this is a ppt for first professional MBBS students

2. B complex vitamins
• Thiamine
• Riboflavin
• Niacin
• Pyridoxine
• Pantothenic acid
• Biotin
• Folic acid
• Vitamin B12

3. • Choline
• Inositol
• Lipoic acid
• PABA

5. Thiamine
• Used by all cells as part of
a coenzyme in energy
metabolism.
• Other names : aneurine
: antineuritic factor
: anti beriberi factor
: Vitamin B1

6. Chemistry
• Thiamine is a basic substance and
contains: (a) a pyrimidine
(b) a thiazole ring
• Both are held by methylene bridges.

7. Biologically active form
(TPP)
Coenzyme for metabolic reactions
N
N
CH3
N
NH2
CH3
CH2
S
CH2-CH2-O-P-O-P-OH
O O
OH OH
Pyrimidine Thiazole
Pyrophosphate
Thiamine
TPP

9. Sources
Whole grain,Cereals
(conc. in outer
germ/bran layers) -
whole wheat flour,
unpolished rice, peas,
beans, whole cereal
grains,nuts, prunes,
liver, egg, meat etc.
RDA: 1-1.5mg/day

10. Metabolic role
• Oxidative decarboxylation
• Transketolase reactions

11. Oxidative decarboxylation of pyruvate

13. Oxidative decarboxylation of ketoglutarate

16. Beri-beri
• Mostly seen in populations consuming exclusively
polished rice
• Early symptoms
anorexia
diminished gastric motility and nausea
weakness
• Biochemical changes
Accumulation of pyruvate
Decreased transketolase activity
Impairment of nerve impulse transmission

17. Types
• Dry beriberi
• Wet beriberi
• Infantile beriberi
• Wernicke – Korsakoff syndrome
Adults

18. Wet beri-beri
• CV manifestations prominent
• Oedema of legs, face, trunk and serous cavities.
• Palpitation, breathlessness
• Swelling of calf muscles.
•  systolic BP,  diostolic BP.
• Death due to cardiac failure.

19. Dry beri-beri
• Neurological manifestations.
• Wasting of muscles, peripheral neuritis with
sensory disturbance leads to paralysis.
• Edema not seen.

20. Infantile beri-beri
• Infants born to mothers with deficiency.
• Restlessness, sleeplessness and bouts of
screaming
• Death due to cardiac failure.

21. Wernicke-Korsakoff syndrome
• Cerebral beri-beri.
• Encephalopathy (ophthalmoplegia, nystagmus,
cerebellar ataxia)
• Psycosis.
• Severe defect in nutrition.

22. Alcoholic polyneuritis
• Polyneuritis with motor and sensory defects
seen in chronic alcoholics.
• Alcoholism
Body demands of thiamine increase.
Insufficient intake
Impaired intestinal absorption
Lactic acidosis

23. Biochemical investigations
•  thiamine level and TPP in blood and urine.
• Diagnosis
Erythrocyte transketolase activity

24. • Certain seafoods –Thiaminase, lead to deficiency
• Antimetabolites
Pyrithiamine
Oxythiamine

26. Chemistry
Orange yellow compound containing:
• A ribose alcohol – ribitol
• A heterocyclic parent ring structure “isoalloxazine”
(flavin nucleus)

27. Sources
•Milk products
(yogurt, cheese)
•Liver
•Enriched or whole
grains
•Germinating seeds
•Green leafy
vegetables
•RDA-1.5mg/day

28. Biological active forms
• FMN & FAD:

29. Functions
• Chief functions in the body
• Part of coenzymes FMN (flavin mononucleotide)
and FAD (flavin adenine dinucleotide) used in
redox reactions responsible for energy metabolism.
• Functional unit- isoalloxazine ring- serves as
acceptor of two H atoms,
FMNH2 or FADH2 formed

30. • These coenzymes remain tightly bound to
respective apoenzymes to form flavoproteins.
• Some flavoprotein enzymes are
metalloflavoproteins containing metals like iron
and molybdenum in addition to FMN or FAD. Eg:
XO, NADH DH.

31. FMN dependent enzymes
• L amino acid L imino acid ketoacid
FMN FMNH2
H2O2
O2

32. • ETC
FMN FeS
Complex I
NAD
Co Q
FeS
FAD
Complex II

33. FAD dependent enzymes
• Succinate Fumarate
FAD FADH2
Succinate dehydrogenase
Pyruvate dehydrogenase complex
-KG dehydrogenase complex

34. Acyl CoA
• Acyl CoA dehydrogenase
αβ unsaturated acyl CoA
FAD
FADH2

35. • Xanthine Uric acid
FAD
FADH2

36. • D AA oxidase
• Glycine cleavage system
• Glutathione reductase

37. Confined to skin and mucous membrane.
• Glossitis
• Magenta colored tongue
• Cheilosis
• Angular stomatitis
-Lesions at the angle of mouth
Deficiency Manifestations

38. • Dermatitis
• Eye manifestations
• Watering, burning, photophobia
• Circum corneal vascularization
• Proliferation of bulbar conjunctival capillaries- earliest
sign

39. • Dermatitis
• Eye manifestations
• Watering, burning, photophobia
• Circum corneal vascularization
• Proliferation of bulbar conjunctival capillaries- earliest
sign

40. Diagnosis
• Clinical features
• Good response to therapy
• Glutathione reductase activity
Antimetabolite - galactoflavin