Economic and facile extraction and analysis of osthole in Fructus cnidii for large-scale production

The cost-effective extraction of osthole and the study of its antioxidant activity are of crucial significance in providing theoretical and technical support for the development and utilization of osthole in Chinese medicine. Fructus cnidii was adopted as the raw material, and osthole was extracted through methanol solvent reflux, followed by isolation and determination using HPLC and HPLC-MS techniques. After carrying out a series of chromatographic applicability tests, single-factor investigations were conducted to explore the influence of methanol concentration, extraction time, liquid-solid ratio, and temperature on the extraction rate of osthole. Subsequently, Design-Expert software was utilized to apply the Box-Behnken response surface methodology in order to optimize the experimental conditions for achieving the maximum extraction rate. Additionally, in vitro antioxidant activity assays were performed to evaluate the scavenging ability of the extracted osthole against ABTS⁺, DPPH radicals, as well as ascorbic acid. The results indicated that the optimal parameters for extracting osthole with methanol included an extraction duration of 1 hour, a liquid-solid ratio of 14 : 1 (v/w), an extraction temperature at 64 °C, and a methanol concentration at 75.8%. Under these conditions, the average extraction rate reached up to 14.66%, with only a relative deviation between the predicted values close to 1%. Furthermore, the in vitro antioxidant studies demonstrated a strong scavenging ability exhibited by the obtained osthole. This finding holds significant potential for the large-scale production of osthole extraction and its subsequent application in anti-corrosion.