Catha edulis

Catha edulis

Khat or Qāt (Catha edulis (Vahl) Endl., 1841) is a shrubby or small tree species belonging to the Celastraceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Magnoliophyta division,
Class Magnoliopsida,
Celastrales Order,
Celastraceae family,
Genus Catha,
C. edulis species.
The terms are synonyms:
– Catha forskalii A.Rich.;
– Catha inermis J.F.Gmel.;
– Celastrus edulis Vahl;
– Dillonia abyssinica Sacleux.;
– Methyscophyllum glaucum Eckl. & Zeyh.;
– Trigonotheca serrata Hochst..

Etymology –
The term Catha comes from khat, the Arabic name of the leaves of Catha edulis, with stimulating properties.
The specific edulis epithet comes from édo to eat: edible.

Geographic Distribution and Habitat –
Catha edulis is a plant native to eastern and southern Africa.
The main center of origin is assumed to be in the southwestern highlands of Ethiopia and its regular use as a stimulant is confined largely to the Muslim communities of southern Arabia and East Africa. It was not known in the West until the late 18th century and its use outside of Africa is still largely confined to ethnic communities.
Its natural habitat is that of the sub-montane or medium-altitude evergreen forest, usually near the margins, or in the woods often on rocky hills at altitudes between 1,100 and 1,435 metres.

Description –
Catha edulis is a plant that grows in the form of a shrub or small tree with evergreen foliage, 1 to 3 meters in height as it is currently cultivated, both due to the environmental conditions (poor and arid soil) and for ease of harvesting.
In nature, on the other hand, in a favorable environment, the plants can reach heights of 10 m, exceptionally up to 18 m.
The appearance of the plant is similar to the strawberry tree in terms of consistency and shape of the leaves; however, the terminal branches are long, thin and pendulous. The shoots of new vegetation (leaves and stems) have a pinkish or reddish colour. The bark of the adult plant is rough and greyish, even noticeably wrinkled and fissured in large trunks.
The leaves are lanceolate in shape, are found in an opposite position and with a serrated margin, glossy green dorsally, pale green ventrally, about 5-8 cm long, coriaceous, initially erect then drooping.
The flowers are very small and creamy white, tending towards greenish, they have five petals, gathered in groups, located in the axils of the leaves at the ends of the branches.
The fruits are reddish-brown, three-lobed capsules (samaras), about 10 mm in size, which in late autumn release the seeds (3 per capsule), briefly winged.

Cultivation –
Khat is a slow growing plant that usually grows in arid environments, at temperatures between 5 and 35 degrees Celsius.
It takes seven to eight years for the plant to reach its full height. Aside from access to sun and water, it requires little maintenance.
In places of cultivation, groundwater is often pumped from deep wells by diesel engines to irrigate crops or brought in by tanker trucks. The plants are watered abundantly starting about a month before harvesting to make the leaves and stems soft and moist. A good plant can be harvested four times a year, providing an annual source of income for the farmer.
It is grown in the mountainous areas of the tropics and subtropics at altitudes of 1,500 – 2,500 meters.
In these areas the average daily temperatures are around 16 – 22°C (within a total range of 6 – 32°C). The annual rainfall requirement is 800 – 1,000 mm for a period of 4 – 6 months.
Frost and high humidity are factors that limit growth.
Catha edulis can be grown in a wide range of moderately acidic to alkaline, sandy clay to heavy clay soils, sufficiently deep and well drained, with a high organic matter content in the loam. It is, however, a plant that does not tolerate salt.
It is mainly cultivated by small owners; farmers intercrop young plants with food crops during the first 5-6 years, after which the shade from the trees becomes too heavy for intercropping. A mixed cultivation system of a few rows of khat alternating with one or two rows of coffee (Coffea arabica L.) is not uncommon in Ethiopia.
The plant is left to grow undisturbed for 3 – years, to about 0.8 – 1 meter in height. Most of the leaves are then removed to induce the development of young shoots for a light first harvest. Normal yield levels are achieved 5 – 8 years after sowing. Plant height is maintained at 2.5 – 5 meters by regular pruning. Trees can be rejuvenated by cutting all stems close to ground level and allowing emerging suckers to develop into new stems.
In this way plantations can be kept productive for 50 – 75 years without replanting.
Flowering generally occurs during the rainy season, the fruits ripen within 4 months.
Khat is often grown for home or local consumption and harvested only when the need arises.
In the market-oriented khat-producing regions of Yemen and Ethiopia, yields can be as high as 2 tons of fresh shoots per hectare per year for well-managed orchards. Average annual yields in Ethiopia are reported to be between 800 and 1,000 kg/Ha.
Propagation can occur by seed; in this case it is best to sow as soon as it is ripe as it quickly loses its vitality. Fresh seeds germinate within 15 – 20 days.
Almost all the propagation takes place, however, by cutting taken from orthotropic shoots (with alternate leaves). Growth of rooted cuttings begins with the emergence of new orthotropic shoots with reddish bark and alternate leaves from the buds above the leaf axils. These stems continue to increase in length for about two years before the first lateral branches with plagiotropic growth appear from the axils of the older leaves, bearing slightly smaller opposite leaves.
Suckers develop at the base of stems in response to heavy pruning.

