Chemistry and biochemistry of flavonoids

Flavonoids are secondary metabolites generally occurring in various plants as glycosides. The chemical structure of flavonoids shows high variety. The basic structure of flavons and flavonols is the 2-phenylbenzo-gamma-pyrone. Flavonoids generally contain two phenol rings linked with a linear three-carbon chain (chalcones) or with three carbon 

HAPTOPHYTE BIOMARKER PIGMENTS OF THE TWO STRAINS ISOLATED FROM BELGIAN COASTAL WATERS EXPRESSED AS RATIOS TO CHLOROPHYLL-A 

Similarly to carotenoids, flavonoids also show considerable biological activity. Their beneficial effect in cancer and heart diseases has been proven many times [86-89], It has further been established that flavonoids improve cardiovascular remodelling and vascular function in NO-deficient hypertension [90], Moreover, flavonoid intake reduces the risk of chronic diseases [91], and beneficially influences inflammations [92], and ulcer formation [93,94], 

It has been established that the free radical scavenger activity of flavonoids is responsible for the antioxidant effect [95,96], The beneficial antitumour effect of quercetin has also been demonstrated [97,98], 

Isoflavones belonging to the phytoestrogens also expose marked biological activity [99], Their effect and fate of isoflavones in organisms have been extensively investigated 

---

Different fruits and vegetables vary significantly in their structural constituents, macronutrients (proteins, oils, and carbohydrates), and micronutrients such as flavonoid profiles. It is almost impossible to develop one optimal method for extraction, separation, and analysis for each and every different fruit or vegetable. However, because of the relatively similar chemistry and biochemistry of flavonoids, some general statements can be abstracted from the existing literature. Flavonoids of fruits and vegetables... 

---