coleus

[New Latin Coleus, genus name, from Greek koleos, sheath (from the way its filaments are joined).]

For more information on coleus, visit Britannica.com.

Description

Coleus forskohlii is a perennial plant, with a strong, camphor-like odor. It is in the mint family. It grows well in warm temperate or subtropical areas. The plant is native to areas of India, Myanmar, Nepal, and Sri Lanka. Coleus has long been used in traditional Indian (Ayurvedic) medicine, but gained popularity when a chemical extract of the root called forskolin demonstrated properties that make it a potential treatment for asthma, bronchitis, glaucoma, congestive heart failure, and other conditions. Forskolin was first identified by Western researchers in the 1970s, but the effects of the whole coleus plant and its extracts have not been as well studied or understood.

Another species of coleus, Coleus kilimandschari, is found in parts of Africa and has been used in Rwandan folk medicine to treat infections and autoimmune diseases. Recent studies of Rwandan coleus indicate that it is effective against a variety of disorders involving destruction of red blood cells. As of 2002, however, Rwandan coleus has not been studied as intensively as Coleus forskohlii, and its extracts await further analysis.

Chinese research indicates that several diterpenoids found in the leaves and stems of coleus may be effective against leukemia cells. These recently discovered compounds, however, require further study and analysis.

General Use

Forskolin increases the levels of a cell-regulating compound called cyclic adenosine monophosphate (cAMP). This property allows it to stabilize mast cells, which contain histamine and other inflammatory substances. Preventing the release of these compounds could make forskolin valuable in the treatment of diseases with an allergic component, such as asthma and eczema.

Another benefit of the increase of cAMP is forskolin's ability to relax smooth muscles. The bronchioles, uterus, arteries, gastrointestinal tract, and bladder all contain smooth muscle that is responsive to the antispasmodic effects of forskolin. As an antispasmodic, it has potential applications for conditions that involve cramping or smooth muscle contraction. These include asthma, painful periods, angina, irritable bowel syndrome, bladder infections, and high blood pressure.

People suffering from asthma may benefit from the use of forskolin in its capacity as an antispasmodic. During an asthma attack, the smooth muscle within small passageways of the lungs (bronchioles) constricts and makes breathing difficult. The action of forskolin is similar to that of some standard inhalers containing such medications as albuterol, a beta agonist bronchodilator. Both substances relax the smooth muscle, and improve the person's breathing ability. Studies of forskolin for the treatment of asthma have shown positive results in both oral and inhaled preparations, although it is not commercially available in an inhaled formula at this time. Other allergic conditions, including eczema, may also respond well to forskolin. Levels of cAMP are reduced in the bronchioles and skin of people suffering from asthma and eczema. The lack of cAMP causes histamine release and subsequent allergic symptoms, including bronchoconstriction and local reaction. Forskolin may be able to prevent the onset of symptoms in susceptible people by increasing cAMP levels. It can theoretically be helpful for any condition that is caused, wholly or partially, by an allergic reaction. Professional help should be sought to use forskolin for this indication, particularly because of potential interactions with other medications used for asthma.

Psoriasis can be treated by taking forskolin supplements. In this condition, skin cells multiply at a rate much greater than normal. Itchy, silvery patches are formed on the skin. This may be due to an imbalance of cell regulating chemicals, including cAMP, that can be normalized by forskolin.

Cardiovascular diseases, such as congestive heart failure, angina, and high blood pressure, have the potential to be treated by forskolin. The extract appears to increase the contractility of the heart, and relax the smooth muscles in the walls of the arteries. The relaxation of the arteries decreases blood pressure, pain due to angina, and strain on the heart. Maximum benefit may be achieved in conjunction with other botanicals or medications, such as dobutamine.

Blood vessels in the brain are dilated by forskolin, which could have clinical applications for patients who are at risk of, or recovering from, stroke. Forskolin also decreases the risk of abnormal clotting. This is another desirable effect for stroke patients and those with other cardiovascular conditions that cause, or result from, increased susceptibility to blood clots.

