PHCH 2202: Pharmacognosy and Plant Chemistry - Endocrine Products

Hormones

• Also known as chemical messengers
• Substances secreted by endocrine or ductless glands of animals
• History: In 1891, Horsley showed that patients with myxoedema and cretinism benefited from the administration of animal thyroid glands

Hormone Therapy vs Organotherapy

• Hormone therapy: using the active principles
• Organotherapy: using the glands or more or less crude preparations of them

Classes of Hormones

Steroid Hormones

• Insoluble in water and transported by transport proteins in blood, resulting in longer circulation than peptide hormones
• Steroid nucleus: any compound having a cyclopentano-perhydrophenanthrene (CPPP) nucleus
• Alpha and beta configuration

Biosynthesis of Steroids

• Formed from isopentenyl pyrophosphate
• Cholesterol is not necessarily the precursor, but its formation is a general mechanism of steroid biosynthesis

Forms of Steroids

• Sterols
• Bile acids
• Cardiac glycosides
• Steroid hormones

Sterols

• Solids and high molecular weight (HMW) with 27-29 carbon atoms
• First isolated from human gallstones
• Other sources: algae, fungi, actinomyces

Examples of Sterols

• Ergosterol: 28 carbon structure, principal fungi sterol, also known as provitamin D2 (exposure to UV produces Vitamin D)
• Beta-Sitosterol: 29 carbon structure, most common plant sterol, from plant-derived oils (corn, cottonseed, etc.), used to treat atherosclerosis and has anti-hypercholesterolemic effects

Bile Acids

• Cholesterol → C24 steroids (where C24 is a carboxyl) → collected in bile and referred to as bile acids
• Conjugated bile acids: released into the duodenum to emulsify meals for fat absorption

Examples of Bile Acids

• Deoxycholic acid (from cholic acid)
• Lithocholic acid (from chenodesoxycholic acid)
• Primary bile acids (liver): cholic acid and chenodesoxycholic acid
• Ox bile extract: partial evaporation of fresh ox bile, precipitation of the mucus and albuminous matter with alcohol, and consequent evaporation (evaporate to dryness at < 80°C), contains Na salts of glycholic acid and taurocholic acid equivalent to not less than 45% cholic acid, used as a laxative

Chenodesoxycholic Acid

• Also known as Chenodiol
• Suppresses hepatic synthesis of cholesterol and cholic acid, leading to biliary cholesterol desaturation and dissolution of cholesterol gallstones
• Types of cholesterol gallstones: radiolucent and radiopaque (calcified)

Cardiac Glycosides

• Review notes on cardiac glycosides as previously discussed

Steroid Hormones

Sex Hormones

• Produced primarily in the gonads
• Mediate the growth, development, maintenance, and function of the reproductive tract and accessory sex organs
• 3 categories:
  • Estrogen and progesterone: female reproductive tract
  • Androgen: male reproductive organs

Adrenocorticoid Hormones

• Produced by the outer cortical portion of the adrenal glands
• 2 classes:
  • Mineralocorticoids: affect the excretion of fluid and electrolytes with subsequent sodium and potassium retention
  • Glucocorticoids: affect intermediary metabolism
• Examples:
  • Aldosterone (principal) and desoxycorticosterone (mineralocorticoids)
  • Cortisone and hydrocortisone (protein and carb metabolism)