1 What Is Phytotherapy?

Phytotherapy encompasses the application of botanical medicine for the prevention, treatment, and healing of disease. Its basic principles are often difficult to extrapolate due to the manifold effects of phytotherapeutics. This is compounded by the fact that the combined effects of its constituents cannot yet be sufficiently assessed through scientific studies. In the words of Johann Wolfgang von Goethe: “To know and note the living, you’ll find it best to first dispense with the spirit: Then with the pieces in your hand, Ah! You’ve only lost the spiritual bond” (Faust, act 1, scene 4).

This chapter describes the basic requirements for “modern” phytotherapy. Based on contemporary research, it seeks to overcome the impossibility postulated by Goethe of connecting the spirit with its individual constituents, which is what makes phytotherapy such an important therapeutic modality.

1.1 Definition

The term phytotherapy describes the use of plants and parts of plants, such as leaves, flowers, roots, fruits, or seeds and their preparations for the prevention and treatment of diseases and health issues. Plants suited to this application have traditionally been referred to as medicinal plants. Of key importance is the fact that the medicinal plant or its parts are used as a holistic substance. Plant medicines therefore always represent multicomponent mixtures. In numerous countries, the quality, effectiveness, and safety of plant medicines must meet the requirements of national drug legislation—for example, in Germany, the Medicininal Products Act (Arzneimittelgesetz—AMG).

The application of isolated, chemically defined constituents derived from plants falls outside of the definition of phytotherapy according to the current AMG. Such products are instead aptly labeled as “natural products as medicines.” Weiss accepted this approach as a part of phytotherapy and classified isolated active constituents as Forte-Phytotherapeutics (powerful phytotherapy). However, according to the definition of the Commission E of the German Federal Ministry of Health, which has jurisdiction over phytotherapy, the application of isolated plant constituents no longer represents phytotherapy. For example, digitalis glycosides such as digoxin or digitoxin extracted from foxglove (Digitalis purpurea, Digitalis lanata) were categorized as phytotherapy in several of the initial German editions of this book. Chemically or synthetically altered derivatives such as acetyl or methyl digoxin, however, are not classified as phytotherapy under any definition because they do not occur “in nature” in this form. In addition, constituents formerly isolated from plants are today primarily chemically synthesized and the source material frequently no longer has any connection with the original medicinal plant.

1.1.1 Constituents and Structural Composition

Understanding phytotherapy seems to require viewing the specific combination of constituents of a whole plant as a compositional secret. What von Goethe recognized as an “open secret” also applies to understanding medicinal plants. Today’s physiochemical processes enable us to analyze a plant or its constituents down to the finest detail. However, this analysis does explain the often incredible diversity of constituents of a single plant or how the plant continuously maintains its characteristic wholeness even though its composition constantly changes with the seasons, growth environment, geological conditions, and other factors. The structural composition of a medicinal plant, can be quantitatively verified, but plants also exhibit a qualitative nature that eludes absolute proof and can only be described.

Nowadays, the natural sciences frequently reduce the spiritual foundational principle referred to in the von Goethe quote above to genetics. No doubt genes are an important physical prerequisite for the survival of a species. It is important to remember, though, that genes are “composed” or created according to their specificity and type of articulation. Musicians also compose symphonies according to the rules of intervals, keys, and rhythms. Even though these are identical for each composer, each finished composition is unique and carries an individual “signature.” A musical expert can listen to a composition and recognize its creator, the composer. In the same way, plant experts can employ pharmacognosy to identify a plant from the whole plant down to its specific composition.

The goal of phytotherapy is not only to discover the plant, its growing conditions, and its constituents, but also its composition and thereby its singularity, the property that differentiates it from all others. Detailed knowledge of the composition of a plant must be in tune with the discovery of its compositional secret, the “spiritual bond.”

1.1.2 Phytotherapy and Herbal Medicine

Phytotherapy is only one part of the comprehensive field of herbal medicine, which includes phytochemistry, phytopharmacy, and phytopharmacology, and phytotherapy.

Phytochemistry exclusively studies the constituents (chemicals) in plants. Its mission is to identify the chemical composition of plants, verify, or control its fingerprint, and to describe potential constituents that can be examined pharmacologically for its effects. The atomistic view of phytochemistry is focused solely on the parts and not the whole. Phytochemistry provides the impulse to examine active constituents for their potential to be synthesized in order to become independent from harvesting in nature.

Phytopharmacy focuses on the drug that provides the basis for an herbal medicinal, and how it is used directly, for example, in teas or in various forms of pharmaceutically prepared extracts. Descriptions of plants in this book name the associated pharmaceutical drug. Pharmacognosy, or the identification of a drug through visual inspection, is an important part of phytopharmacy. In the past, pharmacognosists identified plants by looking at, touching, tasting, and smelling the plant. This approach to identifying and determining the quality of a medicinal plant can still be important. However, in the meantime, highly specialized physiochemical analysis methods are the preferred method of identifying drugs. It is not unusual for a pharmacist to know and be able to differentiate the entire fingerprint of a medicinal herb, but to no longer be able to recognize the plant in nature. There are now many pharmacologists in pharmaceutical university faculties who examine the pharmacokinetics and pharmacodynamics of medicinal plants under a primary pharmaceutical point of view.

Medical schools are still in the beginning stages of recognizing phytopharmacology as a specific field of study. An increasing number of pharmacologists study plant constituents, but they rarely practice the specific task of analyzing the pharmacokinetics and pharmacodynamics of multichemical and polychemical compositions. This monocausal approach to medicine seems to impede a shift in thinking. Clinical pharmacology, the stepchild of pharmacology, could certainly play a significant role in assessing the efficacy of phytotherapeutics. Phytotherapeutics are known more for their comprehensive efficacy than for their specialized effects. Therefore, they should be studied directly in human trials because transferring the results of animal trials of these multicomponent substances to humans is much more problematic than for defined isolated synthetic constituents. The same applies to manifold questions of toxicology. Frequently, risks of medicinal plants are cited in an entirely unscientific manner based on a purely theoretical background or self-selected paradigm even though these results have not been observed in humans.

Phytotherapy is the fourth component of the comprehensive field of herbal medicine. It describes the possibilities and limitations of using medicinal plants to treat indications in human medicine. It belongs primarily in the hands of physicians or other therapists such as chiropractors, physical therapists, nursing professionals, or—especially in the legal framework of the United States—certified herbalists and naturopaths, using herbal medicine. Many phytopharmaceuticals are also suited for self-medication, especially in a preventive sense.

Practicing pharmacists play an important advisory role in this context. For this reason, the possibilities and limitations of phytotherapy should be covered even more comprehensively in the education of pharmacists. Prof. Weiss frequently observed in his day that pharmacists recommended synthetic-chemical drugs for minor illnesses when a phytopharmaceutical with similar efficacy, but more favorable tolerability, could have been the drug of first choice. Most pharmacists at German universities learn at least the basics of pharmacognosy. In contrast, the present curriculum for medical doctors does not include any training in herbal medicine. In contrast to the time of Prof. Weiss, contemporary medical doctors in Germany are therefore not sufficiently exposed to phytotherapy during their training.

1.2 History

Medicinal plant therapy is found worldwide in medical systems that are often thousands of years old. Examples...