In vitro and in vivo anti-influenza H1N1 activities of a hydroethanolic extract of Cupressus sempervirens cones

Cupresssus sempervirens cones are rich in condensed tannins. A proanthocyanidin fraction exhibited in vitro antiviral activity against two retroviruses [1]. A standardized hydroethanolic extract of fresh cones extract [HCE] (Phytostandard® process, PiLeJe Laboratoire) showed virucidal activity using EN14476+A1 standard against common respiratory viruses, including H1N1 [2].

To further assess the HCE properties on H1N1, we used two tests: 1) an in vitro cell model of the human airway epithelium cultured at the air liquid interface (MucilAir™) in which the virus and HCE were co-incubated during 3 hours on the apical surface, HCE being replaced every 24 hours during 4 days. Viral replication was assessed by quantitative RT-PCR; 2) An in vivo model in which mice were orally treated 14 days with HCE before nasal infection with H1N1. The HCE was administered for another 5 days after infection, then mice were followed for another 5 days.

In vitro, the HCE significantly delayed viral replication and reduced it according to dose and time. In vivo, the HCE significantly limited weight loss compared to infected mice without treatment at Days 7, 8 and 9. These results confirm and strengthen the antiviral properties of the HCE tested on H1N1. Further investigations will be needed to determine underlying mechanisms.

Publication History

Article published online:
13 December 2021

• References

• 1 Amouroux P.. et al. Phytotherapy Research (1998) 12 (5), 367-368
• 2 Guinobert I. et al. Phytothérapie (2018) 16:281-289