pcog

• Pharmacognosy is an applied science that focuses on the biological, biochemical, and economic features of drugs of biological origin and their constituents
• Medicinal products in pharmacognosy are in their crude or unprepared form
• History of Pharmacognosy:

  • Babylonians: Laws of Hammurabi, medicinal effects of 250 plants, mages and physician, wheat and barley
  • Ayurveta: Traditional medicine, "Science of life", Charaka's text on internal medicine, Sushruta's 184 chapters on 1120 illnesses
  • Egyptians: Embalming, George Ebers, human anatomy, use of plants
  • Greeks: Dioscorides wrote "De Materia Medica" on 600 plants, Claudius Galen described methods of preparing formulas containing plant and animal drugs, known as the FATHER OF PHARMACEUTICAL COMPOUNDING
• • Germans: Coined the term "pharmacognosy", described study of medicinal plants and their properties, discovered Quinine and Morphine
• Crude drugs are vegetable or animal drugs that consist of natural substances that have undergone only the processes of collection and drying, including plant exudates
• Natural substances in pharmacognosy are formed in nature and can be whole plants or parts, animals or organs, with no molecular modifications made
• Derivatives of extractives are the chief principles or constituents of crude drugs that are separated and used in a specific manner
• Methods of Extraction:

  • Infusion: hot water, short contact of action
  • Maceration: soaked in solvent for a long period of time
  • Percolation: passage through percolate
  • Digestion: below 35-40°C
  • Decoction: boiling water
  • Liquid-Liquid Extraction Partitioning, Distillation
• Indigenous Plants are plants growing in their native countries, while naturalized plants are plants that grow in foreign lands other than their native homes
• Preparation of Crude Drugs:

  1. Collection: ensuring the true natural source of the drug, proper harvesting

  2. Drying: remove moisture, prevent bacterial and fungal growth, facilitate grinding and milling

  3. Curing: special drying process that enhances properties of plants' active ingredients

  4. Garbling: removal of extraneous matter
• Evaluation of Crude Drugs involves determining quality and purity through organoleptic evaluation, microscopic evaluation, pharmacologic evaluation, and chemical evaluation
• Classification of Drugs:

  • Morphology: forms, plant part used
  • Taxonomic: evolutionary development
  • Pharmacologic: based on therapeutic effect on the body
  • Chemical: based on active constituents present
• Active Constituents in drugs are considered secondary metabolites produced through drug biosynthesis or biogenesis
• Biosynthesis involves stages of development like Ontogemy, Heredity, and Environment
• Carbohydrates are polyhydric aldehyde or ketone alcohols containing C, H, and O, with the same ratio of H and O as water
• Classification of Carbohydrates:

  • Monosaccharides: simplest carbohydrate unit, cannot be hydrolyzed, includes Pentoses and Hexoses
  • Disaccharides: composed of two monosaccharide units, includes Sucrose, Maltose, and Lactose
• Products of Oxidative Metabolism:

  • Cherry Juice: ripe fruit of Prunus cerasus, contains pectin and 1% malic acid
  • Plant Acids: such as Citric Acid, used as acidulants in effervescent formulations and buffer systems
• Plant Acids:

  • Contains pectin and 1% malic acid
  • Cherry syrup
  • Uses: acidulants in effervescent formulations; component of buffer systems
• Citric Acid:

  • Discovered by Scheele in lemon juice (1784)
  • Also known as Tricarboxylic acid (TCA)
  • Deniges Test leads to tartaric acid (by product, dicarboxylic) used in wine production
• Lactic Acid:

  • Used as an acidulant in infant feeding formula and feminine wash
  • Concentrations: 0.2% chlohexidine for vaginal use, 0.6% for mouth use
• Alcohol/Ethanol:

  • 95% ethanol by volume at 15.56°C
  • Product of fermentation
  • Concentration increased to 40-55% through distillation
  • Low concentration acts as a CNS stimulant, high concentration acts as a CNS depressant
• Products of Reductive Metabolism:

  • Mannitol: from manna, dried exudate of Franxinus ornus; osmotic diuretic and laxative
  • Sorbitol: from berries of mountain ash, Sorbus aucuparia; tastes half as sweet as sugar; used in toothpaste and chewing gum production
• Polysaccharides:

  • Homoglycans yield one type of monosaccharide unit upon hydrolysis
  • Starch: temporary storage form of photosynthetic products from various sources like corn, wheat, potato, rice, arrowroot
  • Enzymes that break down starches: Alpha amylase and Beta amylase
• Gums and Mucilages:

  • Natural plant hydrocolloids classified as anionic or non-ionic polysaccharides
  • Produced by plants as protection after injury
  • Examples: Acacia (Gum Arabic), Tragacanth, Agar, Guar Gum, Locust Bean Gum
• Plant Extractives:

  • Pectin: intracellular cementing material, extract of inner portion of citrus fruits and apple pomace; antidiarrheal agent
  • Kaopectate: Kaolin + Pectin combination for antidiarrheal preparation
• Glycosides:

