Á¦  ¸ñ :   oxidant-antioxidant

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4310837/  Free Radicals: Properties, Sources, Targets, and Their Implication in Various Diseases

https://www.slideshare.net/alokbharti18/free-radicals-and-antioxidants

https://www.slideshare.net/YESANNA/free-radicales-antioxidants

http://articles.mercola.com/sites/articles/archive/2011/05/16/all-about-antioxidants.aspx


Five 5Types of Free Radicals

==Free radicals can be broken down into five types. The first four types come from oxygen atoms and are called Reactive Oxygen Species (ROS), but the fifth type derives from nitrogen:

Superoxide ion (O): An oxygen molecule with an extra electron that can damage mitochondria, DNA and other molecules.

Hydroxyl radical (OH): A highly reactive molecule formed by the reduction of an oxygen molecule, capable of damaging almost any organic molecule in its vicinity, including carbohydrates, lipids, proteins, and DNA. OH cannot be eliminated by an enzymatic reaction.

Singlet oxygen: Formed by your immune system, singlet oxygen causes oxidation of your LDL.

Hydrogen peroxide (H2O2): Not a free radical itself, but easily converts to free radicals like OH, which then do the damage. Hydrogen peroxide is neutralized by peroxidase (an enzymatic antioxidant). H2O2Á¦°Å¿¡´Â catalase, glutathione peroxidase, peroxiredoxinsÀÌ °ü¿©

Reactive Nitrogen Species (RNS) (NO): Nitric acid is the most important RNS.

----These various free radical species can damage DNA in different ways.

----They can disrupt duplication of DNA, interfere with DNA maintenance, break open the molecule or alter the structure by reacting with the DNA bases. Cancer, atherosclerosis, Parkinson's, Alzheimer's disease, and cataracts are examples of diseases thought to result from free radical damage. In fact, free radicals are implicated in more than 60 different diseases.

Lipids in cell membranes are quite prone to oxidative damage because free radicals tend to collect in cell membranes, known as "lipid peroxidation." (The lipid peroxide radical is sometimes abbreviated as LOO.) When a cell membrane becomes oxidized by an ROS, it becomes brittle and leaky. Eventually, the cell falls apart and dies.

>>singlet oxygen ==>LDL cholesterol »êÈ­, °á°úÀûÀ¸·Î ½ÉÇ÷°üÁúȯ ÃÊ·¡---Æú¸®Æä³î·Î ÁßÈ­ °¡´É..

 Singlet Oxygen (1O2)...meloperoxidase¸¦ ÀÌ¿ëÇؼ­  H2O2 +  Cl-  →  HOCl +  OH·¸¦ »ý¼ºÇÏ°í À̾....HOCL + H2O2 --> 1O2 + H2O+Cl-À» »êÃâÇÏ´Â Áß¼º±¸ È£»ê±¸ ³» ±Õ»ç¸ê°úÁ¤¿¡¼­ »ý¼º.....¶ÇÇÑ, .lipoxygenases [39], dioxygenases [40],  lactoperoxidase¿¡ ÀÇÇؼ­µµ ¹ß»ý ..........DNA damage [42]¿Í tissue damageÀ¯¹ß

