Mahmud's Portfolio - Flavonoids

Flavonoids

Objective:

This chapter enables the reader to know about what is flavonoids, their structural features and some health benifits.

Key words:

Flavonoids, Quercetin, Kaempferol,

Flavonoids, are a a group of natural polyphenolic secondary metabolites with variable phenolic structures, found in plants occurring in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine, and thus commonly consumed in the diets of humans. Chemically, flavonoids have the general structure of a 15-carbon skeleton, which consists of two phenyl rings and a heterocyclic ring. This carbon structure can be abbreviated C6-C3-C6. These natural products are well known for their beneficial effects on health and efforts are being made to isolate the ingredients so called flavonoids.

There are mainly six major classes of flavonoids involved in medicines and supplements.

Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor and is used as an ingredient in dietary supplements, beverages, and foods.

Kaempferol is a natural flavonol, a type of flavonoid, found in a variety of plants and plant-derived foods including kale, beans, tea, spinach, and broccoli. widely distributed in different plant genera such as Delphinium, Camellia, Berberis, Citrus, etc. Kaempferol has a beneficial role on different inflammatory-related diseases such as cardiovascular, cancers, and neurodegenerative diseases.

Rhamnetin is an O-methylated flavonol, a type of chemical compound. It can be isolated from cloves. Rhamnetin is a monomethoxyflavone that is quercetin methylated at position 7. It has a role as a metabolite, an antioxidant and an anti-inflammatory agent.

Isorhamnetin is an O-methylated flavon-ol from the class of flavonoids. A common food source of this 3'-methoxylated derivative of quercetin and its glucoside conjugates are pungent yellow or red onions, in which it is a minor pigment, quercetin-3,4'-diglucoside and quercetin-4'-glucoside and the aglycone quercetin being the major pigments. Pears, olive oil, wine and tomato sauce are rich in isorhamnetin.[2] Others sources include the spice, herbal medicinal[3] and psychoactive Mexican tarragon (Tagetes lucida), which is described as accumulating isorhamnetin and its 7-O-glucoside derivate.[4] Nopal (Opuntia ficus-indica (L.)) is also a good source of isorhamnetin, which can be extracted by supercritical fluid extraction assisted by enzymes. Isorhamnetin is an important monomethoxyflavonol found in Ginkgo biloba leaf extract (Fig. 11.24). It is naturally occurring compound in vegetables and fruits. It is tyrosinase inhibitor, a metabolite, antitumor agent, and an anticoagulant. It is an antagonist of peroxisome proliferator-activated receptor.

Myricetin is a member of the flavonoid class of polyphenolic compounds, with antioxidant properties. Common dietary sources include vegetables, fruits, nuts, berries, tea, and red wine. Myricetin is a flavone (similar to quercetin with an additional single hydroxyl group in the chemical moiety), present in berries, onion, grapes, and red wine [44], which has been reported to suppress the carcinogenesis in skin [45], lung [46], and colorectal carcinoma.

Apigenin, found in many plants, is a natural product belonging to the flavone class that is the aglycone of several naturally occurring glycosides. It is a yellow crystalline solid that has been used to dye wool. Apigenin (4′, 5, 7-trihydroxyflavone) is a flavone under the category of natural flavonoid that is abundantly present in common fruits, vegetables, nuts, onions, oranges, and tea. From: Bioactive Food as Dietary Interventions for Arthritis and Related Inflammatory Diseases (Second Edition), 2019.

Luteolin, 3′,4′,5,7-tetrahydroxyflavone, a flavone with a yellow crystalline appearance, is a type of flavonoid that exists in many types of plants including fruits, vegetables, and medicinal herbs. Plants rich in luteolin have been used in Chinese traditional medicine for treating various diseases such as hypertension, inflammatory disorders, and cancer (Lin et al. 2008). Luteolin is the principal yellow dye compound that is obtained from the plant Reseda luteola, which has been used as a source of the dye since at least the first millennium B.C.