Corrigendum to "Quercitrin loaded cyclodextrin based nanosponge as a promising approach for management of lung cancer and COVID-19" [J. Drug Deliv. Sci. Technol. 77 (2022) 103921]

[This corrects the article DOI: 10.1016/j.jddst.2022.103921.].

Quercitrin loaded cyclodextrin based nanosponge as a promising approach for management of lung cancer and COVID-19

Lung cancer and pandemic acute respiratory disease, COVID-19, are examples of the most worldwide widespread diseases. The aim of the current study is to develop cyclodextrin based nanosponge (CD-NS) for loading the flavonoid drug, quercitrin (QCT). This is to improve its solubility in an attempt to enhance its activity against lung cancer as well as SARS-CoV-2 virus responsible for COVID-19. Preparation of CD-NS was performed by ultrasound-assisted synthesis method. Two CDs were employed, namely, β cyclodextrin (βCD) and 2-hydroxy propyl-β-cyclodextrin (2-HPβCD) that were crosslinked with diphenyl carbonate, one at a time. QCT loaded CD-NS revealed entrapment efficiency and particle size ranged between 94.17 and 99.03% and 97.10–325.90 nm, respectively. QCT loaded 2-HPβCD-NS revealed smaller particle size compared with that of QCT loaded βCD-NS. Zeta potential absolute values of the prepared formulations were >20 mV, indicating physically stable nanosystems. The selected formulations were investigated by Fourier transform infrared spectroscopy, X-ray powder diffraction and scanning electron microscopy which proved the formation of QCT loaded CD-NS exhibiting porous structure. QCT exhibited partial and complete amorphization in βCD-NS and 2-HPβCD-NS, respectively. In vitro release revealed an improved release of QCT from CD-NS formulations. The biological activity of free QCT and QCT loaded CD-NS was investigated against lung cancer cell line A549 as well as SARS-CoV-2 virus. The results revealed that IC₅₀ values of free QCT against lung cancer cell line A549 and SARS-CoV-2 were higher than those exhibited by QCT loaded CD-NS by 1.57–5.35 and 5.95–26.95 folds, respectively. QCT loaded 2-HPβCD-NS revealed enhanced in vitro release and superior biological activity compared with QCT loaded βCD-NS.

Determinants of having severe acute respiratory syndrome coronavirus 2 neutralizing antibodies in Egypt

BACKGROUND

Reported laboratory-confirmed COVID-19 cases underestimate the true burden of disease as cases without laboratory confirmation, and asymptomatic and mild cases are missed by local surveillance systems. Population-based seroprevalence studies can provide better estimates of burden of disease by taking into account infections that were missed by surveillance systems. Additionally, little is known about the determinants of seroconversion in community settings.

METHODS

We conducted a cross-sectional serologic survey among 888 participants in Egypt.

RESULTS

Neutralizing antibodies were detected in 30% of study volunteers. Age and educational level were associated with being seropositive as people older than 70 years and people with graduate degrees had lower seroprevalence. Self-reporting cases having COVID-19-related symptoms such as fever, malaise, headache, dyspnea, dry cough, chest pain, diarrhea, and loss of taste or smell were all associated with having antibodies. Fever and loss of taste or smell were strong predictors with odds ratios of 2.1 (95% confidence interval: 1.3-3.5) and 4.5 (95% confidence interval: 2.6-7.8), respectively.

CONCLUSIONS

Our results can guide COVID-19 prevention and control policies and assist in determining the immunity level in some Egyptian communities.

Naturally Available Flavonoid Aglycones as Potential Antiviral Drug Candidates against SARS-CoV-2

Flavonoids are important secondary plant metabolites that have been studied for a long time for their therapeutic potential in inflammatory diseases because of their cytokine-modulatory effects. Five flavonoid aglycones were isolated and identified from the hydrolyzed aqueous methanol extracts of Anastatica hierochuntica L., Citrus reticulata Blanco, and Kickxia aegyptiaca (L.) Nabelek. They were identified as taxifolin (1), pectolinarigenin (2), tangeretin (3), gardenin B (4), and hispidulin (5). These structures were elucidated based on chromatographic and spectral analysis. In this study, molecular docking studies were carried out for the isolated and identified compounds against SARS-CoV-2 main protease (Mpro) compared to the co-crystallized inhibitor of SARS-CoV-2 Mpro (α-ketoamide inhibitor (KI), IC50 = 66.72 µg/mL) as a reference standard. Moreover, in vitro screening against SARS-CoV-2 was evaluated. Compounds 2 and 3 showed the highest virus inhibition with IC50 12.4 and 2.5 µg/mL, respectively. Our findings recommend further advanced in vitro and in vivo studies of the examined isolated flavonoids, especially pectolinarigenin (2), tangeretin (3), and gardenin B (4), either alone or in combination with each other to identify a promising lead to target SARS-CoV-2 effectively. This is the first report of the activity of these compounds against SARS-CoV-2.

