Perillaldehyde: A promising antibacterial agent for the treatment of pneumonia caused by Acinetobacter baumannii infection.

Perillaldehyde is a monoterpene compound mainly from the medicinal plant Perilla frutescens (L.) Britt., which has hypolipidemic, antioxidant, antibacterial and anti-inflammatory functions. In this investigation, we discovered that Perillaldehyde had powerful antimicrobial activity against Acinetobacter baumannii 5F1, and its minimum inhibitory concentration was 287.08 µg/mL. A. baumannii is a conditionally pathogenic bacterium with a high clinical resistance rate and is a major source of hospital infections, especially in intensive care units, which is one of the main causes of pneumonia. Inflammatory immune response is characteristic of pneumonia caused by A. baumannii infection. The results of our in vitro experiments indicate that Perillaldehyde disrupts the cell membrane of A. baumannii 5F1 and inhibits its quorum sensing to inhibit biofilm formation, among other effects. With an experimental model of murine pneumonia, we investigated that Perillaldehyde decreased NLRP3 inflammasome activation and TNF-α expression in lung tissues by inhibiting the NF-κB pathway, and also impacted MAPKs protein signaling pathway through the activation of TLR4. Notably, the use of high doses of Perillaldehyde for the treatment of pneumonia caused by A. baumannii 5F1 infection resulted in a survival rate of up to 80 % in mice. In summary, we demonstrated that Perillaldehyde is promising as a new drug for the treatment of pneumonia caused by A. baumannii 5F1 infection.

Study on the mechanism of active components of Liupao tea on 3CLpro based on HPLC-DAD fingerprint and molecular docking technique.

Liupao tea, a drink homologous to medicine and food. It can treat dysentery, relieve heat, remove dampness, and regulate the intestines and stomach. The objective of this study is to explore the material basis and mechanism of Liupao tea intervention in COVID-19 and to provide a new prevention and treatment programme for COVID-19. We used high performance liquid chromatography to analyze the extract of Liupao tea and establish its fingerprint. The main index components of the fingerprint were determined using SARS-COV-2 3-chymotrypsin-like protease (3CLpro ), and an in vitro drug screening model based on fluorescence resonance energy transfer was used to evaluate its inhibitory activity in vitro. The fingerprint results showed that the alcohol extract of Liupao tea contained gallic acid, epigallocatechin gallate (EGCG), caffeine, epicatechin gallate, rutin, and ellagic acid. The molecular docking binding energies of the six index components of SARS-CoV-2 3Clpro were all less than -5.0 kJ/mol and showed strong binding affinity. The results of in vitro activity showed that the IC50 of EGCG was 8.84 µmol/L, which could inhibit SARS-CoV-2 3Clpro to a certain extent. This study unleashed that EGCG has a certain inhibitory effect on SARS-CoV-2 3CLpro , and Liupao tea has a certain significance as a tea drink for the prevention of COVID-19. PRACTICAL APPLICATIONS: The objective of this study was to explore the material basis and mechanism of Liupao tea intervention in COVID-19 and to provide a new prevention and treatment programme for COVID-19. The molecular docking binding energies of the six index components of Liupao tea with SARS-CoV-2 3CLpro were all less than -5.0 kJ/mol, among them, the enzyme activity experiment shows that EGCG has a certain inhibitory effect on SARS-CoV-2 3CLpro , it can be used as a potential SARS-CoV-2 3CLpro inhibitor. We predicted that the understandings gained in the current research may evidence that Liupao tea has a certain significance as a tea drink for the prevention of COVID-19.