Drugs and Their Medicinal Value

What are drugs?

Mostly in ancient times natural properties of plants are used for the treatment which is known as Ayurveda but in modern times chemicals are used for the treatment. ” The synthetic chemicals used for the treatment of diseases, analgesic, curing or reducing pain are known as drugs which are also called medicines”. Bark of the willow plant is used as an analgesic in ayurveda because this plant carries 2-hydroxy benzoic acid (Salicylic acid) which is similar to compound used in Aspirin (Analgesic). In short, Drugs or medicines are used to destroy microorganisms such as bacteria or viruses which are harmful to our body, curing the injuries by speeding up the metabolic activities etc.

Things to remember while designing a drug:-

While designing a drug the following four facts are viewed:

(i) Drug target

(ii) Drug Metabolism

(iii) Physiological function of drug target

(iv) Mechanism of action of the drug

(i) Drug target: Drugs usually interact with biomolecules like carbohydrates, lipids, proteins, and nucleic acids which are known as drug targets. Correct selection of target molecules for a drug is necessary for maximum medical effect.

(ii) Drug Metabolism: When a drug is introduced into the body, it travels in the body to reach the target molecule. Thus, a drug should be designed in such a way that it should reach the target without being metabolised. Thus, it acts in the body without any harm.

(iii) Physiological function of drug target: Knowledge of the physiological function of drug target helps us to select a compound that helps in interaction with the target and is medically active. These compounds are known as lead compounds and drugs are prepared to start from these lead compounds

(iv) Mechanism of action of drug: Knowledge of the mechanism of the drug and of the metabolic path of biosystem helps us in improving the quality of drug and helpful in preventing its ill effects.

How do drugs work and interact with targets?

Drugs interact with macromolecules like-carbohydrate, protein, lipid and nucleic acids. Biomolecules play an important role in the functioning of our body. For example: Protein is the structural unit of our body. Proteins which act as biomolecules are known as enzymes, proteins which are very important for the communication system in the human body are known as receptors whereas proteins which carry the polar molecules around the cell membrane are known as carrier proteins.

Similar types of nucleic acid (DNA and RNA) code genetic information whereas carbohydrates and lipids are the structural part of cell membrane.Drug target interaction can be explained with examples considering enzymes and receptors.If we explain by the example of enzymes and receptors of drug target interaction then:- 

Enzymes as drug targets: Nearly all biological activities are performed by the catalytic effect of enzymes. Thus, enzymes are the important targets of drug action. In catalytic activity,two major functions are performed by enzymes.

(a) Keeping hold on the substrate in reaction: The first function is to keep hold of the substrate in a chemical reaction.Active site work to hold substrate to be attacked by reagents effectively. Substrates bind the active sites by ionic bonding, hydrogen bonding. These bonding forces are quite strong so as to bind the substrate for a long time by which the enzyme can catalyse the reaction but are so weak also that after the formation of product, they are separated from the active site.

(b) To provide functional groups that will interact with the substrate: The second function of an enzyme is to provide a functional group which will attack the substrate and carry out chemical reactions. This function is performed by certain amino acids residue present in proteins which act as enzymes.

Types and medical value of this medicines :-

Medicines are used for many purposes such as:-

1. When we have fever then we use medicines to lower the temperature of our body.
2. When we are injured we use medicines for curing ourselves.
3. When we are in pain we use pain killers or anaesthesia.
4. Medicines are used for birth controls.

Some categories are :-

Antipyretic

Antipyretics are used to decrease the body temperature in case of high fever. For example: Aspirin, Paracetamol and phenacetin etc. Paracetamol is the best antipyretic. Aspirin is used both as an antipyretic as well as an analgesic. It reduces fever and prevents platelet coagulation or blood clotting. Therefore, aspirin is used in the prevention of heart attack. Aspirin should not take an empty stomach, because it increases the acidity of the stomach, by which internal membranes may develop wounds and cause bleeding. Thus, minor ulcers may be produced. Antipyretics often lead to perspiration which helps in bringing down the body temperature.

Antimicrobials

Antimicrobials are drugs which are used for the treatment of disease caused by microorganisms like bacteria or viruses.Microorganisms which cause disease are called Pathogens. Naturally,our body gives out resistance,in response to them. Liquids secreted by the body either destroy these microorganisms or prevent their growth like secretion of dil. HCI by stomach and secretion of fatty acid are lactic acid by sweat.

Some important antimicrobials are :

(a) Antibiotic 

(b) Antiseptic

(c) Disinfectant

Antihypertensive

Increase in blood pressure causes heart attack, dementia etc so for this treatment antihypertensive drugs are used . Antihypertensive drugs are used to control the blood pressure.

Antiviral 

Virus causes many diseases, infections so for the treatment of a wide range of viruses antiviral drugs are used.

Antimalarial

Chemical substances which are used to decrease the body temperature during malarial fever are known as antimalarials. Quinine (an alkaloid) is an ancient medicine used for the treatment of malaria. Nowadays, synthetic drugs like: Chloroquine, Paraquine, Primaquine etc. are used.

Conclusion:-

Medicines or drugs should be used by the advice of the doctor as it normally produces poisonous effect and can be dangerous to life if we take it in excess or any other unwanted cause.Antibiotics are chemical substances which are produced by microorganisms and are used to destroy other microorganism.Antiseptic are molecules which prevent microorganisms from growing and kills them, without harming living tissue. It is applied on wounds, Ulcer and skin surface. Disinfectants are chemical substances which stop the growth of microorganism or destroy it, but it also destroys living tissue called disinfectants. Disinfectants are harmful for living tissues, therefore it is not used directly on wounds.