The high pressure inside the eye that occurs with glaucoma has been reduced in research studies with the use of forskolin drops. Eye drops made with forskolin are not yet available to the consumer, but oral preparations have the potential for beneficial effects.

An infusion of the leaves of Coleus forskohlii has traditionally been used in Indian medicine for the treatment of gas and bloating. This effect has not been subjected to study.

Other potential applications for forskolin, which are not yet adequately studied, include treatment for weight loss, hypothyroidism, malabsorptive conditions, depression, cancer metastasis, and immune dysfunction.

Preparations

Crude preparations of Coleus forskohlii may not contain enough forskolin to exert a clinical effect. Forskolin extracts are available. One recommended dose is 50 mg two or three times daily of a preparation containing 18% forskolin. A health care provider knowledgeable in the clinical use of botanicals should be consulted before undertaking treatment with this extract.

Precautions

Forskolin can be a powerful medication, and has effects on many systems of the body. It has been described as a central nervous system depressant. It should not be taken for an indication without a person being aware of potential effects on other parts of the body. For this reason, professional supervision is recommended.

People with low blood pressure or gastric ulcers may wish to avoid forskolin due to potential exacerbation of these conditions. Children, or women who are pregnant or breastfeeding, should also avoid this substance due to the current lack of data about potential risks. Similarly, those who have chronic liver or kidney disease should use great caution in taking this medication, particularly if other herbs or medications are being used.

Side Effects

Forskolin does not appear to be toxic based on studies done on animals; however, it has been reported by veterinarians to lower the blood pressure of cats and dogs. As of 2002, the most common side effect reported for coleus leaves is contact dermatitis (skin rash) in people who are allergic to the plant. The overall safety and side effects of forskolin, however, have not yet received an in-depth analysis.

Interactions

Forskolin may intensify the effects of other medications taken concurrently. Caution should be used when taking any botanical or prescription medication. Forskolin should not be taken in conjunction with anti-asthmatic, anticoagulant or antihypertensive medications without the supervision of a health care provider.

Resources

Books

Bratman, Steven and David Kroll. Natural Health Bible. Roseville, CA: Prima Publishing, 1999.

Chevallier, Andrew. The Encyclopedia of Medicinal Plants. New York: DK Publishing, Inc., 1996.

Murray, Michael. The Healing Power of Herbs. Roseville, CA: Prima Publishing, 1995.

Periodicals

Cos, P., N. Hermans, P. B. Van, et al. "Complement Modulating Activity of Rwandan Medicinal Plants" Phytomedicine 9 (January 2002): 56-61.

Mei, S. X., B. Jiang, X. M. Niu, et al. "Abietane Diterpenoids from Coleus xanthanthus." Journal of Natural Products 65 (May 2002): 633-637.

Organizations

The Ayurvedic Institute. 11311 Menaul NE, Albuquerque, NM 87112. (505) 291-9698. .

National Institute of Ayurvedic Medicine. 584 Milltown Road, Brewster, NY 10509. (845) 278-8700. .

[Article by: Judith Turner]

Ko'lee-us. About 150 species of foliage plants of the Old World tropics. In the Midwest, called the Foliage Plant.

Description
Mostly succulent herbs, with stems square, leaves opposite and toothed. Flowers in clusters of 6 or more, with a short 2-lipped calyx, lower lip with 4 teeth; corolla 2-lipped, the upper short with 2-4 lobes, the lower boat-shaped. Stamens 4.

How to Grow
Start seeds indoors 10 weeks before last spring frost, providing 70-75° F (21-24° C) bottom heat, but raising this to 80° F (26.5° C) if germination does not occur in 10 days. Do not cover the seeds with soil. Cover pots with plastic wrap. After last frost, plant in moderately shady site outdoors. Keep moist. Pinch off flowers to promote bushy plants. Where summers are humid, Coleus will grow in full sun, but the foliage will be less vividly colored and will droop in the afternoon. This species prefers warm weather.

