**Calendula (Calendula officinalis)**, commonly known as pot marigold, is an annual herbaceous plant belonging to the Asteraceae (sunflower) family. It is also referred to as common marigold, garden marigold, or simply golds. The botanical name is derived from the Latin word Calendae, meaning "the first day of the month," as it was believed to bloom at the start of every month. Its common name "marigold" is a contraction of "Mary's gold," reflecting its historical association with the Virgin Mary.

Origin and Distribution

The precise origin of Calendula remains uncertain due to its long history of cultivation, but it is generally considered native to Southern Europe. It is widely distributed across the Mediterranean region, Europe, North Africa, and Southwestern Asia. Today, it is naturalized in many temperate regions worldwide and is cultivated both as an ornamental and medicinal plant. In India, it is grown successfully during the winter months, from November to February, when the weather is cool and humidity is low. Research on its cultivation has been conducted in regions such as Prayagraj and Madhya Pradesh.

Botanical Description

The plant typically reaches a height of 30 to 60 centimetres. Its leaves are hairy, alternate, oblong, and spatula-shaped. The flowers are daisy-like, ranging in colour from bright yellow to deep orange. Calendula blooms throughout most of the year. A notable characteristic is that the flowers open at sunrise and close at sunset, a daily cycle symbolising beginnings and endings.

Chemical Composition

The medicinal properties of Calendula are attributed to a diverse array of bioactive compounds present primarily in its flowers. The key constituents include:

Triterpenoids: These are the principal active components, including saponins derived from oleanolic acid, such as calendulosides A–F. They possess significant anti-inflammatory properties.
Flavonoids: Compounds such as quercetin and isorhamnetin derivatives act as potent antioxidants.
Carotenoids: These pigments impart the bright yellow-orange colour to the flowers and function as antioxidants.
Polysaccharides: These include rhamnoarabinogalactans and arabinogalactans, which exhibit immunostimulatory and antitumor activities.
Essential Oil: The volatile oil contains various sesquiterpenes.
Coumarins and Quinones: These also contribute to the plant's bioactivity.

Additionally, the flowers contain triterpene alcohols (such as α- and β-amyrin), amino acids, and various minerals. The British and European Pharmacopoeias specify a minimum flavonoid content of 0.4%, calculated as hyperoside.

Pharmacological Properties and Health Benefits

Calendula's medicinal properties have been extensively studied. It is employed in homeopathic, Unani, and Ayurvedic systems of medicine as a diaphoretic, analgesic, antimicrobial, and anti-inflammatory agent. The World Health Organization (WHO) recognises its use for the external treatment of superficial wounds, minor inflammations of the skin and oral mucosa, and wound healing.

1. Wound Healing and Skin Health:

Calendula is most renowned for its wound-healing capabilities. It promotes collagen synthesis by enhancing fibroblast activation, proliferation, and migration, thereby accelerating the healing process. Due to its anti-inflammatory and antimicrobial properties, it is highly beneficial for burns, abrasions, insect bites, eczema, and dermatitis. Clinical trials have demonstrated its efficacy in treating radiodermatitis, burn wounds, and oropharyngeal mucositis.

2. Anti-inflammatory and Antioxidant Activities:

The flavonoids and triterpenoids present in Calendula exhibit potent anti-inflammatory and antioxidant effects. They help reduce oxidative stress and soothe inflammation within the body.

3. Gastroprotective and Digestive Benefits:

In traditional medicine, Calendula is used internally for gastrointestinal disorders, liver and gallbladder complaints, and nausea. It is considered beneficial for gastric and hepatic ulcers.

4. Oral Health:

Calendula is effective against gingivitis and inflammation of the oral mucosa. Its antimicrobial and anti-inflammatory properties support overall oral hygiene.

5. Antimicrobial and Antiviral Activities:

Studies have confirmed that Calendula possesses antibacterial, antifungal, and antiviral properties, making it useful in combating various infections.

6. Antidiabetic Properties:

Animal studies have indicated antidiabetic effects of Calendula, though further research in humans is required to substantiate these findings.

7. Immunostimulation:

The polysaccharides found in Calendula stimulate the immune system and enhance phagocytosis.

8. Anticancer Properties:

In vitro studies have demonstrated that Calendula extracts exhibit anticancer and antitumor activities, suggesting potential for further investigation.

