Home > Encyclopedia of Food & Culture > Botanicals

BOTANICALS. Botanicals are fresh or dried plants, plant parts, or plants' isolated or collective chemical components, extracted in water, ethanol, or other organic solvents, plus essential oils, oleoresins, and other extractives used for flavoring, fragrance, functional health benefits, medicine, or other biological and technical activities. Many botanicals, broadly speaking, also can be classified as herbs, plants used for flavor, fragrance, or medicinal qualities, such as caraway, parsley, rosemary, sage, and thyme. Other botanicals fall under the classification of spices, piquant aromatic plant materials, usually of tropical origin, used to season food. Examples include cloves, cinnamon, nutmeg, and pepper. Botanicals commonly are used in foods, drugs, and cosmetics. The cosmetic industry uses over 360 botanical ingredients, classified as "biological additives," to enhance the fragrance, performance, or consumer appeal of products. Botanicals, either in crude form (whole dried plants or plant parts) or in their isolated or modified chemical constituents, also are used in prescription and nonprescription (over-thecounter) drugs. In addition, over 1,600 botanicals and their derivatives are sold in the United States in a special food category called "dietary supplements." In commercial trade, botanicals, though not defined as such, generally refer to dried materials of plant origin sold in bulk form as whole, cut-and-sifted, or powdered ingredients.

Botanicals in Human Experience

Botanists conservatively estimate that 250,000 species of flowering plants exist on Earth. At least 85,000 plant species worldwide have been documented as being used as medicinal botanicals, at least in folk medicine. The World Health Organization estimates that as much as three-quarters of the world's population relies on traditional forms of medicine, chiefly herbal or botanical medicine. Botanicals used in foods, drugs, and cosmetics are an integral part of daily life.

The human experience in the use of botanicals is inextricably interwoven with human history. The first known historical evidence for the use of plants comes from the Middle Paleolithic burial site in Iraq known as Shanidar IV, a Neanderthal grave containing remains of yarrow flowers (Achillea spp.), marshmallow (Althaea spp.), and ephedra (Ephedra spp.), all of which are botanicals still in use in the twenty-first century.

The Ebers papyrus, dating to 1500 B.C.E., was discovered in 1876. This ancient Egyptian manuscript mentions 876 medicines, most of which are of botanical origins. Undoubtedly, ancient Greek scholars learned from their Egyptian predecessors about the use of botanicals in medicine. The writings of Hippocrates (466–377 B.C.E.) refer to many botanical substances. The starting point for Western medicine, and in particular botanical ingredients used in the West in the nineteenth and twentieth centuries, is the first-century work De Materia Medica of Dioscorides of Anazarba in Cilicia. For more than fifteen centuries, all Western cultures depended on this source for information on botanicals. It includes over six hundred botanicals, most of which are in use in the twenty-first century.

Botanicals as Food Additives

Over 250 botanical substances are added during food product manufacturing for flavor, fragrance, or technical characteristics, such as coloring, thickening, or preservative activity. These botanicals are used commonly and extensively, often in the form of concentrated extracts at parts per million levels, as natural ingredient additives for many categories of food products, including baked goods, canned goods, meat products, dairy products, nonalcoholic beverages, and alcoholic beverages. Many botanical ingredients have a long history of use and generally are recognized as safe. However, for a new ingredient, not previously marketed materially in the United States, to enter the American market, it must receive prior approval by the Food and Drug Administration (FDA). The manufacturer (or industry trade organization) may submit toxicological data to the FDA in support of the ingredient's safety.

Botanicals as Dietary Supplements

In 1994 the U.S. Congress passed the Dietary Supplement Health and Education Act, which created a special food regulatory category for dietary supplements, including vitamins, minerals, herbs or other botanicals, amino acids, or other dietary substances used to supplement the diet by increasing the total dietary intake. Concentrates, metabolites, constituents, extracts, or their combinations also are included in the definition. Dietary supplements are regulated as foods rather than as drugs despite the fact that most such products are intended to provide a health benefit. The vast majority of botanicals available on the American market, from over 1,600 plant species, are sold as dietary supplements.

Many well-known botanicals sold as dietary supplements in the United States also are available in other Western countries, notably Germany, where they are regulated as drugs under a special category called phytomedicines. By definition, phytomedicines include the totality of chemical constituents within a botanical or plant part rather than a single isolated chemical component. Well-known botanicals in this category are garlic (Allium sativum), ginkgo leaf extracts (Ginkgo biloba), echinacea (Echinacea purpurea, E. angustifolia, and E. pallida), ginseng (Panax ginseng), kava kava (Piper methysticum), saw palmetto (Serenoa repens), St. John's wort (Hypericum perforatum), and valerian (Valeriana officinalis). In the European markets for these botanicals, quality is strictly regulated. In the United States, it is not; therefore dietary supplements are perceived as "unregulated."

