Medical Chemistry 2
April 21, 2022
Vitamins
Keep
Calm
and take
Vitamins
Medical Chemistry 2
Objectives
1
Definition
3
Classification
2
Vitamins VS Biomolecules
4
Vitamins in metabolism
What are vitamins ?
A vitamin is an essential
organic nutrient that functions
as a coenzyme in vital
enzymatic reactions.
Vitamins VS Biomolcules
Vitamins
Organic
Micronutrients.
No calorie.
Food contain
small amounts.
( micro/
milligram)
Carbs, fats and proteins
Organic
Macronutrients.
provide calories.
Food contain
large amounts.
( grams )
CLASSIFICATION
Fat- Soluble Vitamins
Excess stored in the body.
Decreased risk of deficiency.
Increased risk of toxicity.
Vitamins K, E, D, A .
Water- Soluble Vitamins
Excess excreted through urine.
Increased risk of deficiency.
Decreased risk of toxicity.
B- Vitamins, C.
Release Energy: 1,2,3,5,7.
Hematopoietic: 9,12.
Other: B6
Fat-soluble
KEEP
GOING
Vitamin A
Active forms: Retinol, retinal and retinoic
acid.
Other forms: Beta-Carotene
Functions: Vision in dim light, antioxidant, has
anticancer activity, formation of mucus
membrane and important for normal growth.
Deficiency: Night blindness, impaired vision,
inability to see in dim light and susceptibility
to infection.
Sources:
Vit A = only in animal product ( liver, butter )
Beta carotene = carrots, sweet potato,
pumpkin, spinach.
Vitamin D
Active form: 1,25-dihydroxycholecalciferol
( Calcitriol - D3 )
Functions: Absorption of Ca+ and P in the gut
and bones.
Deficiency:
- Children ( Rickets ) weak & deformed bones.
- Adults ( Osteoporosis ) loss of Ca+.
Sources:
- Synthesis under skin in sun light.
- Animal & milk products ( fish, eggs, vit D
fortified milk, cheese, yogurt)
RDA:
Women/men = 5μg
Over 50= 10μg
Over 70 = 15μg
Vitamin E
Active forms: α-tocopherol
Functions: Antioxidant against peroxidation
of polyunsaturated FA in phospholipids of
cellular and sub-cellular. The first defensive
mechanism. (Enhanced by selenium).
Deficiency: Neurologic disorders, hemolytic
anemia.
Sources: oils, fats, whole grains, wheat germ
leafy green vegetables, tomatoes, eggs,
nuts and seed.
RDA: Women/Men = 15mg
Vitamin k
Active form: K1- Phylloquinone,
K2- Menaquinone, K3- synthetic
Functions: important for blood clotting and
aid in Ca+ Corporation in bones.
Deficiency: Bleeding and bruises
Sources:
- Half Synthesis in the gut by bacteria.
- Green leafy vegetables, grain products.
RDA:
Women = 90μg.
Men = 120μg.
Water-soluble
KEEP
GOING
Vitamin C ( Ascorbic Acid )
Functions:
Collagen
Cholesterol ( synth of steroids & bile acids )
no Casts ( bone formation )
no Cuts ( wound healing )
no Cough ( immune function- Antioxidant)
hemoChromatosis ( iron absorption ).
Deficiency: Scurvy, bleeding, poor wound healing.
Sources: Fruits (citrus, kiwi, mango, papaya)
Vegetables (broccoli, green & red pepper,
parsley, sweet potato).
RDA:
Women = 75mg. Men = 90mg. Smokers = 200mg
Vitamin B1 (Thiamine)
Functions: maintain nerves and muscles,
coenzyme thiamin pyrophosphate (TPP).
Deficiency: Beri Beri
CVS - heart irregularity, heart failure.
Nervous - nerve disorders, mental
confusion.
Sources: Grain products, meat, liver, beans,
seeds, nuts, milk & cheese (LOW).
RDA:
Women = 1.1mg.
