Anti-HIV-1 activity and mechanism of action of homoplantaginin: A multitarget flavonoid compound.

OBJECTIVES

To systematically investigate the anti-HIV-1 activity and underlying mechanisms of the flavonoid homoplantaginin (Homo), employing integrated virological, pharmacological, and bioinformatic strategies, and to provide a theoretical foundation for its development as a multitarget anti-HIV-1 candidate .

METHODS

Anti-HIV-1 activity was assessed using three cellular infection models: TZM-bl/HIV-1IIIB, MT-2/HIV-1IIIB, and PBMCs/HIV-1Bal. Cell viability was measured with the CellTiter-Glo luminescence assay; antiviral activity was determined via luciferase reporter expression and HIV-1 p24 antigen detection. Key pharmacological parameters (CC50, IC50, SI) were derived, and cytopathic effects were observed microscopically. Mechanistic investigations included: (1) assays of HIV-1 key enzyme activities and molecular docking; (2) network pharmacology-based target prediction; (3) analysis of relevant factors by reverse-transcription quantitative PCR (RT-qPCR).

RESULTS

1. Homo exhibited moderate but significant anti-HIV-1 activity, with IC50 values of 43.52 μmol/L (TZM-bl), 13.69 μmol/L (MT-2), and 18.49 μmol/L (PBMCs), and corresponding SI values of 22.97, 57.60, and 54.08. Morphological observation confirmed that Homo reduced HIV-1-induced cytopathic effects. 2. Mechanism studies revealed that Homo dose-dependently inhibited HIV-1 reverse transcriptase (RT) and protease (PR) activities within safe concentration ranges, while showing no significant effect on integrase (IN). The molecular docking results show that Homo may have good binding activity with RT and PR. RT-qPCR demonstrated that Homo suppressed HIV-1-induced expression of pro-inflammatory factors (down-regulation of IL-6 and CXCL10) and enhanced interferon responses (up-regulation of IFN-β and IFN-γ).

CONCLUSIONS

Homo exerts anti-HIV-1 activity through multitarget mechanisms, including inhibition of key viral enzymes, suppression of virus-induced pro-inflammatory factors, enhancement of interferon mediated antiviral immune responses. These findings highlight Homo as a promising candidate for further development as a multitarget anti-HIV therapeutic agent.