LAUSR

SGLT inhibitors, are contemporaneously considered a “hot topic” in the field diabetology and as an introduction, it is commonplace for presentations on this topic to start with a historical retrospect on the discovery of phlorizin and its glucosuric effect. In point of fact, it was mentioned during the presentation of a major trial during the 2017 ADA Scientific Sessions, as well as in recent publications, that phlorizin was discovered by “French” chemists. The reality, however, is that phlorozin was discovered in Belgium by Belgian researchers. Furthermore, it is often cited that Josef von Mering discovered the glucosuric effect of phlorizin. Nonetheless, what is perhaps not so widely known is the fact that Freiherr Josef von Mering had already described the glucose lowering effect of phlorozin and had postulated that the action of phlorizin occurs in the kidney—a hypothesis which was latterly proven to be correct by Oscar Minkowski. Hence, the roots of SGLT inhibition are actually Belgian and German and not, as is so often echoed, French. Phlorizin was discovered by Laurent-Guillaume de Koninck together with Jean Servais Stas. De Koninck was born in Louvain on March 5th, 1809. At this time, Louvain was part of the French Empire, eventually becoming part of the Netherlands in 1814. Ultimately, the city of Louvain became a part of the Kingdom of Belgium following the “Belgian revolution” in 1830. De Koninck studied in Louvain, graduating in Medicine, Pharmacy and Natural Sciences. His main interest, however, was chemistry. A grant, awarded by the Belgian government, gave him the opportunity, during the period of 1834–1835, to visit two of the most distinguished chemists of that time, Gay-Lussac in Paris and Justus Liebig in Giessen. He also visited laboratories in Berlin, Bonn, Magdeburg, Heidelberg, Jena and Göttingen—an early illustration of the efficacy of awarding travel grants to young European scientists [1]. Jean Servais Stas (1813–1891) received his M.D. in 1835 [2] and became assistant to his former professor of chemistry, Jean-Baptiste Van Mons (1765–1842). Van Mons himself was a renowned expert in pomology whose experiments on fruit trees, particularly pear trees, brought him much recognition. Here is where destiny, and luck, came into play—Van Mons also happened to own an apple nursery, and, when this nursery needed to be displanted, Stas and Van Mons’s other assistant, De Koninck, were fortuitously supplied with a large supply of fresh apple tree roots. It was from these roots, or, more specifically the bark of these roots, that they isolated a crystalline glycoside which they named phloridzine—later called phlorizin. De Koninck published the discovery, in German [3], in 1835. Customarily, however, the half page report on the discovery which was published in a French Journal is quoted as being the original publication. This report mentions Stas and de Konninck (sic!) [4]. Contemporary authors gave the distinction for the discovery of phlorizin to de Koninck and Stas as early as in May 1835 [5]. Stas continued his research on phlorizin. In 1837, he moved to Paris where he performed a detailed study on phlorizin, splitting it into phloretin and glucose [6]. De Koninck was employed by the University of Liège to teach chemistry. His main interest moved to palaeontology and he went on to become a renowned specialist of Palaeozoic fauna. Today a street in Liège is named in his honour. De Koninck communicated that he had attempted to treat fever with phlorizin with “some success” [3]. Others had also experimented with phlorizin as an antipyretic and this may have been the reason why Prof. Freiherr Josef von Mering became interested in this substance half a century later. Von Mering, born in Cologne in 1849, worked in the University of Strassburg in the department of biochemistry headed by Prof. Hoppe-Seyler. The German University of Strassburg was, at the time, the best funded place for medical research Managed by Antonio Secchi.