Marigold

Botanical Name: Calendula officinalis, Asteraceae

Common names: Calendula, Marigold, Pot Marigold, Mary Bud, Gold Bloom

Plant description: Calendula has a fibrous annual root, with a hollow, angularly branched stem about a 30-60 cm in height. The green leaves are alternate, sessile, spatulate to oblanceolate, tips acute, the margins entire or finely serrate, covered in a fine pubescence. The bright orange flowers are borne on crown-shaped receptacles, succeeded by a circular corona of seeds. One feature of Calendula is that the flowers open with the rising of the sun and the close again as its sets. Many cultivars of Calendula exist, and may not conform to the above botanical description. The name ‘Marigold’ is also used for species in another genus within the Asteraceae called Tagetes, which does not have the same properties as Calendula.

Habitat, ecology and distribution: Calendula is originally native to the Mediterranean and northern Africa, and has since become a popular and common garden ornamental.

Part used: Petals (no bracts).

History: Calendula has long been utilized as an ornamental, medicinal and food plant throughout the ages. Its particular feature of opening and closing with the sun attracted the attention of early commentators, and hence acquired the names of solis sponsa (‘bride of the sun’). The 12^th century text Macer's Herbal states that it “…drawyth owt of ye heed wikked hirores [humours],” and that if you “…loke wyscely on golde erly at morwe [morning] yat day fro feures it schall ye borwe: ye odour of ye golde is good to smelle.” In the Winter's Tale, Shakespeare writes of it, saying “…the marigold, that goes to bed wi' the sun and with him rises weeping: these are flowers of middle summer, and I think they are given to men of middle age” (Act 4, Scene IV). Calendula was commonly harvested and dried for use in soups and broths, and in L'Agriculture et Maison Rustique by Estienne and Liebault (1564), translated into English by Charles Stevens as the Countrie Farme (1699), mentions Calendula as a specific for headache, jaundice, red eyes, toothache and ague. Stevens adds that the “…conserve made of the flowers and sugar, taken in the morning fasting, cureth the trembling of the harte, and is also given in the time of plague or pestilence.” Culpepper states that it is a “…herb of the Sun, and under Leo. They strengthen the heart exceedingly, and are very expulsive…much used in possets, broths, and drink, as a comforter of the heart and spirits, and to expel any malignant or pestilential quality that might annoy them.”

Constituents: Calendula has undergone a significant degree of analysis for its constituents. Among the more important components are the flavonoids (e.g. isorhamnetin, quercitin, isoquercitin, narcissin, neohesperidoside and rutin) and triterpenoid saponins (e.g. amyrin, lupeol, longispinogenin, oleanic acid, arnidol, brein, calenduladiol, campesterol, erythrodiol, faradiol, helantriols, maniladiol, sitosterol, stigmasterol and taraxasterol). Other constituents include volatile oils (e.g. menthone, isomenthone, caryophyllene, pedunculatine, ionine, and dihydroactinidiolide), bitter principles (e.g. loliolide), carotenoids, calendulin, gum, resins, mucilage and polysaccharides (Duke 2003; Newall et al 1996, 58-9)

Medical Research: There are no reported human clinical trials for Calendula and internal usage, but a few uncontrolled human clinic trials have shown the efficacy of Calendula in the treatment of chronic suppurative otitis, and has been shown to speed healing and reduce inflammation with topical use (Newall et al 1996, 58-9).

Antioxidant: A butanolic fraction (BF) of Calendula officinalis, rich in a variety of bioactive metabolites including flavonoids and terpenoids, was found to possess free-radical scavenging activity against superoxide and hydroxyl radicals. Lipid peroxidation in liver microsomes induced by Fe(2+)/ascorbate was 100% inhibited by BF. The total reactive antioxidant potential of BF (TRAP) (in microM Trolox equivalents) was 368.14 +/- 23.03 and its total antioxidant reactivity (TAR) was calculated to be 249.19 +/- 14.5 microM (Cordova et al 2002).

