Optimization of Extraction, Chemical Profiling, and Evaluation of Antioxidant and Antibacterial Activities of Cortex Dictamni Extract

Cortex Dictamni, the dried root bark of the plant Dictamnus dasycarpus Turcz. from the Rutaceae family, contains alkaloids as its primary bioactive components, which exhibit a wide range of pharmacological effects. This study aims to optimize the extraction process and to characterize the chemical composition of Cortex Dictamni extract (CDE), as well as to evaluate its in vitro antioxidant and antibacterial activities. The response surface methodology (RSM) was employed to optimize the extraction process of CDE, while Q-Orbitrap high-resolution liquid chromatography–mass spectrometry (LC-MS) was utilized to identify the chemical components in the CDE. Antioxidant and antibacterial activities were evaluated using ABTS and DPPH radical scavenging assays and by determining the minimum inhibitory concentration (MIC), respectively. The results indicated that the optimized extraction yield of CDE was 44.73%. The optimal extraction conditions were: ethanol concentration of 70%, material-to-liquid ratio of 1:40 g/mL, and extraction time of 35 min. A total of 10 components were identified in the extract, including alkaloids, lactones, terpenes, and flavonoids. The extract demonstrated notable oxygen-free radical scavenging capabilities, as evidenced by its DPPH (IC50 = 0.316 mg/mL) and ABTS (IC50 = 0.166 mg/mL) values. Additionally, it exhibited antibacterial effects, particularly against Escherichia coli and Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of ≥128 mg/mL. CDE may serve as a potential natural compound for applications in the food and pharmaceutical industries.