Botanicals in Modern Medicine

Prescription and nonprescription drugs of botanical origin are used widely in modern medicine, primarily as purified derivatives or partially modified secondary chemical compounds. Remarkably it is estimated that approximately 25 percent of drugs in the average American pharmacy are botanical derivatives. Of 121 prescription drugs in use in the early twenty-first century that originate from 90 plant species, 74 percent were discovered in scientific follow-up of historical or folkloric claims of medicinal value. Botanical derivatives used in chemotherapy include paclitaxel (taxol), extracted from yew species (Taxus spp.), used for certain forms of breast and ovarian cancer; vincristine and vinblastine, purified alkaloids extracted from the Madagascar periwinkle (Catharanthus roseus), used in the treatment of leukemias and Hodgkin's disease; and semisynthetic compounds from mayapple (Podophyllum spp.), used in the treatment of testicular and small-cell lung cancers. Nonprescription botanical ingredients include the laxatives psyllium seed (Plantago spp.) and senna leaves (Senna spp.). Some botanicals are the source of both drugs and foods. Morphine, codeine, and other chemical analogs from the opium poppy (Papaver somniferum L.) are used for the management of pain. The opium poppy is also the source of poppy seeds, used as a decorative and flavoring component in the culinary arts.

Foxglove: From Folk Medicine to Modern Botanical

The cardiac glycosides digoxin and digitoxin, extracted from several species of foxglove (Digitalis spp.), are used in the treatment of heart diseases, such as atrial fibrillation and congestive heart failure. This botanical was not well known to the ancients as a medicinal plant. Instead, it was considered a poisonous plant. A British physician, William Withering, introduced the drug to medicine in 1785 in An Account of the Foxglove and Some of Its Medical Uses: With Practical Remarks on Dropsy and Other Diseases, published in Birmingham, England, where Withering served as a physician at the general hospital. In 1775 Withering became aware of the secret family recipe of an elderly patient, Mrs. Hutton, in Shropshire, England. She had developed a reputation for curing "dropsy" (congestive heart failure) when physicians had failed. Withering discovered that the active ingredient was foxglove. Crude extracts of the botanical were prescribed widely in the 1800s, although exact dosing requirements sometimes resulted in fatal overdoses. The crude drug and its preparations have a narrow therapeutic ratio. A small increase in dose, only slightly above that necessary for therapeutic results, can produce toxicity. The discovery and isolation in the leaves of the glycosides responsible for the botanical's pharmacological cardiac effects led to more exact controlled dosage forms with lower risks of toxic effects.

"The Dose Makes the Poison"

Foxglove and its isolated chemicals are a good example of a fundamental principle in the response of a cell, organ, or organism to a botanical drug or food ingredient. The response or expected activity is proportional to the dose. Therefore, research on the effects of a substance on an organism requires measurement of a dose-response relationship. Such information is gathered by measuring responses to appropriately variable amounts of the active agent (usually in laboratory animals). Doses are increased incrementally until 80 percent of the maximal response is achieved. Above the level of 80 percent, usually only small changes in activity are observed. Higher doses also may result in toxic effects. Quantitative analyses of the dose-response curve measure the relative potencies of a drug or extract and help determine at what levels a beneficial or a toxic reaction may occur.

Inhibition or potentiation of a response often involves attachment of a molecule to a cellular receptor site. Targeting cell receptor sites helps direct research to specific activities, such as anti-inflammatory or analgesic (pain-relieving) effects, or to diseases, such as diabetes mellitus or cancer. Mechanisms of action of potential interest often relate to cell receptor site competition. Sometimes effects are mechanical. For example, psyllium seed works as a bulk laxative by absorbing moisture in the intestines, thus increasing bulk and stimulating mechanical peristalsis.

A common adage in toxicology is "the dose makes the poison." In pharmacology, the measure of a substance's margin of safety is known as the "therapeutic index." This index is expressed as the ratio of the dose causing harmful effects to the dose causing a therapeutic effect in a specific proportion of individuals. The amount of a substance that causes death in 50 percent of laboratory animals is expressed as LD50 (dose lethal to 50 percent).

Botanicals Withdrawn Due to Safety Concerns

Most botanicals have a long history of apparent safe use. Ingredients may be withdrawn when new information raises safety concerns. Sassafras (Sassafras albidum) is an example. Sassafras derives its flavor and fragrances from an essential oil comprised of up to 80 percent safrole. In the late 1950s safrole, then used as a primary root beer flavoring, was banned as a food additive due to concerns over serious liver toxicity and carcinogenicity. The ban was subsequently extended to dried sassafras bark sold for the intended purpose of making an herbal tea. Dried sassafras leaves (used as a base for gumbo filé) must also be free of safrole. Another example of a botanical no longer considered safe is comfrey (Symphytum spp.). Popular in the 1970s and 1980s, comfrey leaves and roots were regarded as a virtual cure-all, earning it the name "all-heal." Apparently used safely for centuries, comfrey was found to contain significant amounts of a class of pyrrolizidine alkaloids that cause a condition known as veno-occlusive disease of the liver (resulting in the occluding or clogging of the major veins in the liver). The rare disease can only be diagnosed with a liver biopsy; thus it went unrecognized for decades. Internal use of comfrey products is restricted or prohibited in many countries.

See also Additives; Flowers; Herbs and Spices; Hippocrates; Processing of Food.

Steven D. Foster