In 1999, radiology technician Nicola H. Strickland was on vacation on the paradise island of Tobago. On her first morning, she and her companion found a totally idyllic desert beach: white sand, palm trees swaying in the breeze and a turquoise sea, with all the uniqueness of the Caribbean atmosphere. As they searched for exotic shells and coral fragments, Strickland saw greenish fruit on the sand. They were round, the size of a tangerine, and had fallen from a large tree.
Strickland, now president of the Royal College of Radiologists, in London, took a bite of the fruit and found it pleasantly sweet. He also offered it to his companion. Moments later, they began to notice a strange itch in the mouth that progressed to a sharp burning and closing of the throat. The symptoms worsened after two hours: they could barely swallow due to excruciating pain and the sensation of a huge lump obstructing their pharynx . In the next eight hours, the oral discomfort began to subside, but her cervical lymph nodes became very tender and easily palpable. They had experienced the terrible effects of the fruit of a plant that, according to Guinness World Records, is the most dangerous tree in the world. We refer to the Manzanillo, Hippomane mancinella , whose toxicity is legendary.
A chemical weapon for the Indians
In the work Summary of the natural history of the Indies (1526), the Madrid chronicler Gonzalo Fernández de Oviedo talks about the effects caused on the discoverers by the arrows that the indigenous peoples impregnated with a herb made from the resin of this plant and other poisons: “The chamomiles that the archery Carib Indians make the grass that they shoot with their arrows are born from trees crowned with many branches and leaves, thick and very green and carry a lot of this bad fruit […] and are born, like I have said, these apple trees near the water of the sea […] there is no such remedy for the wounded of this herb […] and out of fifty that hurt, not three escape “.
Hippomane mancinella belongs to the long and diverse family of the euphorbiaceae, which also includes the decorative – and slightly poisonous – poinsettia or poinsettia. Manzanillo is a tall tree that can reach up to twenty meters in height if its stem grows straight. It is native to areas of southern North America, Central America, the Caribbean, and northern parts of South America . It can live in environments with very high salinity and, for this reason, it is normally found in coastal environments. Due to its coastal distribution, it is not uncommon for it to collapse during the growth phase because the sand on the beach cannot support its weight. In those cases, it takes on an almost creeping and quite tortuous shape. The leaves are simple, alternate and with finely serrated edges.
The pommel-shaped fruits give off a sweet aroma when ripe and are attractive to the eye. They look like small green apples about 4 cm in diameter. They exhibit a glossy, glaucous appearance that turns to greenish-yellow when mature, and contain a highly poisonous off-white latex for which they have earned the nickname Chamomile of Death.
When the fruit falls from the tree, it dries and acquires a spongy texture and a black color. But not only the fruits give off the terrible latex; it can be said that the whole plant exudes it through the bark, branches and stems. This circumstance causes that approaching a manzanillo entails an unexpected splash that, if it falls on the skin, can cause burning and serious blisters .
It exudes a very poisonous latex
This tree has a plethora of toxins in the latex it gives off; Among them, phorbol, an organic compound that belongs to the diterpene family, stands out as a fundamental element. These are made up of four units of the chemical component isoprene, which has the ability to form linear chains or rings of organic compounds. One of the properties of phorbol is that it is very soluble in water, which increases the danger and toxicity of the plant. In fact, if someone takes refuge under it during a downpour, the phorbol diluted in the drops that fall from the tree will splash on the person’s skin and cause severe burns.
In this regard, Fernández de Oviedo recounted his poison with astonishment: “Only a man lay down for a short time to sleep in the shade of one of these apple trees, when he gets up his head and eyes are so swollen that his eyebrows come together with the cheeks, and if by chance a drop or more of the dew of these trees falls in the eyes, it breaks them, or at least blinds them. “
Certainly, the contact of latex with the eyes can cause keratoconjunctivitis , an inflammation of the cornea and conjunctiva of the eye. In a study published by the British Journal of Ophthalmology in 1993, John F. Pitts and his collaborators at the Tennent Institute of Ophthalmology, in Glasgow, indicated that, of twenty people with eye damage from chamomile, fourteen had both eyes affected. The cornea had been damaged in 16 of the cases, and its extent varied from great damage to the corneal epithelium –one of the six microscopic layers that make up the cornea– to punctual superficial keratitis –inflammation–.
As if that were not enough, the various phorbol esters contained in the latex of the manzanillo have the terrible property of being triggers of carcinogenic tumors through the activation of protein kinase C, a family of enzymes that is involved in the control of the function of other proteins. In an article published in the Journal of Natural Products , German biochemists W. Adolf and E. Hecker advised against prolonged contact with this wood because of its carcinogenic properties.
Even dead can be harmful
However, the Manzanillo wood has been highly valued in the manufacture of colonial furniture . In the Memories of the Patriotic Society of Havana (1842), the obtaining of it is related. To this end, the tree was set on fire to evaporate the juice from the bark. Then, the risky loggers cut the log with the force of an ax, with the only protection of gloves and gauze covering the face, since the smoke is also highly irritating. Once on the ground, it was left abandoned until all its soft parts had decomposed in the sun and it was devoid of all interior moisture. From then on, and not without first covering themselves with some kind of mask, the cabinetmakers worked the manzanillo, which had already become harmless.
However, its sawdust was still irritating, as noted in 1938 by physician K. Vigors Earle, a surgeon at Barbados General Hospital, in his study entitled The Toxic Effects of ‘Hippomane mancinella’ . Breathing in the wood dust directly can cause the familiar eye and throat inflammations, as well as swelling and headaches.
Due to its proven bad reputation, the Manzanillo was the object of very ill-considered extermination campaigns. In almost all the places where it grows, it has been, to a greater or lesser extent, destroyed by fire. The French West Indies got the worst of it. Thus, the Memoirs of the Patriotic Society of Havana record that on the island of Martinique entire forests of the proscribed tree were burned. And a French royal decree of 1733 ordered their extermination on the island of San Bartolomé. Even the US state of Florida has been so decimated that it is now in danger of extinction.
It also plays a positive role
However, Manzanillo carries out a fundamental task in environmental protection: its extensive root system establishes the fragile coastal stratum and prevents erosion of the coastline; it is also an excellent windbreaker. In addition, although eating the fruits can be lethal for many animals, some species, such as the striped iguana, are immune to its venom . For its part, the phorbol that contains the toxic latex of this tree can also be beneficial: scientists from the Scripps Research Institute have managed to synthesize it to manufacture it in quantities useful for research and drug development. For these reasons, Manzanillos have been replanted in areas where they had been eliminated. Of course, to prevent people from getting too close to the settlement areas of these trees, in many places the bark is painted with a red cross or circle. Signs are also placed warning of its danger.
In 2000, Strickland recorded his ordeal with Hippomane mancinella in a letter published in the prestigious British Medical Journal . “In our case, swallowing only a small amount of fruit juice clearly produced ulceration and severe edema of the mouth and esophagus. Drainage of the toxin to the regional lymph nodes could presumably cause subsequent neck pain.” .
Strickland concluded the document by explaining that those people who plan their vacations in the paradisiacal Caribbean should receive information about the serious danger that this fruit can pose to their health, and pointed out that mainly parents should remain vigilant and watch that their children do not eat it. Because of its aroma and sweet taste, similar to that of a ripe plum, it is especially appetizing. Like the apple Snow White should never have bitten.
Images: Pancrat via Wikimedia / GNU / CC – NPS – CC0 – The Scripps Research Institute
