Fresh beaver activities marked my trail for a hike on a cold winter day. Patterns swirled across the thin ice on a no-name Arkansas creek, where a beaver darted from its den to a dark tangle of shallow submerged roots. Its small dam, still under construction, had soaked the thicket and made for muddy progress. Fortunately, the beaver had left a collection of neatly carved “walking sticks” along the creek’s edge. As I poled my way through the damp woods, I noticed a nearby stand of old sweet gum trees, girdled with scars by the beaver and his relatives. Sweetgum’s botanical name is Liquidambar styraciflua, the inspiration for which was obvious: Atop the girdled scars, streams of amber- colored resin oozed from the trees’ veins.
One can imagine that the first human who had a similar experience of seeing resin oozing out of an injured tree’s bark was quick to smell it, taste it, and find a way to use it. Resins, balsams, and gums have a rich history dating back thousands of years as items of human commerce. They have always been valued for their fragrant and medicinal properties; the precious droplets have served as gifts to and from kings, as trappings for religious ceremonies, and as the embalming fluid that prepared human remains for their journey into the afterlife. In its hardened, petrified form, resin is valued as the semiprecious stone amber.
More recently, resins, balsams, and gums have been studied for their medicinal compounds. The subjects of these studies include familiar items such as myrrh and frankincense, but also dietary supplements from India such as boswellia and guggul. Their uses range from lowering cholesterol and easing arthritis to fighting bacteria and mouth irritations.
What are resins?
Resins, balsams, and related substances are complex chemical products produced by specialized ducts, cavities, or metabolic by-products of trees and other plant forms. Resins are insoluble in water and are usually hard, transparent, or translucent. When heated, they soften and usually melt. Their chemistry is elaborate, containing mixtures of resin acids, alcohols, tannins, esters, and other compounds.
Oleoresins are mixtures of resins and volatile oils. Oleoresins include turpentine and Canada balsam.
Sometimes resins are mixed with gums. These are called gum resins. Gums are water soluble, so the resins within them can be separated relatively easily.
Another class of resins, called oleo gum resins, includes frankincense and myrrh. Oleo gum resins are a mix of resin, gums, and volatile oils.
Balsams are a fourth class of tree exudates. They are resinous in physical nature, but unlike resins, they contain mixtures of cinnamic and/or benzoic acids. True balsams include balsam of Peru, Tolu balsam, and styrax. Canada balsam, derived from the familiar balsam fir tree Abies balsamea, is not a true balsam but an oleoresin.
As a class of herbal substances, resins and related exudates are among the most fascinating in human history. Interest in their healing potential continues to grow.
Myrrh: The ancient pain reliever
The history of myrrh is nearly as ancient as written history itself. In biblical times, the price of myrrh was equal to that of gold. The Ebers papyrus, written in 1500 b.c., describes the use of myrrh for wounds, sores, and as an ingredient in embalming solution. Ancient Sumerian records document its use for worms and the treatment of infected teeth.
The best-known association with myrrh is the gift of the Magi to Christ at his birth, by which time it was a well-known product of commerce. Myrrh symbolized suffering. Christ was offered wine with myrrh to attempt to alleviate his pain before the crucifixion (he refused). Following an already centuries-old tradition, his body was embalmed with myrrh.
In Western herbal traditions, myrrh has been used for mouth infections, mouth ulcerations, and as a general oral astringent. Today it is an ingredient in over-the-counter drugs, fragrances, cosmetics, toothpastes, mouthwashes, ointments, and salves.
The golden-yellow to reddish, translucent, round, or irregular drops of myrrh, known as tears, are derived from several species in the genus Commiphora (Burseraceae family). These land shrubs or trees are found in mostly arid parts of northeast tropical Africa, Arabia, and Sri Lanka, with a handful of species in Mexico and South America. There are more than 190 species in the genus. The principal source of the oleo gum resin known as myrrh is Commiphora myrrha, a small tree or large shrub that grows to about ten feet in height. Other sources of myrrh include C. erythraea (bisabol myrrh), C. madagascariensis (Abyssian myrrh), C. opobalsamum (Mecca myrrh), C. molmol (Somalian myrrh), C. africana (African myrrh), and C. schimperi (Arabian myrrh). All these are sold in the United States, but they are difficult to distinguish in their raw form, making chemical reports of myrrh’s use in studies somewhat unreliable.
What is the scientific evidence supporting myrrh’s use? Researchers at the University of Florence in Italy have recently published a study that found a mixture of eight sesquiterpene compounds in the resin of C. molmol that had moderate antibacterial and antifungal activity against E. coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. They also found that two chemical fractions had significant local anesthetic activity, due to a selective and reversible blockage of sodium channels (a similar mechanism to opiate drugs). This helps to explain myrrh’s ancient use to relieve pain and to treat wounds, sores, and mouth infections. Several animal studies have also hinted at a possible blood-sugar-lowering effect for diabetics.