>>superoxide ÀÌ¿Â == *¹ÌÅäÄܵ帮¾Æ È£Èí°úÁ¤¿¡¼­ Complex I and Complex III·ÎºÎÅÍ Áß°£´ë»ç»ê¹°·Î ¸¸µé¾îÁö±âµµ Çϸç *´Ù¸¥ È¿¼Òµé, ¿¹¸¦ µé¸é xanthine oxidase¿¡ ÀÇÇؼ­µµ ¹ß»ý..*ħÀÔ¼¼±Õ Ž½Ä/»ç¸ê°úÁ¤¿¡ ¹Ýµå½Ã ÇÊ¿äÇϹǷΠNADPH oxidase¿¡ ÀÇÇØ ´ë·®»ý»êµÊ((NADPHÀ¯ÀüÀÚºÎÀ§ÀÇ À¯Àüº¯À̴ ƯÈ÷ catalase¾ç¼º±Õ¹Ýº¹°¨¿°ÀÌ  Æ¯Â¡ÀÎ ¸é¿ª°áÇÌÁõÈıºÀÎ ¸¸¼ºÀ°¾ÆÁ¾Áõ ¹ß»ý°ú °ü°èµÇ´Âµ¥, À̾ ¼¼±ÕÀÇ À¯ÀüÀÚ Á¶ÀÛÀ» ÅëÇؼ­ SOD°áÇÌÀ» À¯¹ß½ÃÄÑ º¸¸é µ¶¼ºÀ» ¼Ò½ÇÇÔÀ» º¼ ¼ö ÀÖ´Ù.((Áï, °ÅÀÇ ¸ðµç È£±â¼º¼¼±ÕÀº SOD¸¦ °¡Áö°í ÀÖÀ½)...superoxide¿¡ ÀÇÇØ »êÈ­-ȯ¿ø µÇ´Â ´Ù¸¥ ´Ü¹éÁúµéÀº ¾àÇÑ SOD°°Àº ¼ºÁúÀ» °¡Áö°í ÀÖ°Ô µÊ. **iron-sulfur cluster¸¦ ÇÔÀ¯ÇÏ°í ÀÖ´Â È¿¼ÒµéÀ» ºÒÈ°È­½ÃÅ´À¸·Î½á free ironÀ» À¯¸®½ÃÄѼ­ °á±¹ ÆæÅæ¹ÝÀÀ ÅëÇÑ È÷µå·Ï½Ã ¶óµðÄ® »ý¼ºÇϴµ¥ °ü¿©ÇÔ..((Fe2+ÈѷνºÀÌ¿Â + H2O2 ----> Fe3+ÈѸ¯ÀÌ¿Â + .OHÈ÷µå·Ï½Ã¶óµðÄ® + OH-¼ö»êÈ­ÀÌ¿Â )) **HO2*(È÷µå·ÎÆÛ¿Á½Ã¶óµðÄ®)ÇüÅ¿¡¼­ PUFAÀÇ ÁöÁú°ú»êÈ­¸¦ °³½ÃÇÔ.....¶ÇÇÑ carbonyl ¼ººÐ°ú halogenated carbon°ú ¹ÝÀÀÇÏ¿© ±× °á°ú peroxy radicalÀ» »êÃâ

Superoxide anion radical  (O2∙)  : °¡Àå Áß¿äÇϸç, ±¤¹üÇÑ ¿µ¿ª¿¡ ¿µÇâ ³¢Ä§// mitochondria, DNA and other moleculesÀ» ¼Õ»ó½ÃÅ´.. È¿¼Ò¹ÝÀÀ(xanthine oxidase [21], lipooxygenase, cyclooxygenase [22, 23] and NADPH dependent oxidase), ºñÈ¿¼Ò¹ÝÀÀ(¹ÌÅäÄܵ帮¾Æ ³» ÀüÀÚÀü´Þ°è ETC complex I&III¿¡¼­ »ê¼Ò¿¡ ÀüÀÚÀü´ÞÇÏ´Â °úÁ¤Áß¿¡¼­)À¸·Î ¹ß»ý.....»ýüºÐÀÚ¿ÍÀÇ ¹ÝÀÀ·ÂÀº ³·ÀºÆí... pH°¡ ³·À» ¶§(»ê¼º??) µÎ ÇüÅ·ΠÁ¸Àç °¡´É... hydroperoxyl radicalÀº °¡Àå Áß¿äÇÑ ÇüÅ·μ­ charged form (O2•−)º¸´Ù ´õ ½±°Ô ÀÎÁöÁú³»·Î À¯ÀÔ °¡´ÉÇÔ . »ý¸®Àû pH¿¡¼­ °¡Àå ¹ß»ýÀÌ ½¬¿î ÇüÅ´ superoxide¿©¼­ ȯ¿øÁ¦·Î¼­ ¿ªÇÒÀ» ³ªÅ¸³»°Ô µÇ´Âµ¥, . cytochrome-c ¹× ferric-ethylene diaminetetraacetic acid (EDTA-Fe3+)°°Àº  iron complexes µéÀ» ȯ¿ø½ÃÅ°°í ±× °á°ú 3°¡ öÀÌ 2°¡ ö·Î ¹Ù²ñ,....¶ÇÇÑ »êÈ­Á¦·Î¼­ ÀÛ¿ëÇϱ⵵ Çϸç(2°¡ ÈѷνºÀÌ¿ÂÀÌ 3°¡ ÈѸ¯ÀÌ¿ÂÀ¸·Î ¹Ù²ñ), ¶ÇÇÑ  ascorbic acid¿Í tocopherolÀ» »êÈ­½ÃÅ´....¶ÇÇÑ µÎ°³ÀÇ superoxide°¡ ¹ÝÀÀÇÏ¸é °ú»êÈ­¼ö¼Ò¿Í »ê¼Ò°¡ ¹ß»ýÇÔ

