Lychee flower extract inhibits proliferation and viral replication of HSV-1-infected corneal epithelial cells

Herpes simplex virus type I (HSV-1) is capable of causing a wide array of human ocular diseases. Herpes simplex virus keratitis (HSK)-induced cytopathogenicity together with the chronic immune-inflammatory reaction can trigger stromal scarring, thinning, and neovascularization which may lead to permanent vision impairment. Lychee flower extract (LFE) is known for its antioxidant and anti-inflammatory effects. Therefore, in this study, we investigated the mechanism of the Statens Seruminstitut rabbit corneal (SIRC) epithelial cells infected by HSV-1 and examined the antiviral capabilities of LFE. SIRC cells were pretreated with different concentrations of LFE (0.2, 0.1, and 0.05 μg/ml) and then infected with 1 MOI of HSV-1 for 24 h. The cell viability or morphology was evaluated in this study. In addition, the supernatants and cell extracts were collected for Cell Counting Kit-8 (CCK), plaque assay, and western blotting. We found that HSV-1-induced cell proliferation is regulated through inhibition of the mammalian target of rapamycin (mTOR) and p70s6k phosphorylation in response to the LFE. In addition, the LFE enhanced the autophagy protein expression (Beclin-1 and light chain 3, LC3) and decreased the viral titers. These results showed the antiviral capabilities and the protective effects of LFE. Taken together, our data indicate that LFE has potential as an anti-HSK (herpes simplex keratitis) for HSV-1 infection.