Composition of Lipophilic Components of Caragana jubata (Pall.) Poir. and Inhibitory Activity Against the Main Protease of SARS-CoV-2

Objective: This study aimed to analyze the composition of lipophilic components of Caragana jubata (Pall.) Poir. and assess their inhibitory activity against the main protease (3CLpro) of SARS-CoV-2. Methods: The composition of lipophilic extracts from Caragana jubata was investigated using gas-liquid chromatography with mass spectrometric detection (GC-MS). Various extraction methods were employed, including hexane, MTBE (methyl tert-butyl ether), and a combination of both. Extracts were tested for their inhibitory activity against 3CLpro, and the half-maximal inhibitory concentration (IC50) was determined using a fluorescence-based protease assay. Results and Discussion: More than 200 lipophilic compounds were identified, including aliphatic, terpene, and sterol components. Among the extracts tested, the one obtained using MTBE after hexane extraction exhibited the highest inhibitory activity against the SARS-CoV-2 main protease, with an IC50 of 0.05 ± 0.005 mg/mL. The composition of the extracts varied significantly in terms of both the quantity and type of components, with the MTBE extracts showing the most potent bioactivity. Conclusions: The study successfully identified a diverse array of lipophilic components in Caragana jubata, some of which exhibit promising inhibitory activity against the SARS-CoV-2 main protease. The results suggest that Caragana jubata extracts, particularly those obtained with MTBE after hexane extraction, may be a valuable resource for antiviral applications.