Plantwatch: how goat’s rue inspired super drug for everything from diabetes to obesity

Galegine compound in plant formed blueprint for metformin drug, but without the toxic side-effects

Goat’s rue or French lilac, Galega officinalis, is a wild plant and often grown in gardens for its clusters of attractive lilac or white flowers. For a long time the plant was also used to treat diabetes. Its key ingredient was later identified as galegine, which lowers blood glucose levels but has toxic side-effects.

Eventually galegine led to the development of the synthetic drug metformin, now the classic treatment for treating diabetes by controlling blood sugar. Metformin has none of the toxic side effects of galegine and is now one of the most prescribed drugs in the world. But for many years metformin was vilified and banned in many countries because of its association with galegine.