Chamomile: A herbal medicine of the past with bright future

Abstract

Chamomile is one of the most ancient medicinal herbs known to mankind. It is a member of Asteraceae/Compositae family and represented by two common varieties viz. German Chamomile (Chamomilla recutita) and Roman Chamomile (Chamaemelum nobile). The dried flowers of chamomile contain many terpenoids and flavonoids contributing to its medicinal properties. Chamomile preparations are commonly used for many human ailments such as hay fever, inflammation, muscle spasms, menstrual disorders, insomnia, ulcers, wounds, gastrointestinal disorders, rheumatic pain, and hemorrhoids. Essential oils of chamomile are used extensively in cosmetics and aromatherapy. Many different preparations of chamomile have been developed, the most popular of which is in the form of herbal tea consumed more than one million cups per day. In this review we describe the use of chamomile in traditional medicine with regard to evaluating its curative and preventive properties, highlight recent findings for its development as a therapeutic agent promoting human health.

Keywords: chamomile, dietary agents, flavonoids, polyphenols, human health

The interplay of plants and human health has been documented for thousands of years (13). Herbs have been integral to both traditional and non-traditional forms of medicine dating back at least 5000 years (2, 46). The enduring popularity of herbal medicines may be explained by the tendency of herbs to work slowly, usually with minimal toxic side effects. One of the most common herbs used for medicinal purposes is chamomile whose standardized tea and herbal extracts are prepared from dried flowers of Matricaria species. Chamomile is one of the oldest, most widely used and well documented medicinal plants in the world and has been recommended for a variety of healing applications (7). Chamomile is a native of the old World and is a member of the daisy family (Asteraceae or Compositae). The hollow, bright gold cones of the flowers are packed with disc or tubular florets and are ringed with about fifteen white ray or ligulate florets, widely represented by two known varieties viz. German chamomile (Matricaria chamomilla) and Roman chamomile (Chamaemelum nobile) (8) . In this review we will discuss the use and possible merits of chamomile, examining its historical use and recent scientific and clinical evaluations of its potential use in the management of various human ailments.

Different classes of bioactive constituents are present in chamomile, which have been isolated and used as medicinal preparations and cosmetics (9). The plant contains 0.24%1.9% volatile oil, composed of a variety of separate oils. When exposed to steam distillation, the oil ranges in color from brilliant blue to deep green when fresh but turns to dark yellow after storage. Despite fading, the oil does not lose its potency. Approximately 120 secondary metabolites have been identified in chamomile, including 28 terpenoids and 36 flavonoids (10, 11). The principal components of the essential oil extracted from the German chamomile flowers are the terpenoids -bisabolol and its oxide azulenes including chamazulene and acetylene derivatives. Chamazulene and bisabolol are very unstable and are best preserved in an alcoholic tincture. The essential oil of Roman chamomile contains less chamazulene and is mainly constituted from esters of angelic acid and tiglic acid. It also contains farnesene and -pinene. Roman chamomile contains up to 0.6% of sesquiterpene lactones of the germacranolide type, mainly nobilin and 3-epinobilin. Both -bisabolol, bisabolol oxides A and B and chamazulene or azulenesse, farnesene and spiro-ether quiterpene lactones, glycosides, hydroxycoumarins, flavanoids (apigenin, luteolin, patuletin, and quercetin), coumarins (herniarin and umbelliferone), terpenoids, and mucilage are considered to be the major bio-active ingredients (12, 13). Other major constituents of the flowers include several phenolic compounds, primarily the flavonoids apigenin, quercetin, patuletin as glucosides and various acetylated derivatives. Among flavonoids, apigenin is the most promising compound. It is present in very small quantities as free apigenin, but predominantly exists in the form of various glycosides (1418).

