Molecules Responsible for the Fragrance of Frankincense Discovered

Efforts could help reproduce frankincense before natural sources disappear.
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Boswellia tree

Trees from the genus Boswellia (shown here in Yemen) produce a resin that is used in incense and perfumes.

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Joel Shurkin, Contributor

(Inside Science) -- A team of French scientists has managed to identify, isolate and synthesize two previously unknown molecules that give frankincense its unique, old church aroma.

It comes not a moment too soon. Frankincense, which has been used for perfume and incense for some 6,000 years, is endangered and may disappear by the middle of the century. Half the world’s supply lies in Somalia and Eritrea, surrounded by a war with no end in sight.

The two newly discovered molecules give frankincense its unique aroma but don’t completely duplicate the smell. Isolating these two, however, would be a step in recreating the whole fragrance.

One of the oldest spices known, it is used in some 50 perfumes, and is reputed to have medicinal qualities, though none have been proven.

The two molecules are some of the around 300 different molecules that make up the smell, said Nicolas Baldovini at the Institut de Chimie de Nice at the Université de Côte D’Azur, in France. They went undiscovered for so long because the fragrance is found in such small quantities. The scientists had to use three kilograms (almost seven pounds) of frankincense to get one milligram (.00004 ounces) of the two molecules.

“It took a long time to fractionate,” he said.

They named the two molecules olibanic acids. Olibanum is another name from frankincense.

The discovery was announced this month in a German chemistry journal, Angewandte.

References to frankincense can be found in both the Old and New Testaments of the Bible. In the Old, it is used by one of the lovers to describe the beauty of the other in the book known as both the Song of Songs and the Song of Solomon, along with myrrh. In a reference believed to be about a queen of the kingdom of Sheba (also called Shaba), in the Arabian Peninsula, the poet writes that she came to visit King Solomon "from the wilderness… perfumed with myrrh and frankincense." (Song of Solomon 3:6, KJV)

In the New Testament's Gospel of St. Matthew, the Wise Men, or Magi, entered where Jesus was born. “They saw the young child with Mary his mother, and fell down, and worshipped him: and when they had opened their treasures, they presented unto him gifts: gold, and frankincense and myrrh.” (Matthew 2:11, KJV) Those were the three most valuable commodities at the time. Frankincense is mentioned in the Bible more than twenty times.

(Myrrh is the resin of another tree, Commiphora.)

There is evidence from ancient Egyptian tombs of frankincense being used thousands of years earlier, sometimes as part of the embalming procedure, including in the tomb of the Pharaoh Tutankhamun.

Frankincense comes from the bark of the Boswellia tree, found around the Red Sea, the Gulf of Aden, including Ethiopia, Somalia, Yemen and India, according to Frans Bongers, professor of tropical forest ecology at Wageningen University in the Netherlands, who has studied it for fifty years.

The Boswellia tree can grow as tall as 50 feet. He said there are 20 different species, five or six of which are harvested commercially.

The resin is drawn from the bark the way maple syrup is extracted from maple trees, using taps. When air-dried, it produces pale yellow pear shaped droplets.

A white powder is extracted which produces the fragrance. Retail prices for the resin is around $9 an ounce while the essential oil costs around $42 an ounce, depending on the quality.

When burned, as in churches, it produces the fragrance of incense.

Bongers said the trees are threatened naturally by long-horned beetles but mostly by the actions of the people who live near the trees, some of whom make their livings from them. Areas containing Boswellia seedlings are burned to clear for raising cattle, and the cattle eat the small plants.

“The small plants don’t pass the stage of seedlings. Also, the trees grow very slowly, perhaps one millimeter (.04 inches) a year.”

The trees, once damaged, do not regenerate, he said.

Fifty years from now, he predicted, 90 percent of the trees will be gone.

The molecules discovered by the French researchers can produce what perfumers call the “basenote” of the fragrance, Baldovini said. The oil used in perfumes also has “endnotes” with a citrusy scent and is more complex. Other molecules would have to be added to duplicate the prized scent.

Baldovini said perfume companies have already expressed interest and the researchers have taken out a patent.

Author Bio & Story Archive

Joel Shurkin is a freelance writer in Baltimore who has also taught journalism and science writing.