Phenolic compound naturally occurring

Phenolic compounds naturally occurring in plants have induced many physiological responses that duplicate those reported for ozone and/or peroxyacetylnitrate (PAN). Chlorogenic acid is a competitive inhibitor of lAA-oxidase (35) and plant growth is adversely affected by increased concentrations of auxins (36). Concentrations of chlorogenic acid are increased in tobacco tissue exposed to ozone ( ) Phenols inhibit ATP synthesis (37), oxidative phosphorylation ( ) and SH enzyme activity (27) they increase respiration (38), reduce CO2 fixation (22), modify both membrane permeability (40) and oxidation rate of reduced NADH... 

Phenolic compounds are commonplace natural products Figure 24 2 presents a sampling of some naturally occurring phenols Phenolic natural products can arise by a number of different biosynthetic pathways In animals aromatic rings are hydroxylated by way of arene oxide intermediates formed by the enzyme catalyzed reaction between an aromatic ring and molecular oxygen... 

Sulfates of sodium are iadustriaUy important materials commonly sold ia three forms (Table 1). In the period from 1970 to 1981, > 1 million metric tons were consumed aimuaHy ia the United States. Siace then, demand has declined. In 1988 consumption dropped to 890,000 t, and ia 1994 to 610,000 t (1,2). Sodium sulfate is used principally (40%) ia the soap (qv) and detergent iadustries. Pulp and paper manufacturers consume 25%, textiles 19%, glass 5%, and miscellaneous iadustries consume 11% (3). About half of all sodium sulfate produced is a synthetic by-product of rayon, dichromate, phenol (qv), or potash (see Chromium compounds Fibers, regenerated cellulosics Potassium compounds). Sodium sulfate made as a by-product is referred to as synthetic. Sodium sulfate made from mirabilite, thenardite, or naturally occurring brine is called natural sodium sulfate. In 1994, about 300,000 t of sodium sulfate were produced as a by-product another 300,000 t were produced from natural sodium sulfate deposits (4). 

As recently as 1970, only about 30 naturally occurring organohalogen compounds were known. It was simply assumed that chloroform, halogenated phenols, chlorinated aromatic compounds called PCBs, and other such substances found in the environment were industrial pollutants. Now, only a third of a century later, the situation js quite different. More than 5000 organohalogen compounds have been found to occur naturally, and tens of thousands more surely exist. From a simple compound like chloromethane to an extremely complex one like vancomycin, a remarkably diverse range of organohalogen compounds exists in plants, bacteria, and animals. Many even have valuable physiological activity. Vancomycin, for instance, is a powerful antibiotic produced by the bacterium Amycolatopsis orientalis and used clinically to treat methicillin-resistant Staphylococcus aureus (MRSA). 

Table I. Effects of naturally-occurring phenolic compounds on mineral absorption in excised roots.

The solubility of most metals is much higher when they exist as organometallic complexes.4445 Naturally occurring chemicals that can partially complex with metal compounds and increase the solubility of the metal include aliphatic acids, aromatic acids, alcohols, aldehydes, ketones, amines, aromatic hydrocarbons, esters, ethers, and phenols. Several complexation processes, including chelation and hydration, can occur in the deep-well environment. 

Oxidation of organic compounds by dioxygen is a phenomenon of exceptional importance in nature, technology, and life. The liquid-phase oxidation of hydrocarbons forms the basis of several efficient technological synthetic processes such as the production of phenol via cumene oxidation, cyclohexanone from cyclohexane, styrene oxide from ethylbenzene, etc. The intensive development of oxidative petrochemical processes was observed in 1950-1970. Free radicals participate in the oxidation of organic compounds. Oxidation occurs very often as a chain reaction. Hydroperoxides are formed as intermediates and accelerate oxidation. The chemistry of the liquid-phase oxidation of organic compounds is closely interwoven with free radical chemistry, chemistry of peroxides, kinetics of chain reactions, and polymer chemistry. 

Isaacson and Sawhney (60) studied the reactions of a number of phenols and smectite with transition metal (Cu, FeJ+) and nontransition metal exchangeable cations. IR spectra of the clay-phenol complexes showed that all the clays studied transformed the sorbed phenols. The transformation occurred to a much greater extent in clays with transition metal cations than in those with the non-transition metal cations. In a subsequent study, Sawhney et al. (61) studied the polymerization of 2,6-dimethylphenol on air-dried homoionic Na-, Ca-, A1-, and Fe-smectite at 50°C. A portion of the adsorbed 2,6-dimethylphenol was transformed into dimers, trimers, tetramers, and quinone-type compounds. The nature of the exchange cations had an effect on both sorption and transformation and decreased in the order Fe Al > Ca > Na. 

Sarkar, S. K., and C. T. Phan. Naturally-occuring and ethylene-induced phenolic compounds in the carrot root. 

There are many compounds that are used as food grade antioxidants. Although, phenolic antioxidants are becoming suspect for health reasons, they are still are being used effectively. However, we should not fear to explore the naturally occurring antioxidants. They too are effective and will probably be the next generation of food antioxidants. 

This is a large group of structurally diverse naturally occurring compounds that possess at least a phenolic moiety in their structures. Eor example, umbelliferone, a coumarin, has a phenolic hydroxyl functionality at C-7 quercetin is a flavonoid that has four phenolic hydroxyls at C-5, C-7, C-3 and C-4. Although the phenolic group of compounds encompasses various... 

Phenylpropanes are aromatic compounds with a propyl side chain attached to the benzene ring, which can be derived directly from phenylalanine. Naturally occurring phenylpropanoids often contain oxygenated substituents, e.g. OH, OMe or methylenedioxy, on the benzene ring. Phenylpropanoids with hydroxyl substituent(s) on the benzene ring belongs to the group of phenolics, e.g. caffeic acid and coumaric acid. 

---