Ma Huang

''Ephedra'' is a genus of gymnosperm shrubs. there were 77 recognized species. The various species of ''Ephedra'' are widespread in many arid regions of the world, ranging across southwestern North America, southern Europe, northern Africa, southwest and central Asia, northern China, and western South America.Kew World Checklist of Selected Plant Families
/ref> It is the only extant genus in its family, Ephedraceae, and order, Ephedrales, and one of the three living members of the division Gnetophyta alongside ''Gnetum'' and ''Welwitschia.''

In temperate climates, most ''Ephedra'' species grow on shores or in sandy soils with direct sun exposure. Common names in English include joint-pine, jointfir, Mormon-tea, or Brigham tea. The Chinese name for ''Ephedra'' species is ''mahuang'' (). ''Ephedra'' is the origin of the name of the stimulant ephedrine, which the plants contain in significant concentration.

Description

The family Ephedraceae, of which ''Ephedra'' is the only extant genus, are gymnosperms, and generally shrubs, sometimes clambering vines, and rarely, small trees. Members of the genus frequently spread by the use of rhizomes.

The stems are green and photosynthetic. The leaves are opposite or whorled. The typical scalelike leaves are fused into a sheath at the base and is often shed soon after development. There are no resin canals. Most species have rudimentary leaves without chlorophyll or photosynthesis, but a few, like ''Ephedra altissima'', develop folious leaves also as adults.

The plants are mostly dioecious, with the pollen strobili in whorls of 1–10, each consisting of a series of decussate bracts. The pollen is furrowed. The female strobili also occur in whorls, with bracts which fuse around a single ovule. Fleshy bracts are white (such as in '' Ephedra frustillata'') or red. There are generally 1–2 yellow to dark brown seeds per strobilus.

Taxonomy

The genus ''Ephedra'' was first described in 1753 by Carl Linnaeus, and the type species is ''Ephedra distachya''. The family, Ephedraceae, was first described in 1829 by Dumortier.The Gymnosperm database: ''Ephedra''.
Retrieved 5 July 2019.

Evolutionary history

The oldest known members of the genus are from the Early Cretaceous around 125 million years ago, with records being known from the Aptian-Albian of Argentina, China, Portugal and the United States. The fossil record of ''Ephedra'' outside of pollen disappears after the Early Cretaceous. Molecular clock estimates have suggested that last common ancestor of living ''Ephedra'' species lived much more recently, during the Early Oligocene around 30 million years ago. However, pollen modified from the ancestral condition of the genus with branched pseudosulci (grooves), which evolved in parallel in the living North American and Asian lineages is known from the Late Cretaceous, suggesting that the last common ancestor is at least this old.

