1. Glycoside

2. Glycosides
Glycosides are non-reducing compounds which upon hydrolysis give one or more sugars (glycon) and a nonsugar (aglycon or genin) compounds. The most frequently occurring sugar is β-D glucose. The other sugars detected in are rhamnose, digitoxose, cymarose.
In glycosides the hydroxyl of a sugar is condensed with a hydroxyl group of the non-sugar component, and the secondary hydroxyl is condensed within the sugar molecule itself to form an oxide ring.
The sugar portion is called glycone and the non-sugar portion is called aglycone.
The aglycone may be an alcohol, phenol, cyanohydrins or complex fused ring or heterocyclic hydroxyl compounds.

4. GENERAL CHARACTERISTICS
Glycoside contains sugar but still the physical, chemical and therapeutic activity is based on aglycon portion. Sugar facilitates the absorption of the glycoside .helping it to reach the site
of action
Glycoside are crystalline, amorphous substance which are soluble in water, and dilute alcohol but in soluble in the CHCl3 and ether. The aglycon moiety is insoluble in non polar solvent like C6H6
The activity of glycoside is due to the aglycone moiety.
Glycosides are easily hydrolyzed by mineral acids, water and enzyme. They show optical activity normally they are levorotatory
Glycoside cannot reduce fehling’s solution until they are hydrolyzed
They are believed to facilitates growth and protection of plant
Chemically glycosides are considered as sugar-ether.
In pure state glycosides are mostly levo-rotatory, colourless, bitter, crystalline compounds.

5. Classification
According to the type of glycosidic linkage: α- glycoside (α-sugar) and β-glycosides (β-sugar).
According to the chemical group of the aglycone involved into the acetal union:
O-glycoside (OH group): In these glycosides the sugar is combined with alcoholic or phenolic hydroxyl function of aglycone.e.g.Digitoxin
S-glycoside (SH group): These glycosides contain a sugar moiety attached to a suphur of the aglycone.e.g. Isothiocyanate glycosides
N-glycoside (NH group): In these glycosides nitrogen of amino group(-NH2/-NH-) is condensed with a sugar. e.g. Nucleoside
C-glycoside (C group): Condensation of a sugar directly to a carbon atom gives rise to C-glycoside. e.g. Aloin

6. Classification (Con.)
According to the nature of the simple sugar component of the glycoside:
Glucosides (the glycone is glucose): A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes.
Galactosides (the glycone is galactose): A galactoside is a glycoside containing galactose. The H of the OH group on carbon-1 of galactose is replaced by an organic moiety.Depending on whether the glycosidic bond lies "above" or "below" the plane of the galactose molecule, galactosides are classified as α-galactosides or β-galactosides.
Mannosides (the glycone is mannose): Glycosides formed by the reaction of the hydroxyl group on the anomeric carbon atom of mannose with an alcohol to form an acetal. They include both alpha- and beta-mannosides.
Arabinosides (the glycone is arabinose): a glycoside that yields arabinose on hydrolysis

7. Classification (Con.)
According to the number of the monosaccharides in the sugar moiety:
Monoside (one monosaccharide) e.g., salicin.
Biosides (two monosaccharide) e.g., gentobioside.
Triosides (three monosaccharide) e.g., strophanthotriose.
  According to the physiological or pharmacological activity ‘therapeutic classification)
Laxative glsycosides: They have laxative property.e.g.Senna
Cardiotonic glycosides: cardiac glycoside any of a group of glycosides occurring in certain plants (Digitalis, etc.), having a characteristic action on the contractile force of the heart muscle.

8. Classification (Con.)
According to the correlation to the parent natural glycoside:
primary glycosides: A molecule with maximum number of aglycone moiety is called primary glycoside. These are more active than secondary and tertiary glycoside. But are not stable. So we will isolate only secondary glycosides which are more stable. These are more active than secondary and tertiary glycoside. But are not stable. So we will isolate only secondary glycosides which are more stable. e.g., amygdalin, purpurea glycoside A,
Secondary glycosides Primary glycosides on hydrolysis yields secondary (gives two sugar moiety e.g., prunasin, digitoxin.
Tertiary glycosides: secondary glycosides on hydrolysis yield tertiary glycosides.
According to the plant families.

