Question

A number of Cytochrome P450 enzymes have evolved to metabolise xenobiotics.

a) Explain the sequence of events that occurs to metabolise medicinal drugs.

b) Explain why dioxin is difficult to metabolise in comparison to medicinal drugs and discuss the molecular consequences of dioxin infiltration into cells that lead to toxic responses

Answer 1

Xenobiotics or chemical substance found but not produced in the organism for the environment. Endobiotics which are the naturally occurring chemicals that become xenobiotics when present in the environment at excessive concentration.

Liver plays the major role in drug metabolism. Metabolic reaction in hepatic and extrahepatic tissues and that can be classified as phase 1 and phase 2. Here phase one is considered as functionalization phase and phase 2 as conjugation phase. And phase of reactions depends upon the product which is formed.

Phase 1 reactions for mainly oxidative, reductive or hydrolytic among which oxidative pathways play the major role and cytochrome p450 enzyme family is the major oxidative enzyme.

Dioxins or environmental pollutants they belong to the so called dirty zone a group of dangerous chemicals known as persistent organic pollutants.

Because of their highly toxic potentiality dioxins are concerning more for the research. Dioxins are chemically more stable. Dioxins affects and harm through similar biological pathways and share common structures. Mostly dioxins or lipophilic and it tends to bioaccumulate and does persist in the environment and the human body for long period of time. Once dioxins are consumed it can stay in the body for a long period of time they are stable chemicals which means it cannot be broken down. Once if it enters the body it takes around 7 to 11 years for the dioxins radioactivity which may it fall to half its original level. It is difficult to metabolize as they are accumulated in the food chain mainly in the fatty tissue of the animals and stays in the body for a long period of time because of its chemical stability.

Organisms which are exposed to dioxins they suffer from a variety of toxicities structures molecular disorders that leads to death and it also causes reproductive toxicity, endocrine dysfunctionality, neurodevelopmental toxicity, immunosuppression, cancer. it may also cause any adverse health effects including hormonal problems in fertility and possibly diabetes. When one is exposed to excessive concentration of dioxins for a short period of time they can lead to chloracne. Which is a skin disease with acne like lesions mainly occurs in the face and in the upper body.