ACT 6: SECONDARY METABOLITES (ALKALOIDS - GLYCOSIDES) Flashcards
- natural products synthesized mainly by bacteria, fungi and plants
- molecules of low molecular weight with diverse chemical structures and biological activities
“___________”: initial observation that their production is not necessary for the growth and reproduction of organisms, in contrast to primary metabolites
“___________”: play key roles in the survival of the organisms that produce them because they mediate interactions within their environment
SECONDARY METABOLITES
- “secondary”
- “specialized metabolites”
________: growth and development of plant
________: regulation
________: environmental interactions
- PRIMARY METABOLITES
- HORMONES
- SECONDARY METABOLITES (all)
- Usually derived from amino acids
- alkali-like (basic in nature)
- Distributed in different plant parts or may be present in the whole plant
Naming: end with the suffix -ine, and begin with a prefix which is usually based on the plant’s genus, species, common name,
discoverer, or physiologic activity
Distribution:
____________:
- Papaveraceae, Fabaceae, Apocynaceae, Solanaceae, Rubiaceae
ANGIOSPERMS
“ALKALOID”
CHEMICAL COMPOSITION
☐ C, H, N, O, sometimes S
☐ the N atom may be:
+ PRIMARY: ______, a hallucinogen
- ______: Lophophora williamsii
+ SECONDARY: _______, a CNS stimulant
- ______: Ephedra sinica
+ TERTIARY: ______, anticholinergic
- ______: Atropa belladonna
+ QUATERNARY: ______, a muscle relaxant
- ______: Chondrodendron tomentosum
+ primary: mescaline, a hallucinogen
- peyote: Lophophora williamsii
+ secondary: ephedrine, a CNS stimulant
- ma huang: Ephedra sinica
+ tertiary: atropine, anticholinergic
- deadly nightshade: Atropa
belladonna
+ quaternary: tubocurarine, a muscle relaxant
- curare: Chondrodendron tomentosum
“ALKALOIDS”
PHYSICAL CHARACTERISTICS
- Generally colorless, but some have color: berberine, betaine
- Bitter in taste
- Salt form and most quaternary alkaloids are water soluble
- SOLIDS
- _______ an antimalarial (Cinchona: Cinchona succirubra)
- _______ an emetic (Ipecac: Carapichea ipecacuanha)
- atropine - LIQUIDS
- _______ a neurotoxin (Poison hemlock: Conium maculatum),
- _______ a stimulant (Tobacco: Nicotiana tabacum)
- Free bases of alkaloids are soluble in organic solvents except caffeine a stimulant
- Coffee: Coffea canephora
- _______ an anti-gout (Autumn crocus, Colchicum autumnale)
- SOLIDS
- quinine an antimalarial (Cinchona: Cinchona succirubra)
- emetine an emetic (Ipecac: Carapichea ipecacuanha)
- atropine - LIQUIDS
- coniine a neurotoxin (Poison hemlock: Conium maculatum),
- nicotine a stimulant (Tobacco: Nicotiana tabacum)
- Free bases of alkaloids are soluble in organic solvents except caffeine a stimulant
- Coffee: Coffea canephora
- colchicine an anti-gout (Autumn crocus, Colchicum autumnale)
“ALKALOIDS”
NOTABLE ALKALOIDS
■ _______: analgesic (Opium poppy: Papaver somniferum)
■ _______: local anesthetic (Coca: Erythroxylum coca)
■ _______: migraine treatment (Ergot: Claviceps purpurea fungus)
■ _______: antispasmodic (Jimson weed: Datura stramonium)
■ _______: miotic in the treatment of glaucoma (Jaborandi: Pilocarpus microphyllus)
■ _______: anti-hypertensive (Indian snakeroot: Rauwolfia serpentina)
■ _______: anti-cancer (Yew: Taxus brevifolia)
■ _______: anti-asthma (tea, cacao, coffee)
■ _______and _______: anti-cancer (Periwinkle: Catharanthus roseus)
■ Morphine: analgesic (Opium poppy: Papaver somniferum)
■ Cocaine: local anesthetic (Coca: Erythroxylum coca)
■ Ergotamine: migraine treatment (Ergot: Claviceps purpurea fungus)
■ Hyoscine: antispasmodic (Jimson weed: Datura stramonium)
■ Pilocarpine: miotic in the treatment of glaucoma (Jaborandi: Pilocarpus microphyllus)
■ Reserpine: anti-hypertensive (Indian snakeroot: Rauwolfia serpentina)
■ Paclitaxel: anti-cancer (Yew: Taxus brevifolia)
■ Theophylline: anti-asthma (tea, cacao, coffee)
■ Vinblastine and Vincristine: anti-cancer (Periwinkle: Catharanthus roseus)
