Anisodus tanguticus
Encyclopedia
Anisodus tanguticus is a species of flowering plant in the family Solanaceae
Solanaceae
Solanaceae are a family of flowering plants that include a number of important agricultural crops as well as many toxic plants. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear...

 which includes many important agricultural plants. It is mostly found growing in the Qinghai-Tibetan Plateau. A. tanguticus are collected and used mostly for its medicinal effects thought to be derived from the plants biologically active nicotine
Nicotine
Nicotine is an alkaloid found in the nightshade family of plants that constitutes approximately 0.6–3.0% of the dry weight of tobacco, with biosynthesis taking place in the roots and accumulation occurring in the leaves...

 and tropane alkaloids. It has a significant impact in China as one of the 50 traditional herbs used in traditional Chinese medicine.

Alternative names

Anisodus tanguticus is more commonly known in China as shān làngdàng (山莨菪) or Zang Qie.

Description

Anisodus tanguticus is a perennial plant
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

. It has flowers that are mostly solitary and borne in leaf axils. The flowers are mostly star shaped and radial. Most of them are nodding but they can sometimes become erect.

The pedicel
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....

s have a range of lengths, but most are around at an average of about 1.5-11 cm long. These pedicels can either have no hair or bristles (glabrous) or be covered with hair (pubescent).

The calyx or sepals are often found in a funnel shape and usually average about 2.5–4 cm long.

Most of the lobes of A. tanguticus appear broadly dentate. Closer examination of these lobes reveal one to two lobes being larger and longer than the other lobes. The apex of these lobes are either acute or obtuse and are slightly unequal and do not have any hair on them.

The petals that make up the corolla appear in a range of colors. Most of the time they are purple to dark purple, but in some cases can even appear pale yellow to green. These petals are also arranged into a funnel and tend to grow between 2.5-4 cm long.

The stamens are located at the base of the corolla tube and are half the length of the corolla. The filaments are about 0.8 cm long and are hairless.

The anthers are shaped oblong with length of about 5-6 mm. Upon maturity, they tend to dehisce longitudinally.

The ovary is shaped like a cone and above it has styles that are approximately 1.2 cm long. The stigma at the top are often shaped like a disc and dehisce a little bit upon maturity.

A few pollinators of the plant include flies, honeybees, and ants.

Distribution

A. tanguticus is mainly distriubuted on the Tibetan Plateau. It is present from altitudes from 2800 m to 4200 m. The population of A. tanguticus has decreased significantly from this region due to extensive collecting primarily due to its medicinal uses.

Due to its distribution on the Tibetan Plateau, which includes many mountains and valleys, A. tanguticus can be found in very isolated areas relative to another patch of the same plant. This has led to a high level of genetic differentiation of A. tanguticus.

However, it is easily found around settlements and monasteries. It seems to thrive on nutrient rich location, fertilized by animal dung.

Medicinal uses

A. tanguticus is one of the 50 fundamental herbs used in traditional Chinese medicine
Traditional Chinese medicine
Traditional Chinese Medicine refers to a broad range of medicine practices sharing common theoretical concepts which have been developed in China and are based on a tradition of more than 2,000 years, including various forms of herbal medicine, acupuncture, massage , exercise , and dietary therapy...

.

It has high levels of two tropane alkaloid
Tropane alkaloid
Tropane alkaloids are a class of alkaloids and secondary metabolites that contain a tropane ring in their chemical structure...

s called hyoscyamine
Hyoscyamine
Hyoscyamine is a tropane alkaloid. It is a secondary metabolite found in certain plants of the Solanaceae family, including henbane , mandrake , jimsonweed , tomato and deadly nightshade...

 and scopolamine
Scopolamine
Scopolamine, also known as levo-duboisine, and hyoscine, is a tropane alkaloid drug with muscarinic antagonist effects. It is among the secondary metabolites of plants from Solanaceae family of plants, such as henbane, jimson weed and Angel's Trumpets , and corkwood...

. These chemicals primarily affect the parasympathetic nervous system and can act as anticholinergic
Anticholinergic
An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. An example of an anticholinergic is dicycloverine, and the classic example is atropine....

 agents.

Derived drugs

Anisodamine
Anisodamine
Anisodamine, also known as 7β-hydroxyhyoscyamine, is an anticholinergic and α1-adrenergic receptor antagonist used in the treatment of acute circulatory shock in China. It is also a naturally occurring tropane alkaloid found in some plants of the Solanaceae family....

 and anisodine
Anisodine
Anisodine, also known as daturamine and α-hydroxyscopolamine, is an antispasmodic and anticholinergic drug used in the treatment of acute circulatory shock in China. It is a tropane alkaloid and is found naturally in species of the Solanaceae family of plants. Anisodine acts as a muscarinic...

 are two drugs that are derived from A. tanguticus. These are primarily from the plant's tropane alkaloids that are harvested through its roots. Both drugs are anticholinergic and are sometimes used to treat acute circulatory shock. These drugs primarily act through by being an anticholinergic agent.

Anisodamine in particular was introduced into clinical use in China in 1965 through the manufacture of a synthetic drug that concentrated the alkaloids from the plant. It was first use to treat epidemic meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

, but was later used to treat other ailments. These included glomerular nephritis, rheumatoid arthritis, hemorrhagic necrotic enteritis, eclampsia, and lung edema, along with shock.

Attempts to increase population

The population of A. tanguticus is starting to dwindle in its main habitat of Qinghai-Tibet Plateau in China. In addition to its collection for its medicinal purposes, the germination rate of A. tanguticus is very low, even under most natural conditions. This is probably due to its seeds which have a very hard seed coat which prevent water absorption and also act to inhibit gaseous exchange. The seeds of A. tanguticus are therefore classified as having coat-imposed dormancy.

A study conducted tried to find a way to break the dormancy in order to help germinate the seeds. They used several combinations of treatments which included chilling, gibberellic acid, and mechanical scarification.

The scarification method, which included breaking, scratching, or softening of the seed coat, was found to be the only way to increase germination. The rate improved to about 70% and the germination time was improved to 4.1 days.

The study hoped to find ways to increase the population of the plant.

External links

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