Sinapic Acid Suppresses SARS CoV-2 Replication by Targeting Its Envelope Protein

SARS CoV-2 is still considered a global health issue, and its threat keeps growing with the emergence of newly evolved strains. Despite the success in developing some vaccines as a protective measure, finding cost-effective treatments is urgent. Accordingly, we screened a number of phenolic natural compounds for their in vitro anti-SARS CoV-2 activity. We found sinapic acid (SA) selectively inhibited the viral replication in vitro with an half-maximal inhibitory concentration (IC50) value of 2.69 µg/mL with significantly low cytotoxicity (CC50 = 189.3 µg/mL). Subsequently, we virtually screened all currently available molecular targets using a multistep in silico protocol to find out the most probable molecular target that mediates this compound's antiviral activity. As a result, the viral envelope protein (E-protein) was suggested as the most possible hit for SA. Further in-depth molecular dynamic simulation-based investigation revealed the essential structural features of SA antiviral activity and its binding mode with E-protein. The structural and experimental results presented in this study strongly recommend SA as a promising structural motif for anti-SARS CoV-2 agent development.

Incidence, household transmission, and neutralizing antibody seroprevalence of Coronavirus Disease 2019 in Egypt: Results of a community-based cohort

SARS-CoV-2 virus is transmitted in closed settings to people in contact with COVID-19 patients such as healthcare workers and household contacts. However, household person-to-person transmission studies are limited. Households participating in an ongoing cohort study of influenza incidence and prevalence in rural Egypt were followed. Baseline enrollment was done from August 2015 to March 2017. The study protocol was amended in April 2020 to allow COVID-19 incidence and seroprevalence studies. A total of 290 households including 1598 participants were enrolled and followed from April to October 2020 in four study sites. When a participant showed respiratory illness symptoms, a serum sample and a nasal and an oropharyngeal swab were obtained. Swabs were tested by RT-PCR for SARS-CoV-2 infection. If positive, the subject was followed and swabs collected on days three, six, nine, and 14 after the first swab day and a serum sample obtained on day 14. All subjects residing with the index case were swabbed following the same sampling schedule. Sera were collected from cohort participants in October 2020 to assess seroprevalence. Swabs were tested by RT-PCR. Sera were tested by Microneutralization Assay to measure the neutralizing antibody titer. Incidence of COVID-19, household secondary attack rate, and seroprevalence in the cohort were determined. The incidence of COVID-19 was 6.9% and the household secondary attack rate was 89.8%. Transmission within households occurred within two-days of confirming the index case. Infections were asymptomatic or mild with symptoms resolving within 10 days. The majority developed a neutralizing antibody titer by day 14 post onset. The overall seroprevalence among cohort participants was 34.8%. These results suggest that within-household transmission is high in Egypt. Asymptomatic or mild illness is common. Most infections seroconvert and have a durable neutralizing antibody titer.

FDA-Approved Drugs with Potent In Vitro Antiviral Activity against Severe Acute Respiratory Syndrome Coronavirus 2

(1) Background: Drug repositioning is an unconventional drug discovery approach to explore new therapeutic benefits of existing drugs. Currently, it emerges as a rapid avenue to alleviate the COVID-19 pandemic disease. (2) Methods: Herein, we tested the antiviral activity of anti-microbial and anti-inflammatory Food and Drug Administration (FDA)-approved drugs, commonly prescribed to relieve respiratory symptoms, against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the viral causative agent of the COVID-19 pandemic. (3) Results: Of these FDA-approved antimicrobial drugs, Azithromycin, Niclosamide, and Nitazoxanide showed a promising ability to hinder the replication of a SARS-CoV-2 isolate, with IC50 of 0.32, 0.16, and 1.29 µM, respectively. We provided evidence that several antihistamine and anti-inflammatory drugs could partially reduce SARS-CoV-2 replication in vitro. Furthermore, this study showed that Azithromycin can selectively impair SARS-CoV-2 replication, but not the Middle East Respiratory Syndrome Coronavirus (MERS-CoV). A virtual screening study illustrated that Azithromycin, Niclosamide, and Nitazoxanide bind to the main protease of SARS-CoV-2 (Protein data bank (PDB) ID: 6lu7) in binding mode similar to the reported co-crystalized ligand. Also, Niclosamide displayed hydrogen bond (HB) interaction with the key peptide moiety GLN: 493A of the spike glycoprotein active site. (4) Conclusions: The results suggest that Piroxicam should be prescribed in combination with Azithromycin for COVID-19 patients.