Hydroxyl radicals...•OH,  neutral form of the hydroxide ion (OH−) [»ý¼º±âÀü] **¿ÜºÎ ±Õħ½À½Ã Macrophages ¹× microglia ¸é¿ª¹ÝÀÀ -->ÁÖÀ§¿¡ ¸é¿ª°úÀ×¹ÝÀÀ ÆÄ±Þ : ÀÚ°¡¸é¿ª½Å°æÁúȯ À¯¹ß **ÆæÅæ¹ÝÀÀ¿¡ ÀÇÇؼ­ »ý¼º..H2O2 + Fe2+ --> Fe3+ OH- £« *OH . [¼¼Æ÷Á¶Á÷ ¼Õ»ó...¸Å¿ì µ¶¼ºÀÌ Å­] ź¼öÈ­¹°, ÇÙ»ê(À¯Àüº¯ÀÌ). ÁöÁú(°ú»êÈ­), ¾Æ¹Ì³ë»ê( Phe¸¦ m-Tyrosine and o-TyrosineÀ¸·Î º¯È¯) [ÆıÞ...ÆÛ¿Á½Ã ¶óµðÄ® »ý¼º] •OH(È÷µå·Ï½Ã ¶óµðÄ®) + RH(¾ËųȭÇÕ¹°)-->H2O + R•(¾Ëų ¶óµðÄ® .CH3*)......R• + O2 → RO2*(ÆÛ¿Á½Ã ¶óµðÄ®)

Hypochlorous Acid (HOCl) Àº »êÈ­ ¹× ¿°¼ÒÈ­ ¹ÝÀÀ¿¡ °ü¿©ÇÏ´Â major oxidant·Î¼­  myeloperoxidae¿¡ ÀÇÇØ À§¿Í °°ÀÌ »ý¼ºµÇ´Âµ¥, thiols¿Í ascorbate, urate, pyridine nucleotides, tryptophanµîÀ» »êÈ­½ÃÅ°¸ç, ¾Æ¹Î·ù¸¦ ¿°¼ÒÈ­½ÃÄѼ­ Ŭ·Î¶ó¹ÎÀ¸·Î º¯È¯½ÃÅ´ ---Ƽ·Î½Å ±âÀÇ ¿°¼ÒÈ­, ÄÝ·¹½ºÅ×·Ñ ¹× ºÒÆ÷È­Áö¹æÀÇ Å¬·Î¸£È÷µå¸° º¯È­ DNAÀÇ ¿°¼ÒÈ­ À¯¹ß...,

Ozone (O3) °­·ÂÇÑ »êÈ­Á¦...ü³»¿¡¼­´Â ¿°Áõ¹ß»ý¿¡ Áß¿äÇÑ ¿ªÇÒÀ» ´ã´çÇÏ´Â water oxidation°æ·Î¿¡ ´ëÇØ Ã˸ÅÀÛ¿ëÇÏ´Â Ç×ü¿¡ ÀÇÇØ »ý¼º °¡´É..´Ù¸¥ »êÈ­¶óµðÄ®À» »ý¼ºÇÏ´Â Áß°£Ã¼ ¿ªÇÒ.....´õºÒ¾î ÁöÁú°ú»êÈ­ ¹× ¾Æ¹Î·ù, ¾ËÄÚ¸£ ¾Ëµ¥È÷µå, ¼³ÆÄÈ÷µå¸±±â¸¦ »êÈ­½ÃÅ´..¶ÇÇÑ Á÷Á¢ ¶Ç´Â ´Ù¸¥ »êÈ­¶óµðÄ® »ý¼ºÀ» ÅëÇØ °£Á¢ÀûÀ¸·Î ¿°»öü¼Õ»óÀ» À¯¹ß½ÃÅ´.