In Germany, myrrh is approved as an ingredient (usually in mouthwashes or tinctures) for topical treatment of mild inflammations of the oral cavity and throat. Myrrh is considered relatively nontoxic; there are, however, several reported cases of rashes caused by myrrh-containing preparations.
Sanskrit text inspires research on guggul
Guggul, an oleo gum resin from the Commiphora mukul or C. wightii species, has attracted attention both in the marketplace and in the scientific literature in recent years. The shrubs or small trees that produce guggul grow in the arid, rocky soils of northwest India and adjacent Pakistan. Growing from three to twelve feet high, the trees yield guggul during the cooler seasons. About ten to fifteen days after making an incision in the bark, native tribes in the area collect the yellow to reddish-brown lumps.
This resin has been used in Ayurvedic medicine as a treatment for arthritis, a weight-reducing agent, and to lower cholesterol. Until the mid-1960s, most attention was focused on guggul’s anti-arthritic properties. But in 1964, G. V. Satyavati, a student at the College of Medical Sciences of the Banaras Hindu University in Varanasi, India, decided to base his doctoral dissertation on the “effect of an indigenous drug on disorders of lipid metabolism with special references to atherosclerosis and obesity (medorga).” Satyavati’s research project was inspired by a stanza in an Ayurvedic treatise, the Sushruta Samhita, a Sanskrit text dating to 600 b.c. He had found a strong correlation between the ancient Sanskrit text’s concept of “medorga” and the modern theory of the development of atherosclerosis. He chose guggul for his animal and patient studies in obesity and high cholesterol based on this ancient knowledge.
Ancient Sumerian records document the use of myrrh for the treatment of infected teeth; it’s still used in dental products today.
Various animals studies have shown that guggul resin, along with two of its components, guggulsterone and guggulipid, can lower blood lipids significantly. This has led to a number of clinical trials, most conducted in India. One preliminary study showed that 500 mg of guggulipid, taken for twelve weeks, lowered serum cholesterol on average by 24 percent and serum triglycerides on average by 23 percent. A follow-up, crossover clinical study evaluated guggulipid and the cholesterol-lowering drug clofibrate in 233 patients. Serum cholesterol and triglycerides fell 11 and 17 percent each in the guggulipid-treated patients after three to four weeks of therapy. In clofibrate-treated patients, the averages were reduced by 10 and 22 percent, respectively. In addition, the guggulipid patients increased their HDL cholesterol–the so-called “good” cholesterol–by as much as 60 percent. In the clofibrate-treated patients, HDL levels did not change.
Another recent study compared the effects of allicin (from garlic) and the germinated seeds of Bengal gram (Cicer arietinum) to guggulipid preparations in thirty volunteers for an eight-week period. In this research, guggulipid was used as the established reference for studying the cholesterol-lowering effects of the other plant preparations. Guggulipid came out on top, lowering serum cholesterol by nearly 33 percent.
Now common in health-food stores, guggulipid products are usually delivered in a dose of 500 mg (with a guggulsterone content of 25 mg). They are usually taken three times per day. Side effects associated with guggul include skin rashes, gastrointestinal tract irritation or upset, and diarrhea.
Frankincense: A gift with healing potential
Frankincense, like myrrh, was once a gift of the Magi to the infant Christ. Frankincense is the original incense. Frankincense is an oleo gum resin from several species of Boswellia, including B. carteri and B. frereana. Historians believe that another species, B. papyrifera, was the ancient source of frankincense while B. sacra was the species used in classical times. Interestingly, B. sacra, once widespread on the Arabian Peninsula, is now scarce due to the slow, methodical desertification of that geographic area.
Today, frankincense is collected from the mohr madow tree (B. carteri) and the yigaar tree (B. frereana). These small trees occur in rock outcroppings in East Africa, Somalia, Iran, and Iraq. The gum is obtained from deep incisions in the bark; it oozes out and forms hardened globular clusters after about two weeks. The ancients used it, like myrrh, for embalming and in cosmetics. Frankincense was also employed as a stimulant and to treat leprosy.
The gum is not used medicinally today, although animal studies have shown some anti-inflammatory activity. However, it is still widely used as an ingredient in perfumes, including those with floral, citrus, and violet scents, as well as in male fragrances with a woody or balsamic note. The chief modern health interest in the genus Boswellia is in the so-called Indian olibanum or Indian frankincense tree–better known today as a dietary supplement called boswellia, derived from B. serrata.
