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Vitamin C, B1, B2


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Title: Vitamin C, B1, B2

Vitamin C, B1, B2 B3
Water soluble vitamins
  • It is water-soluble vitamin.
  • Most animals are able to synthesize all vitamin C
    they need from dietary sugars but humans are
  • Also, animals are able to increase synthesis of
    vitamin C during stress but humans strictly
    depend on dietary sources, increases risk of
    deficiency during stress time.

Natural Source of Vitamin C
Red pepper
Vitamin C
L- Ascorbic Acid (Reduced Form)
L-Dehydroascorbic Acid (Oxidised Form)
Physiologically active forms for vitamin C
RDA Adults 60 mg/day Children 30 mg/day
Chemistry and Stability of Vitamin C
  • It is a weak acid and its salts called ascorbate.
  • Unstable in alkaline pH, high temperature, and in
    the presence of oxygen or metals.
  • The D-enantiomer of ascorbic acid shows no
    biological activity.
  • Ascorbic acid is strong reducing agent, serves as
    an anti-oxidant and co-factor in hydroxylation
  • Ascorbic acid is reversibly oxidized to L-
    dehydroascorbic acid and both L-ascorbic and
    L-dehydroascorbic acids are physiologically
    active forms for vitamin C.

Functions of Vitamin C
  • Antioxidant function It helps protect against
    oxidation by free radicals.
  • Helps in detoxification and excretion of drugs
  • It maintains the enzyme systems in liver that
    detoxify and excrete drugs and toxic pollutants.
  • Synthesis of collagen The major component of
    connective tissue in skin, joints, muscles,
    bones ligaments, tendons, and cartilages.
  • Involved in carnitine synthesis (along with
    niacin and vitamin B6) which is an amino acid
    required in breakdown of fats for energy.
  • It is a cofactor in the synthesis of
    neurotransmitters as epinephrine ,
    norepinephrine and serotonin.

  • Important for healthy immune function It is
    essential for optimum activity of WBCs and
    production of chemical mediators which direct
    the immune response. Vitamin C seems to increase
    T-lymphocyte activity, phagocyte function,
    leukocyte mobility, and possibly antibody and
    interferon production.
  • Involved in cholesterol breakdown and excretion
    (cholesterol level increase if vitamin C status
    is impaired).
  • Protection of folate and vitamin E from
  • Involved in control of histamine levels When
    vitamin C status is poor High levels of
    histamine aggravate allergies, asthma,
    stomach ulcers, and certain psychiatric

Symptoms of Vitamin C Deficiency
  • Scurvy Impaired connective tissue synthesis and
    fragility of blood vessels causes abnormal
    bleeding easy bruising, subcutaneous
    hemorrhagic spots, inflamed and bleeding gums,
    joint stiffness and pain (due to bleeding into
  • Impaired wound healing.
  • Build-up of keratin in hair follicles producing
  • sandpaper skin.
  • Weakness, exhaustion, fatigue (due to impaired
    carnitine synthesis).
  • Impaired immunity with increased risk of
  • Diminished antioxidant defenses increase risk of
    cancer, heart disease, stroke, cataract.

Scurvy was common between Sailors, Pirates and
others who were on ships for months without
eating fresh fruits and vegetables.
People at High Risk of Vitamin C Deficiency
1. Increased physical stress (e.g. infection,
fever, burns, surgery, trauma to soft tissues or
bones, and chronic illnesses such as
hyperthyroidism, diabetes, rheumatoid arthritis,
alcoholism, and kidney failure). 2. Chronic use
of drugs such as aspirin and oral contraceptives
impair vitamin C status. 3. Older people,
particularly those with chronic illness, and
aging. 4. Periods of rapid growthchildhood,
adolescence, pregnancy, and lactation. 5.
Regular cigarette smoking sharply increases
breakdown and excretion of vitamin C.
Uses of Vitamin C in Prevention and Therapy
  • Enhance ability to fight infection Vitamin C
    stimulates the activity and ability of WBCs to
    destroy bacteria and viruses.
  • Treatment of cold and flu At doses of 1-2 g, it
    slightly increases body temp. functions
    of WBCs and blood histamine immune
    response and nasal and bronchial
    congestion duration and symptoms of Cold and
  • Helps reduce risk of cancer particularly
    cancers of GIT, bladder, breast, pancreas, and
    uterus (antioxidant enhancer for immune
    defenses against cancer and helps detoxify
    carcinogenic food additives e.g. nitrates,
    pesticides, and other chemicals and heavy

