Why do plants heal?

Medicinal plants have been widely used by our ancestors, and it seems that now, after two centuries of distancing ourselves from natural remedies, Western society is rediscovering them.

The healing and restorative power of plants is provided by the great variety of active ingredients that plants synthesize and store in the course of their growth with the aid of metabolism. They do so from substances as simple as water, nitrogen, or carbon dioxide, through the process known as photosynthesis. However, not all products derived from metabolism are medicinal, but they do contribute to accelerating or slowing down absorption by the organism.

Due to this, we find a different therapeutic action when the plant's active ingredient is administered in isolation compared to when we take the whole plant, since the action is reinforced by all of its components.

We cannot, therefore, begin to understand medicinal plants without first knowing the active ingredients they may contain, which determine the therapeutic properties of each plant species.

Tannins. Tannins are polyphenolic compounds with the ability to precipitate proteins. They have astringent, healing, and antiseptic actions. They are used in specific tonic lotions for oily skin and in cases of couperose. Plants with tannins used in cosmetics include: rosehip (fruit of Rosa canina L.), witch hazel (leaves), yarrow (flowering tops), walnut (leaves), and cinchona (bark), among others.

Flavonoids. They have the following actions: vasoconstrictor, by decreasing the permeability of capillary vessels; vasoprotective and anti-inflammatory; they increase blood circulation at the subepidermal level; and they improve the transfer of micronutrients across the cell membrane, which leads to an increase in the supply of oxygen to the cells and therefore improves the texture and appearance of the skin.
There are many plants containing flavonoids whose extracts are used in cosmetics: cornflower, calendula, horse chestnut, centella asiatica, rosehip, hawthorn, ginkgo biloba, witch hazel, lemon, chamomile, pansy, grapefruit, butcher's broom, sage, linden are some of the best known. Currently, extract obtained from grape seeds (Vitis vinifera L.), rich in proanthocyanidins (grape flavonoids), has been incorporated as a cosmetic ingredient due to its anti-irritant, vasoprotective, and anti-aging (antioxidant) properties.
Plant extracts rich in flavonoids are used in a wide range of cosmetics, particularly: anti-aging products, products for the care of sensitive or irritated skin, skin with redness and couperose, and in many anti-cellulite products.

Anthraquinones. These are the main component of many medicinal plants such as senna, buckthorn, or cascara sagrada. They are components that act mainly against constipation, as they exert an irritant laxative effect on the large intestine that causes contractions of the intestinal walls, leading to evacuation about 8 hours after ingestion and making stools more liquid. The use of substances with anthracenic principles must be limited to short periods, not exceeding 8 to 10 days, as it can lead to dependency or the so-called “laxative disease”: colitis with diarrhea, abdominal pain, alterations of the colon mucosa, hydroelectrolytic disorders, etc.

Mucilages: In a botanical-pharmacological sense, these are substances containing carbohydrates that swell strongly in water and provide a viscous liquid. This gives them the virtue of lubricating and protecting the mucous membranes of the digestive tract, preventing inflammation. Plants rich in mucilage include plantain, marshmallow, mullein, and linden.

Saponins. These are plant glycosides (generally triterpenoids) with surfactant and detergent properties, and in some cases, rubefacient (cinchona bark) or vasoprotective (aescin in horse chestnut) properties. They are also natural emulsifiers. Licorice root is a great source of saponins in cosmetics. It also inhibits tyrosinase (skin whitener) and has antioxidant action. Glycyrrhetinic acid and its potassium salts (as an anti-inflammatory and soothing agent for delicate skin) and zinc salts (for acne-prone skin) are widely used.

Proteins. Mainly hydrolyzed vegetable proteins and isolated amino acids are used. Hydrolysates (such as soy protein hydrolysate) retain water and have texturizing and firming properties; they are used in moisturizing and skin-firming products and also for hair care, as they make hair more flexible and shiny.
High molecular weight proteins barely penetrate the epidermis; they remain on the surface of the stratum corneum and give firmness to the skin by smoothing it. Example: wheat and oat proteins, and their polymers with polysiloxane.

Alkaloids. These are generally nitrogenous substances with marked pharmacological properties. All plants that have them as a main component are therefore not indicated for tea-based therapy. However, the pharmaceutical industry uses them in large quantities. Examples of alkaloids are vinblastine (anti-tumor), an alkaloid from Catharanthus roseus; morphine (CNS depressant), from the opium poppy (Papaver somniferum); or quinine from cinchona (Cinchona sp. - antimalarial).

Among the alkaloids, xanthine bases (mainly caffeine and theophylline) are primarily used in the preparation of anti-cellulite products.

Essential oils: They have an oily odor and feel and are obtained by distillation after grinding fresh plants. An essential oil from a specific plant may contain more than 60 different volatile components, such as tea tree, which contains 68 different components. They are found in all parts of the plants: leaves, flowers, stems, branches, and roots. Their concentration is favored by warm, sunny climates.

In medicine and phytotherapy, they are used for their disinfectant, bactericidal, expectorant, stomachic, carminative, and cholagogue properties. In perfumery, they are used for their aroma. Plants rich in essential oils include: anise, fennel, caraway, thyme, marjoram, sage, chamomile, oregano, rosemary, lavender, mint.

Bibliographic References

• Bruneton, J. Fitoquímica de las plantas medicinales. Ed. Acribia, S.A. 1993.
• J.B. Peris, G. Stübing, B. Vanaclocha. Fitoterapia Aplicada, Edit. M.I.C.O.F. Valencia. 1st Edition.
• Pahlow, M. El gran libro de las plantas medicinales. La salud mediante las fuerzas curativas de la naturaleza. Ed. Everest, 1987.
• Diccionario integral de las plantas medicinales, 1st Edition, Edit. RBA Integral.
• Hoffmann, D. Plantas medicinales. Fitoterapia práctica para el bienestar integral. Ed Susaeta, 1996.
• Fitoterapia Aplicada, completada con curas dermatológicas y aromaterapia, 2015, C.O.F Barcelona y C.O.F Madrid.
• Fernández-Montes, E. A. Técnicas y procedimientos en formulación magistral dermatológica. Ed. E. Alía, 2005.