Case Studies With Medicinal Plants

8.2.1 Azadirachtin from the Neem Tree (Azadirachta indica)*

Neem, Azadiractica indica (Juss), in the family Meliaceae, or mahogany family, has a long history of use in human civilization. As with many plant species long used by humanity, its exact origins are unknown. Some have suggested southern India and Burma as the region where neem originated, while others have suggested locations ranging from Indonesia to Iran.1 Neem grows well in dry tropical and subtropical regions, and has been introduced to hospitable regions throughout the world including Africa, Australia, the South Pacific, and the Americas. Figure 8.1A illustrates a 1-year seedling of the neem tree and a leaf from a 3-year-old tree is shown in Figure 8.1B.

Neem produces a wide variety of compounds, including several groups of tetranortriterpenoids, the azadirones, gedunins, amoorastatins, vepinins, vilasi-nins, c-seco meliacins, nimbolinins, salaninins, and azadirachtins. Over 100 ter-penoid-based compounds have been identified. It is these compounds that provide a truly astounding variety of uses for medicine, agriculture, domestic products, and food preparation. The numerous and complex nature of these compounds has proven to be a formidable challenge to modern researchers attempting to isolate and characterize their chemistry, biosynthesis, and activity. One compound, azadirachtin or aza (Figure 8.2), has attracted special interest due to its twin effects as an insect antifeedant and as an insect growth inhibitor. Though other compounds have been found to have similar effects, aza remains the most inten-

* This section was prepared by James E. Hoyt. Copyright © 1999 CRC Press, LLC.

FIGURE 8.1A James E. Hoyt in greenhouse holding a pot containing a 1-year-old neem tree, Azadirachta indica. (Photo by David Bay.)

sively investigated component of neem. Investigations using the right and left parts of the aza molecule indicate that the antifeedant activity occurs with the right part; however, the ester group attached to the C-4 carbon of the left part seems to be essential. The right part seems to be the moiety that is important for the growth inhibition action of aza. A complete understanding of the relationship between the molecule's structure and its effect on insects remains to be discovered, while the mode of action of aza and the other constituents of neem on human physiology is generally unknown at this time.

Neem has been used in medicine for thousands of years. References to the medicinal use of neem are found in the earliest Sanskrit writings and its use is described in Ayurvedic, Unani, and homeopathic medicine1 All parts of the plant has been used in various preparations. Leaves, seeds, bark, and roots are made into teas and washes for various conditions. Seeds are also used in poultices, while twigs are used as toothbrushes. Gum from older trees is used to treat skin

FIGURE 8.1B A single neem tree leaf, about one-half its natural size. (Photo by David Bay.)

FIGURE 8.2 Structural formula of azadirachtin (aza), C35H44016.

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FIGURE 8.2 Structural formula of azadirachtin (aza), C35H44016.

disorders, while flowers are used to treat intestinal worms, reduce phlegm, and suppress bile. Western medicine has confirmed the efficacy of many of these traditional uses. It has found components of neem to be effective against malaria and to be useful as an antibiotic, anti-inflammatory, antidiabetic, and antifer-tility agent.2

In agriculture, neem has been used as an insecticide and animal feed. Seeds are soaked in water which is then applied to crops as an insecticide. Crushed seed that has had its azadirachtin extracted, called "cake", is used as an animal feed. Leaves and bark are also used as an insecticidal mulch. The trees themselves are used for shade; this is no small benefit in dry tropical climates. In the home, neem leaves and twigs are used in beds, chests, and cupboards to repel insects. Neem oil is used in food storage as well as in making soap. Food containers may be treated with leaf preparations or sometimes fumigated with the smoke of burning leaves. Timber from neem wood is used in construction, where it has proven to be resistant to termites and other wood-damaging insects. Finally, it is used as firewood; its vigorous ability to resprout permits regular harvesting for this purpose.

8.2.2 Medicinal Uses of Balsam Fir (Abies balsamea) and Arborvitae/Eastern White Cedar (Thuja occidentals)*

Presently, there are hundreds of species of plants being used for medicinal purposes. Many of these plants (or more often compounds derived from these plants) are used in Western medical practices, such as codeine and morphine from Papaver somniferum, but the majority are still used only in herbal healing and other forms of non-Western medicine. Yet, in the last decade there has been a resurgence in the use of medicinal plants as pharmaceutical companies search for the compounds that will be used to cure such major diseases as cancer and HIV/AIDS.

There are references to the use of medicinal plants almost as far back as recorded history. Almost every civilization has had some sort of medicine man or woman who was responsible for knowing which plants would cure which diseases. In the present day U.S. the only medicine men or women that exist are those on Indian reservations or those few who have had extensive training in herbal healing. These people treat only a minuscule portion of our population, while most people still believe that the only method of treatment for an illness comes in a pill of synthesized compounds.

