricts its clinical application. Reconstruction of porphyrin into carbon dots is expected to possess better solubility and bioavailability as well as lower biotoxicity.

METHODS AND RESULTS

In this study, we investigated the antiviral activity of porphyrin and porphyrin-derived carbon dots against SARS-CoV-2. Through the in silico analysis and assessment using a novel drug screening platform, namely dimer-based screening system, we demonstrated the capability of the antivirus candidates in inhibiting the dimerization of the C-terminal domain of SARS-CoV-2 Nucleocapsid. It was shown that porphyrin-derived carbon dots possessed lower cytotoxicity on Vero E6 cells than porphyrin. Furthermore, we also assessed their antiviral activity on the SARS-CoV-2-infected Vero E6 cells. The transformation of porphyrin into carbon dots substantially augmented its performance in disrupting SARS-CoV-2 propagation in vitro.

CONCLUSIONS

Therefore, this study comprehensively demonstrated the potential of porphyrin-derived carbon dots to be developed further as a promisingly safe and effective COVID-19 antiviral drug.

Curcumin-derived carbon-dots as a potential COVID-19 antiviral drug

Even entering the third year of the COVID-19 pandemic, only a small number of COVID-19 antiviral drugs are approved. Curcumin has previously shown antiviral activity against SARS-CoV-2 nucleocapsid, but its poor bioavailability limits its clinical uses. Utilizing nanotechnology structures, curcumin-derived carbon-dots (cur-CDs) were synthesized to increase low bioavailability of curcumin. In-silico analyses were performed using molecular docking, inhibition of SARS-CoV-2 nucleocapsid C-terminal domain (N-CTD) and antiviral activity were assessed in dimer-based screening system (DBSS) and in vitro respectively. Curcumin bound with the N-CTD at ΔG = -7.6 kcal/mol, however modifications into cur-CDs significantly improved the binding affinity and %interaction. Cur-CDs also significantly increased protection against SARS-CoV-2 in both DBSS and in vitro at MOI = 0.1. This study demonstrated the effect of post-infection treatment of curcumin and novel curcumin-derived carbon-dots on SARS-CoV-2 N-CTD dimerization. Further investigation on pre-infection and in-vivo treatment of curcumin and cur-CDs are required for a comprehensive understanding on the carbon-dots enhanced antiviral activity of curcumin against SARS-CoV-2.

Leveraging Genomic and Bioinformatic Analysis to Enhance Drug Repositioning for Dermatomyositis

Dermatomyositis (DM) is an autoimmune disease that is classified as a type of idiopathic inflammatory myopathy, which affects human skin and muscles. The most common clinical symptoms of DM are muscle weakness, rash, and scaly skin. There is currently no cure for DM. Genetic factors are known to play a pivotal role in DM progression, but few have utilized this information geared toward drug discovery for the disease. Here, we exploited genomic variation associated with DM and integrated this with genomic and bioinformatic analyses to discover new drug candidates. We first integrated genome-wide association study (GWAS) and phenome-wide association study (PheWAS) catalogs to identify disease-associated genomic variants. Biological risk genes for DM were prioritized using strict functional annotations, further identifying candidate drug targets based on druggable genes from databases. Overall, we analyzed 1239 variants associated with DM and obtained 43 drugs that overlapped with 13 target genes (JAK2, FCGR3B, CD4, CD3D, LCK, CD2, CD3E, FCGR3A, CD3G, IFNAR1, CD247, JAK1, IFNAR2). Six drugs clinically investigated for DM, as well as eight drugs under pre-clinical investigation, are candidate drugs that could be repositioned for DM. Further studies are necessary to validate potential biomarkers for novel DM therapeutics from our findings.

Cytotoxic Test of Cassia alata L. Leaves Ethanol Extracts, Fractions, and Main Compounds against MCF-7 Cells

Cancer is the primary cause of death worldwide. Conventional cancer treatment is known to be less than optimal because of its chemoresistance and toxicity to normal cells. The search for cancer drugs from natural ingredients is still being carried out as an effort to overcome these problems. Cassia alata L. leaf extract is known to have antibacterial and antitumor activities. The main compounds of C. alata L. leaves (emodin, aloe-emodin, and kaempferol) have been reported to have antiproliferative activity. This study aimed to examine the cytotoxic activity of the C. alata L. leaves ethanol extracts, fractions, and main compounds against breast cancer cells (MCF-7). Cytotoxic activity was carried out by the MTT method. IC50 was determined by linear regression analysis describing the relationship between concentration and % cell viability. The results showed that aloe-emodin, emodin, and kaempferol had better cytotoxic activity than the extract and fractions of the C. alata L. leaves with IC50 values respectively 12.7 ppm, 18.1 ppm, and 131.3 ppm.Keywords: Breast cancer, cytotoxic assay, Cassia alata L., ketepeng cina, MCF-7.

