''Euphorbia resinifera'', the resin spurge, is a species of

spurge ''Euphorbia'' is a very large and diverse genus of flowering plants, commonly called spurge, in the family Euphorbiaceae. "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae (in deference to t ...

native to

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

, where it occurs on the slopes of the

Atlas Mountains The Atlas Mountains are a mountain range in the Maghreb in North Africa. It separates the Sahara Desert from the Mediterranean Sea and the Atlantic Ocean; the name "Atlantic" is derived from the mountain range. It stretches around through Moroc ...

. The dried latex of the plant was used in ancient medicine. It contains

resiniferatoxin Resiniferatoxin (RTX) is a naturally occurring chemical found in resin spurge (''Euphorbia resinifera''), a cactus-like plant commonly found in Morocco, and in '' Euphorbia poissonii'' found in northern Nigeria.

, an extremely potent

capsaicin Capsaicin (8-methyl-''N''-vanillyl-6-nonenamide) ( or ) is an active component of chili peppers, which are plants belonging to the genus ''Capsicum''. It is a chemical irritant for mammals, including humans, and produces a sensation of burning ...

analog tested as an

analgesic An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

since 1997.

Growth

It is a

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

growing to tall, forming multi-stemmed cushion-shaped clumps up to wide. The stems are erect,

succulent In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meani ...

, superficially like a

cactus A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...

, four-angled, with short but sharp pairs of spines on the angles, spaced about apart up the stem.

Geographical distribution

''Euphorbia resinifera'' is a species of

native to

, where it occurs on the slopes of the

. It is similar to its relative ''

Euphorbia echinus ''Euphorbia'' is a very large and diverse genus of flowering plants, commonly called spurge, in the family Euphorbiaceae. "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae (in deference to t ...

'', which occurs on the Moroccan coast and the

Canary Island The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocco ...

s. Due to its origin it is also called the African spurge.

Chemical constituents

''Euphorbia resinifera'' contains a milky fluid or latex, which in its dried form is called

Euphorbium :''Euphorbium can also be a synonym of the genus Euphorbia.'' Euphorbium, an acrid dull-yellow or brown resin, consisting of the concreted milky juice of several species of Euphorbia, cactus-like perennial plants indigenous to Morocco. It dissolves ...

. It has high concentration of

, an analog of

, the primary vanilloid compound found in hot peppers. It can interact with a

vanilloid The vanilloids are compounds which possess a vanillyl group. They include vanillyl alcohol, vanillin, vanillic acid, acetovanillon, vanillylmandelic acid, homovanillic acid, capsaicin, etc. Isomers are the isovanilloids. : A number of vanilloi ...

receptor on primary sensory neurons mediating pain (nociception) and neurogenic inflammation. The pain sensing cation channel is

TRPV1 The transient receptor potential cation channel subfamily V member 1 (TrpV1), also known as the capsaicin receptor and the vanilloid receptor 1, is a protein that, in humans, is encoded by the ''TRPV1'' gene. It was the first isolated member of th ...

. Resiniferatoxin has been used as a starting point in the

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

of a novel class of

s. Desensitization to topical resiniferatoxin has been tested in clinical trials to evaluate its potential to relieve neuropathic pain, as in diabetic polyneuropathy and postherpetic neuralgia. Resiniferatoxin injected subcutaneously into a rat hind paw several minutes before a surgical incision reduced postsurgical pain for 10 days in a NIH study published March 2018. It has been tested to treat pain with advanced cancer.National Institute of Dental and Craniofacial Researc
Resiniferatoxin to Treat Severe Pain Associated With Advanced Cancer
December 8, 2008, retrieved February 28, 2018 Resiniferatoxin was isolated in 1975. Euphorbium has been used since at least its first written record from the time of Roman Emperor Augustus.

References

{{Taxonbar, from=Q2658650 resinifera Endemic flora of Morocco resinifera

• In typography, a bullet or bullet point, , is a typographical symbol or glyph used to introduce items in a list. For example: *Point 1 *Point 2 *Point 3 The bullet symbol may take any of a variety of shapes, such as circular, square, diamo ...

Medicinal plants of Africa Garden plants of Africa Drought-tolerant plants