[An in vitro study on the pharmacological ascorbate treatment of influenza virus].
Level 5 - mechanism / opinion, no new human data
In vitro bench research with no human clinical data
What was done
Normal human bronchial epithelial (NHBE) cell monolayers were exposed to Influenza A/CA/7/09 (H1N12009) virus at a multiplicity of infection of 0.01 for 1 hour, rinsed, and incubated with medium containing 20 mmol/L ascorbate or 20 mmol/L ascorbate plus 600 IU/ml catalase for 4 to 12 hours. Viral titers were quantified by TCID₅₀ assay in MDCK cells. Ascorbate concentration was measured using HPLC with coulometric electrochemical detection, and hydrogen peroxide was detected indirectly using a Clark-type oxygen electrode.
What was found
Ascorbate demonstrated dose-dependent antiviral activity against both isolated virus and infected epithelial cells. Ascorbic acid at 2.5 mmol/L eliminated 90% of viruses, and 20 mmol/L completely blocked viral replication in vitro. Antiviral effects occurred within 4 hours when administered during the early stage of infection. The antiviral action was reversed by the addition of catalase.
Why it matters
This study outlines a plausible in vitro mechanism showing that high concentrations of ascorbate act as a pro-drug generating extracellular hydrogen peroxide to inactivate influenza virus in respiratory epithelial cell cultures.
Limits
This is an in vitro laboratory study with no animal or human clinical data. The concentrations tested (2.5 to 20 mmol/L) cannot be achieved through oral intake, and specific host cell cytotoxicity thresholds and long-term antiviral dynamics were not evaluated in the abstract.
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