The Main Types Of Natural Antioxidants

The chemical substances that help to avoid the oxidative strain are known as antioxidants. Free radicals cause oxidative stress. Changing environmental conditions are giving rise to a variety of free radicals, which plants have to deal with them in order to survive. Reactive oxygen species, such as singlet oxygen, superoxide ion, hydroxyl ion and hydrogen peroxide, are highly reactive, toxic molecules, which are generated normally in cells during metabolism. Through lipid peroxidation and covalent binding, free redicals cause harsh oxidative damage to DNA, lipids, proteins and enzymes with successive tissue injury. Scavenging free radicals is an ability of natural antioxidants. Therefore, they are gaining greater interest for researchers. Antioxidant studies are now being more familiar as they can help in treatment of diseases and their prevention. Free radicals are being responsible for the development of numerous disorders, as well as cancer, inflammation and neurodegeneration. The natural antioxidants present in plants like flavonoids, phenolic components, proanthocyanidins and tannins provide greater protection from diseases. Hence, due to the antioxidant properties medicinal plants, fruits, vegetables are being investigated.

Phenolic antioxidants

Phytochemicals present inside the plants and they are based mostly on phenolic compounds. They are responsible of color, taste, texture and odor of vegetables and fruits. The most frequently present phenolics are flavonoids and polyphenols. Phenolic phytochemicals provide protection in plants against damages and protects them against pests and other infections. Stress and some other plant disorders increase the quantity of these bioactives. Phenolic bioactives provide health benefits against cardiovascular diseases, diversity of chronic disorder, immature aging, and degenerative health diseases. They also have extensive applications in cosmetic and food industries. Phenolic bioactives are classified into two categories i.e. free and bound phenolics.

Flavonoids

More than 4000 compounds among phenolic compounds are identified flavonoids and are found mostly in plants. Flavonoids are of yellow colour and they were originated from Latin word “Flaves” which means yellow. Flavonide construct their structure in the arrangement of C6-C3-C6 containing fifteen colour atoms. Flavonides build their main structure with our aromatic benzene ring A attached with our other aromatic benzene ring B which is attached to heterocyclic ring C containing our oxygen with the C3 bridge.

Malonate cycle is responsible for the origin of aromatic benzene ring A while for the aromatic benzene ring B, phenylalanine is responsible. Sources of flavonoids are as follows

• All types of berries and grapes contain Anthocyanin.
• Colorful fruits and vegetables contain huge amount of flavonols.
• Grapes contain flavonols.
• All types of apples, berries, lettuce, leeks, onion, tomato and beans contain rich amount of flavonols.
• Soyabeans are rich source of isoflavones.
• Citrus fruits contain flavonones.
• Green leafy vegetables and citrus fruits contain flavones.
• Xanthones are found in stone fruits like mango (magnifera indica) and mangosteen (gracinia mangostana).
• Chalcones are present in apple (malus domestica).

Flavonides have versatile applications in food, health as well as in pharmaceutical industries. Flavonides possess antioxidant activity along with anti-inflammatory, anti-viral, anti-cancer, anti-allergic activities. Flavonides have influence in preventing disease such as asthma sinusitis and hay fever. Flavonoids can also help to cure diabetes and tumor. Flavonoid can act as good reducing agent can donate hydrogen and can quench single oxygen and for this reason flavonoids are said to possess ability of redox potential with a single metal flavonoids can make several bound. Flavonides are classified into isoflavonoids, flavones, flavanols, flavanous, and anthocycniodeans on basis of their substitutions.

Phenolic Acid

The chemical structural formula of phenolic acid comprises our aromatic ring with carboxylic acid attached to it. One third of phenolic acid are contained in dietary product. Plants are considered the richest source of phenolic acids. Phenolic acids can found in both bound and free forms. Specific bonding like acetal, ether or ester bonds join bond phenolics in different plants. The fruits (apples, mangoes, kiwis, cherries, plum and berries), grains and different food items (oat tea, wheat, corn, rice, coffee, red wine) contain a huge amount of phenolic acids. Phenolic acids remain stable under optimized conditions during the extraction method. Phenolic acids are clasiified into two acids:

Hydroxycinnamic acid It contains nine carbon atoms in its structural formula. The examples of cinnamic acid are Caffeic acid, Sinapic acid, Ferulic acid and are found largely in green plants.

