Table 1.
Classification of flavonoids and their classes according to their skeletal structure.
| Flavonoid group | Compound | Skeletal structure | 3′ | 4′ | 5′ | 3 | 5 | 7 |
|---|---|---|---|---|---|---|---|---|
| Flavonol | Quercetin |  |
OH | OH | – | OH | – | – |
| Isorhamnetin | O-CH3 | OH | – | OH | – | – | ||
| Kaempferol | H | OH | – | OH | – | – | ||
| Spiraeoside | OH | O-glucose | – | OH | – | – | ||
| Quercitrin | OH | OH | – | O-rhamnose | – | – | ||
| Isoquercitrin | OH | OH | – | O-glucose | – | – | ||
| Isoflavone | Genistein |  |
– | OH | – | – | OH | OH |
| Genistin | – | OH | – | – | OH | O-glucose | ||
| Daidzein | OH | – | – | – | OH | |||
| Daidzin | OH | – | – | – | O-glucose | |||
| Biochanin A | O-CH3 | – | – | OH | OH | |||
| Formononetin | O-CH3 | – | – | – | OH | |||
| Flavone | Apigenin |  |
H | – | – | – | – | – |
| Luteolin | OH | – | – | – | – | – | ||
| Chalcones | Phloretin |  |
OH | – | OH | – | – | – |
| Chalconarigenin |  |
– | – | OH | – | – | – | |
| Flavanone | Narigenin |  |
H | OH | – | – | – | OH |
| Hesperitin | OH | O-CH3 | – | – | – | OH | ||
| Narirutin | H | OH | – | – | – | O-rutinoside | ||
| Naringin | H | OH | – | – | – | O-neohesperidose | ||
| Hesperidin | OH | O-CH3 | – | – | – | O-rutinoside | ||
| Anthocyanins | Cyanidin |  |
OH | OH | – | OH | OH | OH |
| Cyanin | OH | OH | – | O-glucose | OH | OH | ||
| Delphinidin | OH | OH | OH | OH | OH | OH | ||
| Pelargonidin | – | OH | OH | OH | OH | OH |