Free radicals

\( \newcommand\) • • • • • • • • • • • • • • In radical (more precisely, a free radical) is an With some exceptions, these "dangling" bonds make free radicals highly A notable example of a free radical is the hydroxyl radical (HO•), a molecule that is one : CH 2), which has two dangling bonds; and the superoxide O −2), the oxygen molecule O 2 with one extra electron, which has one dangling bond. In contrast, the HO −), the O 2−) and the CH +3) are not radicals, since the bonds that may appear to be dangling are in fact resolved by the addition or removal of electrons. Free radicals may be created in a number of ways, including synthesis with very dilute or rarefied reagents, reactions at very low temperatures, or breakup of larger molecules. The latter can be affected by any process that puts enough energy into the parent molecule, such as Free radicals play an important role in combustion, solvent cage or be otherwise bound. Until late in the 20th century the word "radical" was used in chemistry to indicate any connected group of atoms, such as a methyl group or a carboxyl, whether it was part of a larger molecule or a molecule on its own. The qualifier "free" was then needed to specify the unbound case. Following recent nomenclature revisions, a part of a larger molecule is now called a functional group or substituent, and "radical" now implies "free". However, the old nomenclature may still occur in the literature. History The first organic free radical identified was t...

Recent Examples on the Web It is made to support joint tissue health, stop oxidation and free radical damage, repair joint damage, and promote cartilage growth. — Discover Magazine, 29 Mar. 2023 This lightweight sunscreen blends in easily and efficiently, creating a barrier to prevent free radical damage to your skin and without ever leaving a chalky white cast behind. — Todd Plummer, Travel + Leisure, 28 Mar. 2023 Often dubbed the gold standard ingredient, the antioxidant boasts a variety of usages, from boosting collagen production to neutralizing free radical damage. — Kiana Murden, Vogue, 23 Mar. 2023 Cosmetics Enhancing Lash & Brow Serum $8 at Ulta Beauty$8 at Walmart$8 at JCPenney Pros Affordable Cons Must apply twice a day The antioxidants in this serum will protect your brows from free radical damage, while amino acids will promote hair growth. — Jesa Marie Calaor, ELLE, 7 Mar. 2023 Proper blood circulation in different body parts also helps reduce oxidative stress and free radical damage. — Jon Goodwin, Discover Magazine, 29 Nov. 2022 Aveeno Absolutely Ageless Daily Moisturizer SPF 30 Most derms recommend a combination of sunscreen and an antioxidant product (to fight aging free radical damage from UV exposure) for the best daily protection. — Neha Tandon, Women's Health, 20 Mar. 2023 Ingredients include baobab, argan and pomegranate oils to detangle and smooth hair, and Vitamin E to hydrate hair while protecting from free radical damage. — Natalie Alcala, The Hol...

Huntington's Outreach Project for Education at Stanford (HOPES) is a student-run project at Stanford University with the goal of making information about Huntington’s Disease (HD) more accessible to audiences worldwide. Our site is intended to be an educational resource, and address a range of topics through written articles and podcasts. • • • • • • • HD and the Brain Huntington’s disease is a neurodegenerative condition, meaning that symptoms are caused by the death of nerve cells in the brain. This section of the website gives an introduction to the brain, focusing on the changes caused by HD. Check out the HOPES Brain Tutorial for an illustrated tour of the brain; look at our “Neurobiology” section for an in-depth look at the cells that make up the brain; go to the “Other Neurodegenerative Conditions” section to learn about diseases that share some similarities to HD. • • • • • • Research and HD Welcome to the Research and HD section of the website! In the past decade, intensive research efforts have given scientists a much better understanding of how HD damages the brain. With this improved insight, researchers throughout the world are actively investigating and testing ways to delay, stop, or reverse the course of the disease. This section is divided into 5 groups. The “Conferences and Conventions” section contains updates from HD conventions around the world. The “Research Basics” section describes how researchers study HD; the “Research Updates” section talks about...

Let me ask you a question: How old do you look and feel? Older than you’d like? Let me ask you a follow-up question: How old would you like to look and feel? Younger than your age—by a couple of years… or decades? One of the keys to healthy aging is to ensure you’re eating antioxidant foods. Why? It starts with free radicals. In the simplest terms, free radicals are unstable atoms that cause damage to cells, leading to aging and illness. What makes a free radical “unstable”? It means they are atoms with an unpaired electron, and because electrons like to be in pairs, free radicals scavenge the body to seek out the needed electron. While free radicals are typically considered a nasty word, they are natural byproducts of chemical processes, such as aerobic metabolism. In other words, when our body uses oxygen to create energy, it results in the production of free radicals. In fact, free radicals are essential to life. However, when our bodies are exposed to excessive amounts of free radicals that exceed our natural ability to quench them, we experience oxidative stress. Lifestyle choices can increase our exposure to free radicals and subsequent oxidative stress, which can potentially lead to accelerated aging. These include: • Exposure to toxic chemicals including air pollution and pesticides • Smoking • Alcohol consumption • Eating fried foods This stress may damage cells and lead to a range of illnesses and cause the body to age—looking more wrinkled, causing grey hairs, i...