  • Large doses platelet aggregation reduce
    risk of blood clots. In addition, vitamin C
    the strength of blood vessel walls. By these
    mechanisms, vitamin C can protect from coronary
    heart disease, thrombotic stroke, and
    peripheral vascular disease.
  • Protection from heavy metals It absorption and
    detoxification and excretion of heavy
  • Improves healing of wounds and fractures in
    burns, trauma, and surgery.
  • Iron deficiency (by iron absorption from meals).
  • Preventing and curing Scurvy.

Recommended Therapeutic Doses
  • For scurvy, 100-250 mg once or twice daily.
  • For treating the common cold, 1-3 g daily.
  • During acute stress, 1 g (3 times daily)
  • For preventing sunburn, 2 g of vitamin C and 1000
    IU vitamin E has been used.

Toxicity and Side Effects of Vitamin C
  • Vitamin C is generally regarded as safe in usual
    doses (up to 1000 mg). Dental erosion may occur
    from chronically chewing vitamin C tablets.
  • High doses of vitamin C more than 2000 mg/day may
    induce kidney stones, severe diarrhea, nausea,
    and gastritis. Large doses may precipitate
    hemolysis in patients with glucose 6-phosphate
    dehydrogenase deficiency.
  • Vitamin C is metabolized to oxalic acid.
    Increased consumption increases the urinary
    concentration of oxalic acid and increases the
    risk of oxalate stone formation.

Vitamin C- Drug Interaction
  • Vitamin C chromium and aluminium absorption.
    Patients with renal failure who take (Al)
    compounds should avoid vitamin C in doses above
    the RDA.
  • Vitamin C can destroy dietary vitamin B12 (so, it
    must be taken at least 2 hours after meals).
  • Acidification of the urine by vitamin C could
    increase re- absorption of salicylates by the
    renal tubules, and increase plasma salicylate
    levels .

  • High doses of vitamin C can the response to
    warfarin, possibly by causing diarrhea and
    reducing Warfarin absorption
  • Aspirin increases elimination of vitamin C. It
    reduces tissue and leukocyte uptake of vitamin
    C, leaving more in the plasma to be excreted
    into the urine.
  • Estrogens can vitamin C absorption or its

Vitamin B Group
5. Vitamin B6 (Pyridoxine) 1. Vitamin B1 (Thiamine)
6. Vitamin B7 or Vitamin H (Biotin) 2. Vitamin B2 (Riboflavin)
7. Vitamin B9 or Vitamin M or (Folic acid) 3. Vitamin B3 (Niacin)
8. Vitamin B12 (Cyanocobalamin) 4. Vitamin B5 (Pantothenic acid)
Water Soluble Vitamins
Vitamin B Group
Vitamin B1 (Thiamine)
Vitamin B1 (Thiamine)
  • The 1st water-soluble B-vitamin family to be
  • Since body reserve of thiamine is small (30mg),
    a steady dietary supply of it is important to
    avoid deficiency.
  • Because of its central role in energy production,
    most of thiamine is located in the muscles.
  • Once thiamine absorbed, it is rapidly transformed
    into the active form, thiamin pyrophosphate
    (TPP) which acts as a coenzyme.