9. Classification (Con.)
According to the chemical nature of the aglycone:
Alcoholic and phenolic glycosides (aglycones are alcohols or phenols)e.g. Salicin
Aldehydic G (aglycones are aldehydes).
Cyanophoric G (aglycones are cyanogens or derivatives of hydrocyanic acid).e.g.Amygdalin
Anthracene or anthraquinone G (aglycones are anthracene derivative).e,g,barbaloin
Steroidal G (aglycones are steroidal in nature, derived from cyclopentanoperhydrophenanthrene).e.g. Diosgenin
Triterpine glycosides (aglycones triterpines).e.g.Glycrrhyzin
Lactone glycosides (aglycones are lactone in nature)e.g. Hydroxy coumarin
Flavonoidal G (aglycones are 2-phenyl chromone structure).e.g.Rutin
Sulphur containing or thioglycosides (aglycones are contain sulphur).e.g. Sinigrin
Saponin glycosides (aglycone is saponinin nature) e.g., Dioscin

10. Sugars in glycosides:
Monosaccharide (glucose in salicin, rhamnose in ouabain)
Disaccharides (gentiobiose in amygdalin).
Trisaccharides (strophanthotriose).
Tetrasaccharides (purpurea glycosides)
Rare sugers (deoxy sugers)
Sugar linked in one position to the aglycone rarely in 2 positions as sennosides.

11. Biosynthesis of glycosides
The biosynthetic pathways are widely variable depending on the type of aglycone as well as the glycone units. The aglycone and the sugar parts are biosynthesized separately, and then coupled to form a glycoside. The coupling of the two parts occurs via phosphorylation of a sugar to yields a sugar 1-phosphate which reacts with a uridine (uracil nucleo base and ribose) triphosphate to form a uridine diphosphate sugar (UDP-sugar) and inorganic phosphate. This UDPsugar reacts with the aglycone to form the glycoside and a free UDP.

12. Discuss about some specific glycosides
1. Cyanogenic glycosides: These glycosides on hydrolysis yield HCN acid as one of the products. Usually they are derived from nitrile of mandelic acid. This glycoside contains nitrogen but the sugar moiety is attached with oxygen. e.g. Wild cherry, Mustard.
2. Anthraquinone glycosides:These glycosides possess anthracene or derivatives as their aglycone. Hydrolysis of these glycosides yield aglycone which are di,tri ot tetrahydroxy anthraquinones. They are found in- Aloe, Senna, Rhubarb
3. Saponin glycosides:These are highly complexed glycosides which are widely distributed in higher plants. They form colloidal solution in water which gives soap like froth on shaking. They are acidic in nature and bitter in taste and drugs containing them are irritating to the mucous membrane.e.g. sarsaparilla, glycyrrhiza, ginseng etc.

13. Discuss about some specific glycosides
4.Cardioactive glycosides: Some steroidal glycosides present in nature are characterized by the highly specific and powerful action that they exert on the cardiac muscle. Because of their action on heart muscle they are called cardiac glycoside.e.g. digitalis
5.Tannin glycoside:Nut gall
6.Simple phenol glycoside: Vanilla
7.Miscellanious: Quassia, Saffron

14. Mustard
Common Name(s): Mustard , black mustard , Indian mustard , leaf mustard , true oriental mustard , white mustard , yellow mustard
Botanical source: Mustard is the dried ripe seed of Brassica nigra or Brassica juncea, Family: Brassicaceae.
Geological source: They are two types –black & brown. The plants are annual herb that are native to Europe, South & Eastern Asia.
Chemical constituents: Brown mustard (B. juncea) contains the glucosinolate sinigrin (potassium myronate) and the enzyme myrosinas; sinapic acid; sinapine; fixed oils (25–37%), consisting mainly of glycerides of erucic, eicosenoic, arachidic, nonadecanoic, behenic, oleic, and palmitic acids, among others; proteins (e.g., globulins); and mucilage. Sinigrin on hydrolysis by myrosin (myrosinase) yields allyl isothiocyanate, glucose, and potassium bisulfate. Allyl isothiocyanate is volatile; its yield from B. juncea is 0.25–1.4% (usually ca. 0.9%). Other minor volatile components that are also set free by enzymatic hydrolysis include methyl, isopropyl, sec-butyl, butyl, 3-butenyl, 4-pentenyl, phenyl, 3-methylthiopropyl, benzyl, and β-phenylethyl isothiocyanates. Black mustard (B. nigra) contains similar constituents as B. juncea.

