Goat’s-Rue, French lilac, Italian fitch, or professor-weed,
G. officinalis has been known since the Middle Ages for relieving the symptoms of diabetes mellitus. Upon analysis, it turned out to contain compounds related to guanidine, a substance that decreases blood sugar by mechanisms including a decrease in insulin resistance, but were too toxic for human use. Georges Tanret identified an alkaloid from this plant, galegine, that was less toxic, and this was evaluated in unsuccessful clinical trials in patients with diabetes in the 1920s and 1930s.
Other related compounds were being investigated clinically at this time, including biguanide derivatives. This work led ultimately to the discovery of metformin (Glucophage), currently used for the management of diabetes and the older agent phenformin. The study of galegine and related molecules in the first half of the 20th century is regarded as an important milestone in the development of oral antidiabetic pharmacotherapy.
Galega, as its name implies, has an ancient reputation as a milk-gland stimulant. The Galegæ are nearly related to Glycyrrhiza, the well-known source of liquorice. Carron de la Carrière (H. W., xxvii. 79) tested its action on the milk glands of nursing women and found it rapidly increased the quantity and quality of the milk and increased the woman’s appetite. Dorretta (H. W., xxix. 177) gave Galega (he calls it “Galega vera,” but doubtless it is Goat’s-rue), in liquid extract of the leaves, for a common form of backache, which he located in the kidneys, though it is unaccompanied by any sign of kidney disease. The medicine he says is also a most excellent reconstructive in cases of anæmia and impaired nutrition.