Methyl Bridge
Thiazole Ring
Pyrimidine Ring
Thiamin or Aneurine
(Coenzyme form)
Daily Required amount and Sources
  • RDA (Recommended Dietary Allowance )is based on
    the number of calories in diet
  • Energy requirement
  • Adult male 3000 k cal.
  • Female 2100 k cal
  • Children 1700-2000 k cal
  • Daily requirement increases with high
    carbohydrate intake and for hard worker or

Vitamin B1 requirement 1.5 mg/day 1.1 mg/day
Stability of Thiamine
  • Stable in crystalline form but not so in
  • Destroyed by prolonged heat, baking soda (with
    heating), sulfite preservatives.
  • Unstable in aqueous solutions with pH gt 5.0. At
    pH 8.0 or above, thiamine turns yellow and is
    destroyed by a complex series of irreversible
  • In strong alkaline solution with the presence of
    oxidizing agents, e.g. potassium ferricyanide,
    thiamine is converted to thiochrome, which is
    blue fluorescent compound and is used for
    fluoremetric determination of vitamin B1 in
    foods, pharmaceutical preparations, and
    biological fluids.

Functions of Vitamin B1
  • It act as co-enzyme (TPP) in carbohydrate
    metabolism (for glycolysis and Krebs cycle
    enzymes pyruvate dehydrogenase and
    a-ketoglutarate dehydrogenase), which enable
    conversion of glucose into biological energy
    through oxidative decarboxylation reactions. This
    role is important
  • To provide energy to the brain.
  • To improve transmission of nerve impulses by
    providing nerves with energy.
  • To increase the efficiency of the heart muscles.
  • For the formation of RBCs.
  • 2. It act as co-enzyme for transketolase which
    functions in
  • The pentose phosphate pathway to synthesize
  • The pentose sugars deoxyribose and ribose are
    involved in nucleic acids biosynthesis.

Thiamine Antagonists
  • Oxythiamine is a competitive inhibitor (Amino
    group in pyrimidine ring is replaced by
    hydroxyl group).
  • Neopyrithiamine (It prevents the phosphorilation
    of hydroxy ethyl group that is essential for
    activity of the vitamin B1).
  • Thiaminase (found in raw fish destroys vitamin

Causes of Thiamine Deficiency
  • Malnutrition.
  • A diet high in thiaminase-rich foods (raw
    freshwater fish, raw shellfish, ferns)
  • Foods having anti-thiamine factors (tea, coffee
  • Chronic consumption of alcohol

Diagnostic Testing for Vitamin B1 deficiency
A diagnosis test for B1 deficiency can be
determined by measuring transketolase levels of
Diseases of Vitamin B1 deficiency
  • Beriberi is the deficiency disease caused by lack
    of thiamine resulted from malnutrition,
    alcoholism or other causes.
  • There are two major types of beriberi
  • Dry beriberi affect the nervous system
  • Wet beriberi affects the cardiovascular system
    and ends by Wernicke-Korsakoff syndrome which
    affect the nervous system.

Wet Beri-beri Dry Beri-beri
Symptoms Dyspnea orthopnea Increased heart rate, enlarged heart, heart failure. Swelling of the lower legs. WernickeKorsakoff syndrome -Ophthalmoplegia (paralysis of one or more extraocular muscles which are responsible for eye movements) -Confusion - Coma - Death if untreated. Symptoms Difficulty in walking Painful tender muscles Loss of sensation in hands and feet Loss of muscle function or paralysis of the lower legs Mental confusion/speech difficulties Vomiting and anorexia.
Diseases of Vitamin B1 deficiency (BERI-BERI)
People at high risk of Vitamin B1 Deficiency
  • Heavy alcohol consumers (Alcohol reduces
    absorption of thiamin and interferes with its
    conversion to TPP).
  • Much consumption of coffee and black tea depletes
    thiamin stores in the body and hinder its
  • Patients having liver cirrhosis, malabsorption
    syndromes, diabetes, kidney disease, or
  • The elderly peoples with poor nutritional status
    and difficulties with absorption.
  • Folate deficiency impairs absorption of thiamin.
  • Infants who are breastfed by thiamin
    deficient-mothers can rapidly develop
    life-threatening signs of thiamin deficiency.

