Co-relation of Free Radicals Theory in Ayurveda:

Aāma vs. Free Radicals Theory:
Aāma:
1)    The substance, which is not digested properly and needs further digestion.
2)    The substance which is incompletely metabolised or partially metabolised is called as Aāma.
3)    The substance which creates disturbance in Srotas (channels) is called Aāma.
4)    A substance or group of substances which is near to poison or acts like poison is known as Aāma.
Above definitions of Aāma clearly shows that Aāma is the root cause of many diseases.
Symptomatology of Aāma:
Various symptoms produced due to presence of Aāma in body. These symptoms help in diagnosis of Aāma clinically. Sāma and Nirāma stage of disease can also be identified with presence or absence of these symptoms. ‘Astang Hridya’ (Ayurvedic Classical Textbook written by Sage Vagbhatta) has clearly given the symptomatology of Aāma as per below.
1) Srotorodha (Obstruction of the channels/ capillaries)–
Normal functioning of srotas are important in maintaining healthy state. Due to the properties like picchilta, snigdhata etc., aāma adheres to walls of srotas( channels/ capillaries) and as a result,  lumen of srotas becomes narrowed. Once this narrowing of lumen occurs, the normal functioning of srotas gets disturbed and this leads to disease production. This mechanism is common to both micro and macro channels.
2) Balabhramsa (Strength of the body get diminished) :
While aāma is circulating in the body, this systemic effect will get arise.
3) Gaurava(Feeling of heaviness in the body) :
When Aāma accumulates at different parts/sites in the body this heaviness is felt.
4) Anilmudhata(Restriction of body movements) :
According to Ayurveda, Anil(or Vāta) is root cause of free flow movements of body, when aāma comes in to the systemic circulation, this free flow movements of body will get restricted.
5) Aālasya : Person become lethargic
6) Apakti : Loss of appetite and digestion is getting weaken.
7) Nisthiva : Excessive salivation
8) Malasanga : Accumulation of body waste
9) Aruchi : Anorexia
10) Klama: Feeling of exhaustion without doing any work.

