7 Toxicology
-
Upload
ruben-marquez -
Category
Documents
-
view
32 -
download
1
Transcript of 7 Toxicology
House-Keeping Items
Today (15th): Toxicology and Phytochemistry Mail your 2009 income tax return!
Tuesday (20th): Beverages and FermentationsThursday (22nd): No class Tuesday (27rd): Additives, Radicals, AntioxidantsThursday (29th): Exam #3. Last class day.
Class Assignment #2 will be posted on-line TODAY.
Due date: On or before April 28th by 5 pm. Follow the directions!
Assignment Topic: Beverages Food Additives Legal Status
Food Toxicology
Food ToxicologyThe study of the nature, properties, effects, and
detection of toxic substances in food, and their impact on humans.
Early on, people were aware that some plants are poisonous and should be avoided as food.
Other plants were found to contain chemicals that have medicinal, stimulatory, hallucinatory, or narcotic effects.
The Dose Makes the Poison
Attributed to Pericles
-a Greek statesman.
“Toxic” to One….not to AnotherFood Allergens (The “Big Eight”)
Cows milk Shellfish (Crustacea) Eggs Fin fish Peanuts Soy Tree nut Wheat
For example: Celiac Disease Ingestion of wheat, barley, ryeProline-rich protein - gliadinsTriggers immune damage to small intestine Impairs absorption of nutrientsDiarrhea, bloating, weight loss, bone pain,
anemia, chronic fatigue, weakness, muscle cramps
Scombroid PoisoningAnaphylactic shockEating fish with high histamine levels
Tuna, mackerel, other pellagic fish species
Histamine from spoilage bacteria in fish Also from putrecine and cadaverine
Everyone is susceptibleSome more sensitive (allergy?) than others.
Sensitivity or Allergy to: Lactose Sulfites Strawberries (internal histamine release) Fava beans/broad beans (enzyme deficiency) Asparagus (sulfur compounds) Red wine (low levels of histamine; SO2)
Fructose intolerance Aspartame (phenylalanine) Tartarazine (FD&C Yellow #5)
MycotoxinsSubstances produced by fungi that are harmful
to animals and humans> 100,000 species of fungi> 300 mycotoxins isolated; 30 with food issuesPlant specific
Environmental Temperature Humidity Moisture Oxygen
Claviceps purpureaGrows in wet and over-wintered grains:
rye, barley, wheatSclerotia or “ergots” (Hard-packed mycelium)“Ergotism”
Convulsions and gastrointestinal symptomsErgotamine is an analogue of lysergic acid
(LSD), a glycoalkaloidVasoconstrictor that may cause hallucinationsSt. Anthony’s firePotential cause of Salem, MA witch trials, 1692.
Aspergillus flavus and A. paraciticusUniversal food contaminant
Corn, peanuts, wheat, rice, pecans, walnuts, etc
Animal carcinogen at 5 ppbHuman liver carcinogenProblem in food industry and grain handling
Harvesting, transport, storage
4 main aflatoxins: B1, B2, G1, G2 In animal feed, B1 and B2 can be converted to
M1 and M2 and secreted in milk (ie. cow or human)
Toxins formed during Food Processing We previously covered the Maillard reaction
Polycyclic aromatic hydrocarbons (benzo(a)pyrine) Carcinogenic agents in almost every model tested But excellent flavor compounds...yet remember Pericles?
Nitrite used in curing meat and fish Antimicrobial agent Reacts with myoglobin and hemoglobin to form red nitrosyl
compounds Nitrite may also react with amines to form nitrosoamines. Carcinogenic, mutagenic.
Toxins formed during Food Processing Acrylamide in foods In 2000-2002 Swedish researchers identified acrylamide
in foods and residues from human samples. Acrylamide is a neurotoxin and carcinogen. Used as:
Cement binder, plastic manufacture, waste water treatment agent, soil conditioner, thickening agent for pesticides, cosmetics, laboratory gels, etc)
Broad range of foods with significant levels of acrylamide. Foods prepared at high temperatures. Fried and baked, but not boiled. Higher in high carbohydrate foods.
