About Botanical Extracts
Plants have been of medicinal importance as far as memory goes back. They contain an extensive range of chemical compounds of varying forms and stability. The most common classifications consist of the following.
- Lipids: these are fixed oils, fats, or waxes. In most cases the lipids are stored in the seeds, the spores, or the bulb. The fats in fixed oils are in general esters of long chain fatty acids such as stearic acid, palmitic acid and oleic acid, combined with a trihydric alcohol, glycerol. They are more commonly known as triglycerides.
- Phenols: A phenol is a compound of one or more hydroxyl group directly attached to a carbon atom or aromatic nucleus. In plants they are usually found combined with a sugar or glycoside. They are water soluble and mildly acidic.
- Tannins: These are chemically complex. This large group of substances is found in plant parts such as the fruit, bark, leaf, stem, and roots. They are generally water soluble and astringent in nature.
- Proteins: Proteins are found in plants in addition to animals. Proteins are derived from amino acids which are the building units. They are important because they possess therapeutic activity.
- Alkaloids: These nitrogenous compounds possess potent physiological activity. The names of alkaloids will end in "ine" for example: atropine, quinine, morphine. They appear in many families of flowering plants and are found in most all parts of the plant.
- Carbohydrates: These are compounds that contain elements such as carbon, hydrogen and oxygen. In cosmetic and pharmaceutical preparations they have a variety of uses. They are broadly classified as monosaccharide, oligosaccharide, polysaccharide, and derived carbohydrates. They can be used as binders, gelling agents, stabilizers and thickeners.
- Glycosides: These substances are extracted during hydrolysis and yield one or more sugars. The non-sugar part of the molecule is called the aglycone and the sugar component is called the glycone. The function of these sugars in plants is to regulate, detoxify and defend. Glycosides possess important pharmacological activity, for example digitoxin is a cardiac stimulant, and salicin is an analgesic.
- Volatile Oils: These oils are more widely known as essential oils. In some plants the volatile oils may occur in all the plant tissues. In other plants such as a rose they occur mostly in the petals. In most cases oils obtained from different organs of the same species will have similar characteristics. In other plants oils from different organs contain different characteristics. Essential oils play an important role because of their therapeutic actions. In addition to their use as flavorings they can be used as stimulants, diuretics, antiseptics, local irritants, and as pesticides.
- Resins: This group of solid or semi-solid substances has a complex chemical nature. They do have some common characteristics but a strict definition of a resin is not possible. As a class they are generally hard, transparent or semi-transparent brittle substances. They are generally heavier than water and upon heating become fluid. Some resins are acidic and when heated with alkalis become soaps. Resins in homogenous mixtures with volatile oils are known as oleoresins.
- Balsams: These are resinous substances that contain various amounts of aromatic balsamic acids.
- Mucilage: These are usually off white viscous masses. These are often applied by medical herbalists to soothe irritated skin. They are not readily absorbed by the skin and tend to be local in action.
There are many methods used to extract all these various chemical compounds. Most of them involve soaking the plant in a suitable solvent for a specific period of time. Some common methods are maceration, expression, digestion, and percolation. Different chemical compounds are soluble in particular solvents. Some solvents include ethyl alcohol, ether and acetone.
Extracts come in many forms. Tinctures are usually high in alcohol and 1/5 to 1/10 the strength of a fluid extract. Fluid extracts are usually 1:1 strength. This means that 1ml fluid is the equivalent of 1 gram dehydrated botanical. Solid Extracts contain no alcohol and are 4-6 times the strength of a fluid extract.Powdered extracts are the same as solid except they are powdered. An Oil extract will contain only the oil soluble constituents of the botanical. Glycerin extract and Propylene Glycol extracts dilutions can vary based on the dilution.
Standardization: A standardization of 10:1 means that 10 kg of botanical was used to produce 1 kg of extract. When standardizing, the strength of the extract is based on a selected ingredient in that extract. For example White Willow Bark is standardized based on the amount of Salicylic Acid in the extract. Care must also be taken not to destroy the holistic balance of the whole extract.
Hopefully this small extract has given you some insight into what botanical herbal extracts are and how they may be used. This just barely touches on the chemistry, methods of extraction and pharmacology of botanicals.