Glycosides - a complex group of nitrogen-free organic compounds consisting of sugar (glucones) and non-sugar (aglycone-genin) parts. Obtained in pure form, they are crystalline substances readily soluble in water and more difficult - in alcohol, bitter taste, many of them are toxic. For therapeutic purposes are used in small doses. They are very similar to hormones.Metabolic engineering of glycosylated polyketid

The therapeutic effect of glycosides is determined mostly by aglycone. Glycosides differ from each other not only by the structure aglycone, but by sugar chain structure. Glycosides, unlike alkaloids are volatile substance, rapidly are degraded by enzymes (enzymes) that are contained in the same plant, and also are degraded rapidly in the presence of water and then lose their therapeutic properties. Therefore, plants should be collected as soon as possible to dry at a temperature of +60 º C and store in a dry place. With this drying enzymes are coagulated and cease to break up glycosides. Glycosides - the major biologically active group, they are widespread among plants. Even in the same plant may be contained several types of glycosides. Most common are 0-glycosides, they are very diverse, which is due to the nature of the aglycone and sugar, which determines their pharmacological action. They stimulate t
he appetite, exhibit local irritant actions, aggressive against pathogenic microorganisms that cause inflammation of the skin, are able to activate the heart muscle (digitalis glycosides).
On these grounds oxy glycosides are divided into groups:
- cyanogenic glycosides, which are aglycones, containing hydrogen cyanide;
- cardiac glycosides, aglycones which are cardenolides and bufadienolides;
- saponins, which are triterpene aglycones and steroidal compounds;
- anthraglycosides glycosides, which are the aglycones anthracene derivatives;
- glycosides, bitter glycosides, included in the plant used as the bitterness;
- flavonoid glycosides;
- glycoalkaloids, which are aglycones of nitrogen-containing steroid compounds.
Unlike alkaloid glycosides are widely distributed in plants and play the role of peculiar regulators of chemical substance conversion processes. Glycosides are cleaved in the presence of dilute acid, and under the action of enzymes, some of them are even hydrolyzed by boiling with water. Glycosides, isolated from the plant in pure form, are amorphous or crystalline substances, soluble in water and alcohol.
In our time, there were reports that the glycosides with the same aglycone by a different structure of the carbohydrate chain can have quite dissimilar biological effects.

Cardiac glycoside containing plants
Cyanogenic glycosides. Contain prussic acid and are considered poisonous. Applied in drops and medicines as sedatives and painkillers. Particularly are common in plum, found in the seeds of plums, bitter almond, cherry, etc. Among cyanogenic glycosides are most common amygdalin, which is found in the seeds of almond, peach, apricot and other plants. Amygdalin soothes cough and normalize the heartbeat.
Cardiac glycosides. The most valuable and widely distributed in the plant kingdom are considered cardiac glycosides - a group of complex organic compounds of glycosides character has a specific effect on the heart muscle. By its action cardiac glycosides have no similar substitutes and plants are the only source to obtain them. In plants usually accumulate 20-30 cardiac glycosides of similar chemical structure. Specific weight of herbal drugs are used in the treatment of cardiovascular diseases, is around 80% of treatment of cardiovascular diseases, is around 80% of all used drugs. Particularly rich in species that grow in tropical and subtropical areas. They are found in various plants: in the seeds of strophanthus, in the flowers of lily of the valley, in the leaves of digitalis, in the grass wallflower, in the roots of dogbane etc. They are rich in adonis, oleander and others. Cardiac glycosides are the most rapidly cleaved by the enzymes, so the plants containing them, need to be dried as quickly as possible. Glycosides of this group have a strong effect on the heart muscle of all vertebrate animals and man. Currently, cardiac glycosides are set among 20 botanical genera. Cardiac glycosides are very unstable, so the collection and drying of plants containing them requires special care. From plants containing cardiac glycosides are prepared tinctures, extracts, concentrates and allocated individual glycosides. All drugs of cardiac glycosides have pronounced effects on the heart, and therefore are used for heart failure. Plants containing cardiac glycosides are highly toxic and can accumulate in the body, which can lead to poisoning, so the preparations of cardiac glycosides are used only as directed and supervised by a doctor.
Glycosides- saponins. The most common are glycosides- saponins. Saponins - the complex nitrogen-free substances of glycosides. These are usually related to plant substances, aqueous solutions have a number of characteristic properties: hemolytic activity, toxicity for cold-blooded animals, and the ability under agitation to form durable, long not disappearing foam. The term “saponin” is derived from the Latin word “sapo” – “soap”, was first proposed in 1819 for a substance isolated from Saponaria. Since then were allocated more than 200 representatives of saponins from 70 families, most often saponins are found in plants of the legume family, Caryophyllaceae, Labiatae and Aralia. Isolated from plants represent a white amorphous powder which, when dissolved in water is frothed. A valuable property of saponins is their ability to regulate water-salt metabolism and have anti-inflammatory action. A number of steroidal saponins are the source (raw material) for the synthesis of hormones that are widely used in violation of cholesterol metabolism. For saponins identified also stimulating, adaptogenic effect on the body, that is especially true for drugs of ginseng, Aralia, Oplopanax. Saponin-containing plants are used in medicine as a means of reducing the pressure of having sweatshops, tonic, emetic, and other properties. Saponins are used in the treatment of many diseases: as an expectorant for severe dry cough (istoda, cyanosis, primrose, licorice, etc.), diuretics (Indian kidney tea, etc.), cholagogic (St. John's wort, celandine, etc.). Steroidal saponins of dioscorea are effectively used in cardiovascular diseases. Have a pungent bitter taste, irritate the throat, stomach, and intestines. Saponins increase bronchial secretions. Some saponins lower blood pressure, cause vomiting, are sweatshops. Because of its ability to foam, saponins are used in the food industry in the manufacture of fizzy drinks and confectionery. Saponins can be a poison in case they enter the bloodstream. They are widely distributed in nature and are found in plants of different climate zones, but the most typical areas of dry and hot climate. They accumulate in significant quantities in the underground organs (cyanosis, licorice, Aralia, ginseng). To the saponin-containing plants refer zamaniha, ginseng, Aralia, Siberian ginseng, licorice, horsetail, etc.
