The popular herbal and homeopathic remedy arnica may indeed work, said UK scientists this week, who claim to have found a scientific basis for arnica's anti-bruising action.
Arnica is a traditional remedy used to alleviate bruising but there has been continued controversy as to whether it really works. Speaking at the British Pharmaceutical Conference this week, researchers from the Drug Delivery Group at Bradford School of Pharmacy said the plant contains potent anti-inflammatory agents that can be absorbed through the skin to protect damaged blood capillaries.
The Drug Delivery Group, experts in transdermal drug delivery, investigated whether bioactive agents from a commercially available tincture of Arnica montana, or Leopard's bane, were transferred across human skin.
Initially, no transfer was detected in the laboratory tests. However, after 12 hours twocomponents were found to have permeated the skin. Chromatography indicated that these were the same anti-inflammatory agents - sesquiterpene lactones - thathave previously been found in arnica.
"This is good evidence - but not yet proof - that these are the vasoactive agentsthat prevent bruising," said Professor Adrian Williams. "The curious aspect is that we did not see permeation in the first 12 hours. To prevent bruising the agents will have to act quickly to stop capillary bleeding. Active agents are presumably getting through the skin but in such small quantitiesthat it takes 12 hours for the amount to be detectable. For such low concentrations to be effective, the active agents must be very potent, " he added.
The currently marketed arnica preparations are not standardised and might not all contain sufficient active agent, which could explain why some people have found that arnica does not work, suggested the researchers.
Having identified the potential active agents, scientists will now be able to purify these and formulate them, in defined concentrations, into a more conventionalpharmaceutical delivery system.
However the active agents in arnica tincture are present in such small amounts that it would be impracticable to extractsufficient quantities, said the Bradford team. To counter this problem, the researchers are currently trying to synthesise the active agents.