15. Uses:
1.Black mustard oil is used for the common cold, painful joints and muscles (rheumatism), and arthritis.
2.Black mustard seed is used for causing vomiting, relieving water retention (edema), and increasing appetite.
3.Paste of black mustard and warm water is used for treating pneumonia, pain and swelling (inflammation) of the lining of the lungs (pleurisy), arthritis, lower back pain (lumbago), and aching feet.
4.In foods, black mustard leaves (greens) are used in salads and other dishes. Seddsare used as spices.
5.Brown mustard has been used for centuries for simple toothaches to severe convulsions in small children.
6.The most common use of brown mustard as a medicine is external as a liniment, poultice, or plaster. Mustard oil, by mildly irritating the skin, stimulates circulation, which relieves muscle pain.
7.Mustard poultices have been attributed to relieving certain cases of bronchitis and pleurisy.
8.The Chinese further use medicinal mustard to treat ulcers, abscesses, and pain resulting from rheumatism and lumbago. They consider the leaves to be especially helpful to treat inflammation of the bladder.

16. Wild cherry(black) Common Name(s):Wild Cherry, Black cherry
Botanical source: Wild Cherry is the carefully dried stem bark of Prunus serotina. Family: Rosaceae.
Geological source: It is widely cultivated in Eastern United States and Canada.
Chemical constituents: Bark contains condensed tannins, prunasin a cyanogenic glucoside (d-mandelonitrile glucoside); emulsin; eudesmic acid (3,4,5-trimethoxybenzoic acid); p-coumaric acid; scopoletin; sugars; prunase enzyme,starch and traces of volatile oil. Fruit skin contains capulin anthocyanins. Leaves also contain amygdalin.
Uses:
Wild cherry is used for colds, whooping cough, bronchitis and other lung problems;
In diarrhea; gout; digestive disorders; pain; and cancer.
It is also used in cough syrups because of its sedative, expectorant, drying, and cough-suppressing effects.
In foods and beverages, wild cherry is used as a flavoring agent.

17. Prunasin

18. Cascara sagrada Other names: Cascara, sacred bark, and chittem bark.
Biological source: It is the dried bark of Rhamnus purshianus, Family: Rhamnaceae.
Geological source: The plant is a tree that is indigenous to pacific coast of North America, British Columbia, Washington, California and Kenya.
Constituents: It contains hydroxyanthraquinone glycosides made up principally of O-glycosides of aloeemodin, chrysophanol and emodin or C-glycosides (cascarosides A, B, C and D as well as aloin barbaloin and chrysaloin).
Uses:
Cascara is used as a laxative for constipation, as well as a treatment for gallstones, liver ailments, and cancer. Some people use it as a “bitter tonic.”
In foods and beverages, a bitter less extract of cascara is sometimes used as a flavoring agent.
In manufacturing, cascara is used in the processing of some sunscreens.

20. Aloe
Common name: Aloe vera, Curacao Aloe, Barbados Aloe, Lily of the Desert.
Botanical source: Aloe is the dried latex of Aloe barbadensis or A.ferox
Family: Liliaceae
Geological source:The plant is a perennial herb that is found in India, Africa, Europe, Westindies
Chemical constituents: Aloe latex contains anthraquinone glycosides the main one of which is barbaloin. Leaf contains more than 200 different constituents. The juice contains, on average, more than 99% water. Some constituents are: Acemannan, Aloe-emodin, Aloins, Isobarbaloin, amino acids, amorphous Aloin, enzymes, essential fatty acids,essential oil, Galactomannans, glycoproteins, minerals, polysaccharides, resin, vitamin C, vitamin E, Zinc and mucopolysaccharide.

21. Uses:
The gel and the outer skin of the leaf is dried and used as a laxative.
It is commonly used in different infections
Lowers blood sugar in people with type 2 (non-insulin- dependent) diabetes.
Relieves hypertension
Inmenstrual cramps and irregularity, suppressed menses
Gastrointestinal Conditions: colic, constipation, dyspepsia, intestinal infection, naturally alkalizes digestive juices to prevent over-acidity, relieves nausea.
Genitourinary Conditions: assists kidney function
allergic reactions
relieves arthritis
helps hypercholesterolemia
Colds
Acne
Boils ,burns
varicose veins
Warts
Wounds
Wrinkles
X-ray burns

