Phenolic compounds, are secondary plant metabolites containing a phenol moiety in their structure. They have been reported to mainly function as antioxidants by chelation of metal ions and removal of free radicals. The metal chelation property of phenolic compounds is mainly by the presence of the ortho-dihydroxy (catechol and galloyl groups) and flavan moiety that exists within the compounds. These moieties, the number and orientation of OH groups and the negative charge density present in some of these phenolic compounds are known iron binding elements . Examples of the phenolic compounds are protocatechuic acid, gallic acid, caffeic acid, vanillic acid, ferulic acid, p-Coumaric acid, apigenin, chlorogenic acid, rosmarinic acid, salicylic acid) [1]. Rosmarinic acid, salvianolic acid B, caffeic acid, fumaric acid,  are examples of phenolic acids and they are water-soluble [2].

Flavonoids, are secondary plant metabolites containing a flavone moiety in their structure. 

The flavonoid nature of the compounds could be confirmed by the IR spectrums [3].

Further reading about the spectral data and UV absorbtion maxima of some flavonoids are available in this article.

Isoflavones, are secondary plant metabolites containing a phenol moiety in their structure. irigenin, nigricin, irisflor-

entin, iriskumaonin, irilon, iriflogenin, etc.

Further reading about the spectral data and UV absorbtion maxima of some isoflavones are available in this article.

Xanthones, are secondary plant metabolites containing a phenol moiety in their structure.xanthone mangiferin etc.

Mangiferin have important and broad pharmacological activity, including antidiabetes, antiviral, antitumor, immunomodulatory, antioxidant, anti-inflammatory and vascular modulatory activity and reported from mango leaf, mangosteen fruit and rhizomes of Iris hungarica.

The UV spectrum of 3 showed the λ max absorptions at 369, 318, 259 and 241 nm suggesting the xanthones skeleton.

Further reading about the spectral data and UV absorbtion maxima of xanthone mangiferin are available in this article.