Vitamin K is essential for blood clotting as it activates clotting factors in the liver through carboxylation. It exists as K1, K2, and K3 and is absorbed in the small intestine before being transported to the liver via LDL. A deficiency results in bleeding issues while toxicity can cause anemia, with good dietary sources including green vegetables, meat, and dairy.

1. Vitamin E
Subtitle

2. Vitamin E
Vitamin E (tocopherol) is a naturally occurring antioxidant.
lt is essential for normal reproduction in many animals, hence
known as anti-sterility vitamin.
Vitamin E is described as a 'vitamin in search of a disease’.
This is due to the lack of any specific vitamin E deficiency
disease in humans.
Evans and his associates (1936) isolated the compounds of
vitamin E activity and named them as tocopherols (Creek :
tokos-child birth; pheros-to bear; ol-alcohol).

3. • Vitamin E is the name given to a group of tocopherols and tocotrienols. About
eight tocopherols (vitamin E vitamers) have been identified- a, p, T, 6 etc.
• Among these, u-tocopherol is the most active. T
• he antioxidant property is due to the chromane ring

4. Absorption, Transportation and Storage
Vitamin E is absorbed along with fat in the small intestine.
Bile salts are necessary for the absorption. In the liver, it is
incorporated into lipoproteins (VLDL and LDL) and transported.
Vitamin E is stored in adipose tissue, liver and muscle.
The normal plasma level of tocopherol (vit-e) is less than 1
mg/dl

5. Bio-chemical function
› Most of the functions of vitamin E are related to its anti-oxidant
property. lt prevents the non-enzymatic oxidations of various cell
components (e.g. unsaturated fatty acids) by molecular oxygen and
free radicals such as superoxide (O2 ^(-1) and hydrogen peroxide
(H2O2).
› Vitamin E is lipophilic in character and is found in association with
lipoproteins, fat deposits and cellular membranes. It protects the
polyunsaturated fatty acids (PUFA) from peroxidation reactions.
Vitamin E acts as a scavenger and gets itself oxidized (to quinone form)
by free radicals (R) and spares PUFA

6. 1. Vitamin E is essential for the membrane structure and integrity of the cell, hence it is
regarded as a membrane antioxidant.
2. lt prevents the peroxidation of polyunsaturated fatty acids in various tissues and
membranes. lt protects RBC from hemolysis by oxidizing agents (e.g. H2O2).
3. lt is closely associated with reproductive functions and prevents sterility. Vitamin E
preserves and maintains germinal epithelium of gonads for proper reproductive
function.
4. lt increases the synthesis of heme by enhancing the activity of enzymes 6-
aminolevulinic acid (ALA) synthase and ALA dehydratase.
5. lt is required for cellular respiration through electron transport chain (believed to
stabilize coenzyme Q).
6. Vitamin E prevents the oxidation of vitamin A and carotenes.
7. lt is required for proper storage of creatine in skeletal muscle.
8. Vitamin E is needed for optimal absorption of amino acids from the intestine.
9. Vitamin E protects liver from being damaged by toxic compounds such as carbon
tetrachloride.
10. lt works in association with vitamins A, C and p-carotene, to delay the onset of cataract.

7. Sources
› Many vegetable oils are rich sources of vitamin E.
› Wheat germ oil, cotton seed oil, peanut oil, corn oil and
sunflower oil are the good sources of this vitamin.
› lt is also present in meat, milk, butter and eggs.

8. Deficiency symptoms
› The symptoms of vitamin E deficiency vary from one animal
species to another.
› In many animals, the deficiency is associated with sterility,
degenerative changes in muscle, megaloblastic anaemia and
changes in central nervous system.
› Severe symptoms of vitamin E deficiency are not seen in
humans except increased fragility of erythrocytes and minor
neurological symptoms,

9. Toxicity of vitamin E
› Among the fat soluble vitamins (A, D, E, K), vitamin E is the
least toxic. No toxic effect has been repofted even after
ingestion of 300 mg/ day for 23 years
› Normal RDA is 8mg -10mg per day

10. Vitamin K
Subtitle

11. Vitamin K
› Vitamin K is the only fat soluble vitamin with a specific
coenzyme function.
› lt is required for the production of blood clotting factors,
essential for coagulation (in German-Koagulation; hence the
name K for this vitamin).