Use of Thiamine in prevention and Therapy
  • Nerve disorders Supplemental thiamin may be
    effective in inflammatory nerve disorders (such
    as trigeminal neuralgia) and in diabetic
  • 2. Central nervous system disorders e.g.
    Alzheimers disease, anxiety, and depression
    associated with anxiety.
  • 3. Heart failure Particularly in the elderly
    chronic heart failure that responds poorly to
    conventional medical therapy.
  • 4. Anemia Thiamin deficiency produces an anemia
    resembling that of folate or vitamin B12
    deficiency (with macrocytosis) that responds to
  • 5. Disease caused by heavy alcohol consumption.

Vitamin B1- Drug Interactions
  • Oral contraceptives, antibiotics, sulfa drugs,
    and certain types of diuretics may lower
    thiamine levels in the body.
  • Vitamin B1 may intensify the effects of
    neuromuscular blockers that are used during
    some surgical procedures.
  • B vitamins are best absorbed as a complex, and
    magnesium also promotes the absorption of

  • Thiamin is virtually nontoxic.
  • Doses gt 200mg may cause drowsiness in some
  • Rare, but severe, allergic reactions may be
    happened with injectable thiamin.

Vitamin B2 (Riboflavin)
Vitamin B2 (Riboflavin)
  • Riboflavin is defined chemically as
    7,8-Dimethyl- 10-(2S,3S,4R)-2,3,4,5-tetrahydrox
    ypentyl benzo g pteridine-2,4-dione and is
    a yellow to orange-yellow powder and soluble
    in water.
  • It is the precursor of phosphorylated coenzymes
    FMN, FAD, and flavin coenzymes linked
    covalently to specific tissue proteins, at
    the 8- a methyl position of the isoalloxazine

Riboflavin is stored mainly in liver, kidney and
heart as it is or as FAD (70- 90) or FMN.
Isoalloxazine moiety
Riboflavin phosphate
Ribose moiety
Riboflavin Vitamin B2
Flavin adenine dinucleotide (FAD)
Required Daily Amount and Sources
RDA is an average of 1.5 mg/ day
Milk Egg
Calf liver
Mature Soya beans
Stability of Riboflavin
  • Riboflavin and its coenzymes are sensitive to
    alkali and acid but in the presence of light or
    UV light.
  • Riboflavin is photodegraded to yield lumiflavin
    (7,8,10- trimethylisoalloxazine) under alkaline
    conditions and to lumichrome (7,8-dimethylalloxaz
    ine) under acidic conditions, and these products
    are biologically inactive .
  • Therefore, phototherapy of neonatal jaundice and
    of certain skin disorders may promote systemic
    riboflavin deficiency.

Functions of Vitamin B2
  • 1. Energy production
  • The active forms of riboflavin are the
    phosphorylated coenzymes FMN and FAD which play
    central roles in about 150 oxidation-reductions
    reactions and are involved in
  • Metabolism of carbohydrates, fat, and protein.
  • Production of adenosine triphosphate (ATP)
    through cellular respiration in mitochondria.
  • Activation of vitamin B12, folate, vitamin B6 and
    the conversion of tryptophan to niacin.
  • 2. Antioxidant action
  • Riboflavin is a cofactor of glutathione
    reductase. This enzyme helps in recycle of
    oxidized glutathione, which plays a key role in
    maintaining proper function and preventing
    oxidative stress in human cells including

Causes of Riboflavin Deficiency
  • Malnutrition.
  • Health conditions which affect intestinal
  • Increase of vitamin excretion from the body.

