Euphorbia poissonii , also known as Euphorbia poissoni and, incorrectly as Euphorbia poisoni is a highly irritant and toxic succulent member of the large and varied spurge

Spurge

Euphorbia is a genus of plants belonging to the family Euphorbiaceae. Consisting of 2008 species, Euphorbia is one of the most diverse genera in the plant kingdom, exceeded possibly only by Senecio. Members of the family and genus are sometimes referred to as Spurges...

 family of plants. It is native to northern Nigeria

Nigeria

Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

, where local farmers extract its latex

Latex

Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...

 for use as a pesticide. Its powerfully irritant and pain-producing nature mandates use as a fencing plant.

Toxic activity

In addition to a variety of irritant phorbol-type esters, the latex contains resiniferatoxin and tinyatoxin, two closely related highly irritant resiniferonol-type esters. The most active toxin

Toxin

A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...

, resiniferatoxin

Resiniferatoxin

Resiniferatoxin is a naturally occurring, ultrapotent capsaicin analog that activates the vanilloid receptor in a subpopulation of primary afferent sensory neurons involved in nociception...

, binds to pain receptors in the same way as capsaicin

Capsaicin

Capsaicin 2CHCH=CH4CONHCH2C6H3-4--3- ) is the active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact...

 but much more powerfully. It stimulates the neurons to fire repeatedly, causing pain.

Due to its selective nature of binding and killing pain receptors while leaving other nerve

Nerve

A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...

 cells intact, resiniferatoxin is currently being researched as a possible treatment for chronic pain

Chronic pain

Chronic pain has several different meanings in medicine. Traditionally, the distinction between acute and chronic pain has relied upon an arbitrary interval of time from onset; the two most commonly used markers being 3 months and 6 months since the initiation of pain, though some theorists and...

.

Sources

Growing Milkweed, a plant with prospective anticancer properties (see pg. 1)

Nicolaou, K. C. and Snyder, Scott A. Classics in Total Synthesis Vol. II. Wiley VCH, 2003. Chapter 6.