Strophanthus kombe

Last updated

Strophanthus kombe
Strophanthus kombe00.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Gentianales
Family: Apocynaceae
Genus: Strophanthus
Species:
S. kombe
Binomial name
Strophanthus kombe

Strophanthus kombe, the kombe arrow poison, [1] is a vine that grows in the tropical regions of Eastern Africa, and is part of the genus Strophanthus, which contains approximately 38 species. S. kombe contains a cardiac glycoside which directly affects the heart. Historically, both the seeds and roots of the plant were used in the preparation of poison arrowheads used for hunting. Today, the seeds are used pharmaceutically for patients with certain heart conditions that affect blood circulation. The seeds are traded primarily with Europe, but have also been exported to the United States and Japan.

Contents

Distribution

Strophanthus kombe is found growing naturally in the tropical regions of southeast Africa. As it is not a commercially cultivated species, it principally occurs as wild plant. It is not typically seen growing outside of its native region, although specimens are sometimes collected from the wild to be grown in foreign botanical gardens.

Habitat and ecology

Strophanthus kombe is usually found on an isolated hill known as a monadnock near water sources such as coastal forests, gallery forests, riparian thickets and woodlands. It is typically found at altitudes ranging from sea level to 1100m. It is usually found growing as vines in the forests between the coast and center of Africa.

Morphology

Strophanthus kombe is a deciduous vine, that under solitary conditions can be found as a shrub. Most frequently, it occurs as a climbing vine that grows to the highest points on tall trees. It is seen curling on the ground and draping from tree to tree. It can grow up to 3.5 meters, with a stem that grows up to 10 cm in diameter. The bark is a reddish brown, with dark brown, grey or black lenticels. The roots are thick and fleshy. The papery leaves are simple, and found in opposite arrangement. The young leaves are exceptionally hairy on both sides, but as they age, the top of the leaves become smooth. One to twelve cream colored flowers can be found on the peduncle. They are narrowly ovate or linear and slightly unequal. The dichasial cyme inflorescence is on the terminal end of the plant.

Flowers and fruits

The flower of Strophanthus kombe is an inflorescent, bisexual, fragrant flower. It is cream colored, yellow at the base with red spots and streaks inside. There is a thick layer of hair on the outside towards the top, while the inside of the flower has very few hairs. The stamen of the flower is found near the base of the corolla tube. The pistil contains a style a few millimeters in length, with a ring-like head surrounding a minuscule stigma. The fruit of the flower contains two follicles that narrow towards the apex and end in a knob of various sizes. It has two thick and hard-walled compartments containing many spindle shaped seeds.

Medicinal

Strophanthus kombe is known for its historical use as a source of arrow poison. Today it is used medicinally to treat heart failure. The plant has been used for two extremes, ending a life and saving a life, so proper dosage is crucial when using this plant medicinally. Cardiac glycosides extracted from the seeds reduce the heart rate but increase the force and efficiency of the contractions. Some glycosides can also be found in the roots and flowers. A mixture of glycosides known as strophanthin-k is found in the seeds. The purified compound is a white crystalline powder that is water-soluble and liable to hydrolysis under warm acidic conditions.

Precursors for a semi-synthetic compound known as acetylstrophanthidin are found within the seeds of Strophanthus kombe. When used clinically, this compound provides a rapid onset of vascular stimulant action.

Trivia

This plant was inadvertently used as a medical experiment by Sir John Kirk, a nineteenth-century plant explorer who brought back specimens of Strophanthus kombe for the Royal Botanic Garden at Kew, United Kingdom. Some of the plant's juice accidentally found its way onto his toothbrush. After brushing his teeth, he reported a quick drop in heart rate.

Related Research Articles

<span class="mw-page-title-main">Cardiac glycoside</span> Class of organic compounds

Cardiac glycosides are a class of organic compounds that increase the output force of the heart and decrease its rate of contractions by inhibiting the cellular sodium-potassium ATPase pump. Their beneficial medical uses are as treatments for congestive heart failure and cardiac arrhythmias; however, their relative toxicity prevents them from being widely used. Most commonly found as secondary metabolites in several plants such as foxglove plants, these compounds nevertheless have a diverse range of biochemical effects regarding cardiac cell function and have also been suggested for use in cancer treatment.

