INTRODUCTION

Botanicals form the largest category of cosmeceutical additives found in the marketplace today. They are plant extracts from leaves, roots, fruits, berries, stems, twigs, barks, and flowers. Crushing, grinding, boiling, distilling, pressing, and drying can prepare the extracts. They can be easily added to cleansers, moisturizers, astringents, treatment creams, colored cosmetics, and face masks. Their popularity as cosmeceutical additives can be attributed to the fact that they are an unregulated category of ingredients that fit nicely into over-the-counter products. Botanical additives for topical application are considered safe by the United States Food and Drug Administration, thus allowing the products to be marketed without obtaining drug status or being restricted by monographed ingredients.

Historically, botanicals formed the basis of all medical treatments at the time European settlers were first coming to America. These Europeans learned that the American Indians had an extensive pharmacopeia, based on native plants, that was passed from generation to generation through the wisdom of the medicine man in each community. These plant concoctions were mastered by the settlers, transported back to England, and incorporated into some of the earliest books on medical treatment. When the new English settlers were learning about North American plant extracts, a large body of knowledge utilizing plants from the Orient was also being developed. The richness of plant material in the tropical Orient led to different plant extracts of great diversity that were used in Oriental medicine and religious practices. Today cosmetic formulators have access to plant materials worldwide for incorporation into cosmeceuticals.

BOTANICAL ADDITIVE MANUFACTURE

The popularity of botanicals is largely due to the aura of natural products. Products derived from plants are felt to be free of synthetic chemicals, somehow providing benefits above and beyond active agents that are created in a laboratory. It may come as a surprise to many that botanicals must undergo a significant amount of chemical processing prior to incorporation into a cosmeceutical and this processing greatly affects the biologic effect of the botanical on the skin surface. Box 11.1 summarizes some of these considerations, which are discussed next.

The most important factor contributing to the biologic activity of botanical cosmeceuticals is the source of the plant material. The chemical constituents of the leaves, berries, stems, roots, and flowers may be different, each containing over 200 different individual chemical constituents. Furthermore, the season in which the plant material was gathered may also greatly influence its composition. Certain actives are present only in the fall when the leaves are shedding while other actives are only present in early spring when immature leaves are present on the branches.

It is also important to consider the processing that a plant-derived material must undergo before it can be placed in a skin care product. Raw crushed leaves added to a moisturizer will not provide an esthetically pleasing result. Usually, the plant material is heated or processed to obtain essential oils or other distillates that can be easily added to a cosmetic formulation; however, heating may destroy some of the active chemicals providing skin benefits.

Lastly, the amount of the active in the botanical extract is important in determining efficacy. Sometimes the botanical active is added in small amounts providing more marketing benefit than skin benefit; however, many botanicals are only required in low concentrations to provide the desired effect. In an attempt to obtain some standardization of botanical fractions, many raw material manufacturers procure the actual plant materials and determine which fraction produces the desired effect. This fraction (e.g. a particular turpene) is analyzed carefully to isolate its chemical composition. Once the mass spectrophotometry is completed, a synthetic copy can be created. In some ways these synthetic copies are better since they eliminate some of the variability associated with plant materials grown in various environments at various times of year. It is also possible to concentrate the active agent. However, there are some that feel plant materials can never be accurately duplicated by organic chemistry.

BOTANICAL ADDITIVES

Botanical pharmacopeias contain thousands of plants with anecdotal purported skin benefits lacking scientific validation. It is not possible to cover all currently existing extracts in this text, yet there are some botanicals that are currently widely used in the cosmeceutical marketplace. These botanicals can be characterized as antioxidants, anti-inflammatories, and skin-soothing agents (Table 11.1).

Table 11.1 Botanical cosmeceutical categories

BOTANICAL ANTIOXIDANTS

There are many botanical antioxidants, since all plants must protect themselves from oxidation following UV exposure in the outdoor environment in which they grow. These protective mechanisms have evolved over many years, providing interesting chemicals for extraction and incorporation into cosmeceuticals. Antioxidant botanicals quench singlet oxygen and reactive oxygen species, such as superoxide anions, hydroxyl radicals, fatty peroxy radicals, and hydroperoxides. Most botanical antioxidants can be classified as flavonoids, carotenoids, and polyphenols. Flavonoids and polyphenols possess a polyphenolic structure accounting for their antioxidant effect while carotenoids are derivatives of vitamin A. The largest source of botanical antioxidants is foods, such as those listed in Table 11.2. These extracts can be used topically, as well as consumed. Other popular botanical antioxidants include soy, curcumin, silymarin, and pycnogenol (Table 11.3).

Table 11.2 Nutritionally derived botanical cosmeceutical antioxidants