Glycosides • Sugar + non-sugar • In the body they are broken down by enzymes or acids into: sugars= glycone/ water soluble non sugar= aglycone/ active portion • Aglycone may be an alcohol, sulfur or phenol compound.
Classification of glycosides • Based on the nature of the aglycone • Aglycones can be: phenols quinones terpenes steroids • Huge variety of medicinal activity from one glycoside to the next.
How are they broken down? • Pro-drugs: glycosides remain inactive until they are hydrolized in the large intestines by the help of specialized bacteria • This leads to the release of the aglycone which is the active constituent • The body can absorb some aglycones better than others depending on the herb
Glycosides and Plant Families • Brassicaceae- glucosinolates • Rosaceae- cyanogenic glycosides • Scrophulariaceae- phenylpropanoid glycosides • Asteraceae- phenylpropanoid, flavinoid glycosides • Polygonaceae- anthraquinones
Cyanogenic Glycosides Wild Cherry
Cyanogenic glycosides • Colorless plant constituent • Hydrogen cyanide was first isolated from Prussian blue dye • aglycone contains nitrogen • BREAK DOWN: • Cyanogenic glycoside hydrocyanic acid (prussic acid) cyanide
Cyanogenic Glycosides • Cyanogenic glycosides are found in pits and seeds of apples, apricots, peaches, plums and elderberries leaves and stems. • Their function in plants is not really known but they are suspected to be anti-feedants.
Cyanogenic glycosides • Main cyanogenic glycosides • Amygdalin- found in bitter almonds and peach kernels (Chinese herb) - used in to make Marizpan flavoring in cooking. 2. Prunusin- found in wild cherry bark 3. Sambunigrin- from the leaves of the elder tree, Sambucusnigra • Other food plants that contain cyanogenic glycosides include flaxseed and manioc. • Manioc root must be boiled and the water discarded in order to remove the toxins.
Cyanogenic glycocides-toxicology • In large doses hydrogen cyanide (hydrocyanic acid) inactivates respiratory enzymes, shuts down the CNS and leads to death. • However large doses of raw plant material are needed for toxicity to occur. • Our bodies can nuetralize cyanides and eliminate them through the urine. • Cyanogenic glycosides are broken down slowly and are easily detoxified by the body in smaller doses. • 500mg three times a day to produce a toxic effect, which is A LOT!!- • there are 4-9 mg hydrogen cyanide per bitter almond • You would have to eat 150 bitter almonds a day for a toxic effect!!!
Cyanogenic Glycosides: Properties • Sedative and expectorant to the respiratory tract. • Wild Cherry Bark (prunusserotina) is a classic prunasinconataining respiratory herb for dry irritable coughs. • Apricot kernels in Chinese medicine are used for coughs and asthma. • Cooling • Hydrocyanic acid cuts down heat at a cellular level. • Ex- peach, apple and pear are all cooling fruits that contain Cyanogens. • Anti-cancer • Amygdalin/Laetrile- has been researched as an anti-tumor remedy.
Cardiac Glycosides Digitalis purpurea
Cardiac Glycosides • Cardiac glycosides have a long history of use in herbalism • The famous cardiac glycoside, digitoxin, was isolated in 1785 by William Withering. He found out about the use of foxglove by an elder lady herbalist in his village using it for CHF (dropsy). Of course she gets no credit! • Digitoxin and other cardiac glycosides from plants day play a large role in modern medicine.
Cardiac Glycosides • Found in many medicinal plants such as Digitalis purpurea and lilly of the valley (Convallaria majalis) • Direct action on the heart supporting its strength and rate of contraction when it is failing.
Cardiac Glycosides- Plant protection Plants and animals create cardiac glycosides as a strategy for protection against being eaten by other creatures. Some animals, like monarch butterflies, have evolved immunity to the toxins. They consume plants like milkweed (Asclepiassyriaca) that are high in cardiac glycosides and store the toxins in their tissues. This makes them poisonous to other predators • Used as arrow poisons by hunters
Cardiac Glycosides- chemistry • Steroidal structure- 3 six carbon rings and one five-carbon ring • The sugar portion of the cardiac glycoside is important in the absorbtion and distribution in the body. • The aglycone portion is important in binding to Na/K pumps in the heart cells
Cardiac Glycosides CONDITIONS: Used in arrhythmias and congestive heart failure(dropsy) • In the past dropsy was the only sign of heart failure. Dropsy (CHF) fluid accumulation in the lower limbs and abdomen due to the heart not being strong enough to handle venous return. ACTIONS: • increase the force and speed of contraction • Inhibit sodium potassium pump leading to a rise in intracellular calcium which increases contraction of the heart. • Decrease heart rate • Slows conduction velocity in the pace maker- used for arryhthmias
Cardiac glycosides • Toxicity- Narrow therapeutic window. The therapeutic dose is not much smaller than the toxic dose. • Too high of a dose can make the pace maker more sensitive and lead to atrial fibrillation. • Cardiac Glycosides are antagonistic to Potassium. If person is low in K+ they will be more likely to have digitalis intoxication. • Taraxicum in combition helps to replenish K+ • Digitalis Intoxication- nausea, vomiting, diarrhea, vision disturbances, headache, arrhythmias.