<i>Robinia pseudoacacia</i> Species of tree native to North America

Robinia pseudoacacia, commonly known in its native territory as black locust, is a medium-sized hardwood deciduous tree, belonging to the tribe Robinieae of the legume family Fabaceae. It is native to a few small areas of the United States, but it has been widely planted and naturalized elsewhere in temperate North America, Europe, Southern Africa and Asia and is considered an invasive species in some areas, such as the temperate east coast of Australia where the cultivar 'Frisia'(Golden Robinia) was widely planted as a street tree before being classed as a weed. Another common name is false acacia, a literal translation of the specific name.

<span class="mw-page-title-main">Apocynaceae</span> Dogbane and oleander family of flowering plants

Apocynaceae is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison. Members of the family are native to the European, Asian, African, Australian, and American tropics or subtropics, with some temperate members. The former family Asclepiadaceae is considered a subfamily of Apocynaceae and contains 348 genera. A list of Apocynaceae genera may be found here.

<span class="mw-page-title-main">Ouabain</span> Chemical substance

Ouabain or also known as g-strophanthin, is a plant derived toxic substance that was traditionally used as an arrow poison in eastern Africa for both hunting and warfare. Ouabain is a cardiac glycoside and in lower doses, can be used medically to treat hypotension and some arrhythmias. It acts by inhibiting the Na/K-ATPase, also known as the sodium–potassium ion pump. However, adaptations to the alpha-subunit of the Na+/K+-ATPase via amino acid substitutions, have been observed in certain species, namely some herbivore- insect species, that have resulted in toxin resistance.

<i>Strychnos nux-vomica</i> Species of plant

Strychnos nux-vomica, the strychnine tree, also known as nux vomica, poison fruit, semen strychnos, and quaker buttons, is a deciduous tree native to India and to southeast Asia. It is a medium-sized tree in the family Loganiaceae that grows in open habitats. Its leaves are ovate and 5–9 centimetres (2–3.5 in) in size. It is known for being the natural source of the extremely poisonous compound strychnine.

<i>Nerium</i> Species of plant

Nerium oleander, most commonly known as oleander or nerium, is a shrub or small tree cultivated worldwide in temperate and subtropical areas as an ornamental and landscaping plant. It is the only species currently classified in the genus Nerium, belonging to subfamily Apocynoideae of the dogbane family Apocynaceae. It is so widely cultivated that no precise region of origin has been identified, though it is usually associated with the Mediterranean Basin.

<i>Strophanthus</i> Genus of plants

Strophanthus is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1802. It is native primarily to tropical Africa, extending to South Africa, with a few species in Asia from southern India to New Guinea and southern China. The genus name is a compound of the Greek words στροφος (strophos) "twisted" and ανθοσ (anthos) "flower", in reference to the corolla lobes which, in some species - notably S. petersianus - resemble long twisted ribbons or threads and can reach a length of 30–35 cm. This trait, in addition to colouring involving combinations of bright pinks, purples and oranges, combine to make the flowers among the most ornamental in the plant kingdom.

Arrow poisons are used to poison arrow heads or darts for the purposes of hunting and warfare. They have been used by indigenous peoples worldwide and are still in use in areas of South America, Africa and Asia. Notable examples are the poisons secreted from the skin of the poison dart frog, and curare, a general term for a range of plant-derived arrow poisons used by the indigenous peoples of South America.

<i>Actaea rubra</i> Species of flowering plant

Actaea rubra, the red baneberry or chinaberry, is a poisonous herbaceous flowering plant in the family Ranunculaceae, native to North America.

<i>Calotropis gigantea</i> Species of plant

Calotropis gigantea, the crown flower, is a species of Calotropis native to Cambodia, Vietnam, Bangladesh, Indonesia, Malaysia, Thailand, Sri Lanka, India, China, Pakistan, and Nepal.

k-Strophanthidin Chemical compound

k-Strophanthidin is a cardenolide found in species of the genus Strophanthus. It is the aglycone of k-strophanthin, an analogue of ouabain. k-strophanthin is found in the ripe seeds of Strophanthus kombé and in the lily Convallaria.

<i>Ximenia americana</i> Species of tree

Ximenia americana, commonly known as tallow wood, hog plum, yellow plum, sea lemon, or pi'ut (Chamorro), is bush-forming shrub/small tree; a species from the Ximenia genus in the Olacaceae family. It is mainly found in the tropics, ranging from Africa, India and southeast Asia, to Australia, New Zealand, Pacific Islands, West Indies, Central, North and South America. It is especially common in Africa and South America. It is not domesticated so it is only found occurring in the wild.

