| Arnica
montana
is a perennial plant of the
Asteraceae or Compositae family with orangy-yellow daisy-like
flowers, native to the mountainous regions of Europe and America.
Arnica is classified by herbalists as a vulnerary, or herb used
for wound healing. Vulnerary comes from the Latin word, vulnus,
meaning wound. Because of its popular use as a natural
medicine and due to its specific habitat, Arnica has become a rare
plant. Therefore, several closely related species are also used,
including A. chamissonis, A. cordifolia, A. fulgens, A.
latifolia, and A. sororia. The medicinal value of
arnica flowers has been known for several centuries by Europeans
who have traditionally used them externally to relieve aches and
pains associated with bruises, sprains, swelling and inflammation.
Arnica is not to be taken orally as it can cause heart
palpitations, increased blood pressure, breathing difficulties,
headaches, and abdominal pains. Arnica flowers can induce allergic
reactions in a small population of individuals who develop contact
dermititis. If this occurs, use of arnica should be discontinued
immediately. This reaction may be due to the presence of a
chemical known as helenalin. Helenalin belongs to a class of plant
chemicals called sesquiterpenoid lactones, that are known to be
allergens which are found in many Asteraceae plants. However,
helenalin, dihydrohelenalin and some esters of these compounds
have been shown by scientific studies to be active constituents of
Arnica species. In fact, they have been shown to be responsible
for many of the pharmacological actions attributed to Arnica
montana, such as its anti-inflammatory and analgesic effects,
as well as some antibiotic properties. Sesquiterpenoid lactones
impart a bitterness to many plants. Helenalin and its derivatives
that are found in arnica have been shown to inhibit the migration
of certain white blood cells known as polynuclear leukocytes as
well as inhibiting the rupture of lysosomal membranes. These
compounds have also been reported to exhibit an inhibitory
activity on platelet aggregation. Although more research is needed
to further determine the pharmacology of arnica species, the
present scientific data, as well as a wealth of empirical data
seem to indicate its efficacy in treating bruises, contusions,
strains, sprains and pain and swelling associated with rheumatism.
Helenalin, a sesquiterpenoid lactone found in Arnica
montana
 |
