The Flavonoid Cyanidin Shows Immunomodulatory and Broad-Spectrum Antiviral Properties, Including SARS-CoV-2

Aesculus hippocastanum extract and the main bioactive constituent β-escin as antivirals agents against coronaviruses, including SARS-CoV-2

Respiratory viruses can cause life-threatening illnesses. The focus of treatment is on supportive therapies and direct antivirals. However, antivirals may cause resistance by exerting selective pressure. Modulating the host response has emerged as a viable therapeutic approach for treating respiratory infections. Additionally, considering the probable future respiratory virus outbreaks emphasizes the need for broad-spectrum therapies to be prepared for the next pandemics. One of the principal bioactive constituents found in the seed extract of Aesculus hippocastanum L. (AH) is β-escin. The clinical therapeutic role of β-escin and AH has been associated with their anti-inflammatory effects. Regarding their mechanism of action, we and others have shown that β-escin and AH affect NF-κB signaling. Furthermore, we have reported the virucidal and broad-spectrum antiviral properties of β-escin and AH against enveloped viruses such as RSV, in vitro and in vivo. In this study, we demonstrate that β-escin and AH have antiviral and virucidal activities against SARS-CoV-2 and CCoV, revealing broad-spectrum antiviral activity against coronaviruses. Likewise, they exhibited NF-κB and cytokine modulating activities in epithelial and macrophage cell lines infected with coronaviruses in vitro. Hence, β-escin and AH are promising broad-spectrum antiviral, immunomodulatory, and virucidal drugs against coronaviruses and respiratory viruses, including SARS-CoV-2.

Flavonoids with Anti-Herpes Simplex Virus Properties: Deciphering Their Mechanisms in Disrupting the Viral Life Cycle

The herpes simplex virus (HSV) is a double-stranded DNA human virus that causes persistent infections with recurrent outbreaks. HSV exists in two forms: HSV-1, responsible for oral herpes, and HSV-2, primarily causing genital herpes. Both types can lead to significant complications, including neurological issues. Conventional treatment, involving acyclovir and its derivatives, faces challenges due to drug resistance. This underscores the imperative for continual research and development of new drugs, with a particular emphasis on exploring the potential of natural antivirals. Flavonoids have demonstrated promise in combating various viruses, including those within the herpesvirus family. This review, delving into recent studies, reveals the intricate mechanisms by which flavonoids decode their antiviral capabilities against HSV. By disrupting key stages of the viral life cycle, such as attachment to host cells, entry, DNA replication, latency, and reactivation, flavonoids emerge as formidable contenders in the ongoing battle against HSV infections.