Histologic comparison of formocresol, platelet-rich fibrin, and hesperidin in pulpotomy: A randomized trial in dogs

Aims

To histologically assess and compare formocresol (FC), platelet-rich fibrin (PRF), and hesperidin (HPN) as pulpotomy agents in dogs.

Materials and Methods

Pulpotomy was attempted from the buccal surface (class V) of 48 teeth in three mongrel dogs (Canis Lupus). Cavities were randomly allocated for three groups (n = 16) according to the pulpotomy agent used; (group I: FC (control), group II: PRF, and group III: HPN). All cavities were then sealed with zinc oxide eugenol followed by resin-modified glass ionomer restoration. Two months later, dogs were euthanized; the specimens were obtained and prepared for histological assessment followed by statistical analysis.

Results

HPN specimens showed the best dentin bridge formation and the least inflammatory signs and pulp disorganization. Followed without statistically significant difference by PRF (P ≥ 0.05). Both of HPN and PRF, however, showed a significant difference statistically (P ≤ 0.05) to FC that showed no dentin bridging with more pronounced inflammation, necrosis, and pulp disorganization.

Conclusions

For pulpotomy, HPN and PRF seemed histologically to be good substitutes for FC in the dog model.

In silico prediction of potential inhibitors for SARS-CoV-2 Omicron variant using molecular docking and dynamics simulation-based drug repurposing

BACKGROUND

In November 2021, variant B.1.1.529 of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified by the World Health Organization (WHO) and designated Omicron. Omicron is characterized by a high number of mutations, thirty-two in total, making it more transmissible than the original virus. More than half of those mutations were found in the receptor-binding domain (RBD) that directly interacts with human angiotensin-converting enzyme 2 (ACE2). This study aimed to discover potent drugs against Omicron, which were previously repurposed for coronavirus disease 2019 (COVID-19). All repurposed anti-COVID-19 drugs were compiled from previous studies and tested against the RBD of SARS-CoV-2 Omicron.

METHODS

As a preliminary step, a molecular docking study was performed to investigate the potency of seventy-one compounds from four classes of inhibitors. The molecular characteristics of the best-performing five compounds were predicted by estimating the drug-likeness and drug score. Molecular dynamics simulations (MD) over 100 ns were performed to inspect the relative stability of the best compound within the Omicron receptor-binding site.

RESULTS

The current findings point out the crucial roles of Q493R, G496S, Q498R, N501Y, and Y505H in the RBD region of SARS-CoV-2 Omicron. Raltegravir, hesperidin, pyronaridine, and difloxacin achieved the highest drug scores compared with the other compounds in the four classes, with values of 81%, 57%, 18%, and 71%, respectively. The calculated results showed that raltegravir and hesperidin had high binding affinities and stabilities to Omicron with ΔGbinding of - 75.7304 ± 0.98324 and - 42.693536 ± 0.979056 kJ/mol, respectively. Further clinical studies should be performed for the two best compounds from this study.

Identification of promising anti-EBOV inhibitors: de novo drug design, molecular docking and molecular dynamics studies

The Ebola virus (EBOV) outbreak was recorded as the largest in history and caused many fatalities. As seen in previous studies, drug repurposing and database filtration were the two major pathways to searching for potent compounds against EBOV. In this study, a deep learning (DL) approach via the LigDream tool was employed to obtain novel and effective anti-EBOV inhibitors. Based on the galidesivir (BCX4430) chemical structure, 100 compounds were collected and inspected using various in silico approaches. Results from the molecular docking study indicated that mol1_069 and mol1_092 were the best two potent compounds with a docking score of -7.1 kcal mol^-1 and -7.0 kcal mol^-1, respectively. Molecular dynamics simulations, in addition to binding energy calculations, were conducted over 100 ns. Both compounds exhibited lower binding energies than BCX4430. Furthermore, compared with BCX4430 (%Absorption = 60.6%), mol1_069 and mol1_092 scored higher values of % Absorption equal to 68.1% and 63.7%, respectively. The current data point to the importance of using DL in the drug design process instead of conventional methods such as drug repurposing or database filtration. In conclusion, mol1_069 and mol1_092 are promising anti-EBOV drug candidates that require further in vitro and in vivo investigations.

Rutin and flavone analogs as prospective SARS-CoV-2 main protease inhibitors: In silico drug discovery study

Coronavirus disease 2019 (COVID-19) is a new pandemic characterized by quick spreading and illness of the respiratory system. To date, there is no specific therapy for Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2). Flavonoids, especially rutin, have attracted considerable interest as a prospective SARS-CoV-2 main protease (M^pro) inhibitor. In this study, a database containing 2017 flavone analogs was prepared and screened against SARS-CoV-2 M^pro using the molecular docking technique. According to the results, 371 flavone analogs exhibited good potency towards M^pro with docking scores less than −9.0 kcal/mol. Molecular dynamics (MD) simulations, followed by molecular mechanics-generalized Born surface area (MM/GBSA) binding energy calculations, were performed for the top potent analogs in complex with M^pro. Compared to rutin, PubChem-129-716-607 and PubChem-885-071-27 showed better binding affinities against SARS-CoV-2 M^pro over 150 ns MD course with ΔG_binding values of −69.0 and −68.1 kcal/mol, respectively. Structural and energetic analyses demonstrated high stability of the identified analogs inside the SARS-CoV-2 M^pro active site over 150 ns MD simulations. The oral bioavailabilities of probable SARS-CoV-2 M^pro inhibitors were underpinned using drug-likeness parameters. A comparison of the binding affinities demonstrated that the MM/GBSA binding energies of the identified flavone analogs were approximately three and two times less than those of lopinavir and baicalein, respectively. In conclusion, PubChem-129-716-607 and PubChem-885-071-27 are promising anti-COVID-19 drug candidates that warrant further clinical investigations.