Diagnostic testing for vitamin B2 Deficiency
A positive diagnostic test of serum riboflavin is
by measuring glutathione reductase levels of
Symptoms of vitamin B2 deficiency
  • Red, scaly, painful, and itchy patches on
    sensitive skin (around nose, ears, mouth, labia
    majora (female), and the scrotum (male).
  • Painful fissures and cracks form at the angles of
    the mouth (angular stomatitis) and on the lips
    (cheilosis), usually associated with bacterial
    and fungal infection. The tongue and throat
    become purplish and painful.
  • Mouth ulcers

Red, scaly, painful skin
Mouth ulcers
angular stomatitis
  • Redness, burning, excessive tearing of eye.
  • Anemia with decreased production of red blood
  • Deficiency of riboflavin typically produces
    symptoms of vitamin B6 and niacin deficiency.

Symptoms of niacin deficiency
Redness, burning, tearing of eyes
People at high risk of vitamin B2 deficiency
  • Children, and adolescent, athletes, as well as
    during pregnancy and lactation (cases with a
    high-energy output) need additional vitamin B2.
  • People under high stress
  • Diabetics may have low level of riboflavin as a
    result of increased urinary excretion.
  • The elderly people (nutritional inadequacy and
    problems with absorption)
  • Patients administering thyroid hormones, oral
    contraceptives, phenothiazines, barbiturates,
    probenacid, and Tricyclic antidepressant.

Use of Vitamin B2 in Prevention and Therapy
  • Detoxification Riboflavin helps liver to
    detoxify pesticides, chemicals, and other
    environmental toxins.
  • Increasing the antioxidant capacity throughout
    the body and especially for lens of the eye.
  • Ample intake of riboflavin help decrease the
    incidence of cataracts.
  • As a cofactor of glutathione reductase,
    riboflavin with vitamin C increase body's level
    of glutathione (antioxidant).
  • Ample riboflavin intake maintains healthy skin
    and mucous membranes.
  • It may be beneficial in stomatitis, cheilosis,
    and skin eruptions and rashes.

Vitamin B2 Drug interaction
  • Probenecid (anti-gout) and propantheline bromide
    (antipeptic ulcers) both delays and impairs its
  • Phenothiazines (antipsychotic drugs) increase the
    excretion of riboflavin, thus lowering serum
  • Oral contraceptives may also decrease its serum
  • Riboflavin interferes with the absorption and
    effectiveness of anti-malarial (ex.
    chloroquine), tetracycline antibiotics and
    sulfa-containing drugs.

Assay of Vitamin B2
Lumiflavin method Riboflavin solution or
biological sample is irradiated in alkaline
medium to yielded a chloroform- soluble
lumiflavin, measured by fluoremetry.
Vitamin B3 (Niacin Niacinamide)
  • Two main forms of Vitamin B3 are found in foods
    nicotinic acid (niacin) and nicotinamide
  • Niacin can be partially satisfied by intake of
    tryptophan, which is converted by the liver
    into niacin.
  • 60 mg of tryptophan can be converted into about
    1mg of niacin.
  • Dietary requirements for niacin are described in
    terms of niacin equivalents (NEs)
  • 1NE 60mg of tryptophan 1mg of niacin

RDA 13- 20 mg/day
Sources of Vitamin B3
Nicotinic acid or Niacin
Nicotinamide or Niacinamide
Cows milk
Sheep liver
Rice bran
Beet greens
Pharmacokinetics of Vitamin B3
Absorption At low concentration by active
transportation. At high concentration by passive
diffusion. Transportation Both Nicotinic acid
and Nicotinamide bind to plasma proteins for
transportation. Biosynthesis The liver can
synthesize Niacin from the essential amino acid
Tryptophan, but the synthesis is extremely slow
and requires vitamin B1, B2, and B6 (60 mg of
Tryptophan 1mg of niacin). Bacteria in the gut
may also perform the conversion but are
Functions of Vitamin B3
  • It acts as a co-enzyme in oxidation reduction
  • Catabolic Rxn in form of NAD/NADH
  • Anabolic Rxn in form of NADP/NADPH
  • Therefore, it is required for functions of gt200
    enzymes dealing with the biosynthesis of several
    compounds e.g. fatty acids, steroids and
    catabolism of fuel molecules for energy.
  • 2. DNA replication and repair
  • It is vital for synthesis of DNA-bound nuclear
    proteins (histones)