22. Senna
Common names: Alexandrian Senna, Cassia lenitiva, Cassia lanceolata, Cassia officinalis, East Indian Senna, Nubian Senna, Tinnevelly Senna
Botanical source: Senna is dried leaflets of Cassia acutifola or C. angustifolia angustifolia
Plant Family: Leguminosae
Geological source: C. acutifolia (Alexandria senna) is native to Egypt and the Sudan while C. angustifolia (Tinnevally senna) is native to Somalia, the Middle East, and India.
Chemical constituents: Leaves contain glycosides, sennoside A, sennoside B, sennoside C and sennoside D. Two naphthalene glycosides have been isolated frofn leaves and pods. Senna also contains the yellow flavonol colouring matter kaempferol, its glucoside kaempferin and isorhamnetin.
Uses: Senna is also used for irritable bowel syndrome (IBS), hemorrhoids, and weight loss.

24. Rhubarb
Common Names: Chinese Rhubarb, Da Huang, Garden Rhubarb, Himalayan Rhubarb, Indian Rhubarb, Medicinal Rhubarb
Biological source: Rhubarb is a plant name for the many different species of Rheum. Two types of rhubard –Cinese and Indian (Dried roots and rhizome) Rheum palmatum and Rheum emodi respectively are generally used. Family: Polygonaceae
Geographical source: Rheum palmatum grows in China whereas the other species Rheum emodi isnative to India, Pakistan or Nepal.
Constituents: Chrysophaool, emodin, aloe-emodin, rhein, physcion were the free anthraquinones to be first isolated and to be found in nearly all species. They also contain monomethyl ether, glycone, gallic acid,catechin,cinnamic acid,Ca-oxalate etc.

25. Uses:
1.Rhubarb is used primarily for digestive complaints including constipation, diarrhea, heartburn, stomach pain, gastrointestinal (GI) bleeding, and preparation for certain GI diagnostic procedures.
2. Some people use rhubarb so they have to strain less during bowel movements; this reduces pain from hemorrhoids or tears in the skin lining the anal canal (anal fissures). 3. Rhubarb is sometimes applied to the skin to treat cold sores. 4. In food, rhubarb stems are eaten in pie and other recipes. Rhubarb is also used as a flavoring agent.

26. Sarsaparila
Common Name(s): Sarsaparilla , smilax , smilace , sarsa , khao yen
Botanical source: It is the Dried roots and rhizome of different species of Smilax. The main botanical sources are-
Smilax febrifuga; Smilax regelii;
Smilax aristolochiifolia; Family: Liliaceae
Geographical source: The plant is widely cultivated in Mexico, Honduras, Equador and central America.
Chemical constituents: Acetyl-parigenin, astilbin, beta-sitosterol, caffeoyl-shikimic acids, dihydroquercetin, diosgenin, engeletin, essential oils, epsilon-sitosterol, eucryphin, eurryphin, ferulic acid, glucopyranosides, isoastilbin, isoengetitin, kaempferol, parigenin, parillin, pollinastanol, resveratrol, rhamnose, saponin, sarasaponin, sarsaparilloside, sarsaponin, sarsasapogenin, shikimic acid, sitosterol-d-glucoside, smilagenin, smilasaponin, smilax saponins A-C, smiglaside A-E, smitilbin, stigmasterol, taxifolin, and titogenin.

27. Uses:
Detoxifies organs
Cleanses blood
Stimulates digestion
Kills germs
Protects liver
Increases urination
Relieves rheumatism
Reduces inflammation and fever

28. Glcyrrhiza Common name: Liquorice
Botanical source: It is the dried root or rhizome of Glycyrrhiza gabra or other species of Glycyrrhiza.
Family:Leguminosae
Geographical source:The plant grows well in England, USA, UK, France, Italy and Germany.
Chemical constituents: The saponin known as glycyrrhizin, also known as glycyrrhizic acid or glycyrrhizinic acid, is the main ingredient in licorice root. It contains 3-dehydro-18 beta-glycyrrhetinic acid, 2-15% triterpenoid saponins, largely glycyrrhizin. There are other triterpenoid saponins, including sitosterol and stigmasterol, flavonoids and isoflavonoids, coumestans, coumarins, resins, gums, tannin, starch and a bitter principle. The isoflavone in licorice called formononetin.

