Phenolic in plants

FMC. 1979. Analysis of aryl phosphates and phenols in plant and environmental samples from Nitro, West Virginia. Technical report [microfiche 0518399]. FMC Corporation, Princeton, NJ, 95. 

The Folin-Denis assay is used as a procedure for the quantification of total phenolics in plant materials, food, and beverages. Reduction of phosphomolybdic-phosphotungstic acid (Folin-Denis reagent) to a blue-colored complex in an alkaline solution occurs in the presence of phenolic compounds (Folin and Denis 1912). 

Stafford HA (2000) The evolution of phenolics in plants. In Romeo JT (ed) Evolution of metabolic pathways. Elsevier, New York, pp 25 17... 

K. Robards Strategies for the determination of bioactive phenols in plants, fruit and vegetables. 

A moderate amount of information is available concerning the factors affecting concentrations of phenolics in plants, and a little research has been completed concerning factors affecting concentrations of alkaloids and terpenoids. Little information is available concerning factors affecting concentrations of other types of allelopathic compounds thus, research is urgently needed in this area. 

Cooper-Driver, G. A. and Bhattacharya, M. 1998. Role of phenolics in plant evolution. Phytochemistry, 49 1165-1174. 

Ozone stimulates the synthesis of anthocyanins 2, caffeoyl derivatives ( ), and total phenols ( ) in plant foliage. It induces necrotic lesions and localized discolored areas of yellow, red or brown on foliage of plants of many species. The size and number of lesions and the intensity of color are related to plant cultivar, maturity of foliage, cultural conditions, concentration of ozone and duration of time after exposure. 

Pridham, J. B. "Phenolics in plants in health and disease." pp. 9-15. Pergamon Press, Oxford, London (1960). 

Grayer, R.J. et al., Phenolics in rice phloem sap as sucking deterrents to the brown planthopper, Nilaparvata lugens, Int. Symp. on Nat. Phenols in Plant Resistance, 2, 691, 1994. 

In the field, a quick test for the general level of total phenolics in a plant can be the starting point for a more detailed quantitative analysis of the nature and amounts of specific compounds. Various oxidation-reduction methods have been exploited to analyze total phenolics in plant extracts. Many, but not all, phenols form complexes with ferric chloride (FeCy. Ferric chloride gives a color reaction with phenolic compounds. While the phenolate ion is oxidized, the ferric ions are reduced to the ferrous state. 

The main problem in the analysis of phenolics in plant-derived food, such as honey, fmit juices, and jam, is the high content of sugars and other polar compounds, which cause interphasing when the liquid-liquid partitions are chosen as a method of extraction. The use of the nonionic... 

Figure 2. Relationships between conjugates of phenol in plants (P) and animals (A).

Today, the most widely used method for the estimation of total phenolics in plant extracts as well as in foods and beverages is the Folin-Ciocalteu method. Some authors prefer the Prussian blue method, because... 

Meuwly, P, Molders, W., Summermatter, K., Sticher, L., Metraux, J.-P. (1994) International Symposium on Natural Phenols in Plant Resistance 1, 371-374. 

Chrysophanol (XXIII), an anthraquinone isolated from the leaves of Rumex alpinus (Polygonaceae), is also formed from acetate (and presumably therefore derived via the acetate-malonate pathway) (Leistner and Zenk, 1969) and not, as previously considered, from shikimic acid and mevalonate. Only anthraquinones such as alizarin lacking a C-methyl group and not hy-droxylated in ring A are made in this way, despite an apparent similarity in structure thus at least two independent routes also exist for the synthesis of these compounds and reflect the diversity available for the biogenesis of multiringed phenols in plants. 

Toxicity seems to be an important attribute of phenols in plants. Essentially, every phenolic compound has some antimicrobial and antifungal activity (Jenkins et al., 1957 Walker, 1975). Antibiotic, antiviral, anticellular, antineoplastic, and related effects of tannins, mostly in vitroy have been reported by several researchers (Alexander, 1965 Herz and Kaplan, 1968 Kreber and Einhellig, 1972 Konowalchuk and Speirs, 1976 Chan et al., 1978 Loub et al., 1973 DeOliveira et al., 1972). 

Pridham, J.B., 1960, "Phenolics in Plants in Health and Disease," Pergamon Press, New York. 

Natural phenolics in plants and oilseeds provide excellent sotuces of antioxidant for food application. Presence of a wide variety of phenolics with varying degrees of polarity avails these preparations to exert their effects via different mechanisms. Thus efficacy of natural oilseed extracts in bulk oil, oil-inwater emulsions, low water activity foods and formulated products is excellent. Furthermore, in addition to their safety advantages, food phenolics may augment body s source of natural antioxidants in different ways, including regeneration of a-tocopherol. 

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