Written by: Ekatrina Barrett (2015)
Editor: Raffael Dudler (Dudler Herbal July 2016).
(We acknowledge and thank Lincoln College for their support in sharing this monograph for educational purposes).
Calendula officinalis is a plant of the Asteraceae (Daisy) family. It is a fast-growing (but short-lived) annual or biennial plant that is found in temperate regions and is native to Eurasia.
Calendula. officinalis has yellow or orange flower heads, composed of tubular disk flowers in the centre, surrounded by ray-like flowers. Calendula flowers in the summer, until the frost hits in late autumn. The leaves are simple and aromatic with a length of 30-180mm, and arranged in an alternate pattern. C. officinalis grows to a height of 80cm tall. (General References: Encyclopaedia Britannica, 2015; Go Botany, 2015; RHS, 2015.)
Marigold, English Marigold, Pot Marigold, Common Marigold, Gold-bloom, Ruddles (Griffiths et al., 1992).
Parts used: Flower
Dosage: For internal use, Calendula can be taken as:
Dried florets by infusion, 1-4g three times daily
Liquid extract (1:1 in 40% alcohol) 0.5-1ml three times daily
Tincture, 0.3-1.2ml (1:5 in 90% alcohol) three times daily (BHP, 1983).
For external use: Calendula can be used by tincture-liquid extract with same ratios as above and applied to wounds directly, or diluted (1:3 with water) for compresses. Ointment should be at 2.5%, although can be different for different conditions (e.g 1.5% for nappy rash, 7.5% for leg ulcers) (Medline Plus, 2015). Calendula is generally safe to use at said dosages with no major toxicity issues. (ESCOP, 1996)
The main active constituents of C. officinalis include phenolic compounds (flavonoids and phenolic acids), saponins (linked to the anti-tumoral properties of Calendula when studied in vitro (Muley et al., 2009)), carotenoids, triterpenic alcohols (in both free and esterified forms), polyunsaturated fatty acids (such as calenic acid) and polycarbohydrates including polysaccharides (linked with the immunostimulant properties of Calendula (Muley et al., 2009)). (Butnariu & Coradini, 2012)
Traditionally, Calendula has been used for inflammation of internal organs and oral cavity, gastrointestinal ulcers, dysmenorrhea, liver obstructions, conjunctivitis, snakebites, poor eyesight, headache, jaundice, varicose veins and haemorrhoids. It was also thought to strengthen the heart (Arora et al., 2013).
Since then, Calendula officinalis has proved its utility through clinical studies and experience. It is used internationally in complementary therapies to promote wound-healing and soothe the central nervous system (Miliauskas et al., 2004). It has anti-inflammatory properties and helps to promote healing on the skin in cases such as soothing inflamed skin lesions, dermatitis and eczema. It also proved to be more effective than the popular drug trolamine in preventing the incidence of radiation-therapy-caused dermatitis in a clinical study (Pommier et al., 2004). It can also be used as a treatment for warts and acne. (Bone & Mills, 2013).
Pharmacological reports show evidence of Calendula having anti-fungal, anti-viral and anti-microbial effects (Bone & Mills, 2013), which no doubt contributes to its efficacy as a topical remedy for various dermatological and microbial conditions.
In vitro, Calendula in various preparations appears to inhibit the growth of a variety of pathogens. One of these is Trichomonas vaginalis when flower extracts were used (Fazakas et al., 1980). Other microbes inhibited by Calendula officinalis included Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans (Chin et al., 1986) Sarcina lutea, Klebsiella pneumoniae and Candida monosa (Dvorzak & Tarle, 1989) However, Calendula officinalis only inhibited these pathogens when used in the form of essential oil and an isolated flavonoid fraction respectively, and not as an ethanol, water, acetone or chloroform extract. In the form of acetone, ethanol and water extracts, Calendula officinalis did prove effective for inhibiting the growth of the fungus Neurospora crassa (Kubas, 1972).
The wound-healing properties of Calendula are not as well researched, but it has been suggested that Calendula extract stimulates phagocytosis by increased granulation, (Dietz, 1988) and via effects on metabolism of glycoproteins, nucleoproteins, and collagen proteins in tissue regeneration (Klouchek-Popova et al., 1982).
Calendula is indicated in some cases of allergic reactions, especially those linked with poor digestion or leaky gut syndrome (Bone & Mills, 2013). Calendula can be taken internally for its effects of healing and protecting the gut wall, as well as stimulating lymphatic activity (Ellis, 2008). This simultaneous action can help dampen or eradicate allergic symptoms where the gut wall is leaky and/or inflamed and allows chemical fragments into the surrounding tissue and portal blood, where they have an immunogenic effect (Bone & Mills, 2013).
Another popular use of Calendula is as an anti-inflammatory for the mucous membranes and remedy for pharyngitis. (Bisset & Wichtl, 2001). Calendula officinalis appears to stimulate surrounding lymphatic tissues in this case through the mildly provocative effect of its resins and essential oils (Bone & Mills, 2013). This immuno-stimulating effect has been confirmed by a study on the reaction of a variety of lymphocytes to 70% ethanol extract of C. officinalis. (Amirghofran et al., 2000). The lymphocytes were stimulated at 0.1-10 μg/ml, with inhibitory activity when higher concentration extracts were used.
Finally, there is evidence of cytotoxic effects using a novel method of extraction (Laser Activated Calendula Extract), where the LACE showed potent in vitro inhibitory action against tumour cells collected from human and murine cell lines. (Algarra et al., 2006) The inhibition ranged from 70 – 100%, and along with Calendula’s lymphocyte stimulating activity suggests that there is a possibility of anti-tumour effects in vivo.
Some individuals report weak skin-sensitisation when using Calendula officinalis topically. (Bruynzeel et al., 1992) There have also been cases of anaphylactic shock when using Calendula officinalis as a gargle. (Goldman, 1974). As such, individuals with known allergies to other plants of the Asteraceae family should avoid Calendula (ESCOP, 1996). There are no known other contraindications.
Algarra, I., Collado, A., Garcia-Lora, A., Garrido, F., Jimenez-Medina, E. and Paco, L. (2006) A new extract of the plant Calendula officinalis produces a dual in vitro effect: cytotoxic anti-tumor activity and lymphocyte activation, BMC Cancer, (6), 119 [on line] Available from http://www.biomedcentral.com/1471-2407/6/119 [accessed 5 October 2015].
Amirghofran, Z., Azadbakht, M. and Karimi, M.H. (2000) Evaluation of the immunomodulatory effects of five herbal plants. Journal of Ethnopharmacology, 72(1-2) pp. 167-72.
Arora, D., Rani, A., Sharma, A. (2013) A review on phytochemistry and ethnopharmacological aspects of genus Calendula. Pharmacognosy Review, 7(14) pp. 179-187
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Bone, K. and Mills, S.(2013) Principles and Practice of Phytotherapy: Modern Herbal Medicine, 2nd edition. London: Churchill Livingstone.
Bruynzeel, D.P., van Joost, T., van Ketel, W.G., Smeenk, G., Young, E. (1992) Contact sensitization by alternative topical medicaments containing plant extracts, Contact Dermatitis, 27(4) pp. 278-279.
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Pommier, P., Gomez, F., Sunyach, M.P., D’Hombres, A., Carrie, C. , Montbarbon, X. (2004) Phase III randomized trial of Calendula officinalis compared with trolamine for the prevention of acute dermatitis during irradiation for breast cancer, Journal Clin Oncol. 22(8) pp. 1447-1453.
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