Xenobiotics are chemical substances foreign to animal life, such as drugs, pesticides, pollutants, and food additives. They are not naturally produced by organisms and can be harmful if they enter the food chain. Xenobiotics are metabolized in two phases - phase I involves reactions like oxidation and reduction, while phase II involves conjugating the intermediates with molecules like glutathione to facilitate excretion. Exposure to xenobiotics can occur through the environment, diet, or occupation and has been linked to both acute and chronic health effects including toxicity, diseases, and reproductive issues.

1. XENOBIOTICS
Presented by:
1. Wahab ul Khairy (5777)
2. Sarah Shoukat (5046)

2. Introduction
■ Xenobiotic is a term used to describe chemical substances that are foreign to
animal life.
■ Examples as plant constituents, drugs, pesticides, cosmetics, flavorings,
fragrances, food additives, industrial chemicals and environmental pollutants.
■ Xenobiotic means ‘foreign to life’.
■ It can also cover the substances in which are present in higher concentrations
than usual in any product.
■ It’s not normally naturally produced.

3. Origin
■ Some organisms may also form them as a part of their defense system,
■ Examples; mycotoxins, bacterial and herbal toxins, etc.
■ Xenobiotics become harmful when entering the food chain.
■ Contemporary human exposure to xenobiotics is unavoidable, as they are
omnipresent.
■ Term xenobiotic is derived from the Greek words ξένος (xenos) = foreigner,
stranger and βίος (bios) = life.
■ Xenobiotics may be grouped as carcinogens, drugs, environmental pollutants,
food additives, hydrocarbons, and pesticides.

4. Purpose
■ Xenobiotic metabolism functions primarily to increase the polarity of
xenobiotics, making them easier to excrete.
■ With passive transport, molecules cross biological membranes without the
consumption of chemical energy.

5. Types
■ Environmental pollutants,
■ Hydrocarbons,
■ Food additives,
■ Oil mixtures,
■ Pesticides,
■ Synthetic polymers,
■ Carcinogens, drugs, and antioxidants are the major groups of xenobiotics

6. The role of xenobiotics in human
health:
■ XENobiotics may alter the microbiota composition, leading to
a state of dysbiosis, which is linked to multiple diseases and
adverse health outcomes, including increased toxicity of
some xenobiotics.

7. Sources
■ Ambient environment : Learn about the various sources of xenbiotics
present in our surrounding including Air pollutants, water Contaminants
and soil contaminants.
■ Dietary Exposure: Explore how Xenbiotics can enter into the human body
through the contaminated food.
■ Occupational exposure: Discover the Potential risks of Xenbiotics exposure
in specific environment , such as Factories, laboratories and agriculture
fields.

8. Effect on human Health
■ Acute Toxicity: Understand the immediate and severe harmful effects
xenobiotics can have on human health, ranging from poisoning to organ
damage.
■ Chronic Diseases: Explore how long-term exposure to xenobiotics can
contribute to the development of chronic diseases, including cancer,
neurological disorders, and respiratory conditions.
■ Reproductive health: Discover the impact of xenobiotics on reproductive
health, including fertility issues, developmental abnormalities in offspring,
and hormonal disruptions.

9. Metabolism of Xenobiotics
■ Phase I Reactions: Learn how xenobiotics are metabolized through oxidation,
reduction, and hydrolysis reactions to generate reactive intermediates.
■ Phase II Reactions: Explore the conjugation processes where reactive
intermediates are combined with molecules like glutathione and glucuronic
acid to facilitate their elimination.
■ Role of Enzymes: Discover the crucial role of enzymes, such as cytochrome
P450 and UDP-glucuronosyltransferase, in metabolizing and biotransforming
xenobiotics.