PHA 010: Pharmacognosy and Plant Chemistry Module 5 Student Activity Sheet PDF

# PHA 010: PHARMACOGNOSY AND PLANT CHEMISTRY ## Module #5 Student Activity Sheet ### Name: ### Section: ### Schedule: ### Class number: ### Date: ## Lesson title: GLYCOSIDES #### Learning Targets: At the end of the module, students will be able to: 1. Discuss the biosynthesis of glycosides 2....

# PHA 010: PHARMACOGNOSY AND PLANT CHEMISTRY ## Module #5 Student Activity Sheet ### Name: ### Section: ### Schedule: ### Class number: ### Date: ## Lesson title: GLYCOSIDES #### Learning Targets: At the end of the module, students will be able to: 1. Discuss the biosynthesis of glycosides 2. Identify the different components of glycosides 3. Recognize the different classifications of glycosides; their specific sources, tests and pharmaceutical/medicinal importance #### Materials: SAS, Book, pen and notebook, laptop #### References: - Tyler, V.E., Brady L.R., Robbers, J.E. Pharmacognosy, Philadelpia: Lea & Febiger, latest ed - Evans, William Charles. Trease and Evans pharmacognosy, 15th ed. Edinburgh: W. B. Saunders, latest ed. ## A. LESSON PREVIEW/REVIEW Review the previous lesson being discussed last meeting. Ask the students if they have some verification or clarification about the previous topic. If no more questions, then start introducing the new topic which is "Glycosides". - Biosynthesis of Glycosides - Classes of Glycosides - Tests for Glycosides ## B. MAIN LESSON The instructor should discuss the following topics or ask the students to read, review and understand the outline of this topic. Then, tell the students to answer the check for understanding activity after the discussion or after reading the main lesson. ### Glycosides Are components or substances which upon hydrolysis yield one or more sugars - Chemically, are cetals in which the hydroxyl of the sugar is condensed with a hydroxyl group of the non sugar component and the secondary hydroxyl is condensed within the molecule itself to form an oxide ring. - Physically, glycosides are crystalline or amorphous, usually colorless and bitter substances and are generally soluble in water and diluted alcohol. ### 2 COMPONENTS OF GLYCOSIDES - **GLYCONE** - Sugar portion (β-D-glucose) - **AGLYCONE** - non sugar portion (-CH3 or methyl group) ### 2 WAYS OF HYDROLYZING GLYCOSIDES: - By the action of mineral acids (HCl, H2SO4) **exogenous** (outside the plant) - By the action of enzymes (**endogenous**) - are present on the same plant tissues which contains the glycoside but they are located in different cell of the plant ### GLYCOSIDES - ENZYME #### HOW DO THEY MEET: - by plant injury - due to germination ## Physiologic activities within the cell Examples of Physiologic Activity: - Osmosis - Diffusion - Cyclosis ## 2 ENZYMES CAUSING THE HYDROLYSIS OF GLYCOSIDES - **EMULSIN** - obtained from almond kernels - **MYROSIN** - obtained from mustard seeds ## BIOSYNTHESIS OF GLYCOSIDES: #### General Reaction of Glycosides: sugar residue + aglycone = glycoside #### Hastened by 2 Enzymes: **A**. Uridyl tranferases – facilitates the transfer of uridyl group from uridine triphosphate thereby forming uridyl sugar & Ppi 1. UTP + Sugar 1-P = UDP - Sugar + Ppi (aglycone) (glycoside) **B**. Glycosyl transferase - facilitates the transfer of the sugar from uridine diphosphate to a suitable acceptor forming the glycoside 2. UDP - Sugar + Acceptor = Sugar-Acceptor + UDP (Glycoside) ## CLASSIFICATION OF GLYCOSIDES: **A**. **CARDIOACTIVE GROUP** - Powerful action on the cardiac muscle - Steroidal in character with cyclopentanoperhydrophenanthrene nucleus #### Steroid Aglycones: 1. **Cardenolides** (C23 steroid) > - 5 member lactone ring 2. **Bufadienelides** (C24 steroid) > - 6 member lactone ring #### TEST TO IDENTIFY CARDIAC GLYCOSIDE COMPONENTS: - DEOXYSUGAR > - Keller-Killiani test > - (+) purple at the interface **B**. **ANTHRAQUINONE GROUP** **C**. **SAPONIN GROUP** **D**. **CYANOPHORE GROUP** **E**. **ISOTHIOCYANATE GROUP** **F**. **FLAVONOL