Species

, Plants of the World Online accepted the following 77 species:
*'' Ephedra alata'' Decne. – North Africa, Arabian Peninsula
*'' Ephedra altissima'' Desf. non-Bové (1834), non-Delile (1813), non-Buch (1828) – high-climbing jointfir – North Africa, Canary Islands
*'' Ephedra americana'' Humb. & Bonpl. ''ex'' Willd. – Bolivia, Ecuador, Peru, Argentina, Chile
*'' Ephedra antisyphilitica'' Berland ''ex'' C.A.Mey. – clapweed, erect ephedra – Texas, Oklahoma, New Mexico, Nuevo León, Coahuila, Chihuahua
*'' Ephedra aphylla'' Forssk. – eastern Mediterranean from Libya and Cyprus to the Persian Gulf
* ''Ephedra'' × ''arenicola'' H.C.Cutler – Arizona, Utah (hybrid, ''E. cutleri'' × ''E. torreyana'')
*'' Ephedra aspera'' Engelm. ''ex'' S.Watson – boundary ephedra, pitamoreal – Texas, New Mexico, Arizona, Utah, Nevada, California, Chihuahua, Durango, Zacatecas, Sinaloa, Sonora, Baja California
*'' Ephedra aurantiaca'' Takht. & Pachom. – Caucasus, Kazakhstan, Turkmenistan
*'' Ephedra aurea'' Brullo et al.
*'' Ephedra boelckei'' F.A.Roig – Argentina
*'' Ephedra botschantzevii'' Pachom. – Kazakhstan, Tuva region of Siberia
*'' Ephedra breana'' Phil. – frutilla de campo – Peru, Bolivia, Chile, Argentina
*'' Ephedra brevifoliata'' Ghahr. – Iran
*'' Ephedra californica'' S.Watson – California ephedra, California jointfir – California, western Arizona, Baja California
*'' Ephedra chengiae'' Yang & Ferguson
*'' Ephedra chilensis'' C.Presl – pingo-pingo - Chile, Argentina
*'' Ephedra compacta'' Rose – widespread in much of Mexico
*'' Ephedra coryi'' E.L.Reed – Cory's ephedra – Texas, New Mexico
*'' Ephedra cutleri'' Peebles – Navajo ephedra, Cutler's ephedra, Cutler Mormon-tea, Cutler's jointfir – Colorado, Utah, Arizona, New Mexico, Wyoming
*'' Ephedra dahurica'' Turcz. – Siberia, Mongolia
*'' Ephedra dawuensis'' Y.Yang – Sichuan
*''Ephedra distachya'' L. – joint-pine, jointfir – southern Europe and central Asia from Portugal to Kazakhstan
*'' Ephedra × eleutherolepis'' V.A.Nikitin – Tajikistan (hybrid ''E. intermedia'' × ''E. strobilacea'')
*'' Ephedra equisetina'' Bunge – ma huang – Caucasus, Central Asia, Siberia, Mongolia, Gansu, Hebei, Inner Mongolia, Ningxia, Qinghai, Shanxi, Xinjiang
*'' Ephedra fasciculata'' A.Nelson – Arizona ephedra, Arizona jointfir, desert Mormon-tea – Arizona, California, Nevada, Utah
*'' Ephedra fedtschenkoae'' Paulsen – Central Asia, Siberia, Mongolia, Xinjiang
*'' Ephedra foeminea'' Forssk. – North Africa, Somalia, Balkans, Italy, Middle East; naturalized in Santa Barbara County of California
*'' Ephedra foliata'' Boiss. ''ex'' C.A.Mey. – shrubby horsetail – North Africa, Somalia, Middle East, India
*'' Ephedra fragilis'' Desf. – joint pine – Mediterranean, Canary Islands, Madeira
*'' Ephedra frustillata'' Miers – Patagonian ephedra – Chile, Argentina
*'' Ephedra funerea'' Coville & C.V.Morton – Death Valley ephedra, Death Valley jointfir – California, Arizona, Nevada
*'' Ephedra gerardiana'' Wall. ''ex'' Klotzsch & Garcke – Gerard's jointfir, shan ling ma huang – Himalayas, Tibet, Yunnan, Siberia, Central Asia
*'' Ephedra gracilis'' Phil. ex Stapf
*'' Ephedra holoptera'' Riedl – Iran
*''Ephedra intermedia'' Schrenk & C.A.Mey. – zhong ma huang – China, Siberia, Central Asia, Himalayas, Iran, Pakistan
