Polyunsaturated fatty acids (PUFA) are those fatty acids which have more than 2 double bonds on their structure. These cannot be synthesized inside the body and requirement must be fulfilled through diet. Nuts, seeds, plant oil, sea food are rich in PUFA.
Methyl end → CH₃CH₂CH=CHCH₂CH=CHCH₂CH=CH(CH₂)₇COOH ← Carboxy end
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Numbering system of PUFA
There are two numbering system for double bonds.
- Delta system (Δ): double bond is numbered 1st.
- Omega system (ω): methyl end is given number 1.
There are two types of PUFA according to the location of their first double bond in the carbon chain.
Omega 3 (ω-3):
First double bond is present at 3rd position. They have cardio protective and antihyperlipidemic effects. Examples: Cervonic acid (Decosa hexaenoic acid, present in breast milk and required for development of nervous system), Alpha linolenic acid, timnodonic acid.
Omega 6 (ω-6):
First double bond is present at 6th position. They metabolized into arachidonic acid which is important precursor to leukotrienes and prostaglandins. Examples: γ-Linolenic acid, Linoleic acid, arachidonic acid.
References
- Harper’s Illustrated Biochemistry Thirty Second Edition.
- Lippincott’s Illustrated Reviews – Biochemistry.