Methods of Use

Calendula can be utilised in several forms:

Topical Application: Calendula is most commonly applied as an ointment, cream, or lotion. It can be used on wounds, burns, rashes, and dry skin.
Tea or Infusion: Steep one to two teaspoons of dried flowers in a cup of hot water for 10 to 15 minutes, then strain. This infusion may be taken internally for digestive complaints.
Gargle or Mouthwash: Calendula tea can be used as a gargle for mouth ulcers or sore throat.
Oil: Calendula oil is used for massage or applied directly to dry skin.

Safety and Precautions

Calendula is generally considered safe and has no known toxicity. However, individuals with known allergies to plants in the Asteraceae family (such as ragweed, chrysanthemums, or daisies) should avoid its use. Internal use during pregnancy and lactation is not recommended without prior consultation with a qualified healthcare professional.

Historical Uses

Calendula has been employed as a medicinal herb since antiquity. Ancient Greek, Indian, and Arab civilisations recognised its therapeutic properties. In 12th-century Europe, Saint Hildegard von Bingen listed Calendula in her medical writings for the treatment of scalp impetigo, cradle cap, and intestinal disorders. During the medieval period in Europe, it was recommended for closing wounds, relieving toothache, and treating stomach and liver ulcers. In the 17th century, Nicholas Culpeper claimed that Calendula benefited the heart.

Beyond medicine, Calendula was known as "poor man's saffron" from medieval times onward. Its petals were used to impart a yellow colour to food, butter, and cheese. It served as an inexpensive alternative to saffron for colouring, though it contributed neither the flavour nor the aroma of true saffron. It was also used to dye hair and fabrics.

Cultural and Mythological References

Calendula holds a rich place in cultural and mythological traditions:

1. The Bride of the Sun:

Calendula was known as Solis Sponsa, or "Bride of the Sun." This association stems from an ancient Greek myth: a maiden named Caltha was deeply in love with the sun god Apollo. She would rise each morning to await his first ray and spend the entire day gazing upon him. Consumed by her passion, she eventually perished, and from the spot where she died, a flower grew that always turned its face toward the sun—the Calendula.

2. Mary's Gold:

In medieval Europe, the flower was called "golds" and was associated with the Virgin Mary. The 13th-century German poet Konrad von Würzburg included Calendula among twelve flowers symbolising Mary in his poem "Die Goldene Schmiede." By the 16th century, the name had evolved into "marigold," a contraction of "Mary's gold."

3. Magical Properties:

Calendula was credited with various magical attributes. Hanging a garland of Calendula on the door was believed to prevent evil from entering. It was also thought to possess the power to strip witches of their will. A 16th-century concoction claimed that drinking a potion containing Calendula could enable one to see fairies. An unmarried woman with two suitors would prepare an ointment of powdered Calendula, marjoram, wormwood, and thyme mixed with honey and white wine; applying this was said to help her discern her true life partner.

4. In Shakespeare's Works:

Shakespeare mentions the marigold six times in his works. In two references, he employs the flower as a metaphor for death and as an ornament of graves, while in the other four, he draws a parallel between the opening and closing of its petals and the rising and setting of the sun.

5. Christian Symbolism:

The flower's scent, which is simultaneously fragrant and reminiscent of decay, made it a symbol of redemption after death in Christian iconography. Its seemingly inexhaustible vegetative growth also rendered it an emblem of eternal life, and it was frequently planted on graves as a funeral flower.

6. Natural Calendar:

The very name Calendula reflects its time-keeping association. It was believed to bloom at the start of each month, hence it was regarded as a natural calendar. The daily opening and closing of its flowers with the sun's movement symbolised the cycle of beginnings and endings associated with the Roman god Janus, the deity of transitions, endings, and beginnings.

7. Renaissance Traditions:

During the Renaissance period in England, men would present baskets of Calendula to young women they wished to court.

Conclusion

Calendula (Calendula officinalis) is a versatile medicinal plant whose utility has endured from ancient civilisations to modern therapeutic practices. The diverse bioactive compounds present in its flowers confer wound-healing, anti-inflammatory, antimicrobial, and antioxidant properties. It is not merely a medicinal agent but also a cultural symbol intertwined with concepts of the sun, time, love, and life after death. Recognised by the World Health Organization and various national pharmacopoeias, this plant remains an integral component of herbal medicine. As with any new medicinal use, consultation with a qualified physician or registered dietitian is strongly advised.

Calendula: The Golden Gift of the Sun — A Scientific and Historical Treatise