A reversed-phase high-performance liquid chromatography assay for mangiferin in rat plasma and urine was developed. Rutin was employed as an internal standard. The mobile phase consisted of acetonitrile-water (16:84, v/v) containing 3% acetic acid at a flow rate of 1 mL/min. Detection was at 257 and 365 nm for mangiferin in plasma and urine, respectively. The limit of quantitation (LOQ) of mangiferin was 0.6 microg/mL in plasma, and 0.48 microg/mL in urine. The standard curve was linear from 0.6 to 24 microg/mL in plasma, and 0.48 to 24 microg/mL in urine, both intra- and inter-day precision of the mangiferin were determined and their RSD did not exceed 10%. The method provides a technique for rapid analysis of mangiferin in rat plasma and urine, which can be used in pharmacokinetic studies.

A novel process has been discovered for the production of glyoxylic acid. When the ozonolysis of maleic acid was conducted in solvents that contained methanol, acetic acid, or formic acid at approximately -5 °C, hydroperoxide compounds and glyoxylic acid hemiacetal were formed in high yield (>95%). The prepared mixture then was dropped into a glyoxal solution (the molar ratio of maleic acid and glyoxal was slightly greater than 1:1) that had been warmed to ∼38 °C. Glyoxal was oxidized by the hydroperoxides in the mixture via a Baeyer-Villiger rearrangement. When the reaction ended, some water was added to the solution and organic solvents were distilled off at reduced pressure at 50 °C. An aqueous solution of glyoxylic acid was obtained. Through this procedure, both maleic acid and glyoxal were converted to glyoxylic acid.