We have chosen two medicinally valuable plants to discuss, the balsam fir, A. balsamea, and arborvitae, T. occidentalis. These plants were widely used by Native Americans, early settlers, and doctors into the late 1800s. Although there are no references to their uses in the present day, perhaps in the near future they will be rediscovered for their medicinal value.

* This section was prepared by Stephanie Bergman.

8.2.2.1 Balsam Fir (Abies balsamea)

The balsam fir (A. balsamea) is in the division Coniferophyta and the family Pinaceae. The fir is also an evergreen, which signifies that its leaves are lost and replaced but not all at the same time.

The balsam fir grows in low swampy areas and moist woods near the tim-berline in cooler climates. The best climate for A. balsamea is where the mean annual temperature does not exceed 4.4°C (40°F) and the average summer temperature is not more than 21.1°C (70°F).3 In forests with 76.2 cm. (30 in.) mean annual rainfall, the balsam fir comprises up to 30% of the total stand, as opposed to areas with rainfall from 25.4 to 63.5 cm. (10 to 25 in.), where the species comprises less than 10% of the total forest stand.3

A. balsamea can be found throughout the northeastern U.S. as well as southeastern Canada. The tree has been found in the New England states, Pennsylvania, and from New York to Virginia, as well as in Minnesota, Wisconsin, and northern Michigan.4

The balsam fir is a slender, tapering tree that grows from 12.2 to 18.3 m (40 to 60 ft) high at maturity. Its branches are arranged in whorls of 4 to 5 with scattered branches in between. These branches diminish in length in proportion to their height from the ground, forming a pyramidal head, or crown, at the top of the tree.5 The branches of the fir are of different sizes and grow in different directions depending on their location on the tree. The apical branches are short and ascending, while those in the midcrown are longer and horizontal. Those branches toward the base of the tree are long and pendulous.3

The leaves of the A. balsamea are needle-shaped and 1.27 to 1.90 cm. (1/2 to 3/4 in.) long. They are narrow, flat, and rigid, with bright green coloring on the upper surface and silvery coloring on the lower surface due to the high prevalence of stomata there. The leaves are mostly sessile on the horizontal branches and spread in two directions so as to seem double-ranked.5

The bark of the balsam fir is smooth, thin, and firm. The bark, which is brownish in color, is seldom more than 1.78 cm. (0.7 in.) thick on any portion of the tree.3 Small blisters containing resin terpenes can be found along the stem.

8.2.2.2 Arborvitae or Eastern White Cedar (Thuja occidentalis)

The arborvitae or eastern white cedar, like the balsam fir, is in the division Coniferophyta, yet is in the family Cupressaceae. T. occidentalis also is an evergreen.

The arborvitae grows in deep, cold swamps where it often forms dense stands. The arborvitae, often associated with the tamarack, can also be found on wet, rocky banks. T. occidentalis can be found in southeastern Canada and in the northeastern U.S. as far south as North Carolina and as far west as Illinois.6

The arborvitae has a conical form that grows up to 20 m (ca. 60 ft) at maturity. The tree has a rapidly tapering trunk with short horizontal branches ascending at the end. These branches form a narrow, pyramidal, compact head at the apex of the tree.6 Although the size of the branches varies from apex to base, with the larger branches at the base and the smaller branches at the apex, the direction of the branches does not vary along the tree.

The leaves of the arborvitae are scale-like needles usually less than 0.31 cm. (1/8 in.) long. The whorled arrangement of the leaves, with alternate lateral and facial scales, create flat sprays.7 These leaves also have a small flattened gland which contains a fragrant turpentine. The coloring on the upper surface of the leaves is of a bright green, while the lower surface is a yellowish-green.8

The bark of the T. occidentalis is thin and scaly. It has a reddish-brown coloring and is shallowly fissured into narrow connecting ridges covered with elongated scales.7,8

8.2.2.3 Medicinal Uses of Abies balsamea

The balsam fir has been used for medicinal purposes by many Native American tribes. Different parts of the tree have been used for the treatment of a great variety of diseases and ailments. The parts most frequently used are the gum (liquid balsam or resin from the bark), roots, bark, and leaves.

