MOLECULAR CHEMICAL CONSTITUENTS IN HERBS

GLOSSARY OF COMMON CHEMICAL CONSTITUENTS IN PLANTS

Alkaloids - Alkaloids are a higher plant constituent that contain nitrogen and tend to have very strong actions on animal physiology. Many of the most toxic plant constituents, like strychnine in nux vomica and atropine in Belladonna, are alkaloids. Many plants with less toxic alkaloids are used as botanical medicines, such as Lobelia containing lobeline, Ephedra containing ephedrine, and Comfrey containing symphytine. Caffeine in coffee is another example of an alkaloid. 

Flavinoids - Flavonoids usually occur together with sugar molecules as a type of glycoside. Flavinoids are derived from phenols within the plant. Flavinoids are sometimes classified as a type of glycoside, and sometimes classified as a type of phenol. Flavinoids are associated with plant pigments and give bright yellow, orange, red, purple, and blue colors to plants. Flavinoids appear to have strong physiologic effects on humans including profound antiinflammatory and antioxidant activities. The flavonoids include procyanidins, anthocyanidins, xanthones, and isoflavones. The antiinflammatory silymarin in Milk Thistle (Silybum marianum) is a flavinoid. The brightly red pigmented hypericine, is an antiinflammatory compound in St. Johnswort (Hypericum perforatum). 

Glycosides - A glycoside is a sugar plus a non-sugar element found bound together as a complex. There are numerous types of glycosides in plants including cardiac glycosides that have an action on the heart, phenolic glycosides that have a disinfecting action, flavonol glycosides that have an antiinflammatory action, and so on. A sugar molecule, typically glucose, is linked to a flavonol, or a phenol, or numerous other non-sugars. The sugar portion of the complex helps to get the non-sugar molecule absorbed in the intestines and into circulation around the body. The glucosides have a wide variety of physiologic actions depending on the type of non-sugar component.

Mucilage - Mucilage is a slimy viscous plant constituent used to soothe and hydrate human tissues. Mucilage will reduce inflammation and allay pain of injured and diseased skin and mucous membranes such as the mouth, the stomach, the intestines, and the urinary tract. Comfrey roots and Aloe vera leaves are high in mucilage and are both used as soothing and healing agents.

Oils - Oils are fluid fatty substances most prominent in the nuts and seeds of plants. Oils are greasy and slippery to the touch and will leave oily stains on paper, fabric and other fibers.. Oils are different than “volatile oils” in that oils are considered a heavy, fixed, stable, plant consituent, where volatile oils are unstable and labile. Oils are soluable in volatile oils and other fatty substances, but not in water, alcohol, or other edible substances. Oils may be used topically on the skin for dryness and irritation such as coconut oil for dry skin, and olive oil salves for diaper rash. Oils may also be taken internally as foods, flavorings, and medicines. Humans have a very small fat and oil requirement, and typically a much larger intake than is required. So usually more attention is pain to getting fat and oil out of the diet, than in. However, there are several types of fat that are trully essential to health and must be consumed in the diet, and these include the essential fatty acids. Essential fatty acids are found in flax, borage, current, and evening primrose seeds in high amounts and are used theraputically for dry skin, skin itching, excema, and psoriasis. An essential fatty acid deficiency can worsen asthma, allergies, irritable syndrome, cancer, arthritis, multiple sclerosis, and numerous other disease processes. Essential fatty acids are destroyed by exposure to heat, light, and break down quickly with aging. Since many people eat no raw nuts or seeds, purchase oils that have been heat processed and sit under flourescent lights in clear glass bottles, and use oils for frying and cooking, essential fatty acid deficiencies are not uncommon. Sunflower, safflower, olive, sesame and many other plants contain high amounts of fixed oils in their fruits/seeds. Cereal grains and all nuts contain fixed oils and often traces of essential fatty acids.

Organic Acids - Organic acids are weak acids commonly occuring in plants, particularly fruits. To a chemist, an organic acid is something that contains a carboxyl molecule and complexes together with a base. To a physiologist, an organic acid is something that tastes sour and has an irritant laxative effect on the bowels. Organic acids such oxalic acid in spinach and many greens, and malic acid in unripe apples, stimulate the intestines when taken to the extreme and promote gas, cramping, and diarrhea. Small amounts of organic acids are used by herbalists to promote digestive function when needed. Yellow dock and coffee are two plants high in laxative organic acids. 

Phenols - Phenols are an enourmous category of compounds that all contain a benzene ring (a 6 sided ring of carbon atoms). Many complex plant constituents contain such a benzene ring, and are therefore considered to be a type of phenol. Simple phenols are usually aromatic volatile compounds. Complex phenols include thousands of different flavonoids, as well as coumarins, lignans, quinones, and other compounds. 

