In silico binding analysis of lutein and rosmarinic acid against envelope domain III protein of dengue virus

In Vitro Determination of Antimicrobial, Antioxidant and Antiviral Properties of Greek Plant Extracts

The medicinal potential of plant extracts, especially their antimicrobial, antioxidant, antiviral and cytotoxic properties, has gained significant attention in recent years. This study examined the in vitro bioactivities of several selected Greek medicinal plants, like Eucalyptus globulus L., Thymus vulgaris L., Salvia rosmarinus L. and Ocimum basilicum L., are well-known for their traditional therapeutic use. Minimum inhibitory concentration (MIC) assays were used to evaluate the antimicrobial activity of the extracts against pathogenic bacteria. The antioxidant activity was carried out using the DPPH method, while the cytotoxicity of the plants was determined using the Alamar Blue method. In addition, the antiviral efficacy of the samples was tested against DENV in different cell lines. The majority of medicinal herbs demonstrated significant antimicrobial action (MIC = 30-3000 μg∙mL-1). The extracts showed great antioxidant activity, while the Salvia rosmarinus L. extract turned out to be the most effective (IC50 = 12.89 ± 0.11 μg∙mL-1). In contrast, the extract of Eucalyptus globulus L. had the lowest antioxidant action (IC50 = 71.02 ± 0.42 μg∙mL-1). The results of the Alamar Blue method were presented with CC50 values, and it was shown that Eucalyptus globulus L. extract exhibited the highest cytotoxicity (CC50 = 5.94% v/v ± 0.04). Similarly, the results of the antiviral potential of extracts were expressed as EC50 values, and Eucalyptus globulus L. was characterized as the most effective sample against dengue virus infection, with EC50 values estimated at 2.37% v/v ± 0.6 (HuhD-2 cells infected with DENV-2) and 0.36% v/v ± 0.004 (Huh7.5 cells infected with DVR2A). These findings provide a foundation for further studies in order to combat infectious diseases and promote human health.

High-throughput computational screening for identification of potential hits against bacterial Acriflavine resistance protein B (AcrB) efflux pump

Antibiotic resistance is a pressing global health challenge, driven in part by the remarkable efflux capabilities of efflux pump in AcrB (Acriflavine Resistance Protein B) protein in Gram-negative bacteria. In this study, a multi-approached computational screening strategy encompassing molecular docking, In silico absorption, distribution, metabolism, excretion and toxicity (ADMET) analysis, druglikeness assessment, molecular dynamics simulations and density functional theory studies was employed to identify novel hits capable of acting against AcrB-mediated antibiotic resistance. Ligand library was acquired from the COCONUT database. Performed computational analyses unveiled four promising hit molecules (CNP0298667, CNP0399927, CNP0321542 and CNP0269513). Notably, CNP0298667 exhibited the highest negative binding affinity of -11.5 kcal/mol, indicating a possibility of strong potential to disrupt AcrB function. Importantly, all four hits met stringent druglikeness criteria and demonstrated favorable in silico ADMET profiles, underscoring their potential for further development. MD simulations over 100 ns revealed that the CNP0321542-4DX5 and CNP0269513-4DX5 complexes formed robust and stable interactions with the AcrB efflux pump. The identified hits represent a promising starting point for the design and optimization of novel therapeutics aimed at combating AcrB-mediated antibiotic resistance in Gram-negative bacteria.Communicated by Ramaswamy H. Sarma.

Antiviral Activity of Rosmarinic Acid Against Four Serotypes of Dengue Virus

The present study was undertaken to evaluate the putative antiviral activity of Rosmarinic acid (RA) against four serotypes of dengue virus (DENV). Our previous in silico binding analysis revealed that RA binds strongly to the envelope domain III (EDIII) protein of all four DENV serotypes. We employed an in vitro Biolayer Interferometry-based OCTET™ platform to study the binding interaction of RA with EDIII protein of the four DENV serotypes. Additionally, a functional plaque assay was developed to investigate the potential inhibition of infection of the four DENV serotypes. Using OCTET™, the binding interaction of RA to DENV-EDIII protein of the four DENV serotypes demonstrates interaction which can be arranged in the following order: EDIII-DENV1 (Koff value of 1.05 s-1) > EDIII-DENV2 (Koff value of 5.63 × 10-01 s-1) > EDIII-DENV3 (Koff value of 4.63 × 10-02 s-1) > EDIII-DENV4 (Koff value of 3.53 × 10-02 s-1). Subsequently, the inhibiting ability of RA using plaque assay confirmed reduction in the number of plaques for all four serotypes, indicating the ability of RA not only to bind, but also to inhibit the infection of four serotypes in cell culture, while being non-toxic at the concentrations used in the study. However, the effect of RA was variable on different serotypes, demonstrating highest effect on DENV1 (EC50 = 13.73 µg/mL, SI ≥ 728) followed by DENV2 (EC50 = 77.74 µg/mL, SI  ≥ 129), DENV3 (EC50 = 244 µg/mL, SI ≥ 41) and DENV4 (EC50 = 280 µg/mL, SI ≥ 36).