Top 7 Examples of Flavnols (With Functions)

This article throws light upon the top seven examples of flavnols. The examples are: 1. Myricetin 2. Quercetin 3. Kaempferol 4. Fissetin 5. Isorhamnetin.

Flavnols Example # 1. Myricetin:

Myricetin is a naturally-occurring flavonoid. It is commonly found in the form of glycosides, such as myricitrin.

Sources:

Grapes, berries, fruits, vegetables, and walnuts

Functions:

i. Antioxidant properties.

ii. In vitro research suggests that myricetin in high concentrations can modify LDL cholesterol such that uptake by white blood cells is in­creased.

iii. A Finish study correlated high myricetin con­sumption with lowered rates of prostate can­cer.

iv. Increasing the DNA-enzyme complex in LI 210 cells and interfering with enzyme-in­duced DNA relaxation.

Flavnols Example # 2. Quercetin:

Quercetin is a flavonoid and, to be more spe­cific, a flavonol. It is the aglycone form of a number of other flavonoid glycosides, such as rutin and quercitrin, found in citrus fruit.

Quercetin forms the glycosides quercitrin and rutin together with rhamnose and rutinose, respectively. Quercetin is found to be the most active of the flavonoids in studies, and many medicinal plants owe much of their activity to their high quercetin content.

Functions:

i. Quercetin has demonstrated significant anti-inflammatory activity because of direct inhi­bition of several initial processes of inflam­mation by inhibiting both the synthesis and release of histamine and other allergic/inflam­matory mediators.

ii. It exerts potent antioxidant activity and vita- mine C-sparing action.

iii. Quercetin also shows anti-tumour properties.

iv. A study showed that, when treated with a combination of quercetin and ultrasound at 20 kHz for 1 minute duration, skin and pros­tate cancers show a 90% mortality within 48 hours with no visible mortality of normal cells. Ultrasound promotes topical absorption by up to 1,000 times making the use of topical quer­cetin.

v. Recent studies have supported that quercetin can help men with chronic prostatitis, and both men and women with interstitial cysti­tis, possibly because of its action as a mast cell inhibitor.

vi. Quercetin may have positive effects in com­bating or helping to prevent cancer, prostati­tis, heart disease, cataracts, allergies/inflam­mations, and respiratory diseases such as bron­chitis and asthma.

vii. In plants, it is a naturally-occurring polar auxin transport inhibitor.

viii. Inhibitory action on both xanthine oxidase and xanthine dehydrogenase activity and reduced brain tumor.

Occurrence:

Capers (1800mg/kg), lovage (1 700mg/kg), apples (440mg/kg), tea (Cemellia sinensis), onions (higher concentrations of quercetin occur in the outermost rings), red grapes, citrus fruits, leafy green vegeta­bles, cherries, raspberry, bog whortleberry (158 mg/kg, fresh weight), lingonberry (cultivated 74mg/ kg, wild 146 mg/kg), cranberry (cultivated 83 mg/ kg, wild 121 mg/kg), chokeberry (89 mg/kg), sweet rowan (85 mg/kg), rowanberry (63 mg/kg), sea buckthorn berry (62 mg/kg), crowberry (cultivated 53mg/kg, wild 56 mg/kg), fruit of the prickly pear cactus, a recent study found that organically grown tomatoes had 79% more quercetin than conven­tionally grown, honey, including honey derived from eucalyptus and tea tree flowers.

Drug Interactions:

i. Quercetin is contraindicated with antibiotics; it may interact with fluoroquinolones, as quer­cetin competitively binds to bacterial DNA gyrase. Whether this inhibits or enhances the effect of fluoroquinolones is not entirely clear.

ii. Quercetin is also a potent inhibitor of CYP3 A4, an enzyme that breaks down most drugs in the body.

Flavnols Example # 3. Kaempferol:

Kaempferol is a natural flavonoid, which is a yellow crystalline solid with a melting point 276- 278 °C. It is slightly soluble in water but soluble in hot ethanol and diethyl ether. Many glycosides of kaempferol, such as kaemferitin and astragalin, have been isolated as natural products from plants.

Sources:

Tea, broccoli, delphinium, witch-hazel, and grape­fruit.

Functions:

i. Kaemphferol consumption in tea and broc­coli has been associated with reduced risk of heart disease.

ii. Kaempferol is what gives the flowers of Aca­cia decurrens and Acacia longifolia their color.

iii. Inhibit the aromatase enzyme activity com­petitively in a human Glyoxalase cell culture system.

iv. Tumor cell inhibition by breaking glucosaminidic bonds.

Flavnols Example # 4. Fissetin:

Naturally occurring flavonoids.

Sources:

Strawberries, tomatoes, onions, oranges, apples, peaches, grapes, kiwifruit, and persimmons.

Functions:

i. Stimulates signalling pathways that enhance long-term memory.

ii. Nevertheless, memory-enhancing drugs can improve Alzheimer’s disease symptoms.

iii. Replication of HIV-I inhibited by inhibiting enzyme activity.

iv. Inhibition of non-activated phosphorylase ki­nase.

Flavnols Example # 5. Isorhamnetin:

Naturally occurring flavonoids. It is a yellow solid which is soluble in acetone, methanol, ethyl acetate, DMSO and water.

Uses:

i. Antiviral agent

ii. Antioxidant

iii. Antitumor compound

iv. Apoptosis inducer

Flavnols Example # 6. Rhamnazin:

Flavnols Example # 7. Pachypodol:

4H-1 -Benzopyran-4-one, 5-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,7-dimethoxy.