Occurrence of Osthole in Commonly Available Citrus Fruits Analyzed With GC-MS and LC-QTOF-MS

Summary: Osthole (CAS 484-12-8) is a compound with numerous possible therapeutic applications. Its occurrence was reported in Cnidium monnieri. In our practice we noted that osthole is present in citrus fruits. The purpose of the study was to examine and quantitatively assess the occurrence of osthole in commercially available citrus fruits. Grapefruit, pomelo, citron, and orange from various markets in Saudi Arabia were collected and subjected to QuEChERS/DPX extraction. As identification techniques, GC-MS (full scan and SIM) and high resolution LC-QToF-MS (MSe mode with three transitions) were applied. Osthole was identified in grapefruit, pomelo, and citron. Orange was practically free of osthole. The highest concentrations of osthole were found in the peel of all fruits, in the range of 7.0-78.5 mg/kg. In conclusion may be stated that the peel of examined citrus fruits may be considered as a valuable and easily available source of osthole. Industrial relevance: The peels of lemon fruits (grapefruit, citron, pomelo), which are treated as a food waste, contain osthole and may appear as valuable source of this compound after proper treatment. Keywords: osthole; GC-MS; LC-ToF-MS; citrus fruits