introduction to antioxidants

Introduction to Antioxidants

Course Author—Dr. Lester Packer, Ph.D.• Nu Skin Professional Advisory Board Member.• Ph.D. in Microbiology and Biochemistry from Yale

University. Worked as Professor and Senior Researcher at the University of California at Berkeley for the past 40 years.

• Has held offices as President of the International Society of Free Radical Research, President of the Oxygen Club of California, and Vice President of UNESCO’s Global Network on Molecular and Cell Biology.

• Has published over 700 scientific papers and 70 books on antioxidants and health.

Did You Know?

Many of the processes we call "aging" can be considered manifestations of the minute, cumulative effects of free radical damage on cells and tissues in the skin, heart, blood vessels, brain, etc. Find out how to prevent free radical damage in this course.

ObjectivesAfter viewing this course, you should have an understanding of the following:

• Free radicals.• Antioxidants.• How free radicals damage cells and tissues and contribute to the

aging process.• How antioxidants help fight free radical damage and can help

prevent the visible signs of aging.• Technical explanation of how free radicals and antioxidants

function.

Introduction

What Are Free Radicals?

Free radicals are highly reactive, unstable molecules that cause damage to healthy cells, leading to internal aging as well as visible signs of external aging.

Unstable free radicals

Cell

DNA

Mitochondria

What Are Antioxidants?

Antioxidants are molecules capable of defending our cells from free radical damage. Since free radicals are not only created in the environment, but also in our bodies, a continuous supply of antioxidants is critical for internal and external health and longevity.

Free radicals

Antioxidants defend cells.

Example of Free Radical Damage: The First Wrinkle

We come into this world with healthy cells, but every day the negative effects of free radicals add to the damage of the previous day. Each day, our young, healthy skin is exposed to trillions of free radicals from a variety of sources, such as the sun’s ultraviolet rays, pollution, smoke, internal processes, and external stress.

The First Wrinkle

Overexposure to free radicals damages not only our cells’ ability to function, but also the integrity of our cells’ overall composition, resulting in a next generation of cells that is less healthy and less productive than the cells they came from.

The First WrinkleIn the case of our skin cells, this can mean, over time, our fibroblasts—cells responsible for collagen and elastin production—will be working less efficiently to produce the skin proteins necessary for skin smoothness, firmness, and elasticity.

Dermis

Epidermis

Blood Vessels

Mast Cell

Collagen Fiber

Elastin Fiber

Fibroblast Cell

Dermal - Epidermal Junction

Glycosaminoglycans

The First WrinkleAlthough this is happening gradually beneath the outermost surface of our skin, this decrease in collagen and elastin production becomes visible sometime in our late twenties or early thirties when we look in the mirror and discover our first wrinkle.

Sources of Free Radicals

Sources of Free RadicalsFree radicals—unstable, highly reactive compounds—are created inside our bodies through normal, necessary chemical reactions and all around us through pollution, UV radiation, x-rays, stress, strenuous exercise, and smoking.Smoking can be particularly harmful: Each cigarette releases 10 quadrillion free radicals into the lungs. This is why smokers age so much faster than non-smokers.

How Free Radicals Age the Skin

Free Radical DamageFree radicals damage lipids, proteins, and DNA. DNA is present in the nucleus of almost every cell, stores all genetic information, and dictates cellular functions. The damage done to lipids, proteins, and DNA by free radicals is the root cause of aging.

Free radicals damage lipids, proteins, and DNA

Damaged Cell

Free Radical Damage

Every day, the DNA in a single cell receives thousands of free radical assaults. Fortunately, our cells have repair enzymes that fix most of this damage. As we get older, the delicate balance between damage and repair becomes unbalanced. When cells with damaged DNA replicate, they create cells with imperfect structure and a compromised ability to function.

Free radicals damage DNA

Nucleus

DNA damage

Cellular Damage

In addition to the molecular DNA damage caused by free radicals, they also cause damage to other basic cellular structures such as mitochondria—structures inside the cell responsible for cellular energy production. If one considers the cell as a small factory, the mitochondria would be the thousands of tiny power generators that enable the cell to function properly. Free radicals damage

lipids, proteins, and DNA

Damaged cell

DNA

Mitochondria

Cellular OxidationWhen scientists talk about the effect of free radicals on cellular components, such as DNA or mitochondria, they say the structure has been “oxidized.” When cell structures are oxidatively damaged by free radicals, the health of the entire cell is weakened.

Cell structures are oxidized.

