Bioactivity-Guided Isolation of Secondary Metabolites from Camellia fascicularis: Antioxidative Antibacterial Activities and Anti-Inflammatory Hypoglycemic Molecular Docking

Camellia fascicularis is a valuable ornamental, edible, and medicinal plant with promising prospects for bioactivity development. We screened the bioactivity of eight fractions (Fr. A-I) obtained from the ethyl acetate phase of C. fascicularis via silica gel column chromatography. The results indicated that the anti-inflammatory, antioxidative, and antimicrobial active components were mainly found in Fr. B*, E, A, and H; Fr. A-G; and Fr. D-I, respectively. Bioactivity-guided isolation identified 18 secondary metabolites. Compounds 1, 3-5, 7, and 15-18 were isolated from the genus Camellia for the first time in this study, whereas the other compounds were also isolated from this plant for the first time. The structures of these compounds were elucidated through comprehensive spectroscopic techniques. Compounds 1, 9-11, 28, 30, and 31 demonstrated antioxidative activities comparable to those of ascorbic acid, whereas the remaining compounds exhibited diminished antioxidative activity. In terms of antimicrobial activity, compounds 7, 18, 22, and 27 exerted inhibitory potency against Pseudomonas aeruginosa, similar to tetracycline (MIC: 125 mu g/mL). Other compounds showed moderate to weak inhibitory effects against Staphylococcus aureus and Escherichia coli (MIC: 250-500 mu g/mL). Molecular docking revealed that compounds 2, 36, 41, and 65 showed strong binding affinity for 8ET0, whereas compounds 2, 36, 38, 40, 63, and 65 showed strong binding affinity for 3A4A. This research further increased the diversity of the secondary metabolites of C. fascicularis, laying a foundation for the subsequent development and utilization of this species.