Study of honey Andromedotoxin in Western Georgia by UPLC-MS method

Abstract

Cases of honey poisoning have been reported in Western Georgia (Adjara), meaning there is a need for methods that detect “mad honey” or honey contaminated with plant-derived toxins to protect human health. The purpose of this study was to determine the levels of Grayanotoxin-III, Total phenolic compounds (TPC) and antioxidant activity of honey produced in mountainous Adjara (West Georgia), using ultra-high-performance liquid chromatography mass spectrometry (UPLC-MS) and by spectrophotometric methods. Honeys were provided by beekeepers and collected from different locations in mountainous Adjara (an altitudinal range of 200–3007 m above sea level). The harvest was taken in the autumn of 2019. In this study, we compared whole of a Flower of Rhododendron extracts, mad honey and 12 samples of autumn honey. Liquid chromatography with mass spectrometry (Waters, UPLC Acquity, QDa Detectore) was used for the identification of andromedotoxin (grayanotoxin-III). The analytical column was a Acquity UPLC BEN C18. GTX-III was eluted using a mobile phase consisting 50:50 water/methanol solution containing 1% acetic acid at flow rate of 0.3 mL/min in 8 min. A Mettler Toledo UV-5 model UV–VIS spectrophotometer was used for Determination of phenolic compounds and Antioxidant activity Results and discussion - Using the UPLC-MS method grayanotoxin-III were identified in the honey samples. MS data were acquired by running electrospray ionization (ESI) in negative ion mode using selected reaction monitoring (SRM) after describing the real molecular weight of GTX-III by full scan in the range of 200–500 m/z. For comparing chromatography analyses was used rhododendron`s flower and mad honey samples, where consistency of toxin was much higher than in other honey`s Samples. The toxin content in honey increases with increasing height (Mean sea level). No correlation is observed between toxin content and antioxidant activity, while there is a direct correlation between phenolic compounds content and antioxidant activity. Honey grown in highlands of Adjara, in parallel with the toxin content (4.2 – 24.0 mg/kg), is characterized by a high content of phenolic compounds (407.54 – 1004.5 g/kg) and it also has a strong antioxidant activity (61.5 j– 175.0 50% inhibition mg of samples).