Customs and Traditions –
Catha edulis, known with various terms (Amharic: ጫት ch’at; Oromo: Jimaa, Somali: qaad, khaad, khat o chat, Arabic: القات al-qāt) is a plant which, according to some sources, was cultivated for first occurred in Kenya, with explorer Sir Richard Burton suggesting that the plant was later introduced to Yemen from Ethiopia in the 15th century. He specifically mentions the eastern city of Harar as the plant’s birthplace.
Among communities in the Horn of Africa (Djibouti, Ethiopia, Somalia) and the Arabian Peninsula, khat chewing has a long history as a social custom dating back thousands of years.
The ancient Egyptian imperial cults considered the khat plant a sacred substance, capable of realizing the divinity of those who used it. These early Egyptians consumed the plant ceremoniously in an attempt to transcend into “apotheosis” and/or harvest and manifest mystical experiences, systemic trances, and other metaphysical experiences rather than habitual recreational use or abuse.
Sufis also used it to heighten their mystical experience and to facilitate a sense of oneness with God.[
The earliest known documented description of khat is found in the Kitab al-Saidala fi al-Tibb كتاب الصيدلة في الطب, an 11th-century work on pharmacy and materia medica written by Abū Rayhān al-Bīrūnī, a Persian scientist and biologist.
The use of khat has grown tremendously in popularity, especially since the 1970s, and the crop has become very lucrative for farmers.
Its flavor is sour in taste and slender in the manner of batan-alu. But khat is reddish with a slight blackish tinge.
Khat contains the alkaloid cathinone, a stimulant, which is said to cause excitement, loss of appetite and euphoria. Among communities in areas where the plant is native, khat chewing has a history as a social custom dating back thousands of years, analogous to the use of coca leaves in South America and the betel nut in Asia.
The part of the plant from which the active principle is extracted consists of the leaves, which are selected according to their size; the best product is obtained from young and intact leaves (softer), followed by the more leathery and lower quality ones. The leaves are collected and immediately distributed, given that the most relevant effect is obtained with consumption within 48 hours of collection. In any case, consumption 3-4 days after harvesting is still satisfactory, and this fact, combined with modern means of distribution and conservation, allows it to spread from the producing countries. It is possible to use with dried leaves. Consumption occurs by chewing the leaves.
The euphoric effect occurs one to three hours after chewing. Chewing and spitting out chewed materials are part of the habitual custom of the populations, especially in Yemen, Arabia and the countries of the Horn of Africa with an Arab tradition. The fact is very evident and characteristic when observed by visitors and tourists.
The stimulating effect of the plant was originally attributed to cathine, a phenethylamine-type substance isolated from the plant. However, the attribution was challenged by reports showing that fresh leaf plant extracts contained another substance that was more behaviorally active than cathine. In 1975, the related alkaloid cathinone was isolated and its absolute configuration, (S)-2-amino-1-phenylpropan-1-one, was established in 1978. Cathinone is not very stable and breaks down to produce cathine and norephedrine. These chemicals belong to the PPA (phenylpropanolamine) family, a subset of the amphetamine-related phenethylamines and the catecholamines epinephrine and norepinephrine. In fact, cathinone and cathine have a very similar molecular structure to amphetamine.
When the khat dries, the more powerful chemical, cathinone, decomposes within 48 hours, leaving behind the milder chemical, cathines. Thus, harvesters transport the khat by packing the fresh leaves and stems in plastic bags or wrapping them in banana leaves to preserve their moisture and keep the cathinone potent. It is also common for them to frequently sprinkle the plant with water or use refrigeration during transport.
When khat leaves are chewed, the cathine and cathinone are released and absorbed through the mucous membranes of the mouth and stomach lining. The action of catin and cathinone on the reuptake of epinephrine and norepinephrine has been demonstrated in laboratory animals, showing that one or both of these chemicals cause the body to recycle these neurotransmitters more slowly, resulting in wakefulness and insomnia associated with khat use.
