A Study on Antioxidant from Natural Origin

Antioxidant Are Nutraceuticals Whose Deficiency States Are Associated with Variety of Dreaded Disease Conditions, Namely, Cardio-Vascular Diseases, Diabetes, Cataracts, Rheumatoid Arthritis, Alzheimers Disease and Many Other. Phytochemicals Might Exert Antioxidant Actionin-Vivo or In Food by Inhibiting Generation of Reactive Oxygen Species (ROS) Or by Directly Scavenging Free Radicals. Certain Compounds May Act in Vivoas Antioxidants by Rising the Level of Indogenous Antioxidant Defenes By Up-Regulating Expression Of The Genes In Coding Synergists Are Substance Which On Their Own Have Little Antioxidant Effect But May Enhance The Effect Of True Antioxidants By Reacting With Heavy Metal Ions Which Catalyse Auto-Oxidation. [1] Natural Antioxidants Compound Can Be Classified as Vitamins, Carotenoids, Hydroxycinnamatesand Flavanoids. Among All the Above, Flavanoids Is the Largest Group Of Antioxidants Which Are Almost Ubiquitous In Nature In Most Of The Fruits, Vegetables And Plant. The Various Types of Natural Antioxidant and Their Dietary Source Are Given In Table superoxide Dismutase (SOD), Catalase Or Glutathione Peroxidase.  Antioxidant Can Be Broadly Derived into Three Categories

1. True Antioxidants 
2. Reducing Agents 
3. Antioxidant Synergist.

True Antioxidant React with Free Radicals and Block the Chain Reaction of The Free Radicals. Reducing Agent Have A Lower Redox Potential and Readily Get Oxidized and Are Found Effective Against Oxidizing Agents. [2] Oxygen Is an Essential Chemical Element in The Metabolism of Aerobic Organisms. However, It May Trigger Unfavorable Reactions, And There Has Been A Growing Interest In Studying The Role Of Its Reactive Species. Reactive Oxygen Species (ROS) Include Free Radicals Like the Superoxide Anion, Singlet Oxygen, Lipid Peroxides and The Hydroxyl Radical. These Reactive Species Are By-Products of The Normal Cellular Energy Production and Functional Activities, Presenting an Important Role In Cell Signaling, Apoptosis, Gene Expression And Ion Transportation. Nevertheless, If ROS Level Increase Intensely, It Can Results in Damage of Many Molecules, Including Proteins, Lipids, RNA and DNA, Since They Are Highly Reactive. Furthermore, The Production of Free Radicals Is Not Only Associated with The Normal Metabolic Processes in The Human Body (Endogenous Sources), But Can Also Be Due To Environmental Factors (Exogenous Sources) Such As Stress, Ozone Radiation, Pollution, Pesticides And Industrial Chemicals. [3,4,5,6,7,8] When Higher Production Of ROS In Relation To Their Removal By Biological Systems (Antioxidant Defenses) D Ion Transportation. Nevertheless, If ROS Levels Increase Intensely, It Can Result In Damage Of Many Molecules, Including Proteins, Lipids, RNA And DNA, Since They Are Highly Reactive. Furthermore occurs, It Is Called Oxidative Stress.

? Antioxidants

Vitamins C or Ascorbic Acid Is Often Claimed To Be An Important Antioxidant In Be Due To Free Radical Scavenging By Ascorbate And Dehydroascorbate Radical. Vitamin E Or -Tocopherol Delays Lipid Peroxidation by Reacting with Chain- Propagating Peroxy Radicals, Faster Than These Radical Can React with Proteins Or Fatty Acid Side-Chains. B-Carotene Has Remarkable Antioxidant Properties By Interacting With A Free Radical To Form B-Carotone-Derived Radical Which In The Presence Of Oxygen Forms A Peroxyl Radical.[10,11,12] Antioxidants Act At Different Levels In The Oxidative Sequence, Involving Lipids And The Extent To Which Oxidation Of Fatty Acids And Their Esters Occurs Depends On The Chemical Nutraceuticals Are The Medicinal Or Nutritional Components That Includes A Food, Plant Or Other Naturally Occurring Material That Is Used For Improvement Of Health By Prevention Or Treatment Of Disease. Their Prominent Health Benefits Can Be Found In The Domain Of Cardiovascular, Mental, Joint, Skin And Womwns Health Some Of The Nutraceuticals Are Prominently Used For Prevention Of Cancer And Others For Enhancement Of Sport Performance And Weight Management. Some of These Substances Can Be Isolated, Purified, Concentrated And Formulated In Variety Of Dosage Form, However Some Are Used Directly As Functional Food. Some Of These Isolated Naturally Nutraceuticals Substances And Herbs Which Are Used As Functional Foods Has Been Discuss Below. 

