Chapter 4C - Xenobiotic Compounds PDF

Part 1  EXOGENOUS DIETARY FOOD INHALATION MEDICINES /DRUGS STUFFS eg THROUGH FOR THERAPEUTIC food additives ENVIRONMENT eg CAUSE  Metabolites are defined as low-molecular-weight organic and inorganic chemicals which are the reactants, interm...

Part 1  EXOGENOUS DIETARY FOOD INHALATION MEDICINES /DRUGS STUFFS eg THROUGH FOR THERAPEUTIC food additives ENVIRONMENT eg CAUSE  Metabolites are defined as low-molecular-weight organic and inorganic chemicals which are the reactants, intermediates, or products of enzyme- mediated biochemical reactions A metabolite is a compound produced by the plant for growth and development (primary metabolite) or as a part of their defense or survival mechanism (secondary metabolite), the Metabolites are the intermediate end product of metabolism usually restricted to small molecules Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, catalytic activity of their own (usually as a cofactor to an enzyme), defense, and interactions with other organisms (e.g. pigments, odorants, and pheromones). Eg Ethylene is an example of a primary metabolite produced in large-scale by industrial microbiology. Eg A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. Examples include antibiotics and pigments such as resins and terpenes etc.  any chemical compounds that are found in a living organism, but which are foreign to that organism, I.E it does not normally produce the compound or consume it as part of its diet Man-made chemicals that are produced at much are present in the lower concentrations environment at unnaturally than man made high concentrations. chemicals. Xenobiotic compounds Microorganism they are unable to s are also able degrade many others. to degrade The compounds that many of the resist biodegradation xenobiotic and thereby persists in compounds the environment are called recalcitrant.  (ii) They are highly stable, (i) They are not i.e., chemically and recognised as substrate biologically inert due to the by the existing presence of substitution degradative enzymes, groups like halogens, nitro-, (vii) lack of the perm- sulphonate, amino-, ease needed for their methoxy- and carbamyl transport into the groups, microbial cells. (iii) They are Reasons for the insoluble in xenobiotic water, or are compounds being adsorbed to (v) Their large recalcitrant external molecular size matrices like prevents entry into soil, microbial cells, (iv) They are highly (vi) Inability of the toxic or give rise to compounds to toxic products due to induce the microbial activity, synthesis of degrading enzymes (i) Presence of halogens Many other xenobiotics in the place of hydrogen resist biodegradation due to in the molecule; the their large molecular size carbon-halogen bond is and insolubility in water. highly stable and its cleavage requires considerable energy The structural features that make these compounds (iii) Cyclic structures, resistant to microbial aromatic compounds, degradation cycloalkanes and the more complex heterocyclic compounds is the structure of are more recalcitrant (ii) Substitution a xenobiotic than linear chain or of H by other compound, the aliphatic compounds, groups like more resistant it nitro-, is to sulphonate, biodegradation methoxy-, amino- and carbomyl groups, (iv) Branched linear chains resist biodegradation etc. Petrochemic Pesticide al industry industry Produced eg Eg benzene, Paint Vinyl chloride benzene industry and benzene derivatives.eg ingredients: Sources of xenobiotic solvents, compounds xylene, toluene, preservative Plastic s industry Others Uses Eg complex Electronic, organic textile , compounds cosmetic eg antioxidants Examples of xenobiotic compounds halocarbo ns Alkylbenzyl Sulfonates (i) Toxicity: Many xenobiotics like halogenated and aromatic hycrocarbons are toxic to (ii) Carcinogenicity: bacteria, lower eukaryotes Certain halogenated and even humans. At low hydrocarbons have been concentrations they may shown to be carcinogenic. cause various skin problems and reduce reproductive (v) They are produced potential. and used in large Hazards from Xenobiotic quantities which Compounds: favours their The xenobiotics present a number of accumulation in potential hazards to man and the nature. (iii) Many environment xenobiotics are (iv) Many xenobiotics recalcitrant and including DDT and PCB’s persist in the are recalcitrant and environment so that lipophilic; as a there is a build up consequence they show in their bioaccumulation or bio- concentration with magnification often by a time. 4 6  Fate of xenobiotics Xenobiotics Outside the body Inside the body Entrance to body Ingestio Inhalati Derm n on al Absorption into blood stream and distribution to body tissues and organ Storag Biotransformati Toxicity e on actions Cell injury Carcinoge nic Excretio ns Outside the body Inorganic Organic compounds compounds  Link to resources related to Xenobiotics https://www.youtube.com/watch?v=8 CENcknqEXM https://www.youtube.com/watch?v=z kS7PZUE27g https://www.youtube.com/watch?v=T oZ-w8cHJs4