Historical background of antibiotics | Unit-1 L-1 | Med chem 6th sem

 INTRODUCTION

• The term antibiotic has its origin in the word antibiosis (i.e. against life).  

• The chemical substances which are obtained from various species of  microorganisms(bacteria, fungi, actinomycetes) and inhibit or destroy the growth of other species of microorganisms in low concentration are called antibiotics.

HISTORY OF ANTIBIOTICS

• There are three phases to explain the history of chemotherapy, such as Empirical period, Ehrlich’s phase, and the modern phase. 

• In empirical period, of , Moulded curd of soybean was used by Chinese for infection and wounds. 

• During these phases,Hindus used chaulmoogra oil for the treatment of leprosy.

•  Paracelsus used mercury for the treatment of syphilis(16th century).

•  Cinchona bark was used for fevers(17th century).

• In Ehrlich’s phase, it was revealed that certain dyes produced toxicity and killed some microorganisms.

• So, neoarsphenamine was developed by Ehrlich for the treatment of syphilis. 

• Ehrlich's coined the term 'chemotherapy'.

• The word antibiosis was coined after the killing of anthrax bacilli when grown in culture media with other bacteria during the 18th century.

• The modern phases demonstrated the therapeutic effect of prontosil (by Domagk) in pyrogenic infections in 19th century.

• In 1929, Sir Alexander Fleming accidentally discovered the antibacterial properties of penicillin by destroying the staphylococcus in culture plate.

• Chain and Florey followed up this observation in 1939 and later penicillin was clinically used during 1941. 

•  In 1942, Waksman proposed the search of actinomycetes and discovered streptomycin in 1944. 

• All of three groups of scientists, Domagk, Fleming-Chain-Florey and Waksman received the Noble Prize for their discoveries.

• Later, the advance in medicinal chemistry produced synthetic and semisynthetic agents.

SOME IMPORTANT POINTS ABOUT ANTIBIOTICS

• Some may be effective against only a few species of micro-organism, they are called narrow spectrum antibiotics.

• Some may be effective against a large variety of species of micro-organism, they are called broad spectrum antibiotics.

• Bactericidal - antibiotics which kill bacteria are called bactericidal.

• Bacteriostatic - antibiotics which inhibit growth of bacteria are called bacteriostatic.

• Microorganism may develop resistance to antibiotics after a time.

•  Resistance may be natural or acquired.

• Microorganism resistant to one antibiotic may become resistant to another and this is called cross-resistance.