29. glycyrrhizin
Use: (a) Demulcent,
(b) Adrenalmodulator,
(c) Antibacterial,
(d) Antiviral,
(e) Antimutagen,
(f) Anti-allergenic,
(g) Expectorant with secretolytic and secretomotor activity,
(h) Anti-inflammatory,
(i) Nutritive,
(j) Spasmolytic,
(k) Antioxidant,
(l) Estrogenic,
(m) Immunomodulator,
(n) Mild laxative,
(o) Hepatoprotective.

30. Dioscorea Common Name: Wild Yam Root , Colic root, rheumatism root
Botanical name: it is the dried root of Dioscorea villosa; Family:Dioscoreaceae
Geological source: Dioscorea villosa is a species of a twining tuberous vine that is native to and found growing wild in North America.
Constituents: Dioscin, Dioscorin, Diosgenin, Aluminum, Ascorbic-acid, Ash, Beta-carotene, Calcium, Chromium, Cobalt, Iron, Magnesium, Manganese, Niacin, Phosphorus, Potassium, Protein, Riboflavin, Selenium, Silicon, Sodium, Thiamin, Tin, Zinc,Tannin, Starch.
Use: Antispasmodic, Anti-fatigue, Anti-inflammatory, Chologogue, Estrogenic, Hypocholesterolemic

32. Digitalis Common name: Foxglove, Woolly Foxglove,
Witch's Bells, Digitale, Dead Man's Bells
Botanical name: It is the dried leaves of Digitalis purpurea L.Family: Scrophulariaceae
Geographical source: It is native and widespread throughout most of temperate Europe. It is also naturalised in parts of North America and some other temperate regions.
Chemical constituents: A number glycosides have been isolated from Foxglove among which 35 are important.Fresh and carefully dried leaves contain purpurea glycosides-A& B. Purpurea glycosides A on hydrolysis yields one molecule Digitoxin (gylycoside) and glucose whereas Purpurea B on hydrolysis yields gitoxin and glucose. Again Digitoxin on hydrolysis yields digitoxigenin and digitoxose while gitoxin on hydrolysis forms gitoxigenin and gitoxose. In addition digitalis also contains tannins, inositol,luteolin, fatty matters, pectin etc.

33. Uses:
Heart Disorders: The digitalis herb is used mainly in the treatment of heart diseases. It stimulates and promotes the activity of all the tissues of the heart muscles in cases of congestive heart failure.
Digitalis helps to improve urination
Calcium: Digitalis helps in stimulating the receptors present in the heart to release more calcium. This leads to the heart beating more forcefully.
Wounds and Burns: Digitalis is used in some ointments for treating burns and wounds as a local application.
Other Medicinal Uses: Digitalis purpurea medicinal uses also include treatments for asthma, epilepsy, tuberculosis, constipation, and headaches.

34. Strophanthus Synonyms Semino stropanthi.
Biological Source These are the dried and ripe seeds of Strophanthus hispidus or of Strophanthus kombe ;Family Apocynaceae
Geographical Source :The plants are native Central and Eastern Africa.
Chemical Constituents The seeds of strophanthus usually contain three vital glycosides, namely:K-strophanthoside, K-strophanthride b and cymarin. Interestingly, all these glycosides undergo hydrolysis to yield strophanthidin.The seed also contains 25-30% fixed oil, trigonelline, choline, mucilage and resin.
Uses
1. It is used intravenously for treating emergency cardiac conditions. However, orally strophanthin is not so active.
2. These glycosides have been found to exert less cumulative effect unlike the digitalis glycosides.
3. Overall their therapeutic actions are very much similar to those of Digitalis.

36. Squill
Common Name(s): European squill , Mediterranean squill , white squill , Indian squill , red squill , sea onion , sea squill , scilla.
Botanical name: It is the dried sliced scales of fleshy inner bulb of Urgenia maitima and U. indica Family: Liliaceae
Geographical source: Squill is commercially collected from Italy, Cyprus, Spain, France.
Chemical constituents: Squill contains about 12 glycosides that are cardioactive, among which Scillaren A is major, others are proscillaridin A, scillicyanoside, scilliglaucoside, etc. It contains Flavonoids- Apigenin, dihydroquercetin, isovitexin,iso-orientin, luteolin, orientin, quercetin, taxifolin and vitexin. It also contains Stigmasterol, tannin, volatile and fixed oils.

37. Uses: The medicinal reputation of Squill was originally as a diuretic
Squill stimulates the bronchial mucous membrane and is given in bronchitis
It has also been given as an emetic in whooping-cough