*'' Ephedra kardangensis'' P.Sharma & P.L.Uniyal – western Himalayas
*'' Ephedra khurikensis'' P.Sharma & P.L.Uniyal – western Himalayas
*'' Ephedra laristanica'' Assadi – Iran
*'' Ephedra likiangensis'' Florin – Guizhou, Sichuan, Tibet, Yunnan
*'' Ephedra lomatolepis'' Schrenk – Kazakhstan, Tuva region of Siberia
*'' Ephedra major'' Host – Mediterranean, Middle East, Central Asia; from Canary Islands to Kashmir
*'' Ephedra milleri'' Freitag & Maier-St. – Oman, Yemen
*'' Ephedra minuta'' Florin – Qinghai, Sichuan
*'' Ephedra monosperma'' J.G.Gmel. ''ex'' C.A.Mey. – dan zi ma huang – Siberia, Mongolia, much of China including Tibet and Xinjiang
*'' Ephedra multiflora'' Phil. ''ex'' Stapf – Chile, Argentina
*''Ephedra nevadensis'' S.Watson – Nevada ephedra, Nevada jointfir, Nevada Mormon-tea – Baja California, California, Arizona, Nevada, Utah, Oregon
*''Ephedra ochreata'' Miers – Argentina
*'' Ephedra oxyphylla'' Riedl – Afghanistan
*'' Ephedra pachyclada'' Boiss. – Middle East from Sinai and Yemen to Pakistan
*'' Ephedra pangiensis'' Rita Singh & P.Sharma
*''Ephedra pedunculata'' Engelm. ''ex'' S.Watson – vine ephedra, vine jointfir – Texas, Chihuahua, Coahuila, Durango, San Luis Potosí, Nuevo León, Zacatecas
*'' Ephedra pentandra'' Pachom. – Iran
*'' Ephedra procera'' Fisch. & C.A.Mey. − Iran, Caucasus
*'' Ephedra przewalskii'' Stapf – Central Asia, Mongolia, Pakistan, Gansu, Inner Mongolia, Ningxia, Qinghai, Tibet
*'' Ephedra pseudodistachya'' Pachom. – Siberia, Mongolia
*'' Ephedra regeliana'' Florin – xi zi ma huang – Central Asia, Siberia, Pakistan, Xinjiang
*'' Ephedra rhytidosperma'' Pachom., syn. ''E. lepidosperma'' C.Y.Cheng – Gansu, Inner Mongolia, Ningxia, Mongolia
*'' Ephedra rituensis'' Y.Yang, D.Z.Fu & G.H.Zhu – Qinghai, Xinjiang, Tibet
*'' Ephedra rupestris'' Benth. – Ecuador, Peru, Bolivia, Argentina
*'' Ephedra sarcocarpa'' Aitch. & Hemsl. – Pakistan, Afghanistan
*'' Ephedra saxatilis'' (Stapf) Royle ex Florin
*''Ephedra sinica'' Stapf – cao ma huang, Chinese ephedra – Mongolia, Siberia, Primorye, Manchuria
*'' Ephedra somalensis'' Freitag & Maier-St. – Somalia, Eritrea
*'' Ephedra stipitata'' Biswas & Rita Singh
*'' Ephedra strobilacea'' Bunge – Iran, Central Asia
*'' Ephedra strongylensis'' Brullo et al.
*'' Ephedra sumlingensis'' P.Sharma & P.L.Uniyal – western Himalayas
*'' Ephedra tilhoana'' Maire – Chad
*'' Ephedra torreyana'' S.Watson – Torrey's ephedra, Torrey's jointfir, Torrey's Mormon-tea, cañutillo – Nevada, Utah, Colorado, Arizona, New Mexico, Texas, Chihuahua
*'' Ephedra transitoria'' Riedl – Iraq, Syria, Palestine, Saudi Arabia
*''Ephedra triandra'' Tul. − Bolivia, Argentina
*''Ephedra trifurca'' Torrey ''ex'' S.Watson – longleaf ephedra, longleaf jointfir, longleaf Mormon-tea, popotilla, teposote – California, Arizona, New Mexico, Texas, Chihuahua, Sonora, Baja California
*'' Ephedra trifurcata'' Zöllner
*'' Ephedra tweedieana'' C.A.Mey. – Brazil, Argentina, Uruguay
*''Ephedra viridis'' Coville – green ephedra, green Mormon-tea – California, Nevada, Utah, Arizona, New Mexico, Colorado, Wyoming, South Dakota, Oregon
*'' Ephedra vvedenskyi'' Pachom. – Iran, Caucasus, Turkmenistan
*'' Ephedra yangthangensis'' Prabha Sharma & Rita Singh – Yangthang to Ka, Leo, Nako, Chango, Chulling, Sumdo, Hoorling and Lira of Kinnaur district of Himachal Pradesh