Arthritis studies focus on boswellia
This oleo gum resin resembles frankincense, which comes from African and Middle Eastern species of Boswellia. But Boswellia serrata is a small tree, up to fifteen feet in height; it is found in dry hilly areas in India.
Boswellia is valued as a traditional anti-inflammatory; it’s used to relieve arthritis and low back pain. The resin is composed mostly of triterpenes including alpha- and beta-boswellic acids and other boswellic acid derivatives. Products standardized to boswellic acid content (usually 65 percent) are considered by Indian researchers to have healing activity similar to nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, acetaminophen, and naproxyn. Compounds in boswellia have been found to suppress proliferating tissue at the site of inflamed areas and to inhibit the breakdown of connective tissues. They have also been shown to increase blood supply to the joints and help restore the structure of blood vessels.
Boswellic acids have been shown to inhibit the synthesis of leukotrienes, compounds that result in inflammation when oxygen interacts with polyunsaturated fatty acids. Finally, clinical studies have confirmed boswellia’s effectiveness in the treatment of bronchial asthma and ulcerative colitis.
Such studies, however, have produced conflicting results for treatment of arthritic and related inflammatory conditions with boswellia. One clinical study showed significant reduction in swelling, pain, and morning stiffness in rheumatoid arthritis patients. Standardized boswellia products have been shown to reduce stiffness and associated inflammation after two to four weeks of taking the herb.
Boswellia does have an advantage over conventional NSAIDs in that it has a much lower rate of side effects, especially gastric irritation and ulcer-inducing activity.
Generally, no side effects are reported.
Sweetgum, an American resin
The common sweetgum, Liquidambar styraciflua, is still a modern source of resin. A North American species, sweetgum is commonly grown as a shade tree outside its natural range of the eastern deciduous forest. Its resin is a liquid, the consistency of honey when fresh, but gradually hardening upon exposure to air. Sweetgum’s resin has an aromatic, balsam fragrance and a mild, pleasant flavor, slightly bitter and warm. The color is more or less transparent yellow, becoming cloudy and darker upon aging. It makes a good chewing gum, though I find the longer I chew it, the more resilient it becomes, giving the jaw muscles a good workout.
The resin develops in response to injuries to the tree. Small canals are formed in the inner bark of the tree by the splitting or pulling apart of some of the cells when the bark is cut or bruised. The resin is secreted by special cells at the edges of the canals. The secretion of the resin may serve as a natural ointment to help heal the tree’s injury, or as a Band-Aid to seal the wound against invading pathogens or insects.
Modern pharmacology confirms that sweetgum’s resins have antiseptic, expectorant, antimicrobial, and anti-inflammatory properties. Its primary commercial use is as an ingredient of the compound tincture of benzoin, available in every drugstore. The essential oil, found in minute parts in the resin, is used along with the resin as a fragrance component or fixative in soaps and perfumes. It’s also used in small amounts as a flavoring in foods.
Other useful resins
These are just a few of the resins and related products still used in the modern herb market. Other prominent resinlike substances, such as balsam of Peru and Tolu balsam, are occasionally used as ingredients in cough or cold formulations. Still others, such as Canada balsam from the balsam fir, have obscure technical uses. For example, because it refracts light to the same degree as glass, Canada balsam has been used as a cement for optical lenses and as a mounting medium for microscope specimens and cover slides.
Resins and their by-products touch our lives every day, often in minute amounts, as flavorings, perfume fragrances, and cosmetics. Science is telling us that the use of resins such as myrrh, boswellia, and guggul is as relevant today as it was in the time of Christ, the days of the ancient Egyptians, and the birth of the Ayurvedic tradition.
Steven Foster is lead adviser of, and a frequent contributor to, Herbs for Health. An author, photographer, and consultant specializing in medicinal plants, he was also technical consultant to The Herbal Drugstore (Rodale, 2000). He makes his home in Fayetteville, Arkansas.
For additional reading
Dolara, P., et al. “Local anaesthetic, antibacterial and antifungal properties of sesquiterpenes from myrrh.” Planta Medica 2000, 66 (4):356-358.
Ghorai, M., et al. “A comparative study on the hypocholesterolaemic effect of allicin, whole germinated seeds of bengal gram and guggulipid of gum guggul.” Phytotherapy Research 2000, 14 (3):200-202.
Satyavati, G. V. “Guggulipid: A promising hypolipidaemic agent from gum guggul (Commiphora wightii).” In Economic and Medicinal Plant Research. Vol. 5. H. Wagner and N. R. Farnsworth, Eds. London: Academic Press, 47-82.
Tucker, A. O. “Frankincense and myrrh.” Economic Botany 1986, 40 (4): 425-433.