GROUP** **G**. **ALCOHOL GROUP** **H**. **ALDEHYDE GROUP** **I**. **LACTONE GROUP** **J**. **PHENOL GROUP** **K**. **OTHER ORGANOSULFUR DRUGS** ## A. CARDIOACTIVE GLYCOSIDES - **STEROID** > - Liebermann-Burchard test > - (+) immediate color changes at the junction of the extract - **STEROLS** > - Salkowski test > - (+) cherry red color - unsaturated sterols - **UNSATURATED LACTONES** > - Kedde reaction/test > - (+) purple #### Mechanism of action: - involves Na+, K+ and ATPase as the receptoenzyme. The enzyme catalyzes the active transport of Na+ out of the cell and subsequent transport of K into the cell. #### DRUG INTERACTION: - Potassium depletion increases susceptibility to cardiac glycosides toxicity therefore patient on concomitant therapy with such K+ depleting drugs such as thiamine diuretics and corticoids may require potassium supplementation or reduce dosage of cardiac glycosides - Patient should not be given parenteral Ca+2 because hypercalcemia can potentiate the cardiac effect ## DRUGS CONTAINING CARDIAC GLYCOSIDES 1. **DIGITALIS** > - SN: Digitalis purpurea (Scrophulariaceae) > - AC: digitoxin, digoxin 2. **CONVALLARIA** > - SN: Convallaria majalis > - AC: convallatoxin 3. **APOCYNUM, DOG BANE, INDIAN HEMP** > - SN: Apocynum cannabinum > - AC: Adonotoxin, cymarin, K-strophantin 4. **BLACK HELLEBORE, CHRISTMAS ROSE** > - SN: Helleborus niger (Ranuculaceae) > - AC: Hellebrin 5. **STROPHANTHUS** > - SN: S. kombe, S. hispidus (Apocynaceae) > - AC: Strophantidin 6. **SQUILL OR SQUILL BULB** > - SN: Urginea maritime (Liliaceae) > - AC: Scillerin A (Scillarenin) ## USES: ## B. ANTHRAQUINONE GLYCOSIDES - Anthracene derivative - Detected by using Borntrager T.S. giving a red, orange or pink color as a positive result ## BIOSYNTHESIS OF ANTHRAQUINONE GLYCOSIDE: - Feedings of labeled acetate to Penicillium islandicum, a species that produces several anthraquinone derivatives, have revealed that the distribution of radioactivity in these compounds is consistent with formation via a head-to-tail condensation of acetate units. - A poly-ẞ-ketomethylene acid is probably first produced and then gives rise to the various oxygenated aromatic compounds following intra-molecular condensation. Anthranols and anthrones. - Presumably the emodin-like anthraquinones in are formed in higher plants by a similar pathway. - The transglycosylation reaction, which creates a glycoside, probably occurs at a late stage in the pathway after the anthraquinone nucleus has been formed. ## DRUGS CONTAINING ANTHRAQUINONE GLYCOSIDE: - **Cascara sagrada** > - SN: Rhmanus purshianus (Rhamnaceae) > - AC: O-glycoside (emodin) > - C-glycosides - barbaloin and deoxybarbaloin (chrysaloin) - **Frangula** > - four additional cascarosides A & B (barbaloin) and cascarisides C & D (chrysaloin) > - SN: Rhamnus frangula > - AC: Frangulins - **Aloe** > - SN: Aloe barbadensis > - AC: Aloin - **Rhubarb** > SN: Rheum officinale > AC: rhein anthrones - **Senna** > - SN: Cassia acutifolia > - AC: Sennosides A & B - rhein dianthrone (Sennidin A + B) #### USE: Stimulant cathartic - exert action by increasing the tone of the smooth muscle in the wall of the colon and stimulate the secretion of water and electrolyte into the large intestine ## C. SAPONIN GLYCOSIDE #### PROPERTIES: - Forms colloidal solutions in water that foams upon shaking - Have bitter or acrid taste - Irritating to mucous membrane (sternutatory) - Destroy red blood cell by hemolysis - saponin causes hemolysis of RBC and therefore toxic - especially for cold blooded animals (used as fish poison) - Upon hydrolysis they yield an aglycone known as "sapogenin" > SAPONIN = SUGAR + SAPOGENIN > (glycone) (aglycone) - "SAPOTOXIN” – poisonous saponin - The so-called **NEUTRAL saponins** are derivatives of **STEROIDS** with spiroketal side chains. - The **ACID saponins** possess triterpenoid structures | **GLYCONE** | **SAPONIN** | **AGLYCONE** | |-------------------|-------------------|-------------------| | **SUGAR** | | **SAPOGENIN** | | 1. Glucose | | Neutral | | 2. Arabinose | | Acid | | 3. Xylose | | Steroids | | 4. Glucoronic acid | | Triterpenoids | ## BIOSYNTHESIS OF SAPONIN GLYCOSIDE: - The main pathway leading to both types of sapogenins is similar and involves the head-to- tail coupling of acetate and mevalonate units. - However a branch occurs, probably after the formation of the triterpenoid hydrocarbon, squalene, that leads to **steroids** (diosgenin) in one direction and to the **cyclic triterpenoids** (β-Amyrin) in the other. ## SIGNIFICANCE: - Under research as possible sources of cortisone (most specially for colloidal saponins) - Cortisones - glucocorticoid which regulates carbohydrate and protein metabolism - **TWO TYPES OF SAPOGENIN:** - **STEROIDAL** - found in monocot families - **TRITERPENOIDS** - found in dicot families ## TEST FOR SAPONIN: - **FROTH TEST** > (+) FORMATION OF BUBBLES - **HEMOLYTIC TEST** > (+) HALO ZONE ## DRUGS CONTAINING SAPONIN: - **GLYCYRRHIZA (licorice root)** > - SN: Glycyrrhiza glabra > - AC: Glycyrrhizin - (50x as sweet as sugar) but once converted to its aglycone glycyrrhetic acid it losses its sweetness - bitter after taste #### USES: - Demulcent - Expectorant - increase fluid retention, - promotes K+ depletion - treatment of peptic ulcer and Addison's disease - Glycyrrhetic acid - used in dermatologic practice as anti-inflammatory - **DIOSCOREA** > - SN: Dioscorea spiculiflora > - AC: botogenin and diosgenin - **Yam (Mexican Yam)** – is a popular name for several of the edible species of Dioscorea > - SN: Dioscorea floribunda - **GINSENG ** > - SN: Panax quinquefolius, P. ginseng > - AC: ginsenosides, panaxosides, chikusetsusaponins #### USES: - tonic, stimulant, diuretic and carminative, adaptogenic (anti stress) - (in the Orient): anemia, diabetes, insomnia, neurasthenia, gastritis and sexual impotence ## D. CYANOPHORE GLYCOSIDES - yields **HYDROCYANIC ACID** after hydrolysis - commonly found in Rosaceous plants - they are designated by **cyanogenic glycosides** and are accompanied in the plant enzymes (β-glucosides) - some common cyanogenic glycosides are derivatives of **mandelonitrile** (benzaldehyde-cyanohydrin) ## 2 MOST IMPOTANT CYANOPHORE GLYCOSIDES: - **AMYGDALIN (amygdalase)** > - found in large quantities in bitter almonds, in kernels of apricots, cherries, peaches, plums, and Rosaceae - **PRUNASIN (prunase)** > - occurs in Prunus serotina - Both amygdalin and prunasin yield D-mandelonitrile as the aglycone. - **Sambucus nigra (sambunigrin)-** liberates L-mandelonitrile as its aglycone ## REACTIONS IN THE HYDROLYSIS OF AMYGDALIN - The molecule is hydrolyzed initially to liberate 1 molecule of glucose and 1 molecule of mandelonitrile glucoside. - The second molecule of glucose is liberated with the formation of mandelonitrile - The mandelonitrile then breaks down with the formation of benzaldehyde and hydrocyanic acid Amygdalin $ +$ H2O $\to$ Prunasin $ +$ C6H12O6 (D-mandelonitrile glucoside) Prunasin $\to$ Benzaldehyde $ + $ HCN C6H12O6 $ + $ D-mandelonitrile ## TEST FOR CYANOGENIC GLYCOSIDE: - Guignard Test (Guignard's rgt.) - (+) Yellow to maroon ## USES: - Employed as flavoring agent - For amygdalin-containing preparation known as the laetrile or Vitamin B17 claims to have an anticancer property and controls sickle cell anemia ## Drugs Containing Cyanophore Glycosides: - **Wild Cherry** (prunus virginiana, wild black cherry tree) > - SN: Prunus serotina > - Prunus - classic name of plum tree > - serotina - means late or backward > - AC: prunasin and p-coumaric acid #### Uses: - flavored vehicle especially in cough remedies - sedative expectorant - **Appricot pits** > - SN: Prunus armeniaca ## E. ISOTHIOCYANATE GLYCOSIDES #### PROPERTIES AND USES: - Also termed as glucosinolates and represent a group of bound toxins, like cyanogenic glycosides - "Glucosinolates" have a distribution limited to a few plant families and are characteristic constituents of the mustard family (Brasicaceae) which includes oilseeds (rapeseed), condiments (mustard and