Abstract
Seasonally circulating viruses, such as Influenza, as well as newly emerging viruses and variants thereof, and waning immunity urge the need for safe, easy-to-use and inexpensive drugs to protect from these challenges. To prevent transmission of these viruses and subsequent excessive inflammatory reactions on mucous membranes, we tested the efficacy of the natural essence P80 as spray and in form of lozenges against respiratory infections caused by SARS-CoV-2 variants of concern (VoCs), influenza A (H3N2) and influenza B (Victoria). P80 natural essence, a Dimocarpus longan extract, shielded highly differentiated human airway epithelia from SARS-CoV-2 wildtype and Omicron variant as well as Influenza A and B infection and dampened inflammation by down-modulating pro-inflammatory cytokine and anaphylatoxin secretion. A single application of P80 natural essence spray maintained tissue integrity long-term. This also significantly reduced the release of infectious viral particles and the secretion of IP10, MCP1, RANTES and C3a, all of which mediate the migration of immune cells to the sites of infection. Even P80 lozenges dissolved in distilled water or non-neutralizing saliva efficiently prevented SARS-CoV-2 and Influenza-induced tissue destruction. Consequently, our in vitro data suggest that P80 natural essence can act as antiviral prophylactic, both in form of nasal or oral spray and in form of lozenges, independent of circulating respiratory challenges.