Many of the Native American tribes used the gum of the tree in a similar manner. The Forest Potawatomi, Menominee, and Ojibwa all applied the gum as salve to cuts and sores. Another common use of the gum of A. balsamea is for relieving cold symptoms or other pulmonary troubles. The Forest Pota-watomi swallowed the gum fresh, while the Ojibwas applied the gum externally to relieve these symptoms. The Chippewas used the gum as an analgesic. The gum was melted on a warm stone and the fumes inhaled as a relief for headaches. The Ojibwa also used the gum, in unknown methods, for relief of chest soreness as well as a treatment for gonorrhea.9,10

The bark of the balsam fir was also used by many of the Native American tribes for medicinal purposes. The Menominee used a decoction (a solution prepared by boiling the inner bark in water and straining the resulting solution) to relieve chest pains.11 This tribe also used the inner bark to prepare a poultice, as well as using it as a seasoner for medicines. The Forest Potawatomi used an infusion (the bark was steeped to extract the essence) of the inner bark for consumption (especially tuberculosis) and other internal affections (gastrointestinal and pulmonary ailments). The Ojibwa used a decoction of the inner bark as a diaphoretic (to induce sweating).9,10

Other parts of A. balsamea also were used by Native Americans in medical treatments. The roots of the balsam fir were used by the Chippewa as an antirheumatic. A decoction of the roots was sprinkled on hot stones and the herbal steam was useful in easing the pain associated with rheumatism, especially in the knees. The leaves of the tree were used by the Ojibwa in a variety of ways. One way in which they were used, the method unknown, is as a stimulant. The smoke of the leaves was inhaled as remedy for cold symptoms, while a compound containing the leaves was used as an antiseptic wash.910

People other than the Native Americans have used the A. balsamea for medicinal purposes. Early New England settlers (who most likely learned to use the tree from the Native Americans) used a variety of plant parts to treat various diseases and ailments. The buds of A. balsamea were used in epithemes to treat corns and warts. The sap was used in an unknown method as a treatment for tumors and prepared as a cataplasm (a viscous preparation intended to be warmed and applied to the body surface) in relieving the pain associated with cancer.11,12 The settlers also made pillows from the dried leaves of the fir, whose pleasant aroma gave relief to those suffering from hay fever and colds.13

A medical book printed by Parke-Davis/Warner-Lambert Pharmaceutical Company in 1890 shows how A. balsamea was used in the medical practices of that era. The bark, prepared in capsules of 10 minims, was used as a stimulant, diuretic, and anthelmintic (destroys parasitic worms). In larger doses, the bark was used as a laxative. The bark was also recommended in treating gonorrhea, gleet, and chronic inflammation of the bladder, due to its stimulating action on the mucous tissues. The oleoresin, prepared in a fluid extract, with a dosage of 0.5 to 1 fluidrachm (1 fluidrachm is about 1/8 fl. oz.), was used in the treatment of chronic bronchitis.1114

8.2.2.4 Medicinal Uses of Thuja occidentalis

The arborvitae also was used in many of the medicinal practices of the Native Americans. Like the balsam fir, many parts of the tree were used by the various tribes to remedy the ailments of the tribe members. The leaves, twigs, and inner bark were the parts of the tree used most often.

The leaves were used by many of the Native American tribes in a variety of medicinal ways. The Chippewa used a compound containing the leaves as cough syrup. The Ojibwa used a decoction of the leaves as a cold remedy, while the Iroquois used the steam from a decoction of the leaves for the same purpose. The leaves of the arborvitae were used by the Menominee in a smudge (a fire made to produce dense smoke) to revive lost consciousness. The Ojibwa used an infusion of the leaves as an analgesic for headaches and a decoction of the leaves as a blood purifier. They also used the leaves in a preparation that worked as a diaphoretic in a sweatbath. Once the leaves were fried, powdered, and compressed, the Menominee also used them in a poultice to reduce swelling. The leaves of T. occidentalis were boiled in lard to yield a leaf oil that made an excellent salve for the Forest Potawatomi. This tribe also used the leaves in many compounds for a variety of illnesses.9,10,13

Other parts of the arborvitae were used by the Native Americans as well. The Menominee used an infusion of the dried inner bark that was taken during a cold to treat suppressed menses. They also used the bark as a seasoner for enhancing medicines. The Chippewa burned its twigs as a disinfectant to fumigate a house for smallpox.9,10

The Iroquois used a variety of parts of the arborvitae for medicinal purposes. The sprigs and leaves of T. occidentalis and A. balsamea were prepared to heal cuts, bruises, sprains, and sores. The sprigs and leaves were pounded and boiled, and the affected sores were washed with a solution as hot as one can stand. The leaves were also used as a poultice to cover the affected areas. The leaves and roots were combined to treat weakness in the hips due to an untreated broken coccyx. One handful of the leaves and two handfuls of the roots were boiled for 20 min in a gallon of water. The water was then cooled to the temperature of bath water, and dashed on the hips. Another preparation the Iroquois used was boiling the tips of the branches in a large tub of water. Patients with rheumatism put their feet in the water, as hot as they could stand, and were covered with a blanket to help relieve their pain.15

