An investigation on methylation methods of hesperidin

Abstract

Since hesperidin is a poor water soluble compound, in pharmaceutical formulations its methylated derivatives (hesperidin methyl chalcone, HMC) are used. The aim of this study was to establish an efficient methylation method for preparation of hesperidin methyl derivatives. For this purpose hesperidin was isolated from tangerine peel, purified and its methyl derivatives were prepared using three different techniques, i.e. diazomethane, methyl iodide-sodium hydride and dimethylsulfate. The efficiency of the methods was evaluated in terms of the percentage of unchanged and intact hesperidin in the final methylated products the and amount of unchanged hesperidin was an indication of the better efficiency of the method. A reversed phase HPLC method was also developed for determination and quantification of hesperidin in the final methylated products. The method involved the use of a Shim pack CLC-ODS column, a mixture of methanol-phosphate buffer (37:63, v/v) of pH = 2.6 as a mobile phase in an isocratic mode at a flow rate of 1 ml/min and UV detection at 280 nm. The results showed that methylation with methyl iodide-sodium hydride have the highest efficiency among different methylation methods.