Frankincense, Myrrh and Amber: Tree Resin Facts and Uses
A natural resin is a viscous secretion produced by certain plants when they're wounded. The liquid resin oozes over the wound and usually hardens over time, acting as a sealant that protects the plant from infection, attack by herbivores and water loss.
Plant resins are useful for plants and are often very useful for humans, too. Resins such as frankincense and myrrh have a lovely fragrance and are used in perfumes and incense. Some resins, including both frankincense and myrrh, seem to have medicinal or antiseptic properties.
Amber is an ancient, fossilized resin that sometimes contains the preserved bodies of small creatures, such as insects. Millions of years ago, these creatures were trapped in the resin when it was in its liquid form. Their bodies became incorporated into the solid amber. Amber is admired for its beautiful appearance and is also used in jewelry.
Types of Plant Resins
Plant resins are made by glands that line resin ducts and are secreted into cavities. They're generally made by woody plants rather than non-woody plants and can be harvested by deliberately injuring or "tapping" tree trunks. In some plants, flowers or buds secrete resin.
Biologists use three general categories to classify plant resins.
- Hard resins contain no oil or only a tiny amount. As they solidify, they become a hard substance that has a high degree of transparency. Amber and natural lacquer are hard resins.
- Oleoresins contain so much oil that they may remain liquid once they're secreted. As a liquid, they have a viscosity resembling honey. If they do solidify, the solid is very soft and breaks easily. Turpentines and balsams are oleoresins.
- Gum resins are sold mixtures of resin and gum. Frankincense and myrrh are gum resins.
Frankincense is a gum resin produced by trees in the genus Boswellia, especially Boswellia sacra. Boswellia is a shrubby tree found in Africa, India and the Middle East. It generally grows in rocky areas with dry soil. The tree's resin is usually pale yellow in color and has a pleasant scent.
The resin is also known as olibanum and is popular in the perfume industry. It's used as incense because when it burns it releases a fragrant smoke. In fact, its name is derived from the Old French "franc encens", which means "pure or high quality incense". The incense is lit in religious ceremonies, used during meditation or aromatherapy or simply lit for pleasure. It's sometimes used as an insect repellent and an air freshener.
Frankincense has been popular as an incense for thousands of years and was used in Ancient Egypt, Greece and Rome. It's mentioned in the Bible as one of the three gifts of the wise men to the baby Jesus, along with myrrh and gold.
An Ancient Bee Trapped in Amber
Health Benefits of Frankincense
Pure, uncontaminated frankincense is edible and can be chewed like gum, although it has a stickier texture than modern chewing gum. An oil can be extracted from the resin. The resin, the oil and the Boswellia plant are said to have many health benefits.
The medicinal effects of frankincense or Boswellia haven't been confirmed by scientists, but there have been some intriguing preliminary discoveries. In one set of experiments, both capsules of frankincense and an extract from Boswellia called 5-Loxin significantly improved the pain caused by osteoarthritis of the knee. Another experiment showed that frankincense oil destroyed bladder cancer cells in lab equipment without harming normal bladder cells.
Myrrh is produced by trees in the Commiphora genus, especially Commiphora myrrha, which grows in Africa, Saudi Arabia and Oman. The tree has spiny branches and small leaves. The resin is yellow to red-brown in color and is aromatic. It contains oil and is used in perfumes and incense.
Myrrh is harvested like frankincense. A cut is made in the tree trunk, which stimulates the release of liquid resin. The resin drips down the tree trunk, forming "tears", which are collected when they have partially hardened.
In addition to providing a lovely scent, myrrh seems to have antiseptic properties. It's added to oral hygiene products such as toothpastes and mouthwash. In the past it was added to embalming mixtures to preserve dead bodies.
As is the case for frankincense, there are many unproven health claims for myrrh. Although frankincense is generally considered to be safe when ingested in small amounts, there are far more concerns about the safety of ingesting myrrh. Myrrh may stimulate the uterus to contract, which could be dangerous during pregnancy. It may also lower blood sugar, which might be harmful for someone taking diabetes medication. In addition, high doses of myrrh may affect the heart rate.