12. Structure of Vitamin K { Different forms }
Vitamin K exists in different forms.
• Vitamin K1 (phylloquinone) is present in plants.
• Vitamin K2 (menaquinone) is produced by the intestinal bacteria and also found in
animals.
• Vitamin K3 (menadione) is a synthetic form. All the three vitamins (K1, K2, K3) are
naphthoquinone derivatives.
• The three vitamins are stable to heat. Their activity is, however, lost by oxidizing agents,
irradiation, strong acids and alkalie. K1 &K2 have Isoprenoid side chain

13. Absorption, transport and storage
› Vitamin K is taken in the diet or synthesized by the intestinal
bacteria.
› Its absorption takes place along with fat (chylomicrons) and is
dependent on bile salts.
› Vitamin K is transported along with LDL and is stored mainly in
liver and, to a lesser extent, in other tissues

14. Biochemical Function
› The functions of vitamin K are concerned with blood clotting
process. lt brings about the post-translational (after protein
biosynthesis in the cell) modification of certain blood clotting
factors.
› The clotting factors ll (prothrombin), 7, 9 and 10 are synthesized as
inactive precursors in the liver. Vitamin K acts as a coenzyme for
the carboxylation of glutamic acid
› Vitamin K is also required for the carboxylation of glutamic acid
residues of osteocalcin, a calcium binding protein present in the
bone
› The formation of ɣ-carboxyglutamate is inhibited by dicumarol, an
anticoagulant found in spoilt sweet clover. Warfarin is a synthetic
analogue that can inhibit vitamin K action,

15. › Conversion of glutamate (Glu) to ɣ-carboxyglutamate (Gla) requires
vitamin K ,02 and CO2 .
› Role of Gla in clotting : The lcarboxyglutamic acid (Cla) residues of
clotting factors are negatively charged (COO-) and they combine
with positively charged calcium ions (Ca2+) to form a complex. The
mechanism of action has been studied for prothrombin. The
prothrombin -Ca complex binds to the phospholipids on the
membrane surface of the platelets . This leads to the increased
conversion of prothrombin to thrombin
› Dicumarol is structurally related to vitamin K and acts as a
competitive inhibitor in the synthesis active prothrombin

16. Dietary sources
› Cabbage, cauliflower, tomatoes, spinach and other green
vegetables are good sources. lt is also present in egg yolk,
meat, liver, cheese and dairy products.
Recommended dietary allowance (RDA)
 Strictly speaking, there is no RDA for vitamin K, since it can be
adequately synthesized in the gut. lt is however,
recommended that half of the body requirement is provided
in the diet, while the other half is met from the bacterial
synthesis. Accordingly, the suggested RDA for an adult is 7o-
140 ug/day.

17. Defeciency symptoms
› The deficiency of vitamin K is uncommon, since it is present in
the diet in sufficient quantity and/or is adequately synthesized
by the intestinal bacteria. However, vitamin K deficiency may
occur due to its faulty absorption (lack of bile salts), loss of
vitamin into feces (diarrhea diseases) and administration of
antibiotics (killing of intestinal flora).
› Deficiency of vitamin K leads to the lack of active prothrombin
in the circulation. The result is that blood coagulation is
adversely affected. The individual bleeds profusely even for
minor injuries. The blood clotting time is increased

18. Hypervitaminosis K
› Administration of large doses of vitamin K produces hemolytic
anaemia and jaundice, particularly in infants. The toxic effect
is due to increased breakdown of RBC
Antagonists of vitamin K
› The compounds-namely heparin, bishydroxycoumarin -act as
anticoagulants and are antagonists to vitamin K. The
salicylates and dicumarol are also antagonists to vitamin K.