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Published byJulian Riley Modified over 8 years ago
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Secondary Products - II Phenolics
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Synthesis of Phenolics Phenolics are synthesized by a number of different pathways Two most important: Shikimic acid pathway - more important in plants Malonic acid pathway - more important in fungi
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Shikimic Acid Pathway Converts intermediates from glycolysis (phosphoenol-pyruvate) and the PPP (erythrose-4-PO 4 ) into the aromatic amino acids: phenylalanine, tryptophan, and tyrosine
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See Shikimic Acid Pathway
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See Pathway for Phenolic Secondary Products
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Simple Phenolics Allelopathic compounds Defense cmpds against insect herbivores and fungi Certain phenolics (furanocoumarins) are phototoxic - not toxic till activated by sunlight (near UV-A) Activated furanocoumarins can insert into DNA and bind to pyrimidine bases - blocks transcription and leads to cell death Abundant in Apiaceae Urushiol in poison ivy
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Urushiol Poison ivy urushiol Poison oak urushiol
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Coumarins Large group – 1300 coumarins have been identified Basic coumarin is a 2 ring structure, phenol and pyrone Many anticoagulants including Warfarin
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Lignin a complex phenolic Polymer of three phenolic alochols Different species have different ratios of these monomers Lignin in beech has 100:70:7 of coniferyl: sinapyl: para-coumaryl Lignin monomers
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Flavinoids One of the largest classes of phenolics Carbon skeleton has 15 carbons with two benzene rings connected by a 3-C bridge -C 3 -
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Flavinoids Flavinoids classified into different groups based on the degree of oxidation of the 3-C bridge Anthocyanins Flavones Flavonols Isoflavones Majority of flavinoids exist as glycosides
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Anthocyanins
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Tannins Tannin a general name for a large group of complex phenolic substances that are capable of tanning animal hides into leather by binding collagen
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Tetrahydrocannabinol
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