T. occidentalis was also used by people other than the Native Americans. The earliest non-Native American reference to the use of the arborvitae is in the early 1800s. The most common use for the arborvitae in this era was for the treatment of warts and venereal excrescences. These were treated by a tincture (alcohol-based solution) of the leaves and twigs.11 A leaf tincture was also used in treating carcinomatous afflictions of the bladder, while a twig decoction was used in treating cancer.12 A decoction of the leaves and twigs was used in treating intermittent fevers, coughs, scurvy, and rheumatism. A saturated tincture was useful as an emmenagogue (inducing menstrual discharge) when 1 teaspoonful was given three times a day.16

8.2.2.5 Chemical Properties of Abies balsamea

The oleoresin of the balsam fir, also known as Canada turpentine, is the plant constituent that was used most often by the Native Americans. Oleoresin is a solution of resins in volatile oils, which when steam distillated yield crude turpentine oil and resin.17 When fresh, Canada turpentine is a pale-yellow liquid with a slight, greenish fluorescence, and has a viscous, honey-like consistency. When exposed to air the Canada turpentine becomes more viscous and forms a glass-like varnish.18 This property is what makes the oleoresin such a good salve. It allows for the oleoresin to cover the sorel(s) and prohibits the entrance of water, dirt, and other agents that could cause infections. The highly viscous property of the oleoresin allows for conformation to the affected area and permits movement there without the gum pulling at or falling off the sore.20

Canada turpentine is composed of 23 to 24% volatile oils, 48 to 50% a-and P-canadinolic acids, 13% canadinic acid, 0.3% canadolic acid, and 11 to 12% resene. 18 Volatile oils are generally the substances that give taste and odor and are made up of various terpenes.17 Terpenes are molecules with the general formula (C5H8)n. These molecules are usually built from C5 units called isopentenylpyrophosphates. Terpenes are classified as mono-, tri-, tetra-, and polyterpenes.

8.2.2.6 Chemical Properties of Thuja occidentalis

The arborvitae has a balsamic, terebinthinate odor and a pungently aromatic, camphoraceous and bitter taste. The odor and taste are due to the number of volatile oils.5 The arborvitae also contains a number of essential oils, as well as sugar, wax, and resin. T. occidentalis also contains the bitter principle, pinipicrin, the tannic acid, pinitannuc acid and the citron-yellow, peculiar crystalline compound called thujin.19

A table of terpenes found in arborvitae could not be located, so instead two of the monoterpenes found in its volatile oils will be mentioned. First is fenchone (Figure 8.3) which is a cyclic monoterpene ketone. The L-form of this molecule is the one that is found in the oil of the arborvitae. Thujone is the second terpene. This is also a cyclic monoterpene ketone. Thujone is a colorless oil that produces a camphor-like smell.17

FIGURE 8.3 Fenchone.

8.2.2.7 Summary

This section has examined the medicinal uses of A. balsamea and T. occi-dentalis by Native Americans and early New England settlers, as well as Western doctors into the late 1800s. Due to the lack of references to herbal healing in

1900s, it seems as if it became obsolete with the turn-of-the-century in t U.S. Cures for diseases in this era have mostly come from synthesized compounds, but it is very likely that these compounds are present in nature as well. The natural compound, as opposed to the synthesized one, would probably be healthier, more readily available, and cheaper. Hopefully within the next century there will be an even greater resurgence in the use of medicinal plants than there has been in the past few decades. We can only hope that there will still be herbal healers around to teach their secrets of natural healing to those in the future who realize the value of this type of healing.

8.2.3 Keewaydinoquay Peschel

Essay on Keewaydinoquay, Botanist, Medicine Woman, and Teacher*

Introduction

Keewaydinoquay (Woman of the Northwest Wind) is a Mashkikiquay (herbalist) of the Crane Clan, Miniss Kitigan Band, Anishinaabeg of the Three Fires Council (triumvirate sovereign nation of the Odawa, Ojibwa, and Potawatomi). A dedicated botanist, medicinalist, conservationist, and teacher, Kee's accomplishments range far in subject, but all share an origin in Native American philospophy.

Within the totality of universal harmony, all matter (and therefore all life) is originally created in balance and interconnection.

The combination of these traditional beliefs and her endless intellectual curiosity has resulted in an extremely knowledgeable and powerful individual.