horseradish), and vegetables (broccoli, cabbage and turnips) - Found to have an anticancer property [indole 3-carbinol (from mustard family vegetables) derived from indolylmethyl glucosinolate reduce the risk of estradiol linked mammary cancer] [ 4-methyl sulfinyl isothiocyanate (broccoli) induce anticarcinogenic protective enzyme] - **DRUGS CONTAINING ISOTHIOCYANATE GLYCOSIDES:** 1. **BLACK MUSTARD** (sinapis nigra or brown mustard) - SN: Brassica nigra (Brassicaceae) - AC: Sinigrin (potassium myronate) #### HYDROLYSIS REACTION OF SINIGRIN Sinigrin + myrosin → Allyl isothiocyanate + glucose + H2SO4 (mustard oil) #### USES: - local irritant, emetic, rubefacient, vesicant and condiment 2. **WHITE MUSTARD** (sinapis alba) - SN: Brassica alba (Brassicaceae) - AC: Sinalbin #### HYDROLYSIS OF SINALBIN: Sinalbin + myrosin → Acrinyl isothiocyanate (parahydroxybenzyl isothiocyanate) - acrinyl isothiocyanate - a pungent - tasting but almost odorless oil that is much less volatile than allyl isothiocyanate. - it also contains 20-25% of fixed oil ## F. FLAVONOL GLYCOSIDES - The flavonol glycosides and their aglycones are generally termed flavonoids - Rutin, quercitrin and the citrus bioflavonoids (including hesperidin, hesperetin, diosmin, and naringen) are among the best-known flavonoid constituents. - Rutin and hesperidin have been called vitamin P or permeability factor. They have been used in the treatment of various conditions characterized by capillary bleeding and increased in capillary fragility - Citrus bioflavonoids - used for the treatment of common cold ## G. ALCOHOL GLYCOSIDES #### HYDROLYZED BY THE FOLLOWING: - mineral acids - emulsin - enzymes - Salicin, populin (benzoyl salicin) and coniferin represent the most typical examples of this group ## DRUG CONTAINING ALCOHOL GLYCOSIDE: - **SALICIN** > - SN: Salix purpurea and S. fragilis (Salicaceae) > - Obtained from Salix and Populus > - It is recognized into D-glucose and and saligenin (salicyl alcohol) by emulsin C13H22O8 $\to$ C6H4OHCH2OH $ + $ C6H12O6 ## H. ALDEHYDE GLYCOSIDES - The aglycones of these drugs are aldehyde. - Amydalin which yields benzaldehyde on hydrolysis may also classified in this group ## DRUG CONTAINING ALDEHYDE GLYCOSIDE: - **VANILLA** (vanilla bean) > - SN: Vanilla planifolia (Orchidaceae) > - AC: Vanillin > - is methylprotocatechuic acid (4-hydroxy-3-methoxybenzaldehyde) aglycone of vanilla which is developed during the curing of vanilla beans #### USES: - flavoring agent and as a pharmaceutic aid ## COMMERCIAL VARIETIES OF VANILLIN: - Mexican or Vera Cruz vanilla - Bourbon vanilla - Tahiti vanilla - Vanilla splits ## SOURCES OF VANILLIN: - Coniferin - present in cadmium sap of pine tree - Eugenol - a phenol present in clove oil - Lignin - a by product of pulp industry ## 1. LACTONE GLYCOSIDES - **DRUGS CONTAINING LACTONE GLYCOSIDES:** - **COUMARIN** - SN: Anthoxanthum odoratum (Poaceae) - AC: Dicumarol (Bishydroxycoumarin) - drug related coumarin which is used as an anticoagulant - **CANTHARIDES** (Spanish flies, Russian flies or blistering flies) - SN: Cantharis vesicatoria (Meloidae) - AC: Cantharidin - **USES:** Irritant, vesicant, rubefacient, aphrodisiac and topical application is effective in the removal of certain warts; preparations containing 0.7% in collodion - **Psoralens** > - are photosensitizing furocoumarin that occur in a number of plant families including Umbelliferae, where they are common cause of phototoxicity - **Methoxalen** (8-methoxypsoralen or xanthotin) - **SN: Ammi majus (Umbelliferae)** #### USES: - It facilitates repigmentation in indopathic vitiligo (leukoderma) and for symptomatic control of severe, disabling psoriasis #### CAUTION: - Therapeutic regimens require cautious patient exposure to ultraviolet radiation(sunlight); repigmentation therapy involves extended period of time. #### Risks inherent in therapy with methoxsalen, including carcinogenesis, cataract development, and actinic degeneration of the skin, restrict its use to specialists. - **SANTONIN** > - SN: