Untitled Quiz

Medicinal Plants - PHG111 - Pharmacognosy I - PG 101

• This course covers Medicinal Plants, Pharmacognosy I, and is part of the Postgraduate program (PG 101) at a university.
• The course is taught by Professor Dr. Mahitab Helmi and Dr. Ibrahim Ezzeldin.

Lecture 5: Chemistry of Crude Drugs

• This lecture focuses on the chemistry of crude drugs.
• The learning objectives for this lecture include classifying secondary metabolites, understanding their chemical nature, and recognizing their tests and uses.
• Interactive learning activities are provided including a youtube link for a quizizz session.

Alkaloids

• Alkaloids are basic organic compounds.
• These compounds are nitrogen-containing.
• Alkaloids exhibit significant physiological activity.
• Detection methods include using Mayer's reagent (potassium mercuric iodide) for white precipitate formation and Wagner's reagent (iodine/potassium iodide) for orange coloration.
• Examples of alkaloids include atropine, caffeine, morphine, Belladonna, tea, opium.

Glycosides

• Glycosides are non-reducing substances.
• Often have a bitter taste and are soluble in water and alcohol.
• Glycosides undergo hydrolysis to yield an aglycone and a glycone (sugar).
• Hydrolysis can occur through acids or enzymes.
• Glycosides are divided into subgroups including A-Phenolic, B-Cardiac, C-Saponin, D-Cyanogenic, and E-Thiolglycosides.
• Example subgroups include flavonoid glycosides (e.g., Boldo, Citrus), anthocyanins (e.g., Karkadeh).

Anthracene Glycosides

• Anthracene glycosides, also known as anthraquinones, are laxative principles found in plants such as Senna and rhubarb.
• Their chemical structure is highlighted, including the anthraquinone moiety.

b-Cardiac Glycosides

• These compounds are heart tonics (cardiotonics) and treat cardiac arrhythmia.
• They increase renal circulation.
• Examples include Digitalis leaves, Squill bulb, and Strophanthus seeds.
• These have a steroidal nucleus, a lactone ring, and sometimes a 6-membered ring.
• Subgroups include Cardenolides, and Bufadenolides.
• Cardenolides have a 5-membered ring while Bufadenolides have a 6-membered ring.
• Example: Digitoxinigenin.
• Specific chemical tests (Baljet's, Kedde's, Liberman-Burchard, Keller-Killiani) are used to identify these compounds based on their structure

c- Saponin Glycosides

• Steroids, or triterpenoids, can form persistent froth in water.
• These compounds exhibit hemolytic properties affecting red blood cells (RBCs).
• They also have biological activities such as expectorant (e.g., licorice) and tonic (e.g., ginseng).

d- Cyanogenic Glycosides

• Upon hydrolysis, these compounds release hydrogen cyanide (HCN).
• Examples include Amygdaline (bitter almonds) and Linamarin (linseed).

e- Thiolglycosides (Glucosinolates)

• These compounds, when hydrolyzed react with Myrosinase enzyme and water to produce Isothiocyanates and Thiocyanates.
• Other hydrolysis products include nitriles and glucose.
• They exhibit chemoprotective, goitre inducing, and antimicrobial actions.
• Example: Sinigrin (black mustard) and Sinalbin (white mustard).

6- Antibiotics

• Antibiotics are compounds produced by molds and fungi.
• They have bacteriostatic activity.
• Penicillin is an example of an antibiotic.

7- Aflatoxins

• Aflatoxins are mycotoxins produced by moldy grains.
• They are potent carcinogens and teratogens.

8- Vitamins

• Vitamins are organic compounds necessary for normal growth and maintenance in animals, including humans.
• They are isolated from plants or animals and used as concentrated drugs. An example is ascorbic acid.

9- Hormones

• Hormones are active substances secreted by endocrine glands.
• They regulate growth, development, and metabolism.
• Insulin is an example of a hormone.

10- Enzymes

• Enzymes are organic biocatalysts produced by living cells.
• They facilitate most chemical reactions in living organisms.
• Amylase is an example of an enzyme.

Comparisons (Lecture 21)

• There are comparisons to be made between different types of plants and their associated components. This includes volatile and fixed oils (4 points), cardiac glycosides and alkaloids (chemical composition, occurrence, tests), and thiolglycosides (glucosinolates) and cyanogenic glycosides (cyanophore glycosides), focusing on their hydrolysis products and examples.