Amantadine derivative Amt-1 enhances antiviral defense against influenza A virus via Nrf2/HO-1 pathway

The rise of drug-resistant influenza A virus (IAV) strains and severe lung injury caused by excessive inflammation highlight the need for new antivirals that combine antiviral and immunomodulatory effects. Adamantane, an established anti-IAV agent, targets the viral M2 matrix protein, but widespread mutations have limited its clinical utility. Previously, we identified that 2,5-dihydroxybenzylalcohol and its derivatives possess anti-IAV activity. In this study, we synthesized a series of adamantane-2,5-dihydroxy-benzylalcohol derivatives via reductive amination. Among these, Amt-1 demonstrated strong antiviral activity against both amantadine-sensitive (H1N1 PR8) and clinical isolates IAV strains (-log IC 50 =6.12–6.51 M). Mechanistic analyses, including immunofluorescence, ITC, qPCR, ELISA, luciferase assays, and Western blotting, revealed that Amt-1 not only interacts with the peptide segment of M2 ion channel protein (-log Kd = 5.08 M) but also activates Nrf2, leading to increased HO-1 expression and reduced production of pro-inflammatory cytokines IL-6, IL-1β, and TNF-α. Additionally, Amt-1 inhibited IAV-induced NF-κB activation, thereby suppressing viral replication. In vivo , Amt-1 reduced lung viral titers and mitigated histopathological damage in mice, surpassing amantadine in controlling inflammation and increased survival to 33%. In summary, Amt-1 is the first adamantane derivative shown to exert anti-IAV effects by modulating Nrf2/HO-1-mediated anti-inflammatory pathways and NF-κB-driven antiviral responses, while retaining M2 ion channel inhibition. This host-directed mechanism addresses drug resistance and limits immunopathology, making Amt-1 a promising therapeutic candidate for resistant influenza infections.