- Condensation of the hydroxyl group of aglycone and hemiacetal hydroxyl group of sugar
- aglycone or genin (nonsugar) + glycone (sugar) joined by a glycosidic linkage
Mostly colorless, crystalline or amorphous, poisonous, soluble in polar solvents, optically active
CLASSIFICATION:
- Based on the glycosidic linkage: O, N, S, C
- Based on the ___________: anthraquinones, saponins…
- Based on the ___________: glucoside, fructoside, glucuronide
- Based on ___________: cardiac, purgative…
- Based on the ___________: digitalis glycosides, senna glycosides
CLASSIFICATION:
- glycosidic linkage
- nature of the aglycone
- glycone component
- pharmacologic activity
- botanical source
“GLYCOSIDES”
- Derivatives of anthraquinone
- Used as dye: often orange-red
- Laxative, antifungal and antiviral activities (purgative)
- soluble in hot water and alcohols
- Sennosides from Senna (Senna alexandrina)
- Aloin from Aloe (Aloe barbadensis)
- Cascarosides from Cascara (Rhamnus purshiana)
- anthraquinone glycosides
- Steroidal aglycone with a 5-membered lactone ring
- Act on the cardiac muscles
- Cardiotonic activity is due to the aglycone, but the sugar component renders the compounds more soluble
- Sub-groups
__________: Digoxin (Foxglove: Digitalis purpurea)
__________: Scillarenin A (Squill: Drimia maritima)
- Cardiac glycosides/Cardiotonic glycosides
- Cardenolides (5-membered lactone ring)
- Bufadienolides (6-membered lactone ring)
- Steroidal aglycone (sapogenin)
- Toxic to cold-blooded animals and lower organisms
- Cause hemolysis of blood
- Possess surface-active or detergent properties – form honey comb foam if shaken ☐
- Soluble in polar solvents
- production of steroid hormones, food additives, anti-inflammatory, hypocholesterolemic, immune-stimulating
2 types (depending on the aglycone moiety)
________: contain the CPPP ring (Diosgenin)
________: Triterpenoid - polymers of isoprenes and mainly derivatives of B-amyrines (Glycyrrhetinic acid)
- Saponin glycosides
- steroidal (tetracyclic triterpenods)
- pentacyclic triterpene
__________
(Glycyrrhiza glabra)
Glycyrrhizin
__________
(Panax ginseng)
Ginseng saponins/ ginsenosides
__________
(Smilax officinalis) Sarsaparillosides
__________
(Entada phaseoloides)
Entada saponins
- Licorice
- Ginseng
- Sarsaparilla
- Gogo/Gugo
saponin glycosides
- Upon hydrolysis, yields hydrocyanic acid, benzaldehyde, and sugars
- Rosaceae, Fabaceae, Asteraceae
- Stone fruits, pome fruits, cassava, bamboo shoots, cashews
- Toxicity depends on the release of hydrogen cyanide – cyanide poisoning
- peeling, drying, grinding, soaking, boiling or cooking, fermentation have been reported to reduce cyanogenic glycosides in food
______: volatile, cyanogenic glycosides are water soluble
_________
(Manihot esculenta)
Linamarin
_________
(Prunus armeniaca, Prunus cerasus, Prunus dulcis)
_________
may have anti-cancer properties (?)
- Cyanophoric/ Cyanogenic glycosides
Cyanide
- Cassava
- Apricots, cherries, almonds
- Amygdalin
- Sulfur and nitrogen-containing compounds
□ Derived from the hydrolysis of glucosinolates – yields isothiocyanate (-NCS)
- Pungent property
- Irritant
- May have cancer preventive properties (?)
□ Abundant in family Brassicaceae
- Mustard (Brassica alba, Brassica nigra): sinalbin, sinigrin
- Broccoli (Brassica oleracea var. italica)
- Horseradish (Armoracia rusticana)
- Isothiocyanate glycosides
- Organic compounds containing lactone ring
- stomachic, ferbifuge, and bitter tonic
Soluble in water and very bitter
______, digestive agents - stimulate GIT secretions
______: Gentian/ Bitter root (Gentiana lutea)
______: Quassia/ Bitter wood (Quassia amara)
- Bitter glycosides
- Tonic
- Gentiopicrin
- Quassin
☐ Aromatic compounds containing the benzo - a - pyrone ring
- Ability to absorb UV radiation
- Used in skin disorders such as vitiligo, phototherapy, and suntan preparations
_______: Horse chestnut (Aesculus hippocastanum)
_______: Psoralea (Psoralea corylifolia)
- Coumarin glycosides
- Esculin
- Psoralen
