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The 17-year-old girl presented in the emergency room feeling nauseous and drowsy. She quickly went downhill, with her heart rate and blood pressure shooting up frighteningly and her heart鈥檚 rhythm becoming erratic. Then, cardiac arrest.
It turned out that in a suicide attempt, she had ingested leaves of the English yew tree, which contains cardiotoxic taxane alkaloids. The young student had come upon the toxic potential of yew leaves while studying British history and learning about the rebellion of the Iceni tribe against the Romans in 60 AD.
The king of the tribe, Prasutagus, tried to secure his kingdom by naming Roman Emperor Nero a co-heir with his daughters. However, when the king died, the Romans ignored the intent, seized the Iceni land, flogged his widow Boudicca and violated her daughters. Outraged, Boudicca led a revolt against the Romans, slaughtering thousands and even setting fire to Londinium, the ancient name for London.
Led by Governor Gaius Suetonius Paulinus, the Romans retaliated and, although greatly outnumbered, routed Boudicca鈥檚 army. The Battle of Watling Street marked the end of resistance to Roman rule in southern Britain, which would last another 400 years. To avoid capture, the Warrior Queen, as she became known, died by suicide,听听with yew leaves. At least so the story goes.
Boudicca is remembered in the collective British imagination as a romantic and tragic figure who led her country against invaders, with her ordering the slaughter of the defeated Romans forgotten.
The yew is a fascinating tree. One in Wales, known as the Llangernyw yew, is estimated to be at least 4,000 years old. The branches of the yew are excellent for making bows. Indeed, Otzi, the 鈥淚ce Man,鈥� whose 3,300-year-old mummy was discovered in 1991 by hikers in the Alps, was carrying arrows and a stick of yew that was to be shaped into a bow. English soldiers in the Middle Ages used longbows made of yew wood and the wood was judged to be so valuable that in 1472 Edward IV passed the Statute of Westminster declaring that every ship arriving at an English port had to bring four yew bowstaves per ton of cargo to ease a shortage of wood for longbows.
Today, the yew plays a different role. In the 1950s, the U.S. National Cancer Institute launched a project to collect and test thousands of plants for anticancer activity. One sample, collected from the bark of a Pacific yew (Taxus brevifolia) in Washington State caught the attention of researchers because an extract killed cancer cells in the lab. It took several years before 鈥減aclitaxel,鈥� a crystalline substance responsible for the anticancer activity, was isolated and given the common name Taxol. By 1971, its molecular structure was determined and the mechanism by which it stops cancer cells from dividing was identified. Clinical trials began in 1982 and 10 years later FDA approved Taxol for the treatment of ovarian cancer. Its use has expanded to breast, lung, endometrial, cervical and gastric cancers as well as HIV-related Kaposi鈥檚 sarcoma.
At first there was a significant problem in producing enough of the drug because paclitaxel is present only to the extent of about 0.01 per cent of the bark by weight. This meant that a great deal of bark had to be harvested and stripping the bark kills the tree. This is when the English yew (Taxus baccata) came to the rescue. Its needle-like leaves were found to contain a hefty supply of the compound 10-deacetylbaccatin, which in a series of steps could be converted into Taxol. This semi-synthetic production of Taxol has been supplemented with production via cell culture. Cells isolated from the leaves can be grown in a nutrient broth from which Taxol can be isolated.
The young girl听听with yew leaves survived. When she went into cardiac arrest, CPR was initiated, she was shocked with a defibrillator and treated with amiodarone, an antiarrhythmic medication. After several days in the intensive care unit, she was released and is apparently well. Learning from history is usually desirable, but not in this case. Reading about Boudicca鈥檚 suicide with yew leaves gave her the idea.
Although the story of Boudicca鈥檚 suicide with yew leaves is often repeated, there is no historical evidence that this was the poison she used. The best account of Boudicca鈥檚 revolt comes from the Roman historian Tacitus, who lived at the same time. All he says is that 鈥淏oudicca ended her days with poison.鈥� That could have been hemlock, aconite or foxglove, all potentially poisonous plants known to Celtic tribes. Or it could have been yew leaves.
There are several cases in medical literature that report death after ingestion of yew leaves. Animals are susceptible as well. In England in 2018, nine cows died when someone dumped yew tree trimmings into the field where they were grazing.
Then there is the tragic case of a Chinese immigrant family in Italy who had apparently heard something about the connection between the yew tree and cancer and misunderstood the information. The parents and a son picked some raw yew needles and blended them to make an infusion they thought would protect them from cancer. They ended up in the emergency room, but despite all efforts they suffered the same fate as Boudicca.
If you ever get a chance to visit London and walk across Westminster Bridge, you will see a large statute of a woman in a chariot holding a spear with a fierce look, accompanied by two younger girls. You will have met Boudicca, the Warrior Queen, and her daughters.