Cardiac Glycosides • Cardiac remedies in other than drop doses should be used with discretion. • Digitalis lasts a long time in the body and its effects are cumulative. Half life is over 6 days! • Convallaria should be considered before digitalis because it has a lower toxicity
Cardiac Glycosides • Plants containing cardiac glycosides include: • Digitalis purpurea- Used for CHF and edema • Apocyanum cannabinum (Dogbane) • Strophanthus hispidus (Kombe Seed) • Adonis vernalis (False Hellibore) • Urginea Maritima (Squill) • Convallaria margalis (Lily of the Valley)
Isothiocyanate glycosides (Glucosinolates) • Found in the Brassicaceae (Mustard) Family. • Sulpher link between the glycone and the aglycone. • Sulpher is what gives the brassicas their pungent quality. ( Horseradish clears the sinuses, mustard oil opens the lungs) • In plants they are used as protection against microbes that disrupt their cell walls.
Isothiocyanate Glycosides • Therapeutic Actions: • Culinary- black and brown mustard seeds used in cooking are high in nutrients, stimulate digestion. • Rubefacients- mustard seed oils act as irritants when applied topically, causing local vasodilation • Mustard poultices over the lungs break up congestion. • Decongestant for the sinus and bronchial conditions (horseradish, onion and garlic). • Large doses may have an emetics effect.
Isothiocyanates- goiterogens • When consumed in excess they inhibit pumping of iodine into the thyroid follicles. This leads to goiter formation especially in those who are iodine deficient. • pertains more to people who are very iodine deficient like in parts of Asia or central Africa. • Isothiocyanate botanicals are low enough not to cause a problem.
Isothiocyanate glycosides- Antitumor • Glucobrassicin is widely distributed amongst the Brassicaceae family • Glucobrassicin produces indoles when broken down. • Indole-3-carbinol and diindoylmethane (DIM) • Indoles are known for their ability to induce tumor inhibiting enzymes. Thus are protective against cancer. • Indoles do not break down under heat.
Isothyocyanate Glycosides • Toxicology: External use of should not be sustained for longer than two weeks because of irritating effects. • mustard seed oils should never be used internally or externally because it toxic to the skin and mucus membranes.
Saponins Wild Yam (Dioscorrea spp.)
Saponins- Definition • Saponins are glycosides with foaming characteristics. • Saponin- comes from “sapo” in Latin which means soap. • Historically soap was made from the soapwart plant. • In plants they are anti-feedants and protect plants against microbes and fungi
Saponins- synthesis • Synthesized from acetyl CoA via the mevalonic pathway (similar to cholesterol in animals) • Major economic importance: saponins are used to synthesize pharmaceutical steroids (corticosteroids, estrogens, progesterone and progestins) • Agave, fenugreek and wild yam root are examples of plants used for their steroidal properties in the laboratory. • Human body doesn’t possess the gut flora to interconvert plant steroids to human steroids.
Saponins- classification • Consist of polycyclic aglycones attached to one or more sugar side chains. • Two subcategories of saponins • Triterpenoid: pentacyclic structure • Steroidal saponins (phytosterols): tetracyclic structure Licorice is a Pentacyclic triterpenoid
Saponins= Suds • The foaming ability of saponins is caused by the combination of a hydrophobic (fat soluble) aglycone along with the the sugar which is hydrophilic (water loving). • Allows lipids to dissolve in water • Emulsification in foods that allow water and fat to mix. • They have a detergent effect on the skin and the mucus membranes.
Saponins Wound healing herbs contain saponins such as calendula.
Saponins- Actions • Saponins are bitter or acrid in taste • If injected intravenously they cause hemolysis. Use only orally! • Destroy the membranes of red blood cells. • Lower cholesterol: • Because they are structurally similar to cholesterol they interfere with cholesterol absorption • Increase cholesterol excretion into the bile which then gets excreted through the feces. • Ex. Trigonella foenum-graecum (fenugreek)
Saponins- Actions • Medicinally they have many uses: • anti-inflammatory: Licorice, wild yam • anti-viral: licorice, ashwaganda • Digestive: licorice, • Expectorant: lobelia, squill • Adaptogenic: licorice, gensing,ashwaganda
Saponins- reflex expectorants • Acrid and flavor of saponins make them reflex expectorants • Reflex expectorants irritate the upper digestive tract causing emesis. This irritation also causes a reflex action via the vagus nerve to promote expectoration. • Historically herbalists have used emesis to clear the lungs in chronic bronchitis
Saponins- reflex expectorants • Lobelia inflata • Cephaelis ipecacuanha (Ipecac) • Urginea maritima (Squill) • Verbasum thapsus (Mullein flowers) • Viola spp (Violet flowers) • Glycyrrhiza glabra (licorice)
Steroidal Saponins • Dioscorea villosa (Mexican wild yam)root • Diosgenin: saponin aglycone • NOT PROGESTROGENIC in the body. Complex chemical reactions in the laboratory make it progestrogenic. Naturally it is antispasmodic and anti-inflammatory. • Human body cannot convert diosgenin into hormones.