Background

Grandmother Kee (Figure 8.4), as nearly everyone calls her, grew up in the Leelanau and Mason counties of the northern lower peninsula of Michigan. It was in this rural pocket of the Old Ways where Kee found her true love: plants. Her mother, Minosoahnikwe, and father, Wauboshtigwan, found great delight in plants, an interest which flowed naturally to their daughter. "Good-Cooking-Woman" had the largest floral and vegetable gardens as well as the most favored cuisine in their area, and her father, "Silver-Head", was a guardian and spokesman for the trees. He made his daughter aware of the interdependence of humans and trees and the virtues of this relationship.

Apprenticeship

Native customs of the area still made provisions for an eager young person to be apprenticed to a knowledgeable elder in order that ancient teachings be preserved. Accordingly, at age nine, an ever-fascinated and inquisitive Kee was apprenticed to Nojimakway, the intrepid herbalist of Onominee, who taught Kee numerous lessons and practices of Native medicine. From Nojimakway, Kee learned the ways in which thought becomes action, "learning through doing", the techniques for transforming the healing energies of plants into forms useful to humans, and the traditional theory behind the remedies.

Western Education

During the 27 years following high school, Kee earned a Bachelor of Science and a Master's Degree in biology from Central Michigan University and completed 2 years of work toward a Ph.D. at the University of Michigan. During these years she also raised two families and taught in both secondary and higher educational institutions. A versatile writer, Kee has published many articles on both botany and Native American philosophy, including a book for the Botanical Museum at Harvard University titled Puhpohwee for the People. An accomplished storyteller, Kee's telling of Ojibwa legends is itself legendary.

conservation

* University of Michigan former undergraduate students, Aaron Thompson and Nate McDowell, helped Sara Warber, M.D. and Keewaydinoquay prepare this essay.

FIGURE 8.4 Ojibwa botanist, medicine woman, and teacher, Keewaydinoquay Peschel, holding a plant of Polygala senega. (Photo courtesy of Keewaydinoquay Peschel.)

Kee firmly believes all things are interconnected and should exist in harmony; thus, the protection of earth and its ecosystems underlies the basic acts of her everyday life. In the Ojibwa traditions, "every action is done with consideration for the seven generations before and the seven generations after." Kee believes that the earth nourishes and supports all life and any harm humans do to it will return to affect The People. In this sense, conservation of the Earth is conservation of all interconnected life, and thus, conservation of the human kind.

Much of this passion to preserve Mother Earth came from Kee's father, who regarded trees as his guardians, "and he definitely was a guardian for the trees," says Kee. Believing that the welfare of the human kind is bound within the welfare of the tree kind, Wauboshtigwan lived a life close to the Earth and encouraged others to do the same. If he were alive in today's world, Kee believes her father would be a powerful speaker for conservation.

The years Kee spent at the University of Michigan alerted her to the numerous endangered plant species and how quickly their last available habitats are being destroyed. This is why she makes every effort to protect the endangered plants on her Great Lakes Island home. Western education and Kee's native philosophy impressed upon her the degree to which the Earth is out of balance. Therefore, in all her teachings, she strives, above all else, to instill a love of the Earth in her students' hearts.

Teaching

Now in her eighties, Kee has taught on three continents and at every level of public education from the one-room country school through the university, always inspiring and exciting her students. For example, when teaching about the botany on her home island, Kee not only gives the student the standard botanical terms, but also the plant's Ojibwa name, its translation, the medicinal value, and any associated legends. What the students cannot retain of this overwhelming introduction, they more than gain in appreciation, respect, and admiration for the plants. No longer objects waiting to be studied, plants come to life; the relationship between plants and people becomes apparent; and a stronger bond is created between student and plant life. This Ojibwa philosophy — the interconnectedness of life — permeates Kee's teachings.

Medicines

Kee's curative practices are also based around this philosophy. To her, healing is a process of restoring balance to the natural mental, physical, and spiritual health, made possible through, she says

...empowerment from Gitchi Manitou, the source of Power, possible through that catalyst which is the energy of pure intent, possible through knowledge of the virtue-filled beings of the blessed plants.

Kee explains that the energies of the plants combine with those of the people and spirits to make healing medicines. A deep respect is shown for the Earth at all times throughout medicinal preparation.

For example, it is considered crucial to maintain a relaxed and focused mind (which promotes good energy) throughout the preparation of medicinals. Before any harvesting is done, an offering of kinnickinnick (a mixture of herbs) is made to the plant species being collected, reminding The People to be grateful for this medicinal gift and asking the plants for their aid in healing. To ensure that those population areas will be available for the use of future people, collections are made only where the species are flourishing or can easily recover from the disturbance. All of these components must exist or the medicines will be unbalanced and less effective in restoring harmony.