DNA

Mitochondria

Antioxidants Are Anti-Aging

AntioxidantsAntioxidants are a category of nutrients that have the ability to fight cell-damaging free radicals. By defending our cells against free radicals, antioxidants can help slow the internal and external aging processes.

Antioxidants neutralize free radicals

Neutralized free radicals

AntioxidantsThere are hundreds of known antioxidants, many of which are derived from plants. Plants, to protect their constantly exposed tissues from free radicals, have developed free radical fighting phytochemicals as a natural defense system. Each plant contains hundreds of phytochemicals, many of which provide antioxidant protection and fulfill many other essential functions. Carotenoids, polyphenols, and flavonoids are some examples.

Skin Beneficial Antioxidants

Key Antioxidants

• Vitamin antioxidants • Carotenoids• Phenolic Compounds

• Flavonoid polyphenols• Other key antioxidants

• Coenzyme Q10• Alpha lipoic acid

O

CH3

CH3

CH3

CH3 CH3 CH3

CH3CH3

OH

Vitamin E

O

OH

SS

Alpha Lipoic Acid

HO

HO OH

Hydroxytyrosol

The Antioxidant NetworkAntioxidants rely on a network for protection and support. Antioxidants work together to fight free radicals directly or to regenerate and support other antioxidants. In the antioxidant network, carotenoids are the first line of defense. By destroying free radicals, carotenoids protect and enable other antioxidants to perform their more specific and critical functions.

The Antioxidant Network

The core of the antioxidant network includes powerful antioxidants such vitamins E, C, and CoQ10. In addition to their free radical fighting properties, these antioxidants have other functions that allow them to make critical contributions to our health and longevity.

Vitamin C

Vitamin EVita

min EVitam

in C

CoQ10

CoQ10

(Carotenoids)

Carotenoids enable other antioxidants to perform more specific functions

Vitamin Antioxidants—Vitamin E Vitamin E is one of the body’s most important fat-soluble antioxidant nutrients. Vitamin E protects healthy cell membranes (largely composed of fatty acids) from oxidative free radical damage.There are eight natural forms of vitamin E (four forms of tocopherols* and four tocotrienols).

*Ingredients in skin care formulations that contain a variation of the name tocopherol (e.g., tocopheryl acetate and tocopheryl lineate) are forms of the antioxidant vitamin E.

Vitamin E

O

CH3

CH3

CH3

CH3 CH3 CH3

CH3CH3

OH

Vitamin Antioxidants—Vitamin C

Vitamin C (ascorbic acid*) is water-soluble, enabling it to scavenge free radicals in aqueous (watery) environments, such as the inside of our cells and extracellular body fluids. Vitamin C works synergistically with vitamin E to quench free radicals and also works to regenerate vitamin E, keeping it active.

* Ingredients in skin care formulations that contain a variation of the term ascorbic (e.g., ascorbyl palmitate) are forms of vitamin C.

CarotenoidsCarotenoids are a major class of phytonutrients. Examples of carotenoids are beta-carotene, alpha-carotene, lutein, and lycopene. They are natural, fat-soluble pigments found principally in plants and algae, where they play a critical role in protecting and aiding the photosynthetic process.Carotenoids are responsible for many of the red, orange, and yellow hues of plant leaves, fruits, and flowers.

CarotenoidsCarotenoids—sometimes referred to as the first line of defense—provide critical antioxidant protection to cells and other antioxidants by absorbing or “blotting up” large amounts of attacking free radicals. This allows other antioxidants to function in more specialized ways.

Phenolic CompoundsJust as plants produce lipid-soluble carotenoids to protect cellular structures composed mostly of lipids, plants also produce phenolic (ring-like structure) compounds to guard their tissues against free radical damage. These compounds can be fat or water-soluble. Examples of phenolic compounds are hydroxytyrosol in olive oil (one phenolic ring) and polyphenols (multiple phenolic rings) in strawberries.

HO

HO OH

Hydroxytyrosol (one ring)

Flavonoid PolyphenolsFlavonoids are a class of polyphenolic compounds, containing multiple ring structures. It is estimated that there are over 600 different flavonoids present in foods and beverages. Some common flavonoids are catechins (green tea), quercetin, proanthocyanidins (grape seed extract), and soy isoflavones.Flavonoids provide increased cell protection for the DNA as well as promote the repair of DNA damaged by free radical oxidation.

OH

O C

O

HOOH

OHOH

OH

OHOH

Flavonoid Polyphenol (multiple rings)

Phenolic Ring Structure

O

Other Key Antioxidants—Alpha Lipoic Acid

Alpha lipoic acid is a naturally occurring molecule in plants and animals that has the ability to neutralize free radicals. Another important function of alpha lipoic acid is its ability, when applied topically, to improve skin tone and texture.