Steroidal Saponins • Panax gensing (Asian) and P.quinquefoium (American gensing): • Gensenosides: immunomodulating, anti-stress, anti-dementia • Saponins foam and enhance absorption of other plant constituents. • Withania somnifra (Ashwaganda) root • Withanolides: calming and immunomodulating Panax gensing
Triterpenoid Saponins • Glycyrrhiza glabra (Licorice) • Glycyrrhizin- reduces toxicity of other saponins • anti-inflammatory, antiviral, immunomodulating, hepatoprotective, anti-ulcer • Used as a synergizer in herbal formulas rendering other ingredients more bioavailabe • Bupleurum falcatum • Hepatoprotective, antiviral, immunostimulating
Saponins in medicine making • Saponins are poorly bioavailable in the human body. Other plant constituents present in the plant aid in assimilation of saponins. • Saponin rich plants influence absorption of other plant constituents: • Help lipophilic constituents of plants be absorbed • Saponins in high doses can cause gastric irritation. Better if they are taken with food. • Mostly soluble in dilute ethanol (30%), water and lipids
Alkaloids • Have had a major impact on humanity • Examples are caffeine, morphine, ephedrine, atropine, cocaine and many more…
Alkaloids • Most potent of all plant constituents • alkaloids are seen in pharmaceuticals such as codeine, morphine, atropine, pseudoepinephrine and vincristine. • High doses will cause vomiting, diarrhea, immediate central nervous system symptoms and death. • Important for the herbalists to be careful with herbs that have a high alkaloid content. • Many herbs that contain alkaloids such as berberis and California poppy are low toxicity.
Alkaloids in the plants • Why do plants have alkaloids? We don’t know, there are just theories… • Unclear • alkaloids are a way for plants to excrete excess nitrogen, like mammals excrete nitrogen though urea in the urine • Alkaloids serve as defenses from predations • Alkaloids are a way for the plant to store nitrogen which is hard element to come by.
Alkaloids in plants • Alkaloids are common in plants: 10-15% of all plants have some kind of alkaloid • May be found in roots, leaves, bark, fruit or seeds. • Over 40 different alkaloids can be present in one plant, like Vinca major. Vinca Major
Alkaloids- chemistry • The word alkaloid is derived from vegetable alkali, which refers to their alkaline nature due to the presence of nitrogen • Alkaloids are best classified according to their biosynthetic origen. • Most are synthesized by the plant from amino acids • Psuedoalkaloids- derived from terpenes
Alkaloids-chemistry • General characteristics • alkaline • Contain a nitrogen • Part of a heterocyclic ring system Berberine
Alkaloids- Properties • Most are white in color when extracted, except berberine alkaloids which are yellow • Bitter in taste • Soluble in alcohol • Tinctures (45% ethanol) are very effective at extracting alkaloids • Acetracts extract alkaloids well, such as apple cider vinegar. • Less soluble in water • This may be a good way to deliver medicine if there is a potential for giving too high of a dose of alkaloids.
Alkaloids- Properties • Irreversibly precipitated by tannins. • Alkaloid containing medicines should not be tinctured with tannins, unless you wish to counteract the alkaloid. • If you want to mix a tincture that has both alkaloids and tannins use 10% glycerine to the tincture. • Black tea (Cameliasinensis), cranesbill (Geranium maculatum) or witch hazel (Hamamelisvirginiana) are the three remedies for alkaloid poisoning
Alkaloids- Actions • Analgesics/narcotics- morphine • Mydriatics- atropine • Hypertensives- ephedrine • Hypotensives- reserpine • Stimulants- caffeine, strychnine • Antimicrobials- berberine • Anti-cancer- vinblastine
Alkaloids • Many different groups of alkaloids exist • The most common groups that we will be covering in this class are: • Tropane Alkaloids- Belladonna, Henbane ect • Isoquinoline- California poppy, berberis • Pyridine- Tobacco, Lobelia • Pyrrolizidine- Comfrey, Western Coltsfoot • Indole- Peyote, Iboga • Purine- Cacoa, Caffeine