Natural Phenolic Compounds

HPLC with coulometric-array detection has been successfully used for the analysis of phenolic compounds in meads [119], natural beverages and plant extracts [117,120], juice beverages [121], beers [118, 122, 123], and wines [124]. 

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E. Menziani, B. Tosi, A. Bonora, P. Reschiglian and G. Eodi, Automated multiple development high-performance thin-layer chromatographic analysis of natural phenolic compounds , 7. Chromatogr. 511 396-401 (1990). 

Long, H., Zhu, Y. X., and Kissinger, P. T. (2003). Liquid chromatography with multi-channel electrochemical detection for the determination of natural phenolic compounds. Chin. J. Anal. Chem. 31, 631-634. 

Baker, W. and Ollis, W.D., Biflavonyls, in Recent Developments in the Chemistry of Natural Phenolic Compounds, Ollis, W.D., Ed., Pergamon, London, 1961, 152-184. 

Almost every class of natural phenolic compounds contains examples of substances with a 2,2-dialkylchromene ring, and the number of those that are discovered increases every year. It would be difficult to give an exhaustive list of these compounds. Their chemistry will be discussed here only when it is related to some particular behavior of the benzo-pyran ring. Examples include simple chromenes substituted in the aromatic ring,3,4,35-44 benzodipyrans,3,39 dimers of chromenes,45 naphthopyrans,46,47 quinones,48 flavones,49 flavonols,49 chalcones,49 flavanones,49 isoflavonoids,50 rotenoids,50 pterocarpans,50 couma-rins,17,51-53 3-arvl-4-hydroxycouniarins,50 4-phenylcoumarins,54 chroma-... 

Given their aromatic nature, phenolic compounds are easily auto-oxidized. The radical that is generated can subsequently react with other radicals to form a dimer. Since the radical electron is delocalized, several structures can be formed depending on the precise location of the radical electrons at the time of the reaction. 

Whiting DA. 2001. Natural phenolic compounds 1900-2000 A bird s eye view of a century s chemistry. Nat Prod Rep 18 583-606. 

Roy M, Chakraborty S, Siddiqi M, Bhattacharya RK. 2002. Induction of apoptosis in tumor cells by natural phenolic compounds. Asian Pac J Cancer Prev 3 61-67. 

Lignans are a well-known class of widespread natural phenolic compounds that exhibit great structural and biological diversity and are commonly found in vascular plants from various families [1]. They are present at different levels of abundance in all plant parts, including roots, rhizomes, hardwood, bark, stems, leaves, flowers, fruits and seeds [2]. Lignans are of considerable pharmacological and clinical interest and are used in the treatment of cancer and other diseases [3]. The extensive pharmaceutical use of lignans is due to their antitumor, antiviral and hepatoprotective properties as well as many other beneficial activities. 

The accessibility of natural phenolic compounds has opened up the intriguing possibility that one could apply these compounds in foods, cosmetics, and other lipid-containing systems. Rosemary and sage are well known for the highest antioxidant activity among herbs, and their extracts are used in foods because of the strong antioxidant properties. 

R. W. Rickards, in Chemistry of Natural Phenolic Compounds (Ed. W. D. OUis), Pergamon Press, Oxford, 1961, pp. Iff. 

Perhaps the process can be extended to natural phenolic compounds to produce inexpensive products independently of petroleum sources. 

Procyanidins are quite reactive and are therefore considered as some of the most unstable natural phenolic compounds [19-20]. They are subject to enzymatic oxidation by polyphenol oxidases as well as to spontaneous oxidation [21], Coupled oxidation reactions involving o-quinones of phenolic acids have been reported [22-24], Procyanidins are thermally labile [25] and can easily undergo molecular rearrangements in acidic or basic media [26]. In model solutions interflavanoid bonds of procyanidins were found to be unstable, but also new carbon-carbon bonds were formed... 

It is also noteworthy that some of the phloroglucinols isolated from Hypericum species, are characterized by O-prenylation, which, in contrast to C-prenylation, is quite rare for natural phenolic compounds. 

Sgambato A, Ardito R, Faraglia B, Boninsegna A, Wolf FI, Cittadini A. Resveratrol, a natural phenolic compound, inhibits cell proliferation and prevents oxidative DNA damage. Mutat Res 2001 496 171-180. 

Hassall, C. H., and A. I. Scott In W. D. Ollis, Recent Developments in the Chemistry of Natural Phenolic Compounds, S. 119. New York Pergamon Press 1961. 

Ollis WD, Sutherland lO (1961) In Ollis WD (ed) Chemistry of natural phenolic compounds. Pergamon, London, p 212... 

Natural phenolic compounds are ubiquitous and widely distributed secondary metabolites in the plant kingdom possessing at least one aromatic ring with one or more hydroxyl groups attached to it. 

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