Quantification of morusin using LC-MS in rat plasma: Application to a pharmacokinetic study

A sensitive LC-MS method was developed for the quantification of morusin in rat plasma using praeruptorin C as internal standard. After extraction with diethyl ether, post-treatment samples were chromatographed on a Hypersil C₁₈ column. An isocratic mobile phase consisting of methanol-water (70:30, v/v) was applied at a flow rate of 0.4 mL/min. Detection was performed via electrospray ionization source with positive ion mode using selected ion monitoring mode at m/z 443.1 for morusin and m/z 451.0 for IS. Acceptable linearity (r²  ≥ 0.99) was observed over the concentration range of 1.5-800 ng/mL. This method was successfully applied in the pharmacokinetics study of morusin in rats.