\( \newcommand\) • • • • • • • • • • • Learning Objectives • Describe how free radicals are generated in the body. • Explain oxidative stress and what diseases it is associated with. In mainstream advertising you may have heard that antioxidants can extend your life by preventing disease and slowing the aging process. But what are antioxidants? And how do they work in the body? Is there any truth to the marketers’ claims? Are there better sources than supplements for antioxidants? After reading this chapter you will be able to answer these questions, and your new knowledge will assist you in making dietary decisions to optimize your health. Keep in mind as you read there is no scientific evidence that antioxidants singularly provide bodily benefits, but there is evidence that certain benefits are achieved by ingesting antioxidants as part of a balanced, healthy, nutrient-rich diet. This is to say antioxidants may go a long way toward preventing damage, but other nutrients are necessary to repair damage and sustain health. No one chemical acts alone! The Atom Before we can talk about the nutritional value of antioxidants we must review a few chemistry basics, starting with the atom. Cells are the basic building blocks of life, but atoms are the basic building blocks of all matter, living and nonliving. The structural elements of an atom are protons (positively charged), neutrons (no charge), and electrons (negatively charged). Protons and neutrons are contained in the dense...

Other Topics Free Radicals and Reactive Oxygen A radical (often, but unnecessarily called a free radical) is an atom or group of atoms that have one or more unpaired electrons. Radicals can have positive, negative or neutral charge. They are formed as necessary intermediates in a variety of normal biochemical reactions, but when generated in excess or not appropriately controlled, radicals can wreak havoc on a broad range of macromolecules. A prominent feature of radicals is that they have extremely high chemical reactivity, which explains not only their normal biological activities, but how they inflict damage on cells. Oxygen Radicals There are many types of radicals, but those of most concern in biological systems are derived from oxygen, and known collectively as reactive oxygen species. Oxygen has two unpaired electrons in separate orbitals in its outer shell. This electronic structure makes oxygen especially susceptible to radical formation. Sequential reduction of molecular oxygen (equivalent to sequential addition of electrons) leads to formation of a group of reactive oxygen species: • superoxide anion • peroxide (hydrogen peroxide) • hydroxyl radical The structure of these radicals is shown in the figure below, along with the notation used to denote them. Note the difference between hydroxyl radical and hydroxyl ion, which is not a radical. Another radical derived from oxygen is singlet oxygen, designated as 1O 2. This is an excited form of oxygen in which one of...

Dedicated June 25, 2000, at the University of Michigan in Ann Arbor, Michigan. Moses Gomberg, a chemistry professor at the University of Michigan, discovered an organic free radical in 1900 and affirmed what had been thought impossible. A century later, free radical organic chemistry researchers look back to Gomberg as the founder of their field. His work led to modern theories of the structure and reactivity of organic molecule—theories whose application has had tremendous impact on modern life. Contents • • • • • • • • Nineteenth century scientists speculated that there could be a free radical containing carbon — an organic free radical. But after many attempts to isolate it failed, they concluded they were wrong and that carbon must always be tetravalent (form four bonds). Moses Gomberg was trying to synthesize a carbon compound called hexaphenylethane when he inadvertently synthesized triphenylmethyl (trityl for short), a mysterious, highly reactive, unstable substance. He recognized that he had found the long-elusive free radical and showed that carbon is not always tetravalent — the then prevailing view. Gomberg published his findings in 1900, but the existence of triphenylmethyl and other organic free radicals remained in dispute for nearly a decade. They were viewed as a curiosity even after the scientific community recognized their existence. Not until the 1930s did free radicals enter the mainstream of organic chemistry. We now know that organic free radicals are...

Previous 1 of 5 Antioxidants: Why are they important? Antioxidants are substances that may protect your cells against free radicals, which may play a role in heart disease, cancer and other diseases. Free radicals are molecules produced when your body breaks down food or when you're exposed to tobacco smoke or radiation. Antioxidants, such as vitamins C and E and carotenoids, may help protect cells from damage caused by free radicals. Other naturally occurring antioxidants include flavonoids, tannins, phenols and lignans. Plant-based foods are the best sources. These include fruits, vegetables, whole grains, nuts, seeds, herbs and spices, and even cocoa. As a bonus, fruits, vegetables and whole grains high in antioxidants are also typically high in fiber, low in saturated fat and cholesterol, and good sources of vitamins and minerals. So enjoy the variety. • Antioxidants and health. National Center for Complementary and Integrative Medicine. https://nccih.nih.gov/health/antioxidants/introduction.htm. Accessed Nov. 20, 2019. • Antioxidants and cancer prevention. National Cancer Institute. https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/antioxidants-fact-sheet. Accessed Nov. 20, 2019. • Duyff RL. Vitamins and minerals. In: Academy of Nutrition and Dietetics Complete Food and Nutrition Guide. 5th ed. Houghton Mifflin Harcourt; 2017. • Aune D, et al. Dietary intake and blood concentrations of antioxidants and the risk of cardiovascular disease, total cancer, an...