Xenobiotics refers to a foreign compound in the body, these compounds could be in the liquid, solid or gaseous form. The study of xenobiotics has become very important because of the problems, as well as possible benefits associated with it. Xenobiotics can be exogenous or endogenous.
These forms of xenobiotics are not normally ingested or utilize by an organism but they gain entry through dietary foodstuff, or in the form of certain medicine/drugs used for a therapeutic cause or inhaled through the environment.
Sources of exogenous xenobiotics
The basic source is environmental contaminants, in the environment, certain food is not the basic food we eat; also the simple air isn’t what we breathe because several substances/compound are present in it.
- The air most times human activities results in xenobiotics for instance in rural areas the air people breathe is cleaner than in the city (urban area) because in the city there is a lot of emissions coming from factories, vehicles and others.
- Chemicals use as a solvent – these substances escape into the environment. A vast majority of these are chemical substances and few may be pollutants. Pollutants are substances present in the air in a small amount. Mechanics throwing oil on the ground which include an essential amount of lead (lead is used as an antidote for petrol, but have been banned)and hydrocarbon, inhale this spills from the air this exposure results to depression, brain damage, and loose of memory.
- In modernized farming the use of pesticide to increase yield, Gamaline is used in fishing to catch fish this substance is toxic to fish and other life forms including humans. Formaline that is very harmful, used to preserve dead bodies, is still used by some to preserve poultry, chicken to be precise.
- Food seasoning like ice cube of various colour, rice preparation of various colour to improve texture, appearance, flavour and consistency produces substances that yield new product when interacted with food material. Certain banned compound but are still in use such as monosodium glutamate(Ajinomoto) is toxic and bleaches the tissues, potassium bromide in bread causes kidney disease, it affects the kidney greatly and is also carcinogenic, agency like National agency for food drug and administration and control NAFDAC in Nigeria have done their best in eradicating that.
- Healthcare diseases have their origin in a sophisticated site, all kinds of drugs been taken to make one happy, depressed, sleep, sports medicine use by athlete have their side effects.
- Occupationally- occupational inhalation of air also occurs in cement factories, insecticide factories, perfume factories, and many more.
- Radioactive waste dumping of toxic waste is another source this substance can result in cancer.
- Dumping of dirt’s in the wrong places messes up the environment because the substances are deleterious.
- Radio waves from a handset, television set, and radio interfere with our system in the body.
Though they are not foreign substances but have effects similar to exogenous xenobiotics. These are synthesized in the body or are produced as metabolites of various processes in the body. Example bilirubin, bile acid, steroids, eicosanoids and certain fatty acid.
Removal of xenobiotics
Two conditions can be used to remove xenobiotics:
- Increase in molecular weight
Both factors increase the probability that the substances are eliminated. There are routes in which they can leave the system. In terms of volume, xenobiotics substance can be excreted through urination, through the skin, bile e.t.c. almost all xenobiotics substances are organic, and being organic they are not water soluble. If they are lipid soluble, it means they can absorb and also pass through the lipid bilayer cells. It is the intrinsic nature that makes them penetrate and enter into our system, while some because of their chemical nature, been lipid soluble they can pass readily to the adipose tissue and have the tendency to accumulate, and these accumulations may sometimes result in substantial damage.
Biomedical importance of xenobiotics
We are exposed to a wide variety of foreign chemicals (xenobiotics), both naturally occurring compounds in plant foods, and synthetic compounds in medicine, food additives, and environmental pollutants. Knowledge of the metabolism of xenobiotics is essential for an understanding of pharmacology and therapeutics, toxicology, and the management of a disease. All these areas involve either administration of or exposure to xenobiotics. Many of the xenobiotics in plant foods have potentially beneficial effects such as acting as antioxidants, and their knowledge of their metabolism will permit extrapolation from in vitro measurement of antioxidant activity to in vivo protective action.
Understanding the mechanisms involved in xenobiotics metabolism will permit the development of transgenic microorganism and plants containing genes that encode enzymes for metabolism of a specific compound that can be used to convert potentially hazardous pollutants to harmless compounds. Similarly, transgenic organisms may be used for biosynthesis of drugs and other chemicals.