Derived lipids These are derivatives obtained on hydrolysis

Derived lipids These are derivatives obtained on hydrolysis of simple and complex lipids n Fatty acids, glycerol, mono and di acyl glycerol , cholesterol, ketonebodies etc n

Fatty acids are key structural components of: triglycerides phospholipids as well as they are sometime attached to cholesterol. Fatty acid

Fatty acids n Fatty Acids are Carboxylic Acid with Hydrocarbon Chains n They are rarely free in nature, but rather occur as the major component of the varies lipids.

Structure of Fatty Acids Fatty acid consists of: Ø long hydrocarbon chain. ØCarboxylic acid group ( ) Ø Methyl group( )

Numbering the carbons in a fatty acid: 1 st carbon 17 15 11 13 18 9 7 7 4 1 3 Omega carbon 6 5 10 8 7 9 2 4 4 10 2 3 5 12 14 16 18 Alpha carbon

Functions of fatty acids 1. Required for membrane structure 2. 3. 4. 5. &function Transport cholesterol Formation of lipoproteins Prevention of fatty liver Synthesis of eicosanoids

Classificaton of fatty acids G Depending on number of carbon atoms: • Odd chain: are of odd carbon Propionic(3), Valeric(5) • Even chain: are of even carbon • Butyric(4), Palmitic(16)

A Length of hydrocarbon chain: • Short(2 -6): Butyric(4) , acetic(2) • Med(8 -14): myristic(14), caprylic(8) • Long(16 -24): Palmitic (16), Stearic(18)

• Nature of hydrocarbon chain: • Saturated: not containing double bonds palmitic, stearic • Unsaturated: contains one or more doublebonds • Mono unsaturated: unsaturated having one doublebond (MUFA) Palmitoleic(Δ 9), Oleic(Δ 9), • Polyunsaturated: having two or more doublebond(PUFA) linoleic, linolenic, arachidonic

Describing the unsaturated fatty acids: • • An example: 18: 1 c 9 oleic acid 18: 3 c 9, 12, 15 linolenic acid The number before the colon gives the total number of carbons and the number after the colon gives the count of double bonds

• The configuration is indicated by c (cis) or t (trans) • The position by double bonds are followed by and one or more numbers. These numbers denote the carbon atom (counting from the carboxyl) where each double bond starts.

Unsaturated Fatty Acids 3 - Octenoic Acid 3, 6 - Octadienoic Acid Short hand: 8: 1 ( 3) 8: 2 ( 3, 6)

Some saturated fatty acids • Butyric: CH 3(CH 2)2 COOH • Lauric (dodecanoic acid): CH 3(CH 2)10 COOH • Myristic (tetradecanoic acid): CH 3(CH 2)12 COOH • Palmitic (hexadecanoic acid): CH 3(CH 2)14 COOH • Stearic (octadecanoic acid): CH 3(CH 2)16 COOH • Arachidic (eicosanoic acid): CH 3(CH 2)18 COOH

Example of unsaturated fatty acids: ØLinoleic acid: CH 3(CH 2)4 CH=CHCH 2 CH=CH(CH 2)7 COOH ØArachidonic acid CH 3(CH 2)4 CH=CHCH 2 CH=CHCH 1 CH=CH(CH ) COOH 2 2 3 ØOleic acid: CH 3(CH 2)7 CH=CH(CH 2)7 COOH ØErucic acid: CH 3(CH 2)7 CH=CH(CH 2)11 COOH

Fats yield fatty acids and glycerol on hydrolysis Fatty acid content of different fats ( in per cent) Fats_______SFA______MUFA_____PUFA Coconut oil 92 6 2 Palm oil 46 44 10 Cotton seed oil 25 25 50 Groundnut oil 19 50 31 Safflower oil 10 15 75 Sunflower oil 8 27 65 Corn oil 8 27 65 Soya bean oil 14 24 62 Butter 60 37 3

Healthy & Unhealthy Fats Healthy fats • MUFA: olive oil, peanut oil, nuts • PUFA: vegetable oil • Alpha-linolenic acid: soybeans, flaxseed Unhealthy fats • Saturated fats: animal fats • Cholesterol: eggs, seafood, meat • Trans fats: margarine, snack and fried foods, bakery goods

Nutritional requuirement: 1. Essential : cannot synthesized in the body, have to be supplied in the deit Eg: Linolenic acid , linoleic acid 2. Non-essntial: can be synthesized in the body Eg: Palmitic acid

Our body can make saturated and omega 9 unsaturated fatty acids. It is not essential to get them in diet. They are named nonessential fatty acids. Eg : ? give example

But our body can not produce double bonds before 9 th carbon from the methyl end, so we not synthesize certain fatty acids such as omega-3 (linolenic), omega-6 (linoleic). They must come from food, so they are called essential fatty acids! Ex ?

Essential Fatty Acids Linoleic (18: 2 9, 12) 6 Linolenic (18: 3 9, 12, 15) 3 Arachidonic (20: 4 5, 8, 11, 14) 6 “omega ( ) 3” or “n-3” are other common designations

Foods with unsaturated FA • MUFA – Olive, canola oil – Nuts • PUFA – Soybean, corn oil – Flaxseed oil – Sunflower oil • Omega 3 FA (EPA, DHA) – – Sardines Mackerel Salmon Fish oil

Eicosanoids • Eicosanoids are synthesized from three 20 carbon fatty acids (20: 3 n-6, 20: 4 n-6 and 20: 5 n-5) lying in cell membranes • Eicosanoids have multiple regulatory functions in the body including regulating the inflammatory response • Eicosanoids synthesized from 20: 5 n-3 (EPA) tend to be anti-inflammatory whereas eicosanoids derived from 20: 4 n-6 (arachidonic acid) may promote inflammation in certain tissues.

Cholesterol – Cell component – Found only in animals – Dietary, 2/3 made in liver – Bile Acids – Sex hormones-testosterone, estrogen – Adrenal hormones - Cortisol – Vitamin D Plant Sterols or phytosterols

Cholesterol & Vitamin D is synthesized from cholesterol