Western and Native American Botany

Kee's background in western and Native American botany allows her a unique viewpoint. Western botany places its focus on the quest for knowledge and intellectual enlightenment, providing a greater factual understanding of nature and occasionally resulting in beneficial products. Conversely, Native American botany is based on the practical aspects of plants, that promotes a spiritual and holistic understanding of the uses and long-term ecology of plants. Kee finds no theoretical conflict between these two missions; yet, she has observed how they can promote a drastically different focus in their followers.

Kee's introduction to western science, via graduate school, was stimulating to her endlessly curious mind. It was also an eye-opening experience to the competitive world of science. Kee had never looked at a plant with anything other than awe and respect. So, the concept of profiting from nature was backward; yet that was what was happening all around her. She remembered...

...people who would travel to South America and spend large amounts of money simply to be the first to discover a new plant. I had no idea how important that kind of thing was to some people. She laughingly concludes, Who is first? So what?!

Conclusion

Keewaydinoquay's appetite for knowledge has hardly diminished over the decades, as she is still coming out to the shores and forests of her home island searching for new and endangered plants. Similarly, she will continue to follow the precepts of the Ojibwa tradition: the universe was created in balance, and thus, all things within it are interconnected. Kee's pursuits of herbal healing, teaching, and botany exemplify her desire to help others through this tradition. When addressing the ominous challenge to protect the Earth from degradation, Kee shows the spirit of her ancestors and followers, "I want to be on the good side, even if its not the winning side."

8.3 CASE STUDIES WITH DYE PLANTS* 8.3.1 The Dyeing Process (Figures 8.5 to 8.10)

For thousands of years, and up until about a century ago, the color of fabrics came chiefly from the crude juices of plants. The use of the indigo plant for dyeing fabrics blue dates beyond 3000 B.C. Probably a thousand years later, people knew how to combine other substances in the dyeing process in order to make colors "fast". This later discovery is now known as mordanting.

Natural dyes come from many parts of plants: roots, leaves, bark, flowers, and fruits. The dye sources in the ancient world included such plants as madder (Rubia tinctorum) for red, saffron (Crocus sativus) and weld (Reseda luteola) for yellow, woad (Isatis tinctoria) for blue. The bark of oak (Quercus spp.), outer shells of fresh walnuts (Juglans spp.), pomegranate flowers (Punica granatum), and dyer's bugloss (Anchusa tinctoria) were among others used. Gall-nuts, woody swellings caused by attack of gallflies, presumably on the Lusitanian oak (Quercus lusitanica) later provided both a dye (brown, gray, and black) and a mordant in the form of a tannin.

Mordanting must be capable of combining chemically with the coloring matter (the dye) being applied, while a few plant dyes may be used directly. The majority require a mordant for permanent color. Besides tannic acid, substances that have been frequently used as mordants include the metallic salts of alum, chrome (now banned because of its toxicity to humans), iron, and copper, as well as acetic acid (as vinegar), ammonia, caustic soda, and tartaric acid. The

* For dye plants not discussed in this section, References 22 through 24 are very helpful for finding information about dye plants and the dyeing process with natural dyes.

FIGURE 8.5 A skein of white, unbleached sheep's wool after washing it in warm water to remove lanolin. (Photo courtesy of Jane LaRue.)
FIGURE 8.6 Mordants used in natural plant dyeing. Left to right: potassium aluminum sulfate (alum), cream of tartar, ferrous sulfate, cupric sulfate, and potassium dichromate (last-mentioned mordant is now banned by the EPA because of its toxicity to humans). (Photo courtesy of Jane LaRue.)

mordant is thoroughly dissolved in soft water and the fiber is submerged in the solution. The mordant bath is usually heated to just below the boiling point of water (100°C) and the fiber is immersed in the hot mordant solution for ca. 30 min. Each skene of wool or other fiber is labelled with a pencil on masking tape to denote the mordant used. The mordanting step is carried out just before

FIGURE 8.7 Preparing the dyebath. After plant parts are boiled in water, then allowed to remain in the cooling water for 2 to 12 h, the plant material is removed by passing it through a screen sieve so that the dyebath is free of plant debris. (Photo courtesy of Jane LaRue.)
FIGURE 8.8 Dyeing the pre-mordanted wool in a simmering (just less than 100°C) dyebath. (Photo courtesy of Jane LaRue.)

immersing the wool or other fiber in a dyebath. Common mordants and their properties are listed in Table 8.1.