Anthraglycosides. Anthraglycosides are derivatives of anthracene. Contain methyl and hydroxy groups. Most of them have a laxative effect. Several anthraglycosides are used for the treatment of renal disease, gallstones, gout, in the treatment of skin diseases, as anti-inflammatory, astringent. These substances can be obtained as a red-orange crystals. (For example, rhubarb numbers determine these glycosides.) They can be easily extracted from the plants with water and a weak alcohol, and even easier with alkalis, the solution is taking blood-red color. Anthraglycosides are non-toxic and relatively rack when stored. Anthraglycosides are slightly toxic and more stable when stored. Widely distributed in the plant kingdom, they are notable for a great variety of chemical composition, are contained in the buckthorn, cassia, aloes, Rubia, Rhamnus and other plants.
Iridoids - bitter, like cardiac glycosides, but unlike the latter are not poisonous. They are used as a means of stimulating the appetite, improve digestion, and are part of the mouth-watering drops. Plants, containing them have bitter taste (wormwood, dandelion, etc.).
Bitterness increase peristalsis of the stomach and increase the secretion of gastric juice, which promotes better digestion. So bitter plants are included in the delicious drops, delicious teas. These plants are really very bitter: for example, a decoction of gentian root at a dilution of 1 g per 25 liters of raw water still gives a sense of bitter taste.
Flavonoid glycosides. Flavonoids - phenolic compounds which accumulate in all plant organs in the form of glycosides. Poorly soluble in water, although there are also water-soluble. Flavonoids are widely distributed in nature, there are more than 150 kinds thereof. They accumulate in all plant organs, often - in the flowers and leaves. Distinguish anthocyanin, catechins, flavones, flavonols, chalcones. Many of them have P-vitamin activity, reduce the effect of toxic substances, possess antimicrobial and anti-allergic action. Flavone compounds are useful in the treatment of asthma, anaphylactic shock, myocardial infarction, diabetes. Flavonoid glycosides have antimicrobial, choleretic effect, contribute to the removal of radioactive substances from the body, strengthen the walls of capillaries increases their elasticity, and increase the intake of oxygen arterial wall, lower blood pressure, thus preventing atherosclerosis. Have anti-inflammatory, wound healing, antitumor, antibacterial, diuretic properties. Sometimes, flavonoids are involved in cellular respiration as catalysts and accelerate the physiological processes in which an active role does vitamin C. Therefore, flavonoids help with varicose veins, blood circulation disorders of the lower extremities, and allow your eyes to quickly get used to the darkness. Enhance the accumulation of ascorbic acid in the liver, adrenal glands and slow down its excretion from the body. As antispasmodic flavonoids are used in cardiovascular diseases, activate action of vitamin P. Recently it's been discovered that certain flavonoid compounds, in particular routines, lower brittleness of the smallest blood vessels, prevent bruising and holding internal hemorrhage. Thus, the deficit in the body of bioflavonoids, R-vitamin deficiencies, lead to fragility of blood vessels, bruising, hematoma formation (bruising), hemorrhagic diathesis, lung, stomach, nasal bleeding. Red blood cells are found in the urine. Disrupted the function of the thyroid gland, there is a weakness, fatigue (as well as at the C-hypovitaminosis). Substances P are also active participants in the redox process. In particular, they protect epinephrine from oxidation. Flavonoids have antitoxic properties, barrier properties during hypoxia, with colds. They are also characterized by the ability to dilate the coronary (heart) blood vessels, reduce swelling, anti-allergic and have antiasthmatic, anti-inflammatory and antipyretic activity. The lack of these substances contributes to disease pleurisy, pericarditis, endometritis, and the appearance of complications of hypertension, arachnoiditis, and the disease with radiation sickness.
The source of flavonoids are many plants, they are in mandarin (hesperidin), chokeberry (rutin, hesperidin, quercetin and others), hawthorn (hyperoside, quercetin), in motherwort (rutin), in helichrysum, licorice and others. From citrus is extracted citrine (vitamin P).
Flavonoids - the main component of propolis, a resinous solid yellow-brown or dark brown color, a valuable product of beekeeping. Flavonoids, along with plant pigments are responsible for the yellow, red, orange colored fruits, flowers and roots. The leaves are expressed by chlorophyll. Anthocyanins are found in the petals of flowers, creating a scarlet, red, purple coloring. Yellow coloration caused by flavonols, chalcones, as well as carotenoids. More flavonoid are found in licorice root, harrow, motherwort grass, water pepper, knotweed, Helichrysum flowers, tansy, Sophora japonica, hawthorn fruit.  From raw materials containing flavonoids, preparing of tinctures, in the various fees are preparing infusions and decoctions. Flavonoids can act as antioxidants - substances that prevent non-enzymatic peroxidation of organic compounds or significantly slow it down. These include naphthols, phenols and aromatic amines. In recent years, is widely held hypothesis that we are able to prolong our lives thanks to antioxidant. They are very important for normal metabolism and lack of antioxidants in the body, as proven by studies, accelerates the aging process. The systematic use of antioxidants prevents the development of atherosclerosis, malignant transformation of cells, positively effect on heart function - increases the amplitude of contractions of the heart and restores its work in fatigue and chloroform poisoning, quinine, normalizes abnormal heart rhythm.