Resins - Resins are sticky, thick fluids exuded by the tissues of some plants. Resins are often produced in response to injury, such as pine tar flowing from a cut in a pine tree, or the white milky fluid flowing from a dandelion that has been picked. Resins are soluble in alcohol and oil, but not very soluble in water. Resins are stimulating, expectorating, and antimicrombial. Many resins contain cinnimic acid and benzoic acid and are sometimes referred to as balsams. Myrrh (Commiphora myrrha) and Gumweed (Grindelia) are very high in resins. Many resinous botanicals are used as lung remedies and topically as skin remedies.

Saponins - Saponins are plant constiuents that are usually found bound to a sugar molecule and are, therefore considered glycosides. (See Glycosides) One characteristic of saponins is that they will foam when shaken, like soaps. The molecular shape of a saponin is structurally very similar to steroids and many plants high in saponins have a hormone-like activity in the body. Wild Yam contains the saponin diosgenin, and Sarsparilla contains the saponin smilagenin. Both of these plants are used for disorders of female hormones. Other saponins can be very irritating and somewhat toxic, such as the plant Devil’s Club, whose prickers exude an irritating saponin that tends to inflame the skin. All saponins are toxic to cold blooded animals such as fish, and many cultures have used high saponin plants as a means of fishing. High saponin plants were mashed to a pulp and thrown into streams and fishponds, after which the fish would simply float to the surface and were harvested. 

Steroids - Plant steroids or “phytosterols” are fairly common in higher plants and may be categorized further as steroidal saponins and steroidal alkaloids. The plant requires steroidal compounds to help direct growth and reproduction. Most phytosterols are not identical to human steroids, but do appear to affect our hormones. Many plants high in steroids are used for menopause, menstrual irregularities, infertility, and muscle building. The Wild Yam (Dioscorrea villosa) and Sarsaparilla (Smilax species) are high in steroidal saponins and have been used in folk medicine, as well as in the modern pharmaceutical industry as a raw material in the manufacture of steroid drugs. Hops (Humulus lupulus), Chestnuts (Castanea species), and Pomegranates (Punica granatum) all have small amounts of actual female estrogens. Soybeans and green beans are also notably high in phytosterols. It has been observed that women who consume a lot of soybeans, tofu and other soy products, experience less breast cancer and less menopausal difficulties. The relationship between phytosterols and breast cancer is currently being investigated. One very commonly occuring phytosterol, known as beta sitosterol, is known to reduce fats in the blood stream and the risk of heart disease. The far reaching effects of plant steroids are not yet well understood. 

Tannin - Tannins are a plant constituent that is able to astringe (dry and tighten) skin and internal tissues. The word tannin comes from the widespread use of these plants in “tanning” animal hides. High tannin plants were used to astringe the raw tissue of the animal hide and fix it into firm dry leather.  Tannins are most prominent in plant leaves and bark, such as oak leaves and Witch Hazel bark. Oak galls are also notably high in tannins. Tannins may be used topically on wounds and inflammed, moist, weeping skin to promotes drying and scabbing over. Tannins may also be used internally to astringes ulcerated stomach and intestines. 

Terpenes - Terpenes are a large category which give rise to numerous other related compounds. Terpenes are synonomous with isoprenoids, and are derived from isoprene units within the plant. Terpenes include the monoterpenes which are used by the plant to attract pollinators, diterpenoids which are used by the plant as growth hormones, triterpenoids which are used to form saponins, and sesquiterpenes which may be used as antimicrobials by the plant. Terpenes are often components of volatile oils. The physiologic effects of terpenes are diverse and of much theraputic significance. The sedative valepotriates in Valerian, for example, are a type of monoterpene. The antiinflammatory glycyrrhizin in Licorice (Glycyyrhiza glabra) is a type of triterpenoid saponin. The antioxidant ginkgolides in Ginkgo biloba are a type of diterpenoid. The anti-cancer beta carotene found in numerous orange and red fruits and vegetables are a type of terpene. 

Volatile Oils - Volatile oils are the strong aroma-producing substances in a plant. These oils are said to be volatile because they are unstable compounds and are given off freely to the atmosphere, which is why we can smell them so readily. Volatile oils are produced by plants to help attract pollinators, so are usually the most abundant when the plant is flowering. Chemically, volatile oils may be esters, aldehydes, terpenes, and other types of molecules. Volatile oils are high in all of the culinary spices such as sage, dill, cinnamon, pepper, rosemary, nutmeg, etc. We enjoy them in our foods precisely because they are high in volatile oils which flavor foods and excite the nose and tastebuds. Many medicinal herbs are high in volatile oils such as thymol, a potent antimicrobial volatile oil in Thyme. Eucaluptus, Valerian, Chamomile and many herbs are high in volatile oils. Any plant with a strong aroma would be expected to be high in volatile oils.