3. Antioxidant functions It plays an important
role in antioxidant systems, particularly in the
4. Blood sugar regulation It is a component of
the glucose tolerance factor (GTF), which
together with insulin, helps to control blood
glucose. 5. Fat and cholesterol metabolism It
lowers levels of total and LDL cholesterol in
the blood, while increasing levels of HDL
cholesterol (the healthy, protective form of
Vitamin B3 Deficiency Diseases
  • 1. Milder deficiency of niacin (as well as
    tryptophan) can cause
  • Glossitis (inflammation of the tongue leading
    to purplish discoloration)
  • Dermatitis around the mouth and rashes
  • Fatigue
  • Irritability
  • Poor appetite
  • Indigestion
  • Weight loss
  • Headache

Dermatitis around mouth
Poor appetite
  • 2. Severe deficiency leads to Pellagra
    Characterized by
  • Inflamed mouth (painful swollen tongue and
    fissured lips) and GIT.
  • Diarrhea
  • Dermatitis in the exposed skin of hands, face,
    neck (Casals necklace)
  • Dementia and mental disorders
  • Death.

It is very rare now, except in alcoholics, strict
vegetarians, and people with very poor nutrition
(or niacin or tryptophan- deficient food e.g
Dermatitis of exposed skin
Mental disorders
Inflamed mouth
People at high risk of vitamin B3 deficiency
  • People with very poor nutrition (or niacin or
    tryptophan- deficient food e.g corn).
  • People with deficiencies in vitamin B6 or
    riboflavin (conversion of tryptophan to niacin
    is reduced niacin stores in the body
    is reduced).
  • People with inflammatory bowel disease and other
    digestive disorders malabsorption of
  • Heavy alcohol consumption interferes with
    absorption and metabolism of niacin.
  • People under high stress, chronic illnesses,
    liver disease.

Uses in prevention and Therapy
  • Mental illness e.g. schizophrenia Niacinamide
    can be effective with traditional medical
  • Atherosclerosis and heart attack Niacin in very
    large doses (2-3 g/day)
  • Lower total and LDL cholesterol and raising HDL
  • (2) Dilates blood vessels lowers
    blood pressure.
  • Arthritis Niacin helps in treatment of
  • Diabetes Niacinamide slow down the development
    of nephropathy in diabetes and delay need for
    insulin therapy in juvenile diabetes.

  • Protection against environmental toxins The
    antioxidant function of niacin help protect
    liver against damage from pesticides, chemicals,
    alcohol, and drugs.
  • Headache Niacin help in prevention of headache.
  • Treatment of Pellagra.

Toxicity and side effects of vitamin B3
  • Large doses (500 mg) of niacin (but not
    niacinamide) can cause dilation of capillaries
    tingling and flushing of the skin.
  • Flushing of the skin is usually worse if
    nicotinic acid is taken on an empty stomach,
    therefore it should be taken just after meals.
  • Niacin in the form of niacinamide does not
    produce these side effects.
  • At doses of gt 2.5 g / day, it can produce
    hypotension, dizziness, increased blood sugar
    and uric acid, liver dysfunction, and increased
    risk of peptic ulcer. These effects are
    gradually adopted and decreased and are
    reversible on withdrawal of nicotinic acid.

Vitamin B3 Drug Interactions
  • Niacin with antihypertensive drugs severe
  • Extra niacin may be required in case of people
    taking Isoniazid (Inhibits biotransformation of
    tryptophan to niacin ), by women taking oral
  • Bile acid sequesterants e.g. Cholestyramine and
    cholestipol should be taken at a different time
    than niacin (not niacinamide) otherwise they
    will reduce its absorption.

  • Carbamazepine may cause toxicity with niacin.
  • The combination of niacin and statin is often
    used to treat lipid triad (high LDL and TG, low
    HDL) may cause myopathy (myopathy is a
    muscular disease in which the muscle fibers do
    not function, resulting in muscular weakness).

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