Acokanthera

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Acokanthera schimperi - Köhler–s Medizinal-Pflanzen-150

Acokanthera is a genus of flowering plants in the Apocynaceae family, which is native to Africa. This genus is known for its toxic properties, as it contains potent cardiac glycosides, particularly acovenoside A and ouabain, which have been used historically as arrow poisons. The plants are evergreen shrubs or small trees with simple, opposite leaves and produce fragrant white or pink flowers.

Description

Members of the Acokanthera genus are characterized by their glossy, dark green leaves and their ability to thrive in a variety of environments, from arid to moist regions. The flowers, which are borne in dense clusters, emit a strong, sweet fragrance, particularly at night, attracting various pollinators. Following the flowering period, the plants produce small, plum-like fruits that turn from green to purple or black as they ripen. Despite their appealing appearance, all parts of the plant, especially the fruit and sap, are highly toxic if ingested.

Distribution and Habitat

Acokanthera species are predominantly found in the eastern and southern regions of Africa, extending from Ethiopia and Somalia down through Kenya, Tanzania, and south to South Africa. They are adaptable and can be found in a range of habitats, including woodland, forest margins, and bushveld.

Toxicity and Uses

The genus Acokanthera is notorious for its use in poison arrows and darts by indigenous peoples in Africa. The potency of its cardiac glycosides, particularly ouabain, has been harnessed for hunting and warfare. These substances work by inhibiting the sodium-potassium ATPase pump, leading to increased intracellular sodium and calcium concentrations, which can cause heart failure.

In addition to their use in poisons, extracts from Acokanthera plants have been used in traditional African medicine to treat various ailments, although such practices are risky due to the plants' high toxicity. Research into the cardiac glycosides found in Acokanthera has also contributed to the development of heart medication, although synthetic alternatives are now more commonly used.

Conservation

While some species of Acokanthera are widespread and not currently considered at risk, habitat destruction and overharvesting for medicinal and toxicological purposes pose threats to certain populations. Conservation efforts are necessary to ensure the survival of these species in their natural habitats.

Species

The genus Acokanthera includes several species, such as:

• Acokanthera oblongifolia – Commonly found in East Africa.
• Acokanthera oppositifolia – Known as the Bushman's poison.
• Acokanthera schimperi – Found in a range of habitats from Ethiopia to South Africa.

See Also

• Apocynaceae
• Cardiac glycoside
• Traditional African medicine
• Poisonous plants