THE MANCHINEEL TREE, HIPPOMANE MANCENILLA, AND THE BLINDING TREE, EXCOECARIA AGALLOCHA
These two tropical trees with toxic and corrosive latex are found near certain tropical beaches; guardians of the Garden of Eden, so to speak.
The MANCHINEEL TREE, Hippomane mancenilla, is native to the Caribbean region: the Antilles, the northern coast of South America, Central America, Mexico and the Greater Antilles.
The BLINDING TREE (or blind-your-eye mangrove), Excoecaria agallocha, is present in the southwest Pacific (particularly in New Caledonia), Australia and the Indo-Malay region.
Both are part of the EUPHORBIACEAE, growing on the coast, including in arid areas, with stony or, on the contrary, humid and marshy soil, but always near the sea.
The MANCHINEEL TREE is a typical and common tree of the Antilles coast, which can reach 15-20 m, with a greyish trunk and shiny leaves; its fruits, which often litter the ground, look like small green apples and have the aldehyde smell of a reinette apple. Near some beaches, manchineel trees are predominant, growing in coppices.
The BLINDING TREE of the Pacific and Indian Oceans is a medium-sized tree with a twisted trunk and foliage that turns red when it fades. The trees are male or female and therefore have very different inflorescences that at first glance could make one doubt that they are the same species. Excoecaria agallocha always grows quite close to the sea coast and often among rocks or stones, isolated or in small groups.
THE SAP (LATEX) OF THESE TWO TREES IS DANGEROUS: CAUSTIC AND VERY TOXIC. Nevertheless, pharmacologists have isolated interesting substances from these two euphorbiaceae.
THE WEST INDIAN MANCHINEEL TREE: HIPPOMANE MANCINELLA
In the Caribbean, it is classic to evoke « the deadly shadow of the manchineel tree » and the West Indians always warn new arrivals of the risk of taking refuge under a manchineel tree in case of rain.
Moreover, the manchineel trees have been almost all cut down near the tourist beaches or have their trunks circled with a red band to distinguish them clearly.
Skin contact with the sap of this tree causes inflammatory dermatitis in a few hours with the appearance of skin ulcers.
Manchineel latex in the eye is a very painful experience and requires immediate care: eye wash, anti-inflammatory eye drops.
When manchineel is burned, the smoke is also very irritating to the eyes and respiratory mucous membranes.
The worst thing is of course to bite into this little apple with a slightly sweet taste and a smell of reinette: in a few seconds or minutes you feel a burning sensation in your mouth and especially your pharynx, with very quickly a near impossibility to swallow because the edema is significant and the pain intense. These painful symptoms and the inflammation of the throat persist for 6 to 12 hours in the best case and are alleviated when you manage to drink milk or a milk-based drink.
It is reported that the « Caribbean » Indians coated some of their war arrows with the latex of the manchineel tree and its plant cousin Hura crepitans. These poisoned arrowheads made of hard wood were cut so as to break and persist in the body of the enemy causing death within a few days.
The manchineel tree was used in the composition of war poisons that were used by the Indians, particularly against the conquistadors and the first « settlers » in the Antilles (poisoning arrows, spears and watering holes).
PHORBOL, TIGLIANE, DAPHNANE, TOXIC SUBSTANCES BUT POTENTIALLY USABLE IN MEDICAL RESEARCH
- Irritants are found in both hydrophobic and water-soluble fractions.
The hydrophobic components are diterpenes of tigliane and daphnane structure that become irritants after activation (esterification); they are in any case much less caustic than the water-soluble compounds also of tigliane and daphnane structure.
The water-soluble irritant factor of the daphnan type is very similar to the huratoxin extracted from Hura crepitans, another tree from the tropical regions of the Americas whose latex is also an arrow poison. - This irritant and caustic compound is also a potentially carcinogenic substance (which promotes the appearance of cancer) in the same way as TPA (12-O-tetradecanoylphorbol-13-acetate) used by cancer researchers to rapidly cause skin cancers in mice. It is a very powerful inducer of tumors, in particular by activation of protein kinase C; active at extremely low concentrations (nanomolar).
- Prostratin (12-Deoxyphorbol-13-acetate) was first isolated from Pimelea prostrata in 1976 and later rediscovered in Homalanthus nutans (commonly known as Malala tree, Euphorbiaceae). It is a phorbol ester but is not carcinogenic, it is studied for its ability to « bring out » latent forms of the AIDS virus hidden in lymphocytes and which are likely to reactivate the disease.
Other diterpenoids tigliane and daphnane, which also activate the latent AIDS virus, apparently have the ability to inhibit the replication of the virus and thus block AIDS disease.
Copyright 2024 : Dr Jean-Michel HURTEL
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