Comfrey

Overview

Symphytum officinale originates from Europe, where it is widespread, and has been introduced in North America and Asia. It is cultivated in several Mediterranean, African and Asian countries. In Africa it is cultivated on a small scale only, mainly in Madagascar and South Africa. It is harvested from the wild for local use as a food, medicine and source of materials. Young leaves and young shoots can be cooked as vegetable. Older leaves can be dried and used as a tea. Comfrey is a commonly used herbal medicine with a long and proven history in the treatment of various complaints. All parts of Symphytum officinale are medicinally used in its area of natural distribution, and the flowers, leaves and rootstocks are official in several European pharmacopoeias. This plant contains small quantities of a toxic alkaloid which can have a cumulative effect upon the liver. Many pyrrolizidine alkaloids are toxic and several have been shown to be hepatotoxic, pneumotoxic, carcinogenic and mutagenic. For this reason it is forbidden by law to use Symphytum officinale as an internal herbal remedy in many European countries. The external application of Symphytum officinale preparations for use in case of contusions, strains and spraining is considered safe because absorption of pyrrolizidine alkaloids through the skin is negligible. All parts of Symphytum officinale also contain allantoin. Allantoin is known for its healing, soothing and anti-irritating properties. In the pharmaceutical industry, the substance in this plant is widely used in anti-acne products, sun care products and clarifying lotions.

Vernacular Names

Grande consoude, Oreille de vache (France).

Agroecology

Symphytum officinale occurs in its natural distribution area in damp grassland and on river banks. It tolerates most soils except the most sandy and dry ones, and grows well on heavy clay soils. Best grown in an open sunny site in a deep rich soil.

Morphology

• Root - taproot, brown.
• Stems - stout, winged, hollow, often branched, with fleshy rootstock.
• Leaves - in a rosette and alternate on the stems, simple and entire, blade ovate-lanceolate to ovate, decurrent at base into petiole or stem, apex acuminate, pinnately veined. Stipules absent.
• Flowers - bisexual, 5-merous, pendulous. Calyx with lanceolate lobes. Corolla with cylindrical tube 12–18 mm long and small lobes, white to pink or purple-violet, with scales at throat. Stamens inserted at the middle of the corolla tube, filaments short, style slender and exserted, stigma head-shaped and small.
• Fruit - consisting of 4 ovoid nutlets 5–6 mm long, glossy dark brown or black, enclosed by the calyx.
• Seeds - small, hard, and black.

Cultivation

• Propagated by seed, division or through in-vitro propagation from root explants.
• Optimal planting distance is 70 cm × 70 cm. It should preferably be planted in open localities or with partial shade in a deep, rich soil.

Chemical Constituents

Allantoin, phenolic acid (rosmarinic, chlorogenic, caffeic, and lithospermic acids), p-hydroxybenzoic, p-coumaric acid, silicic acid, pyrrolizidine alkaloids (heliosupine, echimidine, echinatin, lasiocarpine, heliosuipine, lycopsamine, 7-acetyllycopsamine and 7-acetyllycopsamine, symphytine, cynoglossine, symlandine, intermedine), tannins, terpenoids, sterols/triterpenoids, flavonoids, amino acids, flavones, saponins, choline, asparagine, essential oils.

Traditional Medicinal Uses

• Roots have been used for wound healing.
• Roots and leaves used for broken bones and wounds.
• In Polish pharmacopoeia, as Radix symphyti, recommended as expectorant, especially for children.
• Decoction of leaves used for a variety of illnesses: asthma, cough, colds, gum problems, rheumatism, arthritis, gout, scrofula, pleuritis, leucorrhoea, ulcers, constipation, hypertension.
• Poultice of fresh leaves used for sprains and fractures, inflammatory swelling, external wounds, sores, athlete's foot, burns, bruises, pulled tendons, irritated skin, insect bites, and abscesses.
• Juice of leaves used for a variety of skin ailments and wounds healing.
• Decoction of tea as a sleep-aid.
• Oil and ointment used to treat acne, boils, and psoriasis.
• The root and leaves are anodyne, demulcent, emollient, expectorant, haemostatic, refrigerant, vulnerary.
• Considered antitussive, expectorant, haemostatic, vulnerary.