Extrato hidroalcoólico de Salvia officinalis: propriedades antioxidantes e triagem in vitro contra a interação Spike-ACE2 do SARS-CoV-2

Introduction: Salvia officinalis L. (sage) belongs to the Lamiaceae family and is native to the Middle East and Mediterranean regions. Sage extract is an excellent source of flavonoids and polyphenolic compounds, such as rosmarinic acid. Rosmarinic acid, a phenolic compound found in various Lamiaceae plants, exhibits antioxidant, anti-inflammatory, antibacterial, and antiviral activities. Objective: This study aimed to characterize the antioxidant capacity of the hydroalcoholic extract (SO-CWB) of the S. officinalis L. and to evaluate its ability to inhibit the interaction between ACE2 and Spike proteins in an in vitro assay. Methodology: The extract was characterized through analyses of total phenolic compounds, flavonoids, reducing sugars, antioxidant activity (DPPH, ABTS, and FRAP), and evaluated through a screening assay for inhibitors of the interaction between the Spike protein of the receptor-binding domain (RBD) of the wild-type (WT) variant of SARS-CoV-2. Results: The hydroethanolic extract showed concentrations of rosmarinic acid (5.1 ± 0.8) µg mg-1, total phenolic compounds (60.9 ± 0.3) µgGAE mg-1, flavonoid compounds (30.11 ± 0.4) µgQEmg-1, and reduced sugar (352.2 ± 31.8) µgGE mg-1. Additionally, it exhibited antioxidant activity against DPPH (135.5 ± 3.8) µmolTE L-1 mg-1, ABTS (221.2 ± 2.7) µmolTE L-1 mg-1, and FRAP (326.1 ± 20.9) µmolFeSO4 L-1 mg-1. The extract and the rosmarinic acid standard were evaluated for their ability to inhibit the interaction between the RBD Spike protein of the wild-type (WT) variant of SARS-CoV-2. The extract and rosmarinic acid did not influence the interaction between ACE2 and Spike proteins in the assay (activity >90%). So, the standard hesperidin was tested as a comparative and to evaluate the efficacy of the test, and hesperidin showed binding-inhibition activity against Spike-ACE2. Conclusion: Although the extract and rosmarinic acid did not interfere with Spike–ACE2 binding, strong antioxidant activity, suggesting potential relevance in mitigating oxidative stress and reactive oxygen species (ROS) during COVID-19.