Amber is a tree resin that has become fossilized. It often has a beautiful golden color and is commonly used in jewelry. It may also be green, blue, red, brown or black. Evidence suggests that trade in amber began in the Stone Age.
Amber has another claim to fame in addition to its lovely appearance. It sometimes contains inclusions, such as the bodies of dead insects. It's fascinating to look at an insect or other animal trapped inside amber. The animal's body is often preserved in exquisite detail.
The preservation of an insect in amber begins when the insect becomes stuck in a sticky resin oozing from a tree and dies. If the resin completely engulfs the insect it preserves the insect's body. Volatile components of the resin (those that escape as a gas) are slowly released. After many thousands of years the resin is transformed into a hard but still slightly gummy material called copal. If it's left undisturbed, copal eventually turns into amber, which is completely hard and is said to be "fossilized" resin.
Colors of Baltic Amber
Ancient Mites Preserved in Amber
Insects in Amber and Dinosaur DNA
Some insects preserved in amber date from the time of the dinosaurs, which became extinct about 65 million years ago. For a long time, it's been hoped that some of the insects fed on dinosaur blood and that scientists would discover dinosaur DNA fragments in the insects' bodies. This idea provided the background for the creation of the dinosaurs in the first Jurassic Park movie.
DNA is a chemical that contains the genetic code. This code contains the instructions for making an organism. We have the ability to insert DNA from one creature into the egg cell of another creature, replacing the egg's own DNA. When the egg develops, the baby that is born will have some or all of the characteristics of the DNA donor, depending on how much DNA has been replaced.
Since insect bodies are preserved in such wonderful condition inside amber, scientists had hoped that the DNA inside them would have survived, too. Surviving dinosaur DNA could be studied and perhaps even transferred into a modern reptile egg or into the egg of an animal believed to be the closest living relative of the dinosaur. If all went according to plan, the infant would exhibit some of the characteristics of the dinosaur. Unfortunately, DNA from such ancient times has not yet been discovered.
A De-extinction Poll
If it's ever possible, do you think we should bring back a dinosaur from extinction?
DNA is a delicate substance and breaks down quickly after an organism dies. DNA of organisms that became extinct relatively recently has survived under special circumstances, however. For example, mammoths found in cold and icy environments sometimes contain intact pieces of DNA. The low temperatures surrounding the mammoth bodies helped to preserve the DNA.
In the 1990s several different scientists claimed that they had found dinosaur DNA in insects preserved in amber. Recently, however, scientists from the University of Manchester in the United Kingdom have concluded that this research involved contamination of the samples with modern DNA.
After following meticulous experimental conditions and using procedures that were designed to prevent any contamination of the samples, the scientists found no convincing evidence of ancient DNA in copal, the forerunner of amber. Some DNA was found, but it was in the form of tiny fragments and is believed to be relatively modern.
The copal that exists today was created from resin that was secreted long after dinosaurs disappeared from the earth. Since the copal that the scientists tested contained no ancient DNA, they say that they have "doubts " that ancient DNA can be found in amber, which is millions of years older than copal.
Other Plant Resins
Many other plant resins are used by humans.
- Turpentines are oleoresins produced by conifers. The resin forms a soft, sticky substance that is sometimes known as pitch. The resin can be distilled to produce oil of turpentine.
- Balsams are oleoresins that contain benzoic acid and/ or cinnamic acid, which gives them a lovely fragrance. Canada balsam is produced by the balsam fir tree and is classified as a turpentine, despite its name. This is an example of how confusing the classification system can be!
- Lacquer is a hard resin produced by the Chinese lacquer tree, also known as the varnish tree. A red resin secreted by the tiny lac insect is also known as lacquer, or as shellac.
The list of resins in current use is very long. The fact that some plant resins are useful and appear to be beneficial for our health is one reason why it's important to help plant life survive on Earth. New medicines that can treat health problems or even save lives may be hiding in plants.
References and Further Reading
© 2013 Linda Crampton