Serotonin receptors show a high affinity for cathinone, suggesting that this chemical is responsible for the euphoric sensations associated with khat chewing. In mice, cathinone produces the same types of nerve stimulation or repetitive scratching behaviors associated with amphetamines. The effects of cathinone peak after 15-30 minutes, with nearly 98% of the substance metabolized to norephedrine by the liver.
Cathine is a little less well known, as it is believed to act on adrenergic receptors causing the release of epinephrine and norepinephrine. It has a half-life of approximately three hours in humans. The drug bromocriptine can reduce cravings and withdrawal symptoms within 24 hours.
Khat consumption induces a mild euphoria and excitement, similar to that conferred by strong coffee. Individuals become very talkative under the influence of the plant. Animal tests have shown that khat causes an increase in motor activity. Khat can induce manic behavior and hyperactivity, similar in effect to that produced by amphetamine.
The use of khat causes constipation. Dilated pupils (mydriasis) are prominent during khat consumption, reflecting the drug’s sympathomimetic effects, which are also reflected in increased heart rate and blood pressure. Long-term use can precipitate permanent tooth darkening (of a greenish tinge), susceptibility to ulcers, and decreased sex drive.
It is unclear whether or not khat consumption directly affects the mental health of those who consume it.
Occasionally, a psychotic episode, resembling a hypomanic state in presentation, may occur. In humans, its prolonged consumption creates an elevated mood and a sense of liberation from time and space.
The World Health Organization (WHO) classified it in 1980 as a drug of abuse capable of producing psychological dependence, although WHO does not consider khat addiction a serious problem.
The legality of khat varies by region. In many countries, khat may not be a specifically controlled substance, but may still be illegal under more general laws. It is a specifically controlled substance in some countries including Canada, Germany, the United Kingdom and the United States. Conversely, its production, sale, and consumption are legal in nations where its use is traditional to those cultures, including Djibouti, Kenya, Uganda, Ethiopia, Somalia, Sudan, and Yemen. In Israel, which is home to a population of Yemeni Jews, only the leaves of the plant in its natural state are permitted.
In traditional African and Arab medicine, the leaves and roots of khat are considered a panacea against all sorts of ailments and diseases.
Among other uses, it should be remembered that the wood of large trees ranges from golden yellow to brown, shiny, straight-grained, fine and uniform in texture, strong and moderately hard. Saws and planes well. When allowed to grow into large trees, it produces a valuable timber for furniture and construction, called Chirinda redwood in South Africa.
Wood pulp is an excellent blotting paper.

Method of Preparation –
Catha edulis is mainly used as a chewing plant. The fresh young leaves, and sometimes the tender tips of the shoots, are chewed for their stimulating and slightly intoxicating effects.
Chewing khat is an age-old custom in rural areas to relieve fatigue during field work or to enliven religious and family gatherings. It is also used for its energizing effect by people such as motorists to help keep them awake and alert on long journeys.
Larger leaves that are too hard to chew and leaves that have lost their freshness can be dried and pulverized to prepare a paste with water, sugar or honey and sometimes even spices.
The paste is chewed and swallowed similar to fresh leaves.
The dried leaves are also used to prepare an infusion in the same way as tea, e.g. in South Africa, or they can be smoked like tobacco, e.g. in Arab countries.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– http://www.westafricanplants.senckenberg.de/images/pictures/cela_catha_edulis_rvbli5272__44_3539_6133a0.jpg

Attention: The pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not in any way represent a medical prescription; we therefore decline all responsibility for their use for curative, aesthetic or food purposes.