Valuable Analytical Tools in Analysis of Honeybee Plant-Derived Compounds: Nuclear Magnetic Resonance Spectroscopy

Abstract

Over the past fifty years, Nuclear Magnetic Resonance (NMR) spectroscopy proved to be a powerful tool in the structural characterisation of bioactive compounds from natural sources. In this chapter we cover the basic theory behind each NMR technique used to determine the structure of several families of compounds (e.g. carbohydrates, phenolics and sesquiterpenoids) present in honey and propolis. We also provide basic information how 1D and 2D NMR techniques can help in the structure establishment of honeybee constituents. The 1H and 13C NMR data of several of these constituents are compiled and described, being some of them used as botanical and geographical markers. In the case of propolis, a list of compounds identified by NMR is presented. A basic overview in quantitative NMR determinations and in NMR coupled to chemometric methodologies highlights their use to detect honey adulteration and assign their authenticity.

Keywords: Adulteration, Authenticity, Botanical marker, 13C NMR, COSY, DEPT, DOSY, Geographical marker, HMBC, HMQC, 1H NMR, Honeybee, HSQC, Natural products, NMR spectroscopy, NOESY, Propolis, ROESY, Structure elucidation, TOCSY.