bims-antpol 2023-08-06 papers

Issue of 2023–08–06
three papers selected by
Rick Sheridan, EMSKE Phytochem

Virol J. 2023 Aug 03. 20(1): 173

Withania somnifera extracts induced attenuation of HIV-1: a mechanistic approach to restrict viral infection.

Pratiksha Jadaun, R Harshithkumar, Shraddha Y Gaikwad, Chandrabhan Seniya, Swapnil Borse, Ashish A Gawai, Preeti Chavan-Gautam, Girish Tillu, Anupam Mukherjee.

BACKGROUND: Several anti-retroviral drugs are available against Human immunodeficiency virus type-1, but have multiple adverse side effects. Hence, there is an incessant compulsion for effectual anti-retroviral agents with minimal or no intricacy. Traditionally, natural products have been the most successful source for the development of new medications. Withania somnifera, also known as Ashwagandha, is the utmost treasured medicinal plant used in Ayurveda, which holds the potential to give adaptogenic, immunomodulatory, and antiviral effects. However, its effect on HIV-1 replication at the cellular level has never been explored. Herein, we focused on the anti-HIV-1 activity and the probable mechanism of action of hydroalcoholic and aqueous extracts of Withania somnifera roots and its phytomolecules.
METHODS: The cytotoxicity of the extracts was determined through MTT assay, while the in vitro anti-HIV-1 activity was assessed in TZM-bl cells against the HIV-1 strains of X4 and R5 subtypes. Results were confirmed in peripheral blood mononuclear cells, using the HIV-1 p24 antigen assay. Additionally, the mechanism of action was determined through the Time of Addition assay, which was further validated through the series of enzymatic assays, i.e. HIV-1 Integrase, Reverse transcriptase, and Protease assays. To explore the role of the identified active metabolites of Withania somnifera in antiretroviral activity, molecular docking analyses were performed against these key HIV-1 replication enzymes.
RESULTS: The hydroalcoholic and aqueous extracts of Withania somnifera roots were found to be safer at the sub-cytotoxic concentrations and exhibited their ability to inhibit replication of two primary isolates of HIV-1 through cell-associated and cell-free assays, in dose-dependent kinetics. Several active phytomolecules found in Withania somnifera successfully established hydrogens bonds in the active binding pocket site residues responsible for the catalytic activity of HIV replication and therefore, signifying their role in the attenuation of HIV-1 infection as implied through the in silico molecular docking studies.
CONCLUSIONS: Our research identified both the hydroalcoholic and aqueous extracts of Withania somnifera roots as potent inhibitors of HIV-1 infection. The in silico analyses also indicated the key components of Withania somnifera with the highest binding affinity against the HIV-1 Integrase by 12-Deoxywithastramonolide and 27-Hydroxywithanone, HIV-1 Protease by Ashwagandhanolide and Withacoagin, and HIV-1 Reverse transcriptase by Ashwagandhanolide and Withanolide B, thereby showing possible mechanisms of HIV-1 extenuation. Overall, this study classified the role of Withania somnifera extracts and their active compounds as potential agents against HIV-1 infection.

Keywords: Anti-HIV-1; Ashwagandha; Ashwagandhanolide; Molecular docking; Withacoagin; Withaferin; Withania somnifera; Withanolide

DOI: https://doi.org/10.1186/s12985-023-02130-y

Mol Med Rep. 2023 Sep;pii: 176. [Epub ahead of print]28(3):

Novel anti‑hepatitis B virus flavonoids sakuranetin and velutin from Rhus retinorrhoea.

Sarfaraz Ahmed, Mohammad K Parvez, Mohammed S Al-Dosari, Mazin A S Abdelwahid, Tawfeq A Alhowiriny, Adnan J Al-Rehaily.

Drug‑resistance in hepatitis B virus (HBV), especially due to prolonged treatment with nucleoside analogs, such as lamivudine (LAM), remains a clinical challenge. Alternatively, several plant products and isolated phytochemicals have been used as promising anti‑HBV therapeutics with no sign of resistance. Among all known Rhus species, R. coriaria, R. succedanea and R. tripartite have been widely studied for their anti‑HBV efficacy, however, the effects of R. retinorrhoea have not been previously investigated. The current study reported the isolation of two flavonoids, namely sakuranetin (SEK) and velutin (VEL), from the dichloromethane fraction of R. retinorrhoea aerial parts using chromatography and spectral analyses. The two flavonoids (6.25‑50 µg/ml) were pre‑tested for non‑hepatocytotoxicity using an MTT assay and their dose‑ and time‑dependent inhibitory activities against HBV [hepatitis B surface antigen (HBsAg) and hepatitis B 'e' antigen (HBeAg)] in cultured HepG2.2.15 cells were assessed by ELISA. SEK and VEL at the selected doses (12.5 µg/ml) significantly inhibited HBsAg by ~58.8 and ~56.4%, respectively, and HBeAg by ~55.5 and ~52.4%, respectively, on day 5. The reference drugs LAM and quercetin (anti‑HBV flavonoids), suppressed the production of HBsAg/HBeAg by ~86.4/~64 and ~84.5/~62%, respectively. Furthermore, molecular docking of the flavonoids with HBV polymerase and capsid proteins revealed the formation of stable complexes with good docking energies, thus supporting their structure‑based antiviral mechanism. In conclusion, the present study was the first to demonstrate the anti‑HBV therapeutic activities of SEK and VEL isolated from R. retinorrhoea.

Keywords: Rhus retinorrhoea; anti‑HBV; flavonoids; hepatitis B virus; sakuranetin; velutin

DOI: https://doi.org/10.3892/mmr.2023.13063

Nat Prod Res. 2023 Aug 01. 1-4

Antiviral activity and active components of the leaves from Sabia parviflora Wall. ex Roxb.

Yongqiang Zhou, Sumei Li, Bowen Pan, Junwei Xiao, Tingting Tang, Shouxia Xie, Xin Yang, Guihui Wu, Jinxin Xiao, Jian Yang, Ying Zhou, Yuxin Pang, Ying Wei.

Sabia parviflora (SP, "xiao hua qing feng teng" in Chinese) was recorded as an important ethnic medicine to be used for treating viral hepatitis. The antiviral activity of four SP extracts and potent antiviral compounds evaluated with cathepsin L protease (Cat L PR) and HIV-1 protease (HIV-1 PR). UPLC-HRMS was used for identifying the bioactive components. In addition, the possible inhibitory mechanism of the identified compounds on viral protease was further discussed by molecular docking. As a result, four extracts of SP exhibited inhibitory activity of HIV-1 PR and Cat L PR with IC50 range from 0.015 to 0.80 mg/mL. Meanwhile, six compounds inhibited HIV-1 PR with IC50 range from 0.032 to 0.80 mg/mL. Moreover, procyanidin B2 had good affinity for HIV-1 PR and CatL PR protein, respectively. These findings suggest S. parviflora leaves can be used for treating HIV and procyanidin B2 may play a role in antiviral protease.

Keywords: Sabia parviflora wall; UPLC-HRMS; active component; molecular docking; protease

DOI: https://doi.org/10.1080/14786419.2023.2239995