Peroxyl Radical (ROO∙) : °¡Àå ´Ü¼øÇÑ ÇüÅ´ superoxide·ÎºÎÅÍ ³ª¿Â perhydroxyl radical (HOO•)·Î¼­ Áö¹æ»ê»êÈ­¸¦ Ã˹ßÇϸç, ¾Ï¹ß»ý¿¡µµ °ü¿©


Enzymatic and Non-Enzymatic Antioxidants

==Antioxidants can be categorized into two types:

>Non-enzymatic antioxidants work by interrupting free radical chain reactions. For example, having vitamin E around may interrupt a chain of free radical activity after only five reactions, instead of its snowballing into 100 reactions. Non-enzymatic antioxidants include vitamin C, vitamin E, plant polyphenols, carotenoids and glutathione (GSH).

Glutathione has been called the “master antioxidant” and is found in every single cell of your body, maximizing the activity of all the other antioxidants.

>Enzymatic antioxidants work by breaking down and removing free radicals. In general, these antioxidant enzymes flush out dangerous oxidative products by converting them into hydrogen peroxide, then into water, in a multi-step process that requires a number of trace metal cofactors (copper, zinc, manganese and iron). You can’t supplement these enzymatic antioxidants orally—they must be produced in your body.

Most antioxidants found in foods and supplements are of the non-enzymatic type. They boost your enzymatic antioxidant defense system by doing a "first sweep," disarming the free radicals, which helps prevent depletion of your enzymatic antioxidants.

---The principle enzymatic antioxidants are the following:

Superoxide dismutase (SOD): Assisted by copper, zinc, manganese and iron, SOD breaks down superoxide (which plays a major role in lipid peroxidation) into oxygen and hydrogen peroxide. SOD is present in nearly all aerobic cells and extracellular fluids.

Catalase (CAT): Converts hydrogen peroxide into water and oxygen (using iron and manganese cofactors), hence finishing up the detoxification process that SOD started.

Glutathione peroxidase (GSHpx) and glutathione reductase: These selenium-containing enzymes help break down hydrogen peroxide and organic peroxides into alcohols, and are particularly abundant in your liver.

As you can see, these powerful enzymes do a wonderful dance in your body that turns toxins into harmless water!


==Water-Soluble and Lipid-Soluble Antioxidants

Another categorization of antioxidants is based on whether they are soluble in water (hydrophilic) or in lipids (hydrophobic). You require both types to protect your cells.

The interior of your cells and the fluid between them are composed mainly of water. But your cell membranes are made largely of fat. As you know, oil and water don't mix. Substances that are soluble in water are not soluble in fat, and vice versa.

>The lipid-soluble antioxidants (such as vitamins E and A, carotenoids, and lipoic acid) are primarily located in your cell membranes, whereas the water-soluble antioxidants (such as vitamin C, polyphenols and glutathione) are present in aqueous fluids, such as your blood and the fluids within and around your cells (the cytosol, or cytoplasmic matrix).

Free radicals can strike the watery cell contents or the fatty cellular membrane, so the cell needs defenses for BOTH. The lipid-soluble antioxidants are the ones that protect your cell membranes from lipid peroxidation.

The fact that antioxidants are so complex and multifactorial has led people to be confused about what antioxidants they should be taking. For example, I have been asked on more than one occasion if it's necessary to take Purple Defense if you are already taking astaxanthin. The short answer is, YES.

Astaxanthin is a lipid-soluble antioxidant, and the antioxidants found in Purple Defense (anthocyanins, polyphenols, resveratrol) are water-soluble antioxidants. As you have now seen, each type has its own special function.

But solubility isn't the only variable among antioxidants.

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