Hydroxybenzoic acidIt contains seven carbon atoms in its structural formula. The examples of benzoic acid are Vanillic acid, Synergic acid, Hydro benzoic acid and Gallic acid are less abundant in nature.

The oxidative ability of phenolic acids is based on hydroxyl groups present in carboxylic compounds. The oxidative activity of hydroxycinnamic acid is higher than hydroxybenzoic acid.

Tannins

Tannins are classified into following subclasses

• Hydrolysable tannins
• Condensed tannins .

Hydrolysable tannins are also known as water soluble tannins for example 3,4,5- trihydroxyl benzoic acid which is Gallic acid’s derivative. Condensed tannins are proanthocyanidin polymers and their examples are catechin and epicatechin. Gallo tannins are multifaceted water soluble tannins and are formed as a result of esterification of Elagic acid and Gallic acid.Biological systems like metal chelation and precipitation of proteins are being affected by tannins. Phloro tannins are another class which is seciuded by various brown algae. Phloro tannins are not being used by human diet.

Stilbenes

Generally, stilbenes exist in glycosylated forms. Stilbene widely occur in plants like peanuts, grapes, berries and in seventy other classes of plants but their less quantity is present in human diet. The most common stilbene is Resveraterol and it has two isomers.

• Cis- Resveraterol
• Trans- Resveraterol.

Chlorogenic acid

Chlorogenic acid was discovered in 1932. An ester is formed between caffeic acid and the 3-hydroxyl position of L-quinic acid; the combination is referred to as Chlorogenic Acid. Chlorogenic acid has several isomers such as 3, 4-dicaffeoyluinic acid and 3, 5-dicaffeoylquinic acid and cynarine (1, 5-dicaffeoylquinic acid). It shows inhibitory activities against hepatitis B virus in vivo and in vitro. The chemichal formula of chlorogenic acid is C16H18O9. Another property of chlorogenic acid explains that it is freely soluble in acetone and ethanol . Chlorogenic acids (CGAs) are naturally occurring phenolic compounds which found in all complex plants. Due to countless biological qualities and properties of chlorogenic acid (CGA) such as antioxidant, antispasmodic, self-consciousness of mutagenicity of carcinogenic composites and inhibition of HIV-1 integrase, they found in certain plants. Where as in some of the plant species it is stored to highest amount. Comparatively, as per studies the occurrence of Chlorogenic acid (CGA) in monocotyledonous plants are very less rather than coffea species or solanum species, whereas this coffea species belongs to Rubiaceen family. Chlorogenic acid occurs in potato, tomato, sweet potato, black nightshade, blue berries, solanum viarum, phureja, and tamarillo. Also it occurs in some of the fruits such as, apples, pears, carrot, oilseeds, Prunus domestica L, cherries, and eggplant. Plants like palm trees, lily, arum, tulip, liliaceae, orchids, agave, arecales and irises also contain chlorogenic acid.

Pure Chlorogenic Acid (CGA) has strong antioxidant possessions and rich in anti-oxidants, as well as it can position strong check on the level of glucose in blood veins and prevent skin cells from getting dented. Meanwhile researches show that consumption of chlorogenic acid (at certain amount) reduces the risk of Low-density Lipoprotein or cardiac disorders. Consumption of Chlorogenic acid (CGA) which can be found in certain molecules improves blood circulation and prevents platelets from getting clustered and also prevents from several fatal diseases such as high blood pressure, stroke, chronic renal failure and heart failure. Although chlorogenic acid (CGA) have tremendous health benefits which has been proven through scientific researches.