Antiinflammatory: A methanolic extract and its 1-butanol-soluble fraction from the flowers of Calendula officinalis displayed a gastroprotective effect in ethanol and indomethacin induced gastric lesions in rats (Yoshikawa et al 2001). The anti-oedematous activities of three isolated faradiol esters from the flower heads of Calendula were examined in Croton oil-induced edema of the mouse ear. These compounds showed nearly the same dose dependent anti-edematous activity (Zitterl-Eglseer et al 1997). Newall et al report that a proprietary cream containing Calendula was found to be effective in lymphedema in rats, primarily due to an enhancement of macrophage poroteolytic activity (1996, 58). Triterpene alcohols derived from Calendula officinalis were evaluated for their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate-induced inflammation (1 microgram per ear) in mice, showing marked inhibitory activity (Akihisa et al 1996). Among the triterpenoids obtained from a CO₂ extract of Calendula flowers, faradiol monoester appeared to be the most active antiinflammatory compound, equal to indomethacin in activity, whereas other Calendula triterpenoids, including psi-taraxasterol, lupeol, taraxasterol, and beta-amyrin, were less active. The authors suggest that faradiol monoester may be a suitable parameter for the quality control of Calendula preparations (Della Loggia et al 1994).

Antiviral: Extracts of dried flowers from Calendula officinalis were examined for their ability to inhibit the human immunodeficiency virus type 1 (HIV-1) replication. The organic extract was found to be relatively nontoxic to human lymphocytic Molt-4 cells and exhibited potent anti-HIV activity in an in vitro MTT/tetrazolium-based assay. This extract also caused a significant dose and time dependent reduction of HIV-1 reverse transcription (Kalvatchev et al 1997).

Antimutagenic: Researchers examined whether Calendula officinalis extracts induce unscheduled DNA synthesis (UDS) in rat liver cell cultures, and if these extracts can reverse diethylnitrosamine (DEN)-induced UDS. Four different flower extracts were prepared: aqueous (AE), aqueous-ethanol (AEE), ethanol (EE) and chloroform (CE). In the UDS assay in liver cell cultures, DEN at 1.25 microM produced a maximal increase of 40% (3)H-thymidine ((3)HdTT) incorporation, and both, AE and AEE showed complete reversion of the DEN effect at around 50 ng/ml and between 0.4 to 16 ng/ml, respectively. In the absence of DEN, these two polar extracts induced UDS at concentrations of 25 microg for AE and 3.7 microg/ml for AEE to 100 microg/ml in rat liver cell cultures. Concentrations producing genotoxic damage were three orders of magnitude above concentrations that conferred total protection against the DEN effect. Thus, at the lower end, ng/ml concentrations of the two polar extracts AE and AEE conferred total protection against the DEN effect and at the higher end, g/ml concentrations produced genotoxic effects. These results justify the study of C. officinalis flower extracts to obtain products with biological activity and to define their genotoxic or chemopreventive properties (Perez- Carreon et al 2002). Saponins isolated and identified from Calendula arvensis were assessed for their mutagenic and antimutagenic activities using a modified liquid incubation technique of the Salmonella/microsomal assay. Screening of the antimutagenic activity was performed with benzo-[a]pyrene (BaP) and a mutagenic urine concentrate from a smoker (SU). Antimutagenic activities were also compared with the activity of chlorophyllin. All the saponins were found to be non-toxic and non-mutagenic, and four saponins from C. arvensis showed antimutagenic activity against BaP (1 microgram) and SU (5 microliters) with a dose-response relationship (Elias et al 1990)

Toxicity: There is no data on the toxicity of Calendula with internal administration. Acute toxicity studies with Calendula officinalis applied topically in rats and mice indicate that the extract is relatively nontoxic. Animal tests showed at most minimal skin irritation, and no sensitization or phototoxicity. Minimal ocular irritation was seen with one formulation and no irritation with others (Int J Toxicol 2001).