Chamomile is known to be used in various forms of its preparations. Dry powder of chamomile flower is recommended and used by many people for traditionally established health problems. Medicinal ingredients are normally extracted from the dry flowers of chamomile by using water, ethanol or methanol as solvents and corresponding extracts are known as aqueous, ethanolic (alcoholic) and/or methanolic extracts. Optimum chamomile extracts contain about 50 percent alcohol. Normally standardized extracts contain 1.2% of apigenin which is one of the most effective bioactive agents. Aqueous extracts, such as in the form of tea, contain quite low concentrations of free apigenin but include high levels of apigenin-7-O-glucoside. Oral infusion of chamomile is recommended by the German Commission E (19, 20).Chamomile tea is one of the worlds most popular herbal teas and about a million cups are consumed every day. Tea bags of chamomile are also available in the market, containing chamomile flower powder, either pure or blended with other popular medicinal herbs. Chamomile tincture may also be prepared as one part chamomile flower in four parts of water having 12% grain alcohol, which is used to correct summer diarrhea in children and also used with purgatives to prevent cramping. Chamomile flowers are extensively used alone, or combined with crushed poppy-heads, as a poultice or hot foment for inflammatory pain or congestive neuralgia, and in cases of external swelling, such as facial swelling associated with underlying infection or abscess. Chamomile whole plant is used for making herb beers, and also for a lotion, for external application in toothache, earache, neuralgia and in cases of external swelling (20). It is also known to be used as bath additive, recommended for soothing ano-genital inflammation (21). The tea infusion is used as a wash or gargle for inflammation of the mucous membranes of the mouth and throat (22, 23). Inhalation of the vaporized essential oils derived from chamomile flowers is recommended to relieve anxiety, general depression. Chamomile oil is a popular ingredient of aromatherapy and hair care (24, 25). Roman chamomile is widely used in cosmetic preparations and in soothing and softening effect on the skin (26, 27).

Traditionally, chamomile has been used for centuries as an anti-inflammatory, antioxidant, mild astringent and healing medicine (28). As a traditional medicine, it is used to treat wounds, ulcers, eczema, gout, skin irritations, bruises, burns, canker sores, neuralgia, sciatica, rheumatic pain, hemorrhoids, mastitis and other ailments (29, 30). Externally, chamomile has been used to treat diaper rash, cracked nipples, chicken pox, ear and eye infections, disorders of the eyes including blocked tear ducts, conjunctivitis, nasal inflammation and poison ivy (31, 32). Chamomile is widely used to treat inflammations of the skin and mucous membranes, and for various bacterial infections of the skin, oral cavity and gums, and respiratory tract. Chamomile in the form of an aqueous extract has been frequently used as a mild sedative to calm nerves and reduce anxiety, to treat hysteria, nightmares, insomnia and other sleep problems (33). Chamomile has been valued as a digestive relaxant and has been used to treat various gastrointestinal disturbances including flatulence, indigestion, diarrhea, anorexia, motion sickness, nausea, and vomiting (34, 35). Chamomile has also been used to treat colic, croup, and fevers in children (36). It has been used as an emmenagogue and a uterine tonic in women. It is also effective in arthritis, back pain, bedsores and stomach cramps.

The flowers of chamomile contain 12% volatile oils including alpha-bisabolol, alpha-bisabolol oxides A & B, and matricin (usually converted to chamazulene and other flavonoids which possess anti-inflammatory and antiphlogistic properties (12, 19, 35, 36). A study in human volunteers demonstrated that chamomile flavonoids and essential oils penetrate below the skin surface into the deeper skin layers (37). This is important for their use as topical antiphlogistic (anti-inflammatory) agents. One of chamomiles anti-inflammatory activities involve the inhibition of LPS-induced prostaglandin E(2) release and attenuation of cyclooxygenase (COX-2) enzyme activity without affecting the constitutive form, COX-1 (38).

Most evaluations of tumor growth inhibition by chamomile involve studies with apigenin which is one of the bioactive constituents of chamomile. Studies on preclinical models of skin, prostate, breast and ovarian cancer have shown promising growth inhibitory effects (3943). In a recently conducted study, chamomile extracts were shown to cause minimal growth inhibitory effects on normal cells, but showed significant reductions in cell viability in various human cancer cell lines. Chamomile exposure induced apoptosis in cancer cells but not in normal cells at similar doses (18). The efficacy of the novel agent TBS-101, a mixture of seven standardized botanical extracts including chamomile has been recently tested. The results confirm it to have a good safety profile with significant anticancer activities against androgen-refractory human prostrate cancer PC-3 cells, both in vitro and in vivo situation (44).

Common cold (acute viral nasopharyngitis) is the most common human disease. It is a mild viral infectious disease of the upper respiratory system. Typically common cold is not life-threatening, although its complications (such as pneumonia) can lead to death, if not properly treated. Studies indicate that inhaling steam with chamomile extract has been helpful in common cold symptoms (45); however, further research is needed to confirm these findings.

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Chamomile: A herbal medicine of the past with bright future