Free Radical Theory:
Concept of free radicals and their role to impair the human body has been considered the biggest advancement since the discovery of ‘germs’ as the causative agents of human disease, by Louis Pasteur. Today, free radicals are known to be involved in the patho-physiology of cancer, heart disease, arthritis and perhaps as many as eighty diseases not caused by infective agents. In accordance with the present scientific knowledge, the excessive production of free radicals in the organism, and the imbalance between the concentrations of these and the antioxidant defences, may be related to processes such as aging and several diseases, among which main are cancer, ischaemic processes, senile dementia, diabetes, pulmonary and pancreatic diseases, lupus-erythematosus, cirrhosis, intestinal inflammatory diseases, multiple sclerosis, arthritis, arteriosclerosis, cardiovascular diseases, diseases of the central nervous system and the brain”. (Bermejo Vicedo T, Antioxidant the therapy of the future).
“A free radical is an atom or molecule that contains one or more unpaired electrons and discontented with such a conformation, it will try to seek stability either by donating its electron to other molecule or acquiring an extra electron from adjacent molecules. Thus free radicals are highly reactive”.
Production of Free Radicals:
Free radicals are produced in a number of ways in biological system:
(a) Exposure to ionising radiation is a major cause of free radical production.
When irradiated water is ionized and electron is removed from the molecule; leaving behind ionised water molecule. The damaging species resulting from the radiolysis of water are free radicals. They are highly reactive and have a lifetime of the order of 10-9 to 10-11 seconds. The hydroxyl radical is extremely reactive and is carcinogenic. Water presents the largest number of target molecules in a cell most of the energy transfer goes on in water when a cell is irradiated rather, then the solute consisting of proteins, carbohydrates, nucleic acids and bioinorganic molecules. Oxygen is an excellent electron acceptor and can combine with the hydrogen radical (HX) to form a peroxyl radical (H2+O2 radical H2O2). Hydrogen peroxide is toxic and when present in sufficient quantity can interfere with normal cellular metabolism.
(b) Enzymes and transport molecules also generate free radicals as a normal consequence of their catalytic functions. Examples of enzymes which have been extensively studied in biological systems are xanthine oxidase and aldehyde oxidase. Both of these enzymes generate the superoxide anion radical (O2-) by adding a single electron to molecular oxygen. Other enzymes may use superoxide for their normal catalytic activity. The mitochondrias of cells are a major source of endogenous free radical generation and are utilised in the synthesis of Adenosine triphosphate(ATP) from adenosine diphosphate (ADP) – the primary currency of the body. Thus the mitochondria serve as the power house of the cell and contain most of the respiratory enzymes of the citric acid cycle.
(c) Auto oxidation reactions produce free radicals from the spontaneous oxidation of biological molecules involved in non-enzymatic electron transfer, although these reactions are a normal part of cellular metabolism. These free radicals may, under certain adverse conditions, achieve serious clinical significance. Examples of compounds that may be auto-oxidised in the body include thiols, hydroquines, catecholamines, flavins, ferredoxins and haemoglobin. In all these auto-oxidation reactions, superoxide is the main free radical species that is produced initially. The process involved in the oxidation reduction reaction is of immense biochemical importance since the transfer of electron is the means by which the body derives most of its free energy. In oxidation electrons are lost while in reduction electrons are gained.
(d) Toxic metals may produce free radicals in the body. The metals copper, iron, cadmium, arsenic, mercury, chromium, antimony, beryllium, thallium, silver and nickel are believed to derive their toxic effects from their inherent ability to transfer electrons which is also an expression of their capability to generate free radicals. Transition metals (scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper and zinc) usually promote free radical reactions. These free radicals can adversely affect cellular health by producing lipid peroxidation of intracellular membranes and crossing linkage of membrane macromolecules. Heavy metal free radicals have a tendency to form covalent bonds with sulfhydral groups. In this manner they are able to modify the functions of many enzymes, not to mention, non-enzymatic antioxidant compounds, such as glutathione, which depends on their groups for their biological activity. Toxic metals are known to affect cell membrane permeability, sub-cellular organelles and the structure and functions of proteins and nucleic acids. Toxic metals may affect the bio-synthetic formation of hormones and depress enzymatic and other metabolic processes. These metals may also stimulate those metabolic functions that lead to free radical production and carcinogenesis. They are found to have a deterious effect on immune system and contribute to atherogenesis.
Free Radical Damage:
Free radical damage may involved any cellular content. These include mitochondria, lysosymes, peroxisomes, nuclear endoplasmic reticulum and plasma membranes as well as sites within the cytosol. All are vital for the normal metabolic functions of the cell. Free radical damage culminates in cross-linkages, denaturation, inactivation. The genetic machinary of the cell may be damaged which is a major disorder in ionizing radiation. Damage to the DNA molecule may result in mutagenesis and carcinogenesis (Floyd 1982).
Oxygen plays a key role in the generation of free radicals and lipid peroxidation. Molecular oxygen is uniquely suited for free radical production because its two unpaired electrons cause the molecule to participate in redox reactions at the kinetic energy levels available in biological systems. Damage to intra cellular membrane lipoprotein assemblies by oxidant free radicals can have profound adverse effect in the cell.
Correlation between concept of Aāma and Free Radical Theory:
From above discussion it becomes clear that the method of production of disease at its basic level is described in similar manner in modern as well as in Ayurvedic literature.

The process of pathogenesis can be presented in a flow chart as follows:
Dhatvagni Daurbalya –> Impaired action of F. R. Scavengers
Sancaya of Aāma at site of production–> Increased production of F.Rs. at this site
Prasara of Aāma –> Circulation of F.Rs.
Sthanasamsrya at the site of Khavaigunya –> Starts reacting to the weak cell membranes.
Production of Disease –> Production of disease.