bims-antpol 2024-09-08 papers

Issue of 2024–09–08
three papers selected by
Rick Sheridan, EMSKE Phytochem

Pharmaceuticals (Basel). 2024 Jul 26. pii: 988. [Epub ahead of print]17(8):

In Vitro Antiviral Activity of Rhodiola crenulata Extract against Zika Virus and Japanese Encephalitis Virus: Viral Binding and Stability.

Zheng-Zong Lai, I-Chuan Yen, Hao-Yuan Hung, Chen-Yang Hong, Chih-Wei Lai, Yen-Mei Lee.

Zika virus (ZIKV) and Japanese encephalitis virus (JEV) can cause permanent neurological damage and death, yet no approved drugs exist for these infections. Rhodiola crenulate, an herb used in traditional Chinese medicine for its antioxidation and antifatigue properties, was studied for its antiviral activity against ZIKV and JEV in vitro. The cytotoxicity of Rhodiola crenulata extract (RCE) was evaluated using the CCK-8 reagent. Antiviral effects of RCE were assessed in ZIKV-infected or JEV-infected Vero cells via quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blotting, fluorescent focus assay (FFA), and immunofluorescence assay (IFA). The cell-free antiviral effects of RCE were evaluated using an inactivation assay. To determine the stage of the viral life cycle affected by RCE, time-of-addition, binding, and entry assays were conducted. Three bioactive constituents of RCE (salidroside, tyrosol, and gallic acid) were tested for antiviral activity. RCE exhibited dose-dependent anti-ZIKV and anti-JEV activities at non-cytotoxic concentrations, which were likely achieved by disrupting viral binding and stability. Gallic acid exhibited antiviral activity against ZIKV and JEV. Our findings indicate that RCE disrupts viral binding and stability, presenting a potential strategy to treat ZIKV and JEV infections.

Keywords: Japanese encephalitis virus; Rhodiola crenulata; Zika virus; antiviral agent; gallic acid; salidroside

DOI: https://doi.org/10.3390/ph17080988

Curr Drug Deliv. 2024 Sep 04.

Cell Culture and Molecular Docking Analysis to Determine the Antiviral Activity of Folklore Medicinal Plants Against Chikungunya Virus.

Sukender Kumar, Samander Kaushik, Munish Garg.

<p> Introduction: Chikungunya Virus (CHIKV), a mosquito-transmitted pathogen, poses a significant global health threat owing to its widespread prevalence and high morbidity. There are no approved vaccines or antivirals for prevention or treatment. Screening of folklore medicinal plants has emerged as a promising approach to finding novel therapeutics to combat pathogens. Hence, this study aimed to evaluate the anti-chikungunya potential of folklore medicinal plants and their phytochemicals. <p> Methods: Maximum non-toxic concentrations (MNTD) of the extracts to Vero cells were determined by the cytotoxicity assay. A Focus-Forming Unit (FFU) assay was used to assess the antiviral activity of the extracts (at MNTD) against CHIKV in Vero cells under pre-, co-, and post-treatment conditions. GC-MS was used to detect the phytochemicals of the extracts, and Schrodinger (Maestro) software was employed for their molecular docking against the target protein of CHIKV. <p> Results: Azadirachta indica exhibited anti-CHIKV activity during pre- and post-treatment, decreasing the virus titer from 8.145 to 7.998 and 8.361 to 8.040 mean log10 FFU/ml, respectively. Calendula officinalis and Piper retrofractum exhibited anti-CHIKV activity only during post-treatment (8.361 to 8.135, 8.361 to 8.075). Moreover, molecular docking studies of phytochemicals detected in GCMS analysis of all the extracts revealed that many phytochemicals (especially F3, F5, F6, and A1) could bind to the non-structural protein (nSP2) target of CHIKV and suppress the viral replication. <p> Conclusion: The screened plants showed the ability to inhibit CHIKV infection and replication and hold potential for further investigation in developing treatments for Chikungunya.

Keywords: Chikungunya virus; antiviral activity; ethanol extract; focus-forming unit assay; gas chromatography-mass spectroscopy; medicinal plant extracts; molecular docking.

DOI: https://doi.org/10.2174/0115672018307676240827103052

Life (Basel). 2024 Aug 18. pii: 1023. [Epub ahead of print]14(8):

Antiviral Efficacy of Coridothymus capitatus Essential Oil Against HSV-1 and HSV-2.

Virginia Fuochi, Pio Maria Furneri, Salvatore Furnari, Adriana Garozzo.

Coridothymus capitatus is a perennial herb with aromatic leaves and flowers, distinct from Thymus vulgaris in its chemical composition, resulting in a unique Thymus Essential Oil (TEO). A main component of TEO, carvacrol, is known for its antimicrobial and insecticidal activity. Carvacrol has potent antibacterial, antioxidant, anti-inflammatory, and antifungal properties, generating interest in traditional medicine. However, studies on its antiviral activity are limited. Given the rise in viral infections and limitations of synthetic antiviral drugs, natural antiviral agents are promising due to their efficacy, lower resistance development, and reduced side effects. This study assessed the antiviral efficacy of TEO compared to that of pure carvacrol. We tested various viruses, revealing significant inhibitory effects of TEO on the replication of only Simplexvirus humanalpha1 (HSV-1) and Simplexvirus humanalpha2 (HSV-2), with specific interference during the early stages of the viral replication cycle after the adsorption period. TEO exhibited inhibitory effects at doses below the cytotoxic threshold, with IC50 values of 47 μg/mL for HSV-1 and 40 μg/mL for HSV-2. Maximum virus inhibition was achieved when TEO was added within 90 min post-infection, indicating interference with early viral replication steps. These findings highlight the potential of TEO as a natural antiviral agent and suggest further research into its mechanisms and clinical applications.

Keywords: Coridothymus capitatus; HSV-1; HSV-2; antiviral activity; carvacrol; essential oil; natural antiviral agents; viral replication

DOI: https://doi.org/10.3390/life14081023