To prepare the dyebath, the plant material, whether dried or fresh, should be crushed or chopped and soaked in water overnight. Then, the mixture is boiled 0.5 to 2 h, the length of time depending on the color desired. Barks and

FIGURE 8.9 Close-up of wool being held out of the dyebath with a long, wooden pot label. (Photo courtesy of Jane LaRue.)
FIGURE 8.10 Dyed wool after washing in several changes of water, starting from dyebath temperature and ending at room temperature (ca. 25 °C). (Photo courtesy of Jane LaRue.)

roots require a longer boiling time than parts of herbaceous plants in order to extract the pigment(s). Most dye plants can be dried for future use, but some give brighter colors when used fresh. Table 8.2 indicates a selected group of plants used commonly for preparing natural dyes, the parts of the plant used as dye sources, and the colors of the dye one obtains from these plant sources.

TABLE 8.1

Common Mordants and Their Properties

Mordant Common name

Alum plus cream of tartar Iron

Mordant Chemical name

Aluminum potassium sulfate plus potassium bitartrate Ferrous sulfate

Stannous chloride

Copper sulfate Cuprous sulfate

Vinegar

Acetic acid

As a Premordant in 1 qt watera

3/4 tsp alum plus 1/4 tsp cream of tartar Primarily used as an additive to darken or "sadden" a dyebath More commonly used as an additive as it can make wool brittle

Primarily used as an addi-tive, gives wool a light blue or blue-green color 1/3 cup a Amount per 1 oz medium-weight 2-ply natural wool.

As an additive

May be used along with wood and dyestuff Use a pinch

To lighten or brighten a dyebath, use a pinch well dissolved in water before adding to bath 1/4 tsp in water

Frequently used to heighten the color of dyebath, especially in the red color range

Modified from Weigle, P., Natural Plant Dyeing, in Natural Plant Dyeing: A Handbook, Brooklyn Botanical Garden, Brooklyn, NY, 5, 1973.

8.3.2 Examples of the Use of Natural Plant Dyes 8.3.2.1 Orchil Dyes from Lichens*

A lichen is a combination of an alga and a fungus growing together. This composite organism has a form unlike either of its constituents. Lichens come in three basic growth forms: crustose (just what the name implies), foliose (as a thin, lobed sheet often quite firmly attached to the substrate), and fruticose (as a 3-D, usually branched growth attached to the substrate at only one or a few points). Lichens produce many unusual chemicals which are made by no other organisms. These chemicals (usually acids) are used by taxonomists to identify many species of lichens but people have also used some of these chemicals to make dyes. Most of these acids (and the lichens which make them) have little or no color in their natural state but must be treated chemically to make colored substances.

The use of lichens in dyeing was mentioned by such ancient authors as Ezekiel, Theophrastus, and Pliny. The most sought after dye in the ancient world was royal purple (actually closer to red than to our modern idea of purple). This, the color of kings, was made from snails of the genus Murex. It was a

* This section prepared by Dr. Barbara J. Madsen.

TABLE 8.2

A Selected Group of Plants Used for Preparing Natural Dyes

Color of dye prepared from plant

Plants

Parts of plant used

Sanguinaria canadensis

(bloodroot) Galium verum (Ladies' Bedstraw) Rhododendron Crocus sativus (Crocus) Rhus typhina (staghorn sumac) Ligustrum vulgare (privet) Solidago (goldenrod)

Rhizomes

Yellow to red Browns, greens, yellows Yellow (saffron) Yellow, khaki brown

Roots Leaves Stigmas Roots, berries Branch tips Flowers Flowers Leaves

Bulbs scales or "skins!

Young shoots

Flowers

Galls

Thallus

Husks — tannins

Yellow, gold Yellow, gold

Yellow, buff, old gold, dark green Tagetes (marigold)

Gold, green-gold Gold, orange, or red Light gray

Chartreuse, yellows, orange Brown, greys, blacks Purples, greens, yellows, browns Yellow, brown

Populus (aspen) Allium cepa (onion) Rubus (blackberry) Dahlia

Oak galls from Quercus (oak) Lichens

Juglans nigra (Black walnut)

beautiful, brilliant, fast color (even after thousands of years) but the snails were scarce and it took 3000 snails to make 1 g of dye extract, and the dye stank. The Phoenicians discovered how to make a similar red dye from a fruticose lichen that grew on rocks by the seashore. This dye was not fast but it had a nice fragrance (some lichens are still used in perfumes today) and was much cheaper to make.

This red lichen dye was imported to Europe about 1300 A.D. by a Florentine merchant named Frederigo Orcelli, whose name was later given to the dye substance, orchil, and slightly altered, to the genus of lichens used, Roccella. For 200 years, the Orcelli family held a monopoly over the collecting of the lichens from various Mediterranean islands and over the production of the red dye. Late in the 15th century, however, Roccella was discovered in the Canary Islands, and was later found on warm seacoasts all over the world, including Sri Lanka, Australia, Madagascar, Chili, Peru, and California. The production of orchil dye was big business — in the 1850s the Canary Islands exported 100 tons/year to England. In 1851, orchil fetched £380/ton. Orchil and other lichen dyes were important until the late 1850s, when the first aniline (coal tar) dyes were discovered by accident. The Wilton Carpet Company used some lichen dyes as late as World War II.