O

OH

SS

Alpha Lipoic Acid

Other Key Antioxidants—CoQ10 Coenzyme Q10, or CoQ10, is found naturally in our cells; however, CoQ10 levels in the body have been shown to decline after age 20.Highly concentrated within the cell’s mitochondria, CoQ10, like vitamins C and E, quenches free radicals and helps regenerate other antioxidants.

Additionally, CoQ10 plays an important role as a co-enzyme in generating cellular energy and offers critical protection to the mitochondria (power generators) in all cells.

O

H3CO

CoQ10

H3CO

CH3

OCH3

H

10

Internal and External Supplementation

Just as health and nutrition experts recommend a high intake of antioxidants from a variety of fruits and vegetables and nutritional supplements, skin care experts are now recognizing the anti-aging benefits of topically applied antioxidants.

Recent scientific studies have shown that supplementing internally and topically with antioxidants results in higher overall antioxidant levels than either delivery method alone.

Topical AntioxidantsSome skin care products offer antioxidant benefits directly to the skin by including antioxidant-rich vitamins and extracts in their formulations. While carotenoids have typically not been included in skin care products due to their intense color, a unique form of colorless carotenoids with enhanced UV-protective properties has been discovered.

Review—Key Antioxidants• Vitamin antioxidants

• Vitamin E • Vitamin C

• Carotenoids (e.g., beta-carotene, alpha-carotene, lutein, and lycopene).• Phenolic Compounds (e.g., hydroxytyrosol in olive oil and

phytochemicals in strawberries). • Flavonoid polyphenols (e.g., green tea catechins, grape seed

proanthocyanidins, and soy isoflavones). • Other key antioxidants

• Coenzyme Q10• Alpha lipoic acid

Review—Antioxidants and Free Radicals• Free radicals are highly unstable, reactive molecules.• Free radicals damage the DNA within cells. This damage

is passed on to newly replicated cells. Over time, genetic damage builds up and interferes with healthy cell function.

• Antioxidants are natural compounds found in fruits and vegetables that fight free radicals, thereby neutralizing their negative effects.

• Some key antioxidants are vitamins E and C, carotenoids, flavonoids, alpha lipoic acid, and CoQ10.

Technical Appendix: How Free Radicals and Antioxidants Function

How Free Radicals Damage CellsFree radicals are unstable, highly reactive molecules because they have one or more unpaired electrons. Note: every atom has protons (positively charged) and neutrons (neutral) in their nucleus, with electrons (negatively charged) circling around the nucleus.

e- e-

e-

e-

Unstable free radical

Stable atom

How Free Radicals Damage Cells

In order to stabilize themselves, free radicals seek ways to pair their unpaired electrons. To do this, they may steal electrons from other stable molecules.

e- e-

e-

e-

Free radical stealing electrons from a stable atom.


This can cause the secondary molecule to become a reactive, unstable free radical.

e- e-

e-

e-


How Free Radicals Damage CellsHaving lost its electron, these secondary molecules become free radicals that, in turn, steal electrons from other molecules.

e- e-

e-

e- e-

e-



This cascading effect sets off a free-radical chain reaction of molecular destabilization.

e- e-

e-

e-e-

e-

Free radical chain reaction


Free radical chain reactions can continue indefinitely, ultimately damaging millions of cells.

e- e-

e-

e- e-

e-

Free Radical DamageMuch of what is damaged by free radicals are DNA, lipids, and proteins that make up the cellular structures in our bodies.

e- e-


Cell

Free Radical DamageAmong other serious consequences, this damage leads to side effects associated with skin-aging, such as poor cell renewal, and slowed collagen and elastin production.

e- e-

Damaged cell

How Antioxidants Work


Antioxidants are stable molecules with electrons to spare or with the ability to receive extra electrons.

e-

e-

e-

Antioxidant


Antioxidants are nature’s defense against the damaging effects of free radicals. They guard cellular structures and DNA against electron-scavenging free radicals.

e- e-

e-

e-

e-

Unstable free radical Antioxidant protecting the cell.


Antioxidants donate or receive one extra electron to neutralize free radicals and stop the cascading effect of oxidation.

e- e-

e-

e-

e-

Stable atom Antioxidant

You have completed Technical Appendix: How Free Radicals and Antioxidants

Function.

Test Your Knowledge

Congratulations!

You have completed the Introduction to Antioxidants course.

introduction to antioxidants

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