Flavonoids In Organic Chemistry

Introduction

Flavonoids are the naturally occurring compounds having multiple phenolic functionalities, found in plants. It was first discovered in 1930's when its isolation and extraction was done from oranges, they were known to have another vitamin which was referred to as Vitamin P. Later on they were named as flavonoids. Basically they consists of 15 carbon atoms arranged in such a way that they are comprised as 2 benzene rings, attached to a hetero-cyclic ring of pyrane or maybe a short chain, which is of 3-Carbon atoms, linking with both benzenes via direct attachment, or with a bridge of oxygen forming a ring at the centre.

Classification of flavonoids

Flavonoids are distributed into different class according to the structural arrangements of their compounds.

Save your time!
We can take care of your essay

• Proper editing and formatting
• Free revision, title page, and bibliography
• Flexible prices and money-back guarantee

Place an order

The sub classes are

• N-flavonoids/ flavones/bioflavonoids
• Iso-flavonoids/isoflavones
• Neo-flavonoids

Besides these, other major groups of flavonoids are:

1. Flavones: It’s the most common and a vast major group of flavonoids, Flavones are generally 2-phenyl- 1,4- benzopyrone, has a planar geometry as it’s having a double bond in the central-ring which is having a ketonic group. Rich source of food I.e. many fruits’ peels, most common in apple’s skin, berries, cranberries, grapes, parsley, vegetable like broccoli ,lettuces, onions & olives.
2. Flavanones: Flavanones are just similar in structure to that of flavones, differing just in lack of double bond in the middle ring. The food source which has flavanones are citrus fruits and peels of such fruits.
3. Flavanols/ Catechins: Flavanols; also known as catechins are derivatives of flavan, they’re 2-phenyl-3,4- dihydro-2H- chromen-3-ols. These are optically active.The ring at centre has an -OH group, with the basic structure of flavonoids. They’re commonly found in wine and tea.
4. Anthocyanins: Anthocyanins have two -OH groups at one benzene ring, an -OH group at a phenyl group and middle ring consists of an -OH group, two double bonds, O+ oxygen. They exists in many fruits and vegetables straw-berries, berries, grapes, red wine, dark-pigmented peels of some fruits. It’s responsible for red-purplish colour of the buds and leaves of autumn. Anthoxanthins are also related but they gives a pigment of yellowish colour in petals.
5. Chalcones:- A Chalcones are may considered as the open chain flavonoids because of their lack of middle ring and instead of it there is just a 3-C chain comprised of a carbonyl group and a double bond, thus having a ketonic group. They are known to show a wide variety of antimicrobial resistance, resistant to inflammation and anti-tumor effects. Chalcones are found in citruses fruits.

Physical and chemical properties of flavonoids

Flavonoids have specific melting point. They are either colorless mostly, but some are yellowish in colour, also. Rare is the case of anthocyanins; which show purplish-red, bluish colours. Changes in the colour is dependent upon environmental factors as ph, as they’re red in acids, and blue in alkaline media.

They’re chemically soluble in water and alcohols, as the glycosidic groups gets soluble in alcohols; which are having diluted concentrations and water at some high degrees of temperature. Flavanols also called as cathechins are the type of flavonoids which can rotate the plane polarised light and are optically active. From these, only one compound L- epicathechin showed the vitamin P activeness. They are reactive species chemically can undergo reactions such as flavanones and flavononones on reactions with oxidants forms chalcones. Hydrolysis of rutins give quercetin, glucose and rhamnose.

Flavonoids are the group of molecules that are involved in the metabolism of plants. Because of their importance in human health in supporting and providing benefits during the transportation of cell signals, they are seeking attention of researchers towards itself for their vast applications in inhibiting oxidation, to reduce inflammation. Flavonoids are discovered in several fruits & vegetables.

Anti-oxidative effects

best-described property of almost every group of Flavonoids of all the groups are best known for their ability to behave as an anti-oxidants. Flavones & catechins are the most effective flavonoids because of their ability to protect the body in preventing reactions of oxygen comprising species. Free-radicals species & those having oxygen species are produced during metabolism and process of exo-genous. It damages the tissues and cells in our body . During damage if cell membranes, lipid peroxidation occurs . This changes net charge on cell, increasing osmotic pressure, thus cell death occurs due to its swell. This is why, Free radical destroy tissue and cause inflammation. Flavonoids interact with these free radicals.

Anti-cancer activity

Food sources containing flavonoids play a vital part in the prevention of lung, prostate, stomach and breast cancer. Flavonoids such as quercetin are richly founded in onions and apples, people who’re having cancer are advised to take these in their nutrition. Adding them in their diet lessens the chance of cancer causing agents. It has been observed that people consuming red wine oftenly are more likely to reduce the cancer of cancer. Flavonoids are considered to inhibit the heat-shock proteins in the malignant lines of the cell,thus they act as to prevent leukaemia, colon and breast cancer etc. Some flavanols reduces the activity of fatty acids synthesis.

Anti-viral activity

Since 1940, natural flavonoids that possess anti-viral activities are known. Flavan -3-ol is used effectively for the inhibitory process of HIV-1 and HIV-2 and such related viruses causing infections Baicalin, separated from Lamieaceae stops the growth of HIV-1, reverse transcriptase & kills them, during the process of replication. Similarly cathechins and flavanones are also used as anti-viral functioning. Quercetin, hesperetin & naringin are used as dengue prevented

Anti-allergic & anti-inflammatory activity

Inflammation are caused due to injured tissues , some sort of microbial infection & hazard chemical interaction. Hesperidin, luteolin, quercetic & apiapigenin works as analgesics aiding in prevention of inflammation

Anti-antherosclerosis

Flavonoids such as catechins & some anthocyanidins prevent the oxidation of lipoproteins of less density & thus risks of anthero-sclerosis is reduced. French people consuming red wine are more likely to have less risks of heart diseases although they consume rich cholesterol nutrients. Some tea and isoflavonnoids also reduces cholesterol levels, preventing them from osteoporosis & menopause.

Anti-bacterial activity

Many flavonoids such as apigenin, chalcones, flavonols, flavanones & isoflavonnoids ets shows antibacterial properties. Cathechins plays the most vital role antibacterial functioning in in-vitro against many bacteria.

References

1. Roman M. Lysiuk, Volodymyr O. Antoniuk, department of pharmacognosy & botany of Danyio Halytsry LNMU.
2. Shawshank Kumar and Abhy K. Pandey , chemistry and biological activities of Flavonoids, University of Allahabad, India.
3. Formic J.V., Regelson W., Review of biology of quercetin and related bioflavonoids.
4. Her tog M.G. Kromhout D., Aravanis et al. , Flavonoids intake and long term risk of coronary heart disease and cancer.
5. Sally Robertson, øyvind M.,Anderea and Kenneth R. Markham. ,Flavonoids Chemistry, Biochemistry and Applications.