Tuesday, 30 November 2010

(3) Therapeutic Profile: Marigold - Calendula officinalis

Marigold - Calendula officinalis

Calendula officinalis, Pot Marigold, is a plant in the genus Calendula, in the family Asteraceae. It is native to Southern Europe, though its long history of cultivation makes it precise origin unknown. Calendula should not be confused with other plants that are also known as marigolds, such as corn marigold, desert marigold, or marsh marigold, or plants of the genus Tagetes.

The name Calendula stems from the Latin kalendae, meaning first day of the month, presumably because pot marigolds are in bloom at the start of most months of the year.

Calendula officinalis is a short-lived aromatic perennial plant, however the flowers may appear all year lond where conditions are suitable. The common name is Pot Marigold, however several other names include, Ruddles, Common Marigold, Garden Marigold, English Marigold and Scottish Marigold.
Calendula officinalis is widely cultivated as a herb and can be grown easily in sunny locations in most kinds of soils. Although perennial, it is commonly treated as an annual plant, particularly in colder regions where its winter survival is poor, or in hot summer location where it also does not survive.

Pot Marigold florets are considered edible, and after often used to add colour to salads, or are added to dishes as a garnish, in lieu of saffron. The leaves are edible but are often not palatable. They have a history of use as a potherb and in salads.

Medicinal Properties

The flowers of Calendula officinalis contain flavonol glycosides, triterpene oligoglycosides, oleanane-type triterpene glycosides, saponins, and a sesquiterpene glucoside.

Plant pharmacological studies have suggested that Calendula extracts have anti-viral, anti-genotoxic (prevents substances deleting cell's genetic material) and anti-inflammatory properties. Calendula in suspension or in tincture is used topically to treat acne, reducing inflammation, controlling bleeding and soothing irritated tissue.
The tincture varies in action according to the concentration of ethanol used to prepare it, frequently either 25% or 90%, due to the variable solubility of different active principles.

In a randomised study of 254 radiation patients, topical application of 4% Calendula ointment resulted in far fewer occurrences of Grade 2 or higher dermatitis than occurred in the group using trolamine. Calendula users also experienced less radiation-induced pain and fewer breaks in treatment. Providing some limited evidence that Calendula cream or ointment is effective in treating radiation dermatitis.

Calendula has been used traditionally for abdominal cramps and constipation. In experiments with rabbit jejunum, that aqueous-ethanol extract of Calendula officinalis flowers was shown to have both spasmolytic and spasmogenic effects, thus providing a scientific rationale for this traditional use. An aqueous extract of Calendula officinalis obtained by a novel extraction method has demonstrated anti-tumor (cytotoxic) activity and immunomodulatory properties (lymphocyte activation) in vitro, as well as anti-tumor activity in mice.

Calendula officinalis is used for the treatment of skin disorders and pain, and as a bactericide, antiseptic and anti-inflammatory. The petals and pollen contain triterpenoid esters (an anti-inflammatory) and the carotenoids flavoxanthin and auroxanthin (antioxidants, and the source of the yellow-orange colouration). The leaves and stems contain other carotenoids, mostly lutein (80%) and zeaxanthin (5%), and beta-carotene. Plant extracts are also widely used by cosmetics, presumably due to presence of compounds such as saponins, resins and essential oils.

Along with Equisetum arvense (Horsetails), Pot Marigold is one of the few plants which is considered astringent despite not being high in tannins.

Pot Margiold is said to be effective against numerous skin complaints such as chilblains, warts, fungual skin infections (ringworm, athlete's foot, cradle cap), eczema, leg ulcers, nappy rash and surgical wounds. It has been taken internally for gastric and duodenal ulcers and various disorders of the digestive system (colitis, diverticulitis), hepatic system (liver and gall bladder) and menstrual problems.

Seed Handling

Calendula seed is an after-ripener. That is, the seed germinates better after 6 months of storage than if planted immediately after maturity. This is an adaption that allows the Calendula seed to lie dormant and unsprouted in the soil all winter long, germinating only in the spring.

The seeds range from biege to black, they have a curled alligator appearance.
For sowing, fill a container with the chosen compost, a place the seeds in regimented rows, about 2 inches apart. Once complete cover the seeds with about 1/4 inch-worth of soil and place in darkness to promote germination. The seeds will germinate in 10 days at 15-20 degrees C.

Potential Uses in Green Pharmacy Preparations

Due to Calendula's history of being used for skin complaints, the most ideal Green Pharmacy remedy that could be made using the plant would be a cream or ointment, something that could be applied directly to the skin.

Making an oil-based ointment from the Pot Marigold flower petals would allow it to be used for topical use when needed. However, making a cream for long-term continual usage would not appear to have any side-effects.

Otherwise devising a Pot Marigold essential oil for using when bathing, would also be an option, as it would be available to use when needed and would be a more sensitive approach if the skin irritation in question was painful to apply a cream or ointment directly to.

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