MEDICINAL HERBS THROUGH THE AGES

Five thousand years ago, Sumerian remedies, using poppies and henbane, were inscribed onto clay tablets; the oldest surviving records of herbal medicine. But herbs were probably used to heal long before this, the remains of medicinal plants having been found in graves dating to circa 60000BC. Chinese systems of herbal medicine were well established by 2500BC, and papyri and depictions on the walls of tombs show the ancient Egyptians had an armoury of plant cures, including meadow saffron for rheumatism and thyme for pain relief.

In the 5th century BC, Hippocrates revolutionised Greek medicine, declaring that disease was rooted in natural causes, rather than inflicted by the gods. He believed the four humours of the body had to be kept in balance for good health, and that diet and exercise were important, using herbs, including myrtle, juniper and spearmint, to treat a range of ailments. Greek ideas were picked up by the Romans and spread throughout the empire; Dioscorides’ De Materia Medica, of AD60, described approximately 1,000 medicines, using 600 different plants.

The oldest surviving European herbal written in a ‘native’ language is the Anglo-Saxon Bald’s Leechbook, probably compiled in the 9th century and kept, at least for a time, in the monastery at Glastonbury. Although parts draw on Mediterranean sources, it is notable for its many original medicines, including one for shingles made from the bark of 15 different trees, and an eye salve which, in 2015, was found to kill bacteria that cause styes and other infections.

In the medieval period, monks translated classical medical works into English and grew herbs in physic gardens; the latter becoming fashionable among the gentry. The great age of herbalism began with William Turner, John Gerard and Nicholas Culpepper writing popular herbals. The ‘doctrine of signatures’ also took hold, according to which the appearance of a plant foretold the part of the body or illness it could cure. Yellow plants were accordingly used to treat jaundice, and walnuts were thought to be good for the brain.

Many people prepared their own remedies gathered from field and hedgerow, often using family recipes passed down the generations. In the mid 18th century, one such Shropshire recipe piqued the interest of local physician William Withering. It was said to be effective against what was then known as dropsy, now understood to be fluid retention often related to heart failure. Realising that the active ingredient of the potion was foxglove, Withering began to use it to treat his own patients, experimenting with different amounts and parts of the plant. In 1785, he published An Account of the Foxglove, and Some of Its Medical Uses, detailing his findings. This led to the identification of digoxin and digitoxin, still used to treat heart conditions today. It was the start of the modern practice of extracting an active element of a plant and using it to synthesise a drug, rather than using the whole plant.