<i>Rauvolfia vomitoria</i> Species of plant

Rauvolfia vomitoria, the poison devil's-pepper, is a plant species in the genus Rauvolfia. It is native from Senegal east to Sudan and Tanzania, south to Angola; and naturalized in China, Bangladesh, different ranges of Himalayan and Puerto Rico. The plant contains a number of compounds of interest to the pharmaceutical industry and is widely used in traditional medicine.

<i>Digitalis obscura</i> Species of plant

Digitalis obscura, commonly called willow-leaved foxglove or dusty foxglove or spanish rusty foxglove, is a flowering plant native to regions in Spain and Morocco. It is also grown as an ornamental flower. This foxglove is a woody perennial plant belonging to the family Plantaginaceae. Along with the other foxgloves it used to be placed in the figwort family, Scrophulariaceae; however, recent genetic research has moved the genus Digitalis to a larger family. It is similar to many of the foxglove species in its high toxicity and medicinal use as a source for the heart-regulating drug digoxin. Its strikingly distinctive amber- to copper-coloured flowers give the species its name and help distinguish it from other members of the genus.

<i>Strophanthus hispidus</i> Species of plant

Strophanthus hispidus, the hispid strophanthus, is a liana or shrub that can grow up to 5 metres (16 ft) tall. Its flowers feature a yellow corolla and yellow corona lobes spotted with red, purple or brown. The seeds, like those of several other Strophanthus species, contain potent cardiac glycosides absorbable through wounds - hence its use in African arrow poisons and later in modern medicine as a digitalis-like heart stimulant. Strophanthus hispidus is native from west tropical Africa east to Tanzania and south to Angola. It is naturalized in China.

<i>Strophanthus preussii</i> Species of plant

Strophanthus preussii, the Preuss' strophanthus, is a plant in the dogbane family Apocynaceae.

<i>Strophanthus sarmentosus</i> Species of shrub

Strophanthus sarmentosus grows as either a deciduous shrub or as a liana up to 40 metres (130 ft) long, with a stem diameter up to 15 centimetres (6 in). Its fragrant flowers feature a white to purple corolla, red or purple-streaked on the inside. Strophanthus sarmentosus is native from west and central tropical Africa to Uganda and Angola. Vernacular names for the plant include spider tresses and poison arrow vine. Its habitat is forested areas from sea level to 1,400 metres (4,600 ft) altitude.

<i>Strophanthus speciosus</i> Species of plant

Strophanthus speciosus, commonly known as the forest poison rope, is a tree, shrub or woody climber which is native to southern Africa.

<i>Strophanthus eminii</i> Species of plant in the family Apocynaceae

Strophanthus eminii is a species of flowering plant in the Apocynaceae family. It is referred to by the common name Emin's strophanthus, and grows as a liana up to 10 metres (33 ft) long or as a shrub or small tree up to 7 metres (23 ft) tall, with a stem diameter up to 6 centimetres (2.4 in). Its fragrant flowers feature a pink with white turning red corolla tube, white turning yellow with red spots and streaks inside. Vernacular names for the plant include "spider tresses" and "poison arrow vine". Its habitat is deciduous woodland or rocky bushland, from 600 metres (2,000 ft) to 1,650 metres (5,400 ft) altitude. Strophanthus eminii is used in local medicinal treatments for snakebites, skin diseases and wounds and also as an anthelmintic. The plant has been used as arrow poison. It is native to Democratic Republic of Congo, Tanzania and Zambia.

<i>Landolphia owariensis</i> Species of plant

Landolphia owariensis is a species of liana from the family Apocynaceae found in tropical Africa. Latex can be extracted from this plant for the manufacture of natural rubber. Other names for this vine are eta, the white rubber vine and the Congo rubber plant. Congo rubber was a commercial rubber exported from the Congo Free State starting in 1890, most notable for its forced harvesting under conditions of great human suffering, in the Congo Free State, detailed in the 1904 Casement Report. From 1885 to 1908, millions died as a result of murder, deprivation, and disease, with population falling by millions in this period; some writers estimate this loss to be as high as 10 million people.

References

  1. USDA, NRCS (n.d.). "Strophanthus kombe". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 4 December 2015.

Further reading