Men = 1.2mg
Ber1 Ber1
Vitamin B2 (Riboflavin)
Functions: Coenzyme flavin mononucleotide
(FMN) & flavin adenine dinucleotide (FAD)
for oxidoreductase involve in oxidation of
glucose, FA, amino acid & alpha keto acids
Deficiency: Riboflavinosis, skin rash,
dermatitis.
- Cheilosis is fissure at the corner of mouth.
- Glossitis is tongue smooth & purple.
Sources: Leafy vegetables (MAJOR) and yeast,
cauliflowe, liver, eggs and milk.
RDA:
1.2-1.7 mg/day
2 coenzymes — 2 lips — RDA 1.2
Vitamin B3 (Niacin)
Functions:
Coenzyme = nicotinamide adenine
dinucleotide (NAD), + phosphate (NADP).
maintain normal nervous system.
vasodilator.
lower blood lipids (Hypolipidemic).
Deficiency:
Pellagra:
4Ds (Dermatitis, dementia, diarrhoea, death)
indigestion.
Sources: same as for B1, tryptophan is a
precursor for B3. (60mg Trp = 1mg B3)
RDA:
Women = 14 mg.
Men = 16mg.
Vitamin B5 (Pantothenic)
Functions: Coenzyme (Co A or Co A-SH) acts
as acyl carrier involved in energy metabolism.
Deficiency: Uncommon.
Sources: yeast, legumes, whole grain cereal,
beans, liver, meat, egg, milk.
RDA:
5-10mg/day
Vitamin B6 (Pyridoxine)
Active form: Pyridoxal phosphate (PLP , Pyr.P).
other forms: Pyridoxine, pyridoxal,
pyridoxamine.
Functions: Coenzyme (PLP or Pyr.P) in amino
acids metabolism.
Deficiency: Neurological diseases.
Sources: mackerel, liver, meat, egg, royal jelly
of bees.
RDA:
Infant & children = 0.5-1.5 mg/day.
Adults = 2 mg/day.
pregnant & lactating women 2.5 mg/day.
Vitamin B7 (Biotin)
Functions: Energy metabolism,
carboxylation reaction (CO2 carrier)
Coenzymes:
CoA carboxylase in FA synthesis.
Pyruvate carboxylase in gluconeogenesis.
Propionyl-CoA carboxylase.
Deficiency: Avidin - protein in raw egg white
that bind to B7 & prevent its absorption.
Dermatitis, glositis and nausea.
Sources: widely distributed + synthesise in
intestinal flora.
RDA: 150-300 μg
Vitamin B9 (Folic Acid)
Forms: Dihydrofolate or tetrahydrofolate.
Functions: Coenzymes Tetrahydrofolate (THF),
formation of new cell (cell division) and RBCs.
Deficiency:
Growth failure.
increased risk of heart disease & strok.
Megaloblastic anemia (due to inhibition of
DNA synthesis).
Sources: leafy veggies, Fruits, milk, liver, dried
beans, bread and enriched cereal.
RDA:
- Women/Men = 400 μg
- Pregnant women = 800 μg
Vitamin B12 (Cobalamin)
Functions: maintain nerve tissue, normal
RBCs development with folate.
Deficiency:
Pernicious Anemia (Autoimmune).
Neurological disorder.
Destroyed parietal cells
( nervousness, tingling, brain degeneration).
Sources: eggs,liver, shrimp, meat, chicken and
milk. (NOT FOUND IN PLANT FOODS )
RDA:
- Women/Men = 2.4 μg
- Pregnant & lactating women = 6 μg
No intrinsic factor
No Vit B12 absorption
Pernicious Anemia
Fat-Soluble vitamins sources
Water-Soluble vitamins sources
References
Devlin, T. M. (2014). Textbook of biochemistry with clinical correlations. Wiley.
Makkieh, P. (2016). The Water Soluble Vitamins (Chapter 10). Retrieved April 6, 2022, from
https://youtu.be/KB_IXQr7Q1w.
Lecture 12: Vitamins, Medical Chemistry course, Taif University.
http://player.slideplayer.com/download/19/5901045/QJJGhV8AL2NMhYfk0tURdg/164997
9211/5901045.ppt
https://youtu.be/yadAyuOvlkc (How vitamins are involved in metabolism)
Thank you!
Happy
weekend!