I like things to be self-explanatory, like Death Camas – with a name like that, you’re fairly certain what you’re going to get. But a plant named Tutu? I don’t blame you if the first thing you think of is a troupe of ballet dancers, but if you’re interested in poisons, know that it’s a source of a great deal of mayhem, even death.
Tutu (Coriaria arborea) is a multi-branched shrub native to New Zealand. It has characteristic square stems, glossy leaves, and drooping terminal branches of bunched flowers (racemes) that develop into sweet-tasting purple berries. Tutu meanders and grows where it wants, but can become tree-like and reach heights of 20 feet. It is found throughout New Zealand: forests, scrubland, and streamside. Physically, it reminds me a lot of pokeweed that grows throughout North Carolina, but definitely not edible, and much more savage.
The poisonous properties of tutu have been recognized for as long as New Zealand has had people. Native Maori were aware that all parts of tutu were poisonous except for the fleshy parts of the berry, and even prepared fermented beverages from the fruits while being careful to remove the toxic seeds. When New Zealand was “discovered” by famed navigator Captain James Cook, his livestock of sheep and goats died after grazing upon tutu. Obviously, Captain Cook didn’t get the memo. Thereafter, early European settlers died from “toot poisoning” after eating tutu berries. They didn’t get the memo either. (1)
So while tutu poisoning has been known for hundreds of years, poisoning continues to be a problem today. An unusual, and notable, cause of poisoning comes from honey. In the summer months of New Zealand, passionvine hoppers (Scolypopa australis) – fuzzy little nymphs that grow into moth-looking insects – feed on tutu, excreting honeydew. Bees feed on the honeydew, then take it back to their hives to make honey. Ingestion of tutu-poisoned honey or honeycomb sickens people every year, with the frequency increasing during droughts, as bees have fewer sources of nectar and honeydew available to them. Symptoms of tutu poisoned honey include vomiting, delirium, seizures, and even coma. If all this sounds a bit like “Mad Honey” due to grayanotoxins, you’d be right. If you thought the same poison was responsible, well, you’d be wrong.
The poison in question here is the aptly named tutin, a glycine receptor antagonist. The glycine receptor is an inhibitory receptor – it controls, or throttles, activity – with a widespread distribution throughout the central nervous system (CNS). The amino acid glycine is its primary neurotransmitter, and when it binds to and activates the glycine receptor, slows down and controls the activity of motor neurons and thus our muscles. Tutin competes with glycine, and when it binds to glycine receptors, neurons are no longer regulated and become hyperpolarized. The consequence is motor neurons, and muscles, running wild. Think of it like the cylinders in your car’s engine. With glycine, the cylinders are firing in the correct order and you’re driving down the road without a care. Throw tutin into the mix, and the cylinders are firing wildly and randomly. Your car is driving herky-jerky like it’s having a seizure. That’s your body on tutin, and if all this sounds familiar, it’s how strychnine works, too. (2)
New Zealander Matthew Pike found this out the hard way. He foraged for supplejack shoots – bamboo-like plants whose shoots are referred to as “New Zealand asparagus.” He found some, compared his shoots to those found on the internet, and feeling confident, took a bite. The taste was so bitter and disgusting he spat it out. Thinking it might taste better cooked, he boiled it up with carrots and broccoli. Again, bitter and disgusting, so he threw away the shoots and ate the carrots and broccoli instead. Big mistake. He had seizures so bad he dislocated his shoulder, but also temporary memory loss. By good luck, and excellent supportive care, he survived to tell the tale. It was later that he discovered he picked tutu shoots – keeping in mind that even though he spat out the shoots, the boiling water extracted tutin from the shoots, contaminating and poisoning his entire meal with tutin. (3 – It’s a fascinating 1st hand account)
So we know animals can be poisoned, like Captain Cook’s sheep and goats, and of course humans from poisoned honey and the plant itself, but what about something larger? Like elephants. Circus elephants.
In 1968 a traveling circus transported two female circus elephants in open-sided trucks – both Indian elephants, Jumbo (60), weighed in at 4,000 kg, and Jahora (40), at 5,600 kg. They were witnessed eating tutu while transported and developed signs of intoxication about 3 hours later. The first signs were salivation, watery diarrhea, and ataxia (the inability to control body movements). An hour after those signs the convulsions started, causing the elephants to fall to the ground. Aside from the seizures and uncontrollable body movements, respiratory depression set in as the trunks of the elephants coiled tightly, restricting their breathing. Fortunately, the keeper was able to communicate with a veterinarian for assistance and treated Jumbo and Jahara with massive amounts of barbiturates for sedation – 24 grams and 38 grams of pentobarbital, respectively (for comparison, humans take about 0.1 grams). Altogether, it was 26 hours of controlling the massive animals’ seizures, but they improved over the course of a week and lived. (4)
I used to think New Zealand was the kinder, gentler neighbor of Australia, where everything seemingly wants to kill you. It turns out New Zealand has some poison up its sleeve, too, but at least they don’t have drop bears. The other reminder trust your taste buds and your gut, and be careful what you forage.
- Ford, William W. “On the toxicology of the tutu plant.” Journal of Pharmacology and Experimental Therapeutics 2.1 (1910): 73-85.
- Fuentealba, Jorge, Braulio Muñoz, Gonzalo Yévenes, Gustavo Moraga-Cid, Claudia Pérez, Leonardo Guzmán, Jean Michel Rigo, and Luis G. Aguayo. “Potentiation and Inhibition of Glycine Receptors by Tutin.” Neuropharmacology 60.2-3 (2011): 453-59.
- Pike, Matthew. “I Ate Tutu… and Lived to Tell the Story.” Wilderness Magazine NZ. N.p., 18 Apr. 2016.
- Anderson, I.l. “Tutu Poisoning in Two Circus Elephants.” New Zealand Veterinary Journal 16.8-9 (1968): 146-47.
** Featured image of Coriaria arborea (tutu) by John Sullivan (CC BY-NC-2.0) **
I believe the toxin in honey is Mellitoxin (4-hydroxy-tutin) formed as a metabolite by the passion-vine hoppers, and excreted in the honeydew. Thanks for the new posts.
I’ll have to look into that. Thanks!
Convulsant sesquiterpene lactones structurally similar to tutin are quite common in plants, e.g., in the Far East, very often together with tutin and other similar lactones. For instance, this is the case of corianin from Coriaria japonica A. GRAY (Okuda T et al. Chem Pharm Bull 1987; 35(1): 182-7). Mother Nature is definitely out to get us, but it could be kinder: I would not wish death form from glycine receptor antagonists, including strychnine, even to my worst enemy, if I had a worst enemy.