A Comprehensive Survey of Phenolic Constituents Reported in Monofloral Honeys around the Globe

The aim of this review is to provide a comprehensive overview of the large variety of phenolic compounds that have to date been identified in a wide range of monofloral honeys found globally. The collated information is structured along several themes, including the botanical family and genus of the monofloral honeys for which phenolic constituents have been reported, the chemical classes the phenolic compounds can be attributed to, and the analytical method employed in compound determination as well as countries with a particular research focus on phenolic honey constituents. This review covers 130 research papers that detail the phenolic constituents of a total of 556 monofloral honeys. Based on the findings of this review, it can be concluded that most of these honeys belong to the Myrtaceae and Fabaceae families and that Robinia (Robinia pseudoacacia, Fabaceae), Manuka (Leptospermum scoparium, Myrtaceae), and Chestnut (Castanea sp., Fagaceae) honeys are to date the most studied honeys for phenolic compound determination. China, Italy, and Turkey are the major honey phenolic research hubs. To date, 161 individual phenolic compounds belonging to five major compound groups have been reported, with caffeic acid, gallic acid, ferulic acid and quercetin being the most widely reported among them. HPLC with photodiode array detection appears to be the most popular method for chemical structure identification.