Friday, December 17, 2010

Gold, frankincense and myrrh

Everyone who has heard the Nativity story will know that the newborn baby Jesus was given gold, frankincense and myrrh by the fabled Three Wise Men. But what do these substances look like, and do they have real medicinal properties?

You’ll recognise gold. Shiny and lustrous, it’s been used in jewellery and decorative arts for millennia throughout the world. The Alexandrian Egyptians believed that gold was the “fountain of youth”, for surely something that glowed so beautifully was innate with health. In medieval times gold was used as a healing remedy and, although the properties assigned to it then were more “magical” than medical, gold is used in many forms of modern medicine.

Gold nanoparticles are used in the diagnosis and treatment of cancer. When coated with a cancer antibody they are effective at binding to tumour cells. When bound to the gold, the tumour cells scatter light, making it very easy to identify the non-cancerous cells from the cancerous ones. The particles shown in this transmission electron micrograph are just 10-90 nanometres across.

Injections of gold salts are used to treat arthritis, and gold alloys are used in dentistry. Gold is used in medical imaging too, to coat a sample before it goes into a scanning electron microscope, a procedure that has been used to created many of Wellcome Images’ scanning electron micrographs.

Frankincense and myrrh have also been used in medicine throughout history, and are now being investigated by scientists to see if they are effective at treating disease.

Myrrh is the resin produced by Commiphora trees when the bark is attacked and the resulting wound reaches the sapwood. It has been valued since ancient times for its perfume and wound healing qualities, due to its antiseptic and anaesthetic properties. Myrrh is named for its bitter taste, so any oral remedies using the resin would have tasted quite unpleasant. The Ancient Egyptians used myrrh as the principal ingredient when embalming mummies. In Ayurvedic and Chinese medicine, it is used for rheumatic and circulatory conditions.

Myrrh is used by many diabetics in Arabic countries to lower blood sugar, although no human studies have proved how effective this treatment is. Bilharzia, a tropical parasitic worm infection, has been treated with a marketed version of myrrh since 2001, although a review of this showed the efficacy of the cure to be low.[1]

Frankincense comes from Boswellia trees. It is a resin like myrrh, and is called ruxiang in Chinese medicine. The name, meaning “nipple-shaped flower”, was first mentioned in Chinese medicine texts around 500 AD. This woodcut from the 19th century Yanhou miji, or Collected Secrets of Laryngology, illustrates an abcess of the throat that is treated with a traditional Chinese medicine six-flower concoction containing ruxiang.

Frankincense looks more promising as a modern medicine than myrrh. A systematic review of the use of frankincense to treat conditions including asthma, rheumatoid arthritis and Crohn’s disease concluded that the results of clinical trials were “encouraging” (though not “compelling”)[2]. Compounds extracted from frankincense have shown anti-inflammatory properties in clinical trials[3] as well as anti-depressive effects in mice[4], so the modern therapeutic potential of frankincense might be fully realised in future years.

[1] Barakat R et al. Efficacy of myrrh in the treatment of human Schistosomiasis mansoni. Am J Trop Med Hyg. 2005 Aug;73(2):365-7. Online here.

[2] E Ernst. Frankincense: systematic review. BMJ 2008;337:a2813. Online here.

[3] Moussaieff A, Mechoulam R. Boswellia resin: from religious ceremonies to medical uses; a review of in-vitro, in-vivo and clinical trials. J Pharm Pharmacol. 2009 Oct;61(10):1281-93. Online here.

[4] Moussaieff A. et al. Incensole acetate, an incense component, elicits psychoactivity by activating TRPV3 channels in the brain. FASEB J. 2008 Aug;22(8):3024-34. Epub 2008 May 20. PubMed link

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