Biosynthesis of polyphenols

With apple plugs, 10 mM cinnamate inhibited browning for several hours but induced severe browning over extended storage times. The combination of cinnamate with AA in dips was more effective than AA alone however, the combination of cinnamate with AAP showed no advantage over AAP alone. The tendency of cinnamate to induce browning indicates a potential problem with this compound which may undergo conversion at the cut surface to a PPO substrate by cinnamate-hydroxylase and other enzymes involved in the biosynthesis of polyphenols (54). 

Dinelli, G. et al.. Biosynthesis of polyphenol phytoestrogens in plants, in Phytoestrogens in Functional Foods, Yildiz, F., Ed., CRC Press, Boca Raton, FL, 2006, 19. 

It is a precept of modern chemical ecology that energy is unlikely to be wasted in the production of secondary metabolites unless there is some compensating adaptive advantage to the organism in question. The biosynthesis of polyphenols involves seemingly a substantial input of... 

SCHEME 1 Shikimic acid pathway for the biosynthesis of polyphenols. 

Table 4. Enzymes Involved With Biosynthesis of Tea Polyphenols ...

Polyphenoloxidase (PPO, EC 1.14.18.1) is one of the most studied oxidative enzymes because it is involved in the biosynthesis of melanins in animals and in the browning of plants. The enzyme seems to be almost universally distributed in animals, plants, fungi, and bacteria (Sanchez-Ferrer and others 1995) and catalyzes two different reactions in which molecular oxygen is involved the o-hydroxylation of monophenols to o-diphenols (monophenolase activity) and the subsequent oxidation of 0-diphenols to o-quinones (diphenolase activity). Several studies have reported that this enzyme is involved in the degradation of natural phenols with complex structures, such as anthocyanins in strawberries and flavanols present in tea leaves. Several polyphenols... 

FIGURE 16.S Reactions catalyzed by the plant polyphenol oxidase, aureusidin synthase (AS), in the transformation of chalcones to aurones. (A) The biosynthesis of aureusidin from either tetra- or pentahydroxychalcone precursors through an ortho-diqmnone intermediate. (B) The aureusidin synthase-catalyzed formation of bracteatin from a pentahydroxychalcone precursor. 

Figure 3-17. Biosynthesis of Tellimagrandin II (3.103) and Comusiin E (3.104) from pentagalloylglucose (3.102) by polyphenol oxidases of the laccase class.

Resveratrol shows a direct inhibitory activity on heart fibroblasts and suppresses the spreading of heart fibrose (05MI1131). The vasoconstrictor peptide endothelin (ET-1) is controlled in its biosynthesis by polyphenols, and especially by resveratrol. Only 5 pmol causes an endothelin-depen-dent vasodilatation and lowers blood pressure (88NAT411, 01MI152, 01NAT863,06NAT566). 

The chalcone synthase (CHS) (EC 2.3.1.74) superfamily of type III Polyketide synthases (PKSs) are pivotal enzymes in the biosynthesis of plant polyphenols. They are structurally and mechanistically different from the modular type I and the dissociated type II PKSs of bacterial origin the simple homodimer of 4CM-5 kDa proteins performs a complete series of decarboxylation, condensation, cyclization,... 

Fig. 1 Biosynthesis of plant polyphenols by CHS-superfamily type III PKSs. CHS chalcone synthase STS stilbene synthase ACS acridone synthase VPS valerophenone synthase SPS styrylpyrone synthase BPS benzophenone synthase OAS olivetolic acid synthase 2PS 2-pyrone synthase BAS benzalacetone synthase CUS curcumin synthase...

FIGURE 7.12 Overview of the biosynthesis of the main polyphenols from the phenylalanine precursor (adapted from Naczk and Shahidi, 2004). 

HALBWIRTH, H., WURST, F FORKMANN, G., STICH, K., Biosynthesis of aurones in Coreopsis grandiflora, in. XIX International Conference on Polyphenols. September 1-4, Lille, France, 1998, pp. 157-160. 

ABSTRACT More than 200 naturally occurring oligostilbenes isolated from plant kingdom are grouped into I-V structural types. They are a special kind of polyphenolic natural products with multi-faceted bioactivities. This article will review their classification, distribution, spectral characteristics, biological activities (anti-fungal, antibacterial, antioxidant, anti-inflammatory and anticarcinogenic activities, etc.) and mimetic biosynthesis. 

The presence of phenoloxidase in all phyla of living organisms demonstrates that their origin is very early in the history of life. It is involved in the biosynthesis of melanins and other polyphenolic compounds. Depending on the species, phenoloxidases are involved in the primary immune response, wound healing, sclerotization, and coloring processes. In mammals, L-tyrosine is the initial substrate in the pathway leading to the final products of black-brown eumelanins, red-yellow pheomelanins, or a mixture of pheo-and eumelanins.Ti ... 

Chemler JA, Lim CG, Daiss JL, Koffas MAG (2010) A versatile microbial system for biosynthesis of novel polyphenols with altered estrogen receptor binding activity. Chem Biol 17 392-401... 

Saigne-Soulard C, Richard T, Merillon JM, Monti JP (2006) C NMR analysis of polyphenol biosynthesis in grape cells Impact of various inducing factors. Anal Chim Acta 563 137-144. doi 10.1016/j.aca.2005.09.073... 

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