This document defines vitamins as organic compounds essential for growth that must be obtained through diet. It focuses on vitamin A, describing it as a group of compounds including retinol, retinal, and provitamin A. Provitamin A, such as beta-carotene, is converted to vitamin A in the intestines. Vitamin A is found in animal liver, fish liver oil, and plants. The biological form, 11-cis retinal, is derived from retinal and involved in rhodopsin formation in the retina. Sources of vitamin A include liver, eggs, dairy, and carotene-rich fruits and vegetables. Vitamin A deficiency can cause vision problems, growth inhibition, and neurological issues.

1. Ms. Funde A.P.
M. Pharmacy (QAT)
Vitamins

2. Definition
 Any group of organic compounds which are
essential for normal growth and nutrition and
are required in small quantities in the diet
because they cannot be synthesized by the
body.
 They are also called as growth factors.

4. Vitamin A
 Vitamin A is a group of unsaturated nutritional
organic compounds that includes retinol, retinal,
and several provitamin A
 In Plants Vitamin A found in the precursor form,
as provitamin A.
 All provitamin A compounds belong to the
family pigmented hydrocarbons are called
carotenoids.
 Conversion of carotenoids to vitamin A take
place in the intestine.

5. ᵦ-carotene(provitamin A)

6.  Vitamin A found in animal liver tissue
 Fish liver oil also contain vitamin A abundantly.
 In intestinal cell, the central double bonds of
carotene are oxidised to alcohol, to give two
molecules of vitamin A.
 The biological active form of vitamin is 11-cis
retinal, which is derived from the vitamin A1 by
the enzyme retinol dehydrogenase.
 Retinal is present in two forms that are all trans-
retinal and 11-cis-retinal.

7. These two forms are interconvertible in the
presense of light.
11 cis retinal all trnas retinal

9. Biochemical functions of Vitamin A
 Vitamin A is needed for the formation of
rhodopsin, which is a light receptor protein
present in the retina of vertibrates.
 Rhodopsin is made up of protein and
chromophore, i.e.retinal chromophore.
Opsin(Protein) + Chromophore(11 cis retinal)
=Rhodopsin
 Rod cells converted vision in dim light and cone
cells are concerned with vision in bright and
coloured light.

10.  Light brings about excitation and the change
from cis to trans configuration.
 In this way light energy is converted into
chemical energy and finally performs a
biological sense.

11. Good sources of vitamin A (retinol) include:
 cheese
 eggs
 oily fish
 fortified low-fat spreads
 milk and yoghurt
 liver and liver products such as liver pate

12.  You can also get vitamin A by including good
sources of beta-carotene in your diet, as the
body can convert this into retinol.
 The main food sources of beta-carotene are:
 yellow, red and green (leafy) vegetables, such as
spinach, carrots, sweet potatoes and red peppers
 yellow fruit, such as mango, papaya and
apricots

13. Deficiency of vitamin A
 Causes growth inhibition and fails to develop
nervous system properly.
 Eyes are mostly affected.
 In adult , the early symptoms of vitamin A
deficiency is night blindness.
 Vitamin A deficiency affects all tissues of
mammals and do not retina alone.
 Vitamin A also plays important role in the
transportation of divalent metal ions Ca++,
Mg++.

14. Thank you