Herbal action: vulnerary, antiinflammatory, styptic, antimicrobial, cholagogue, mild antispasmodic, emmenagogue, mild diaphoretic, lymphagogue

Indications: abrasions, wounds, burns, eczema, varicosities, inflammation and irritation of the respiratory and digestive tracts, lymphadenopathy, vaginitis, urethritis, conjunctivitis

Contraindications and cautions: Calendula is contraindicated for internal usage during pregnancy due to reported emmenagogue activity (Newall et al 1996, 59).

Medicinal uses: Calendula is a styptic vulnerary that contains little tannin, with an antiinflammatory property that makes it an effective topical remedy in the treatment of infected and poorly healing wounds, especially in sensitive skin. Its gentle activity makes it particularly suitable for pediatrics, as in diaper rash and skinned knees. But before relegating Calendula to such conditions, it is wise to remember just how valuable a topical remedy Calendula has been considered in the past. According to Simon Mills, a physician from the American Civil war named Dr. R.G. Reynolds used it as a compress for healing bullet wounds. Similarly, Felter and Lloyd state that Calendula was valued by surgeons as a local application to heal surgical wounds and prevent gangrene and tetanus (Felter and Lloyd 1893). It has also been used in the local treatment of “…indolent ulcers with capillary impairment,” and has been used as a wash in abscesses, eczema, ulceration and vaginitis, endocervicitis, gonorrhoea, and urethritis (Felter and Lloyd 1893). Applied as a wash or as succus (fresh juice extract) Calendula is particularly useful in burns, broken capillaries or sunburn. In the treatment of conjunctivitis King’s mentions it in doses of five drops to 30 mL of rose water, instilled into the eye (Felter and Lloyd 1893). Similarly, the cooled infusion is an effective eye wash for conjunctivitis and blepharitis. Combined with Echinacea and Tabebiua, Calendula can be used treat fungal and bacterial infections of the vagina, used in infusion as a sitz bath, particularly to heal irritations and ulcerations. It is similarly used as a sitz bath for lacerations of the perineum after delivery, and can be used to heal sore, cracked and otherwise painful nipples. Calendula also has a history of use as a uterine antispasmodic, indicated in dysmenorrhea, acting as a cholagogue to relieve pelvic congestion. Felter and Lloyd state that Calendula is a “vaso-motor stimulant,” acting to relieve capillary engorgement, and is thus used both topically and internally in varicose veins. Cook states that the flowers are “…a mild and diffusive stimulant, with some relaxing properties, expending their power chiefly upon the nerves, and moderately upon the capillary circulation. Like all other articles of such qualities, they are nervine and antispasmodic; and have been used in hysteria and general nervousness, and to promote moisture at the surface. They are reputed to act upon the uterus beneficially in painful menstruation” (1869). Many herbalists both report that Calendula is an effective remedy in lymphatic stasis, where the glands appear swollen, with or without fever (Wood 1997, 182; Mills 1991, 544). It is particularly indicated in “…catarrhal conditions of the nose and throat, with raw and tender membranes” (Felter and Lloyd 1893), and “…wherever there is unresolved infection or erosion in the upper [respiratory and digestive] tracts, particularly if there is evidence of bleeding” (Mills 1991, 543). The bright orange flowers were traditionally thought of as encompassing the energy of more solar influences, and perhaps this quality is activated when dampness and congestion set it. These solar influences appear to indicate that Calendula may be an effective remedy in seasonal affective disorder, to clear the mind of negative and morose thoughts during winter. For this purpose a cup of the tea or a handful of the flowers thrown into soups and broths may be the best usage of the herb.

Pharmacy and dosage:

• Fresh Plant Tincture: fresh flowers, no bracts, 1:2, 95% alcohol, 3-20 gtt.
• Dry Plant Tincture: recently dried flowers, no bracts, 1:5, 70% alcohol 3-30 gtt., 1-3 mL
• Succus: fresh juice combined with an equal volume of 95% alcohol, reduced by low heat to half the total volume, 5-30 gtt.
• Hot Infusion: recently dried flowers, no bracts, 1:20, 30-120 mL