Estudo de estabilidade, análise in silico contra alvos da COVID-19 e avaliação da atividade anti-inflamatória das brachydinas extraídas das raízes de Fridericia platyphylla

Abstract

COVID-19 is a viral respiratory infection associated with severe inflammatory complications, such as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Although antiinflammatory drugs are commonly used in treatment, their side effects underscore the need for safer alternative therapies. Natural products such as Fridericia platyphylla traditionally used to treat inflammation, stand out for their biopharmaceutical potential. Furthermore, assessing the stability of bioactive molecules is essential to ensure their therapeutic efficacy and safety. Therefore, the aim of this study was to evaluate the stability of brachydins isolated from the dichloromethane fraction, assess their in silico potential against SARS-CoV-2, and investigate the anti-inflammatory potential of the fraction containing brachydins in a model of acute lung injury. Brachydins were isolated from the dichloromethane partition of the hydroethanolic extract of F. platyphylla roots using column chromatography and identified by mass spectrometry. Their anti-SARS-CoV-2 potential was assessed through molecular docking with various target proteins. Stability was evaluated using thermogravimetric analysis, evolved gas analysis, and photostability testing. In A549 cells, cytotoxicity of the dichloromethane fraction (Fr. DCM) was assessed, and in both cellular and murine models of LPS-induced ALI, the antiinflammatory activity of Fr. DCM was analyzed. Six hours after LPS instillation, mice were treated with two doses of Fr. DCM, and after 24 hours, lungs and bronchoalveolar lavage fluid (BALF) were collected to analyze inflammatory cells, cytokines and edema. Mass spectrometry identified three brachydins (BrA, BrB, and BrC). Thermogravimetric analysis revealed distinct degradation profiles, with the highest mass loss for BrA in stage 6 (21.94%) and for BrB and BrC in stage 2 (38.86% and 38.50%, respectively), suggesting differences in degradation mechanisms. Activation energy (Ea) ranged from 135.8 to 159.4 kJ/ mol, with BrA exhibiting the highest value, possibly due to hydrogen bonding interactions. BrC showed the greatest estimated stability (4 to 5 years). In photostability testing, Fr. DCM exhibited 32.8% degradation after 14 h of light exposure, which increased to 52.9% in the presence of TiO. In molecular docking, BrC showed the best affinity for the Spike protein, while BrA had the highest affinity for ACE2, suggesting potential to block viral entry. In A549 cells, Fr. DCM maintained 85% cell viability at 12.5 μg/mL, with significant reductions only observed at concentrations of 25 μg/mL or higher, which were selected for further experiments. At these concentrations, under LPS-induced inflammatory conditions, Fr. DCM was not effective at 12.5 μg/mL, but showed a strong reduction in cell viability at 25 μg/mL, especially with higher LPS doses. In BALB/c mice, Fr. DCM significantly reduced inflammatory cells and cytokines in BALF, showing results comparable to the control and dexamethasone groups. Edema was also reduced at both tested doses. These findings highlight F. platyphylla as a promising source of bioactive compounds, particularly brachydins, which combine chemical stability with antiviral and anti-inflammatory activities, reinforcing the relevance of studying natural compounds in the fight against high-mortality diseases.