Coleus - hybridus
Garden Coleus . To 3 ft. (90 cm) high. Grown for its showy, variously colored leaves, which may be scalloped or fringed. Stem cuttings make attractive winter houseplants. Hundreds of cultivars. Also sold as C. blumei . Tender perennial grown as a tender annual.

Coleus
Hybrid Coleus leaves
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Lamiales
Family:	Lamiaceae
Genus:	Solenostemon
Species
See text.

Solenostemon is a genus of perennial plants, native to tropical Africa, Asia, Australia, the East Indies, the Malay Archipelago, and the Philippines. They are commonly known as Coleus, a name which derives from an earlier classification under the genus name Coleus, species of which are currently included in either Solenostemon or another genus, Plectranthus.

Contents 1 Species 2 Cultivation 2.1 Diseases 2.2 Propagation 2.3 Psychoactivity 3 References

Species

Species include:

• Solenostemon autranii (Briq.) J. K. Morton
• Solenostemon rotundifolius (Poiret) J. K. Morton
• Solenostemon scutellarioides (Linnaeus) Codd (syn. Coleus blumei)
• Solenostemon shirensis (Gürke) Codd
• Solenostemon pumilus

Cultivation

Yellow Solenostemon scutellarioides

Many cultivars of the southeast Asian species Solenostemon scutellarioides have been selected for their colorful variegated leaves, typically with sharp contrast between the colors; the leaves may be green, pink, yellow, black (a very dark purple), maroon, and red (somewhat resembling the unrelated caladium). New cultivars with varieties of colors are constantly being made. The plants grow well in moist well-drained soil, and typically grow 0.5-1 m tall, though some may grow as tall as 2 meters. Coleus are typically grown as ornamental plants. They are heat-tolerant, though they do less well in full sun in subtropical areas than in the shade. In mild areas (no snow in winter), plants can usually be kept as perennials if well managed. Whereas cultivation in colder areas, they are often grown as annuals as they are not hardy and become leggy and unattractive with age. Though this is usually resolved by pinching back growing tips to encourage bushing. In bright hot areas, the colors of the plant will typically be more intense in shaded areas than in full sun, and the plants will require less water there. Coleus also make low-maintenance houseplants, and can often be propagated by clipping a length of stem just below the leaves and putting the stem in water to root. The plant's flowers grow on a stem above that stem's leaves, and tend to be purple and quite small in comparison to the leaves. The plant is not generally grown for its flowers, as it promotes stem elongation (remove to halt this).

A cultivated variety of coleus

Diseases

One disease that can affect coleus is downy mildew. This mildew appears on the leaves making the plant look dirty because it is brown in color. The organism is called Peronospora sp. and can also result in curled and twisted leaves. Sometimes symptoms are not found on leaves which make the disease harder to control.[1] Another disease is Impatiens necrotic spot virus which causes brown or yellow spots on leaves, rings, black or brown stem discoloration, and brown leaf veins, ultimately resulting in plant death. The disease is spread by an insect called a thrips that carries the virus from an infected plant to an uninfected plant. It only takes a few of these insects to infect a whole greenhouse. [2]

Propagation

A cultivated coleus grown as a small tree

There are two ways to propagate Coleus. Seeds are inexpensive and easily obtainable. To germinate, simply sprinkle seeds on the surface soil and press down. Seeds need light to germinate, so avoid covering the seeds. To keep seeds moist, grow in a container and cover with plastic, or mist seeds daily (if starting seeds directly in the garden). Sprouts can show color in as little as two weeks. Alternatively, cuttings can be taken. Cuttings root readily in plain water, without the addition of rooting hormone (although it is still beneficial).

Psychoactivity

Coleus Blumei has very mild relaxing and hallucinating effects. Coleus has not been explored very much but has been known to have been used by the Mazatec indians.

References

• Annotated Checklist of Cultivated Plants of Hawai‘i: Solenostemon
• USDA Germplasm Resources Information Network (GRIN): Species Records of Solenostemon
• Erowid

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