Quantification of Melittin in Iranian Honey Bee (Apis mellifera meda) Venom by Liquid Chromatography-electrospray Ionization-ion Trap Tandem Mass Spectrometry (LC-ESI-IT-MS/MS).

The current research aimed to quantify melittin (MEL) in Iranian honey bee (Apis mellifera meda) venom. To this end, a liquid chromatography-electrospray ionization-ion trap tandem mass spectrometry (LC-ESI-IT-MS/MS) approach was employed. Melittin is the main toxic peptide of honey bee venom with various biological and pharmacological activities. It was extracted with pure water from the bee venom samples. The analyses were performed on XBridge BEH300 C4 column using a gradient method with the mobile phase consisting of ultrapure water and acetonitrile (containing 0.1% formic acid). Signals of the melittin were recorded with the selected reaction monitoring (SRM) mode, which is a quantitative approach capable of quantifying analyte peptides with high sensitivity and. The mass spectrum of MEL was obtained in the positive ion mode and the quantification analysis was performed using precursor to product ion transition of m/z 570.2/669.9. This method demonstrated good linearity (R2˃0.997) in the range of 1-100 µg mL-1, with a limit of quantification (LOQ) of 1.0 µg mL-1. The content of MEL in Iranian honey bee venom accounts for 43–55% of total dry weight. This method can be used to evaluate the quality and authenticity of bee venom samples for different therapeutic applications of MEL.