This document discusses antibiotics and provides details about penicillin. It begins with definitions of antibiotics and describes how they are classified based on their effects, the types of bacteria they target, and their structure and functions. It then focuses on penicillin, noting that it was one of the first widely used antibiotics, derived from penicillium mold. The document outlines the history of penicillin's discovery and development. It also describes penicillin's structure, mechanism of action in inhibiting bacterial cell wall synthesis, and early synthesis methods.

1. GUIDEDBY-
Dr. CHANDA
VERMA
SUBMITTEDBY-
OMPRAKASH PATEL
(M.Sc. 4TH sem.)

2. INTRODUCTION
CLASSIFICATION
PENICILLLIN
HISTORY OF PENICILLIN
STRUCTURE
MECHANISM
SYNTHESIS
REFERENCES

3.  An antibiotic is a type of antimicrobial
substance active against bacteria and is the
most important type of antibacterial agent for
fighting bacterial infections.
 Antibiotic is a chemical that is produced by a
micro-organism and that, in a relatively high
dilution, inhibits the growth or reproduction of
some other micro-organism.
 Antibiotics are required only in low
concentrations these are also called
chemotherapeutic agents.
 Antibiotics are not effective against viruses
such as the common cold or influenza.

4. ANTIBIOTICS
BACTERIAL
SPECTRUM
BROAD
NARROW
ROUTEOF
ADMINISTRATION
INJECTIBLE
ORAL
TYPEOF ACTIVITY
BACTERICIDA
L
BACTERIOST
ATIC

5. 1. On the basis of effects of their activity.
 BACTERICIDAL
• Kills bacteria
• Examples: penicillin, aminoglycosides,
cephalosporin.
 BACTERIOSTATIC
• Inhibits the growth of bacteria
• Examples: sulphonamide, tetracycline,
chloroamphenicol, trimethoprin.

6. 2. On the basis of type of bacteria attacked.
 This classification was originally given by Christian
Gram & it is called Gram-staining method.
 The fixed bacterial smear is then treated first with a
solution of crystal violet(a dye) & then with iodine
solution.
 The smear is then washed with alcohol.
 The colour attained by the bacteria divides them into
two types:-
i. Gram-positive bacteria- appear deep violet colour.
E.g.- Diphtheria bacillus, pneumococcus,
staphylococcus, leprocy bacillus.
ii. Gram-negative bacteria- appear red in colour.
E.g.- coil bacillus, typhoid bacillus, meningococcus,
plague bacillus.

7. 3. On the basis of structure & functions.
a. Penicillins:- These are derived from amino
acids. E.g.- penicillin, cephalosporin etc.
b. Tetracyclines:- These have four-six
membered fused ring system. E.g.-
achromycin, aureomycin etc.
c. Macrolides:- These contain a large lactone
ring. E.g.- erythromycin, oleandomycin etc.
d. Polypeptides:- These contain a polypeptide
chain. E.g.- bacitracin, tyrothyricin etc.
e. Lincomycins:- These are sulphur containing
antibiotics in which sulphur atom is not present
in the ring. E.g.- lincomycin, clindomycin etc.

8.  It is one of the first and still one of the most
widely used antibiotic agents, derived from the
penicillium mold.
 Penicillin is a group of antibiotic that the
commonly used to treat different types of Gram-
positive & Gram-negative bacterial infections.
 In there structure, ß-lactum ring is located due
to this reason their drugs are also called as ß-
lactum antibiotics.
 It destroys bacteria by inhibiting the enzymes
responsible for the formation of the cell wall in
the bacterial cell.

9.  In 1928 Scottish bacteriologist
Alexander Fleming discover the
compound reduced by the fungus.
 The fungus was called penicillium
notatum, the isolated compound he
called penicillin.
 Fleming noted a fungus growing on
his bacterial plates had killed off the
surrounding bacteria.
 Fleming, Florey & Chain received a
noble prize in 1945 for medicine for
their work on penicillin.

10.  It is a generic term which refers to a class of
compound of the molecular formula
C9H11N2O4SR.

13.  Penicillins are bactericidal antibiotics as they
kill the micro-organisms when used at
therapeutic dose.
 The synthesis of cell wall of bacteria is
completely dependent upon an enzyme
named as transpeptidase.
 Primarily, penicillin inhibits the cell wall of
bacteria by blocking transpeptidase after
binding the penicillin binding protein &
prevents its synthesis. Resulting the bacterial
cells dies from cell lysis.
 Penicillins do not kill other cells in the body.

15.  De-Vigneaud et al (1946) obtained small
quantities of penicillin by condensing
D-penicillamine, I with 2-benzyl-4-methoxy
methylene oxazolone, II in pyridine at 70ºC,
the benzyl penicillin was isolated as the
crystalline triethyl amine salt.
 the starting material II is again obtained from
methyl phenaceturate in the following
manner-

17.  https://en.wikipedia.org/wiki/Penicillin#Mechanis
m_of_action
 https://www.britannica.com/science/penicillin
 https://www.youtube.com/watch?v=gTWiaH_oC
CY
 Book- Chemistry of organic natural products (Vol.
II), By O.P. Agrawal, Page no.- 98 – 133.