  • Heteroglycans known as "sugar ethers"
  • Components: glycone (inactive) and aglycone (active)
  • Cardiac Glycosides: Digoxin, Digitoxin, Convallaria, Apocynum, Adonis, Black Hellebore, Strophantus, Squill
• Anthraquinone Glycosides:

  • A glycone: Anthracene
  • Used as cathartics
  • Examples: Cascara Sagrada, Frangula, Aloe, Rhubarb, Senna, Chrysarobin
• Chrysarobin:

  • From Goa powder, Andira araroba
  • Only anthraquinone glycoside NOT used as cathartic because it is very irritating
  • Used as keratolytic
  • Hot benzene is used to extract this substance
• Saponins:

  • Foam upon shaking (froth test)
  • Bitter, acrid taste
  • Sternutatory (may irritate mucous membrane = sneezing)
  • Destroy RBCs of cold-blooded animals -> fish poisons
  • Froth, hemolysis, capillary
• Glycyrrhiza or Licorice:

  • Dried roots of Glycyrrhiza glabra
  • Increase foaminess of beer
  • Constituents: glycrrrhizia, glycyrrhziac acid
• Dioscorea or Yam:

  • Dioscorea spiculiflora contains diosgenin which is a glucocorticoid precursor
  • Dioscorea floribunda is the best source of steroids
  • Diosgenin is anti-inflammatory
• Ginseng:

  • Panax ginseng (Asia); Panax quinquefolius (American)
  • Aphrodisiac and an adaptogen
  • Constituents: panaxosides, ginsenosides, chikusetsusaponins
• Cyanophoic or Cyanogenic Glycosides:

  • Amygdalin (H2O and amygdalase) -> mandelonitrile glucose (H2O and prunase) -> mandelonitrile + glucose -> benzaldehyde + HCN
  • Rosaceae
  • Emulsin - amygdalase and prunase (collectively)
  • Guingard’s Test = brick red/red coloration
• Isothiocyanate Glycosides:

  • Rapeseed - Brassicca napus; gluconapin
  • Watercress - Nastutium officinale; gluconasturtiin
  • Odor test -> mustard smell (volatile); garlic (allicin)
  • Ferric chloride test -> blood red (non-volatile)
  • Black Mustard or Sinapis Nigra - Brassica nigra - sinigrin
  • White Mustard - Brassica alba - sinalbin
• Flavonol Glycosides:

  • Rutin and Hesperidin - vitamin P or permeability factors; treatment of capillary bleeding secondary to capillary fragility
  • Hesperitin, Diosmin, and Naringen - treatment of symptoms of common colds
  • Yellow Pigment - rutin and quercetin
  • Milk Thistle - Silybum marianum; silibinin, silymarin, hepatoprotective
  • Gingko - Ginggko biloba; gingkolides, bilolabides; memory enhancement
• Alcohol Glycosides:

  • Salicin - salix and populous
  • Salix purpurea and Salix fragilis
  • Aglycone: saligenin
  • Anti-inflammatory; anti-rheumatic
  • Tests: Fehling’s – brick red, Nessler’s – gray, Tollen’s – silver mirror, Schiff’s – recolorization
• Aldehyde Glycosides:

  • Vanilla - cured fruit of Vanilla planifolia (orchidaceae) - Mexican, Vera Cruz, Bourbon
  • Constituent: vanillin
  • Use: flavoring agents
• Phenol Glycosides:

  • Urva ursi - dried leaf of Arctostaphylos urva ursi
  • Constituents: arbutin (hydroquinone + sugar)
  • Use: astringent and diuretic
  • Poison Ivy (Rhus radicans) and Poison Oak (Rhus toxicondendron); uroshiol - delayed contact dermatitis (type IV)
• Lactone Glycosides:

  • Coumarin - from Tonka beans, Dipteryx odorata; constituents: dicoumarol bishydroxycoumarin -> anticoagulant, Warfarin; Test for unsaturated lactone: Kedde’s = blue-violet
  • Cantharides - from dried insect, Cantharis vesicatoria; Russian/Spanish fly; Blistering fly
  • Constituents: cantharidin-irritant, vesicant and rubefacient
  • Causes priaprism - sustained erection
  • Psoralens - photosensitizing furocoumarins; from Bishop’s flower, Ammi majus
  • Methoxsalen - repigmentation in vitiligo
  • Trioxsalen
• Tannins:

  • Complex substances or polypeptides that are difficult to separate because they do not crystallize
  • Phenolic in nature; non-crystallizable polyphenols; protein precipitant (astringent); found in barks and leaves
  • Local sources: Guava - Psidium guajava, Kamachile - Pithecolobium dulce, Duhat - Syzigium cumini
  • Characteristics: acidic, sharp puckering taste, causes precipitation of alkaloids
  • Industrial - leather and ink
  • Clinical - astringents - GI or skin, treatment of burns