Lipids chemistry 2024-25-Dentistry

Page 4: Definition of Lipids

• Characteristics of Lipids:

  • Insoluble in water (hydrophobic)

  • Soluble in fat solvents (non-polar solvents) such as benzene, chloroform, acetone, and ether

  • Esters of fatty acids or associated substances in nature

Page 5: Simple Lipids

1. Neutral Fats (Triacylglycerols - Triglycerides):

   • Contain glycerol alcohol (colorless, odorless, sweet taste)

   • Storage form of energy in adipose tissue

   • Classified into:

     • Oils: Liquid at room temperature (high unsaturated fatty acids)

     • Solid Fats: Solid at room temperature (high saturated fatty acids)

2. Waxes:

   • Esters of fatty acids with higher molecular weight monohydric alcohols

   • Complex mixtures of non-polar lipids, insoluble in water

   • Include cholesterol, vitamins A and D, and Myristyl alcohol

Page 6: Glycerol and Fatty Acids

• Glycerol:

  • Trihydric alcohol, can form Mono-, Di-, or Triacylglycerol

  • Used in toothpaste to prevent drying

• Fatty Acids:

  • Hydrocarbon chain with terminal carboxylic group

  • Commonly long-chain, straight-chain with even carbon numbers

Page 7: Nomenclature of Fatty Acids

• Carbon numbering starts from the carboxyl carbon

• Terminal methyl group known as ω carbon

• Double bond positions indicated by ω and ∆ notation

Page 8: Chain Length of Fatty Acids

• Saturated Fatty Acids (SFA):

  • No double bonds, classified by chain length:

    • Short (C2-C6)

    • Medium (C8-C14)

    • Long (C16-C22)

    • Very Long (≥ C24)

Page 9: Unsaturated Fatty Acids (USFA)

• Contain one or more double bonds

• Cis-type double bonds: Liquid at room temperature

• Trans-type double bonds: Solid at room temperature, toxic, and carcinogenic

• Health impacts include increased LDL, decreased HDL, and systemic inflammation

Page 10: Types of Unsaturated Fatty Acids

1. Monounsaturated (Monoenoic) Acids:

   • Examples: Palmitoleic acid, Oleic acid, Nervonic acid

2. Polyunsaturated (Polyenoic) Acids:

   • ω3 PUFA: α-Linolenic acid, Timnodonic acid

   • ω6 PUFA: Linoleic acid, Arachidonic acid

Page 11: Essential vs. Non-Essential Fatty Acids

• Essential Fatty Acids: Not synthesized in the body; must be obtained from diet (e.g., α-linolenic, linoleic acids)

• Non-Essential Fatty Acids: Synthesized in the body; not essential to consume

Deficiency Effects

• Fatty liver, sterility in adults

• Impaired growth, dermatitis in infants

Dietary Sources

• Fish, nuts, seeds, plant oils, cod liver oil

Page 12: Compound Lipids

1. Phospholipids:

   • Composed of alcohol, fatty acids, phosphoric acid

   • Types: Glycerophospholipids, Sphingophospholipids

Page 14: Importance of Phospholipids

• Amphipathic nature (hydrophobic and hydrophilic)

• Functions:

  • Micelle formation for lipid solubilization

  • Liposomes for drug delivery

  • Biomembranes for cellular structure

  • Rich in liver, brain, and blood cells

  • Role in fat mobilization, nerve myelination, blood clotting, and signal transduction

Page 16: Glycolipids and Lipoproteins

• Glycolipids: Responsible for cell antigenicity and interaction

• Lipoproteins: Transport lipids in blood, classified by density (e.g., HDL, LDL)

Page 17: Derived Lipids

• Produced by hydrolysis of simple or conjugated lipids

• Include fatty acids, alcohols, steroids, carotenoids, fat-soluble vitamins, and eicosanoids

Page 18: Importance of Cholesterol

• Structural role in membranes, precursor for vitamin D3, bile acids, and steroid hormones

• Esterification prevents deposition in blood vessels

Oral Health and Atherosclerosis

• Bacterial inflammation linked to atherosclerosis

• Periodontal health influenced by dietary fat intake

Page 19: Dietary Fats and Dental Health

• Essential for oral health, incorporated into tooth structure

• Benefits include:

  • Reducing caries

  • Lubricating tooth surfaces

  • Enhancing fluoride absorption

  • Delaying gastric emptying

This note summarizes the key concepts and details regarding lipids, their classification, structure, and biological importance, particularly in relation to