Artemisia cina (Asteraceae) #### USE: - Formerly use as an anthelmintic, but discotinued in US because of potential toxicity ## J. PHENOL GLYCOSIDES - **DRUG CONTAINING PHENOL GLYCOSIDE:** - **UVA URSI (bearberry)** - SN: Arctostaphylos uva-ursi - ACs: arbutin, corilagin, pyroside, several esters of arbutin, quercitin, gallic acid, elagic acid and ursolic acid - The arbutin, found in uva ursi chimapila, and other ericaceous drugs, yields hydoquinone and glucose upon hydrolysis: - Reaction: Arbutin acid or emulsin $\to$ Hydroquinone + Glucose #### USES: - Diuretic and Astringent ## K. OTHER ORGANOSULFUR DRUGS - **GARLIC** > - SN: Allium sativum (Alliaceae) > - AC: Allicin - The intact cells of garlic contain the odorless, sulfur-containing amino acid derivative (+)- S-allyl-L-cysteine sulfoxide, commonly known as alliin. - It occurs in garlic in a concentration of up to 1.2% of the fresh weight - When the cells are crushed, it comes in contact with the enzyme alliinase which is stored in vacoules within the cell and is converted to allicin (diallyl thiosulfinate). #### USES OF ALLICIN: - Potent antibacterial - It is responsible for the characteristic odor and flavor of garlic, decomposing readily in the presence of air and water to yield diallyl disulfide, diallyl trisulfide, and the corresponding polysulfides, all of which are strong smelling compounds. - It also possesses antilipidemic activity, enhances fibrinolytic activity and inhibits platelet aggregation (E)-Ajoene and (Z)-ajoene are formed from allicin and have antithrombotic properties with the Z isomer being the more bioactive #### MODE OF ACTION: - It involves inhibition of fibrinogen receptors on blood platelets. ## CHECK FOR UNDERSTANDING: Answer the following questions accordingly. Write the letter of the correct answer on the space provided. 1. Used to disguise the bitterness of quinine by paralyzing the taste buds a. Yerba Buena b. Yerba santa c. Glycyrrhiza d. Cascara sagrada **Ans: c** 2. The active component of Spanish flies used as an aphrodisiac a. Methoxsalen b. Cantharidin c. Chrysaloin d. Barbaloin **Ans: b** 3. This is the most powerful glycoside extracted from digitalis a. Digitanin b. Digitonin c. Digitoxin d. Lanatoside C **Ans: c** 4. Photosensitizing furocoumarins that occur in a number of plant families where they are a common cause of phototoxicity a. Psoralens b. Coumarins c. Dioscorea d. None of the choices **Ans: a** 5. This sugar occurs most frequently in glycosides a. Rhamnose b. Cymarose c. a-D-glucose d. B-D-glucose **Ans: d** 6. This glycoside has anti-rheumatic properties since it is probably oxidized to salicylic acid and in the human system a. Sinalbin b. Sinigrin c. Salicin d. Vanillin **Ans: c** 7. Which of the following is not an aglycone of certain glycosides? a. Cantharidin b. Glucovanillin c. Coumarin d. Santonin **Ans: d** 8. What type of saponin glycosides are derivatives of steroids with spiroketal side chains? a. Acid saponins b. Alkaline saponins c. Neutral saponins d. None of the choices **Ans: c** 9. What is the pungent-tasting oil that is produced by the hydrolysis of Sanapis alba? a. Sinalbin b. Mustard oil c. Acrinyl isothiocyanate d. Allyl isothiocyanate **Ans: d** 10. Which glycosidic drug is cultivated on lands resembling rice paddies? a. Rheum b. Senna c. Chrysazin d. Frangula **Ans: d** ## C. LESSON WRAP-UP Teacher directs the student to mark (encircle) their place in the work tracker which is simply a visual to help students track how much work they have accomplished and how much work there is left to do. This tracker will be part of the student activity sheet. You are done with the session! Let's track your progress. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | |---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---| | **Period 1** | **Period 2** | **Period 3** | ### Thinking about Learning: Whip Around Students quickly and verbally share one thing they learned in the class today. The instructor can ask 3 - 5 volunteers