Harpagophytum procumbens

Harpagophytum procumbens is a species of herbaceous plant in the Pedaliaceae family native to southern Africa. It is commonly known as harpagophyte (plant with hooks in Greek) or "devil's claw" due to the morphology of its fruits, woody capsules covered with hooked and steely thorns.

Fruits.

Harpagophytum procumbens - MHNT

Illustration of its fruit (a) and fruit Ibicella lutea (b).

Distribution

The plant grows mainly in sandy soil. The two subspecies recognized for the plant have non-overlapping ranges and alternate with the three subspecies of Harpagophytum zeyheri. Thus Harpagophytum procumbens sbsp procumbens occupies both regions of Botswana, Namibia and the Northern Cape province of South Africa. For its part, Harpagophytum procumbens sbsp transvaalensis is present in the South African province of Limpopo and the area adjacent to the border between Botswana and Zimbabwe.

Description

It is a xerophytic plant. Its thallus is prostrate and is made up of several stems up to 1'5 meters in length and a very extensive rhizome with tubers of a maximum of 20 centimeters in length in its secondary roots. The leaves are opposite, petiolate and three to five lobed, up to 65 mm long and 40 mm wide. Its color is grayish green due to the presence of mucilage glands, the underside is pubescent.

The flowers have funnel-shaped (funnel-shaped) morphology, up to 7 centimeters long and variable colors from red to purple in their distal area and yellowish at their base. Its fruit is a flat, ovate dehiscent bilocular capsule. Characteristically, this capsule is armed with two central spines up to 7 centimeters in length and two rows of between 12 and 16 curved lateral spines perpendicular to the main axis.

Chemical composition

Harpagósido.

The best-known secondary metabolites in Harpagophytum procumbens are iridoid terpene derivatives, characteristic of the order Lamiales, which may have various functions as active principles in Pharmacology. The Procumbido stands out as an epimer of the Antirhinoside, the 8-O-cinnamoyl or Harpagósido, the 8-O-(4-hydroxycinnamoyl) and the Procumbósido, all of them present in the root.

Properties and pharmacological activity

The secondary root of Harpagophytum procumbens dried, powdered or infused is used in traditional medicine to treat joint pain and tendinitis, digestive problems such as flatulence, bloating or loss of appetite. According to the European Medicines Agency, there are no medical studies that support such properties, based solely on its prolonged use over time.

Several studies carried out with root extract in animals indicate that it has some peripheral analgesic and anti-inflammatory capacity. This activity is highly dependent on the route of administration, the intraperitoneal route being effective, although the oral route is not (at least with respect to anti-inflammatory activity). It also shows complete independence with respect to any of the known active principles in the plant, so it is unknown which compound causes the observed effects. Activity in the cardiovascular system, a reduction in blood pressure and heart rate, appear to be promoted by harpagoside and other unidentified substances.

Preparations made from this vegetable can cause various disorders due to hypersensitivity to its active ingredients, causing diarrhea, vomiting, nausea, abdominal pain, headache, dizziness, and skin reactions. Its ingestion is not recommended by pregnant women, lactating women or by patients with gastric or duodenal ulcers or cardiovascular problems.

Taxonomy

Harpagophytum procumbens was described by (Burch.) DC. ex Meisn. and published in Pl. Basque Gen. 206 1840.