Distribution

The genus is found worldwide, in desert regions, but not in Australia.

Ecology

Ephedraceae are adapted to extremely arid regions, growing often in high sunny habitats, and occur as high as 4000 m above sea level in both the Andes and the Himalayas. They make up a significant part of the North American Great Basin sage brush ecosystem.

Today, Ephedra plants are found no further south than 3°N in the Saharo-Arabian zone. However, researchers have discovered evidence of this drought-resistant plant living over 1,000 km further south at Oldupai Gorge around one million years ago, based on fossil pollen, preserved tap roots, and supporting indicators of arid conditions.

Human use

Remains of a buried Neanderthal found at Shanidar cave in Iraqi Kurdistan, over 50,000 years old was found associated with ''Ephedra'' pollen among those of other plants. While some authors have suggested that these represent plant remains deliberately buried alongside the Neanderthal, other authors have suggested that natural agents like bees may have been responsible for the accumulation of pollen.

In addition, archaeological remains of ''Ephedra'' dating back 15,000 years have been discovered at Taforalt Cave in Morocco. Fossil cones of ''Ephedra'' were found concentrated in the cemetery area, specifically within a human burial.

The ''Ephedra'' alkaloids, ephedrine and pseudoephedrine constituents of ''E. sinica'' and other members of the genus have sympathomimetic and decongestant qualities, and have been used as dietary supplements, mainly for weight loss. The drug ephedrine is used to prevent low blood pressure during spinal anesthesia.

In the United States, ephedra supplements were banned from the market in the early 21st century due to serious safety risks. Plants of the genus ''Ephedra'', including '' E. sinica'' and others, were used in traditional medicine for treating headache and respiratory infections, but there is no scientific evidence they are effective or safe for these purposes.

Ephedra has also had a role as a precursor in the clandestine manufacture of methamphetamine.

Adverse effects

Alkaloids obtained from the species of ''Ephedra'' used in herbal medicines, such as pseudoephedrine and ephedrine, can cause cardiovascular events. These events have been associated with arrhythmias, palpitations, tachycardia and myocardial infarction. Caffeine consumption in combination with ephedrine has been reported to increase the risk of these cardiovascular events.

Economic botany and alkaloid content

The earliest uses of ''Ephedra'' species (mahuang) for specific illnesses date back to 5000 BC. Ephedrine and its isomers were isolated in 1881 from ''Ephedra distachya'' and characterized by the Japanese organic chemist Nagai Nagayoshi. His work to access ''Ephedra's'' active ingredients to isolate a pure pharmaceutical substance led to the systematic production of semi-synthetic derivatives thereof and is still relevant today. Three species, ''Ephedra sinica'', ''Ephedra vulgaris'', and to a lesser extent '' Ephedra equisetina'', are commercially grown in Mainland China as a source for natural ephedrines and isomers for use in pharmaceuticals. ''E. sinica'' and ''E. distachya'' usually carry six optically active phenylethylamines, mostly ephedrine and pseudoephedrine with minor amounts of norephedrine, norpseudoephedrine as well as the three methylated analogs. Reliable information on the total alkaloid content of the crude drug is difficult to obtain. Based on HPLC analyses in industrial settings, the concentrations of total alkaloids in dried ''Herba Ephedra'' ranged between 1 and 4%, and in some cases up to 6%.

For a review of the alkaloid distribution in different species of the genus ''Ephedra'' see Jian-fang Cui (1991). Other American and European species of ''Ephedra'', e.g. ''Ephedra nevadensis'' (Nevada Mormon tea) have not been systematically assayed; based on unpublished field investigations, they contain very low levels (less than 0.1%) or none at all.Hegnauer R. (1962) "Chemotaxonomie der Pflanzen. I". Birkhauser Verlag, Basel; Switzerland, pp. 460–462 as cited in

References

External links

''Ephedra viridis'' (Plants for a Future Database)Ephedra fact sheet
NIH National Center for Complementary and Integrative Health
Ephedrea (Evidence and dosing)
, Mayo Clinic
Ephedra – Clinical summary and mechanism of action
MSKCC Memorial Sloan Kettering Cancer Center
Ephedraceae of Mongolia in FloraGREIF

{{Taxonbar, from=Q838000
Gymnosperm genera

Medicinal plants
Soma (drink)
Plants used in traditional Chinese medicine
Aptian genus first appearances
Extant Aptian first appearances