Considering Their Important Health Effects, The Efficient Extraction Methods Of Natural Antioxidants, Appropriate Assessment Of Antioxidant Activity As Well As Their Main Resources From Food And Medicinal Plants Are Drawing Great Attention In Food Science And Nutrition. To Improve The Extraction Efficiency Of Antioxidant Components From Plant Materials, Several Green Nonconventional Methods Have Been Developed For Reducing Operational Time And Usage Of Organic Solvents, Such As Ultrasound-Assisted Extraction, Microwave-Assisted Extraction, Enzyme-Assisted Extraction, Pressurized Liquid Extraction, Supercritical Fluid Extraction, High Hydrostatic Pressure Extraction, Pulsed Electric Field Extraction And High Voltage Electrical Discharges Extraction. Moreover, To Further Assess the Antioxidant Capacities Of Extracts From Natural Products, Especially Those Frequently Consumed By People, Different Evaluation Assays Have Been Developed, E.G., Trolox Equivalence Antioxidant Capacity (TEAC) Assay, Ferric Ion Reducing Antioxidant Power (FRAP) Assay, Oxygen Radical Absorbance Capacity (ORAC) Assay, Inhibiting The Oxidation Of Low-density Lipoprotein (LDL) Assay, Cellular Antioxidant Activity Assay, Etc. These Assays Have Been Used for Ranking the Antioxidant Plants and Recommending Best Antioxidant Foods for Consumption. This Review Is Aimed At Summarizing The Extraction Methods of Natural Antioxidants, Assessment Methods Of Antioxidant Activity And Their Main Resources From Food And Medicinal Plants. [16,17,18,19,20]

Natural Nutraceuticals Substances: -

Certain Medicinal or Nutritional Components in Plants, Animals or Marine Sources Are Present in Very Small Proportion Such Components Can Be Isolated and Used as Supplement for Specific Health Benefit Or For Prevention Or Treatment Of Ill Health Polyunsaturated Fatty Acids, Glucosamine, Chondroitin, Methylsulphonylmethane, Melatonin, Carnitine, Octacosanol, Resveratrol, Etc., Are Such Substances That Cause Amelioration Of Health. [1]

Table No.1 Naturally Occurring Antioxidants

 ? Classification of Antioxidants Antioxidants Are Grouped into Two Namely.

(1) Primary or Natural Antioxidants.

(2) Secondary or Synthetic Antioxidants

(1) Primary or Natural Antioxidants

They Are the Chain Breaking Antioxidants Which React with Lipid Radicals and Convert Them Into more Stable Products Antioxidants of This Group Are Mainly Phenolic.

Antioxidants Minerals

These Are Co Factor of Antioxidants Enzymes. Their Absence Will Definitely Affect Metabolism of Many Macromolecules Such Carbohydrates. Examples Include Solenium, Copper, Iron, As Zinc and Manganese Anti-Oxidants Vitamins It Is Needed for Most Body Metabolic Functions. They Include Vitamin C (Figure 1). Vitamin E, Vitamin B

Phytochemicals - These Are Phenolic Compounds That Are Neither Vitamins nor Minerals. These Include:

Flavonoids: 

These Are Phenolic Compounds That Give Vegetables, Fruits, Grains, Seeds Leaves, Flowers and Bark Their Colours, Catechins Are the Most Active Antioxidants In Green And Black Tea And Sesamol. Carotenoids Are Fat Soluble Colour In Fruits and Vegetables. Beta Carotene, Which Is Rich in Carrot And Converted To Vitamin A When The Body Lacks Enough Of The Vitamin, Lycopene, High In Tomatoes And Zeaxantin Is High In Spinach And Other Dark Greens. Herbs and Spices-Source Include Diterpene, Rosmariquinone, Thyme, Nutmeg, Clove, Black Pepper, Ginger, Garlic and Curcumin and Derivatives.

(2) Secondary or Synthetic Antioxidants

These Are Phenolic Compounds That Pedorm The Function of Capturing Free Radicals and Stopping the Chain Reactions.

1. Butylated Hydroxyl Anisole (BHA) Ii.
2. Butylatedhydroxyrotoluene (BHT) Iii.                
3. Propyl Gallate (PG) And Metal Chelating Agent (EDTA).
4. Tertiary Butyl Hydroquinone (TBHQ)
5. Nordihydroguaretic Acid (NDGA). Primary or Natural Antioxidants [21,22,23]

 Extraction Methods of Antioxidants from Foods and Medicinal Plants

Extraction Is the First and Crucial Step for Studying the Natural Antioxidants from Plants (Figure 1). Many Extraction Factors Play Important Roles in The Extraction Efficiency, Such as Type and Concentration Of Extraction Solvent, Extraction Temperature, Extraction Time, And Extraction Ph. Among Them, The Solvent Is One of The Most Influential Factors. Numerous Solvents Have Been Used for The Extraction Of Antioxidants From Food And Medicinal Plants. The Selection of Solvents Is Based on The Chemical Nature And Polarity Of Antioxidant Compounds To Be Extracted. Most of The Phenolics, Flavanoids And Anthocyanins Are Hydro Soluble Antioxidants. The Polar and Medium Polar Solvents, Such As Water, Ethanol, Methanol, Propanol, Acetone And Their Aqueous Mixtures, Are Widely Used For Extraction. [24,25,26,27] Carotenoids Are Lipid-Soluble Antioxidants, And Common Organic Solvents, Such As The Mixtures Of Hexane With Acetone, Ethanol, Methanol, Or Mixtures Of Ethyl Acetate With Acetone, Ethanol, Methanol, Have Been Used For Extraction. [28,29,30]. Various Extraction Procedures, Including Conventional Extraction Methods and Non-Conventional Extraction Methods, Can Be Chosen to Extract Antioxidants from Food and Medicinal Plants. The Conventional Extraction Methods Are Mainly Hot Water Bath, Maceration and Soxhlet Extraction, Which Are Very Time-Consuming and Require Relatively Large Amounts Of Organic Solvents With Low Extraction Yields. Furthermore, The Long Heating Process Such as Hot Water Bath and Soxhlet Extraction May Lead to the Degradation of the Thermolabile Compounds.