Orchil dye can be produced from a number of different lichen acids. The acids are broken down by ammonia in the presence of oxygen to form carbonic acid and orcin, which is further modified to produce orcein, the colored substance, which is itself a mixture of three compounds. The process is fairly simple.

• Break up or pulverize the lichen and sieve to remove impurities.

• Put in a vat with stale human urine (historically, the only source of ammonia — used until the 1800s) or ammonia and stir once a day for as long as 4 weeks.

• Add lime, potash, or wood ashes to intensify the color, or acids to modify it.

• Dry resulting paste for storage and later dissolve in water for use.

In northern European countries, many species of lichens have been used for hundreds of years to make red, brown, or yellow dyes, using a similar process. Species of Umbilicaria, Parmelia, Pertusaria, and Ochrolechia were most commonly used. At one time, every cottage in Scotland had its barrel ("litpig") of stale urine ("graith") into which the lichens ("crottles") were placed for fermentation. The dye paste (formed into cakes) from Scotland became known as "cudbear", from a corruption of the name of Dr. Cuthbert Gordon of Glasgow, who patented a process for making such lichen dyes. Harris tweeds were traditionally dyed with lichen dyes, especially before World War II, and some still are today. The cakes of dye used to be dried over peat fires so the tweads also acquired the smell of peat smoke. There has been some interest, particularly in Ireland and Scandinavia, in reviving the use of lichen dyes as a cottage industry both because the interesting variation of color makes the finished products more valuable and because (it is said) wool dyed with lichen dyes is not attacked by moths.

Some lichen dyes, including orchil, are also sensitive to acidity. In fact, litmus paper was made from an orchil dye, which changes from blue to red when exposed to acid.

The best time to collect lichens for dyeing is said to be in late August just after the season of greatest light and heat. This is when the accumulation of acids is at its maximum. Another practical note: English dyers of the 18th and early 19th centuries "learned by experience to avoid urine from beer drinkers, which is excessive in quantity, but frequently deficient in urea, ammonia, and solids, while it is abundant in water."

8.3.2.2 Saffron (Yellow) Dyes from Crocus Flowers

Saffron has been widely used as a food coloring and as a dye for cloth. It continues to be used in developing countries and by dyers worldwide. Saffron comes from the stigmas of the flowers of crocus, Crocus sativus. These stigmas are rich in riboflavin, which is a yellow pigment and is also a vitamin (vitamin B2).

Mature stigmas are collected from the flowers when they develop in the spring. Over 200,000 dried stigmas, obtained from about 70,000 flowers, yield 1 lb (454 g) of saffron. The saffron has a value of $30 (U.S.) per ounce (ca. 28 g).

More information about saffron and its uses is found in The Review of Natural Products, l996.21

8.3.2.3 Indigo (Blue Dye) from the Indigo Plant (Indigofera tinctoria)

Indigo refers to the several species of Indigofera that are known for the natural blue colors that are obtained from the leaves and stems of this herbaceous plant. Before synthetic indigo and aniline dyes were developed, indigo plants were grown commercially in the East Indies and in South and Central America, especially during the middle ages, for the popular blue dye obtained from the plants.

The blue indigo dye is produced during the fermentation of the leaves in combination with caustic soda or sodium hydrosulfite. In this process, a paste exudes from the fermenting plant material. This is processed into cakes that in turn are finely ground to a powder. The blue color develops as the powder is exposed to the air.

The dye, indigo, is a derivative of indican, a glucoside found in the Indigo plants. By enzymatic hydrolysis of the glucoside by P-glucosidase derived from the leaves, indoxyl is formed. It is the oxidation step (exposure to air) that converts two molecules of indoxyl to a single molecule of indigo, or indigotin

(Ci6HioN2O2>.

More information about indigo and its uses is found in The Review of Natural Products, 1996.21

8.3.2.4 Brown Dyes from Black Walnut (Juglans nigra) Husks

The husks of black walnut, or other walnuts, are used as a brown dye source for dyeing wool. They are soaked overnight, simmered for 60 min, then strained for dyebath use. A mordant is not necessary, but ferrous sulfate can be used to give a dark brown color that is almost black. The metabolite in walnut hulls that is the brown dye is called juglone. It is a naturally occurring naphthoquinone.

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