The inhibitory activity of Cassia alata leaves extract on denv-2 replication infected mice

Dengue fever is widely prevalent in Indonesia and many other tropical countries. There has been no antiviral protection against DENV (dengue virus) due to the scarcity of animal models that replicate the symptoms of its infection in humans. Subsequently, Balb/c mice were used to optimize the animal models that were infected with DENV, and measurements of DENV titer, platelet count and leukocytes counts were taken after six days of CA (Cassia alata leaves extract) treatment to examine the inhibitory activity of viral replication on dengue-infected mice. The results showed that CA significantly reduced DENV titer and increased platelet count compared to the control group (P < 0.05) but had no significant effect on leukocyte counts (P > 0.05). Therefore, it could be implied that Cassia alata could be further investigated for medication against DENV, prospectively.

Magnetic Graphene-Based Nanosheets with Pluronic F127-Chitosan Biopolymers Encapsulated α-Mangosteen Drugs for Breast Cancer Cells Therapy

In this study, multifunctional chitosan-pluronic F127 with magnetic reduced graphene oxide (MRGO) nanocomposites were developed through the immobilization of chitosan and an amphiphilic polymer (pluronic F127) onto the MRGO. Physicochemical characterizations and in-vitro cytotoxicity of nanocomposites were investigated through field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, particle size analysis, vibrating sample magnetometer, Raman spectroscopy and resazurin-based in-vitro cytotoxicity assay. FESEM observation shows that the magnetic nanoparticles could tethered on the surface of MRGO, promoting the magnetic properties of the nanocomposites. FTIR identification analysis revealed that the chitosan/pluronic F127 were successfully immobilized on the surface of MRGO. Furthermore, α-mangosteen, as a model of natural drug compound, was successfully encapsulated onto the chitosan/pluronic F127@MRGO nanocomposites. According to in-vitro cytotoxicity assay, α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could significantly reduce the proliferation of human breast cancer (MFC-7) cells. Eventually, it would be anticipated that the novel α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could be promoted as a new potential material for magnetically targeting and killing cancer cells.

Physicochemical and phytochemical standardization, and antibacterial evaluation of Cassia alata leaves from different locations in Indonesia

Physicochemical analysis for simplicia and extract, respectively: water content 2.12–4% for simplicia; drying losses 3.93–5.47% and 8.51–19.76%; total ash 5.14–9.41% and 6.22–17.07%; total ash acid-insoluble content 0.29–5.41% and 0.52–3.82%; total ash water-soluble content 1.26–7.14% and 1.43–8.54%; water-soluble content 19.60–39.43% and 58.45–77.51%; ethanol-soluble content 13.99–33.76% and 59.79–75.39%. The phytochemical analysis showed that the extracts contain alkaloids, flavonoids, saponins, tannins, and terpenoids. Total flavonoids and total phenolics content were 9.86–15.74% QE/g and 6.67–7.65% GAE/g, respectively. Based on LC-MS results, the extract contained emodin, kaempferol, kaempferol-3,7-diglucoside, and kaempferol-3-O-β-D-glucopyranoside. The extracts possessed antibacterial activity against bacteria tested.

Antiviral effect of <em>Archidendron pauciflorum</em> leaves extract to hepatitis C virus: An <em>in vitro</em> study in JFH-1 strain

Background: Hepatitis C virus (HCV) is a leading cause of chronic liver diseases. Drug resistance to the regimen is also increasing. Hence, there is a need for new anti-HCV agents that are less toxic and more efficacious. The aim of this study is to evaluate the  possibility of A. pauciflorum extracts can be a antiviral drug.Methods: Huh-7it cells were infected with the HCV genotype 2a strain JFH-I in the presence of methanol extracts of Archidenron pauciflorum. The methanol extract further partition used n-hexane, ethyl acetate, n-butanol, and water showed in which butanol extracts exerted the strongest IC50 (6.3 g/ml). Further, the butanol fraction was fractionated and yielded into 13 fractions.Results: The methanol extract of the leaves of A. pauciflorum exhibited concentration dependent inhibition against the JFH1 strain of HCV genotype 2a with an IC50 is 72.5 μg/ml. The butanol fraction exhibited the highest anti-HCV activity with an IC50 is 6.3 μg/ml. The butanol fraction was fractionated which yielded 13 fractions. Fractions 5 and 13 exhibited high anti-HCV activities with IC50 is 5.0 μg/ml and 8.5 μg/ml and a time-of-addition study demonstrated that fraction 5 inhibited viral infection at the post-entry step, whereas fraction 13 primarily inhibited the viral entry step.Conclusion: The extract A. pauciflorum can be used as a herbal-based antiviral drug.