Unveiling Annona Reticulata's Bioactive Arsenal for Enhanced Antibiotic Effects.

OBJECTIVE: To study the antibacterial and phytochemical activities of bioactive elements in the leaves of Annona reticulata Linn, a historically used Bangladeshi medicinal plant. METHODS: Shade-dried and crushed plant leaves were soaked with various solvents to obtain samples for different chemical analyses. All extracts were selected for antimicrobial, physicochemical, and Pharmacological investigations. The antimicrobial activity was evaluated using disc diffusion assay, and broth microdilution methods determined potentiation of the activities of the antibiotic antibacterial activity of the plant extracts was investigated using either gram-positive or gram-negative pathogenic wild-type bacteria. RESULTS: From the initial phytochemical and pharmacological studies, it was clear that all extracts, methanol, chloroform, and ethyl acetate, of the leaves of A. reticulata, were proven to process potent bioactive constituents. While differential antimicrobial properties were found to be possessed by all extracts, methanolic extract was the most potent one against all tested microorganisms. It also has potentiated the activities of antibiotics in E. coli. CONCLUSION: Bioactive constituents in the plant extracts were shown to possess phytochemical and antimicrobial activities. More investigation is needed to segregate the chemical components responsible for the respective phytochemical and antimicrobial activities.

A molecular modelling approach for identifying antiviral selenium-containing heterocyclic compounds that inhibit the main protease of SARS-CoV-2: an in silico investigation.

Coronavirus disease 2019 (COVID-19), an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared a global pandemic by the World Health Organization, and the situation worsens daily, associated with acute increases in case fatality rates. The main protease (Mpro) enzyme produced by SARS-CoV-2 was recently demonstrated to be responsible for not only viral reproduction but also impeding host immune responses. The element selenium (Se) plays a vital role in immune functions, both directly and indirectly. Thus, we hypothesised that Se-containing heterocyclic compounds might curb the activity of SARS-CoV-2 Mpro. We performed a molecular docking analysis and found that several of the selected selenocompounds showed potential binding affinities for SARS-CoV-2 Mpro, especially ethaselen (49), which exhibited a docking score of -6.7 kcal/mol compared with the -6.5 kcal/mol score for GC376 (positive control). Drug-likeness calculations suggested that these compounds are biologically active and possess the characteristics of ideal drug candidates. Based on the binding affinity and drug-likeness results, we selected the 16 most effective selenocompounds as potential anti-COVID-19 drug candidates. We also validated the structural integrity and stability of the drug candidate through molecular dynamics simulation. Using further in vitro and in vivo experiments, we believe that the targeted compound identified in this study (ethaselen) could pave the way for the development of prospective drugs to combat SARS-CoV-2 infections and trigger specific host immune responses.