Acrylamide in PotatoesAcrylamide derived from asparagine in the
presence of sugar.Carbonyl carbon in glucose facilitates the reactionAsparagine + Sugar + Heat = Acrylamide
Natural Food “Toxins” in Plants
Metabolism and Plant Primary CompoundsPlant metabolism:
Used to describe the chemical reactions and interactions that take place in a biological system.
Includes reactions that cause a plant to shift its leaves towards a light source
Cause chloroplasts to produce photosynthetic sugars from sunlight, carbon dioxide, and water, ect
Includes the production of plant primary and secondary compounds.
Plant Primary Compounds Those compounds which are formed as a part of the
normal anabolic and catabolic processes.
Plant Secondary Compounds Secondary Compounds
Those compounds that are not primary compounds. A compound that does not seem to directly function in the
processes of growth and development. Some regarded these substances as waste products of a cell. At least one major benefit a plant gains from producing
secondary compounds was later discovered: protection from certain types of herbivory.
The most obvious way to discourage this was to synthesize a substance to make the plant taste bad.
The bitter taste of tea is due to the secondary compounds found in the tea leaves (caffeine and tannins).
Other Mean Tricks Secondary Compounds
Another way to hinder herbivory was to synthesize compounds that would cause temporary or permanent physiological changes in the herbivore (Toxins)
Caffeine and morphine are good examples. Isoflavonoids affect reproduction in mammals. Found in
alfalfa, soy, and some clover species, it mimics the hormone progesterone and may cause infertility, reduced lactation, or difficulties in labor.
These types of secondary compounds make an animal "think twice" about eating off the same plant again.
Not so coincidentally, this same type of physiological effect is what people refer to as the "high" after consuming certain plants (mushrooms, nutmeg, “weed”, coffee, etc)
Do plants experience stress the way humans do?
Hypericum perforatun Lycopersicum esculentun
Causes of Plant Stress (Elicitors)
Insects (US est. at $100M annum)Weather (drought, flood, wind, hail)Ethylene (ppb levels)Post-harvest storage UV lightPhysical wounds (harvest, transport)Microbial contamination
(polysaccharides)
Results of Plant Stress
Phytoalexins (Phyto = “plant” and alexin = “to ward off”)
Low MW organic metabolites produced by plants in response to stress
“Self-made antibiotics”We consume ~10,000 times more “natural”
chemicals than man-made chemicals~150 true phytoalexins known
What? Toxic Chemicals in My Food!!Phytochemical ParadoxDangerous pesticide or antioxidant wonder??For the plant:UV light protection (Nature’s sun-screen)Oxidative protectionAnti-microbial (Anti-Herbivores?)For the consumer (us):ROS quencherBitter, astringent and sour flavors
Pre-existing defenses
Induced/Biochemical defenses
Hypersensitive responses
DEFENSE MECHANISMS
Production of phytoalexins may be stimulated by certain compounds called elicitors.
High molecular weight substances found in the cell wall such as glucans, glycoprotein, or other polysaccharides.
Gases such as ethylene (C2H4)
PRODUCTION OF PHYTOALEXINS
In susceptible plants, a pathogen may prevent the formation of phytoalexins, by the action of suppressors produced by the pathogen.
The suppressor also can be a glucan, a glycoprotein, or a toxin produced by the pathogen
PRODUCTION OF PHYTOALEXINS
Chemical and Sensory Properties of Food “Toxins”
Aromatic Sour Bitter Astringent Sulfurous Medicinal Smoky Animal-like
Metal chelator Antioxidant (-OH groups)
Free radical terminators
ROO. + AH = ROH + A.
Resonance stability
O O O O
. ..
OH
Phytoalexic Toxins In Our Food
PotatoStress MetabolitesCinnamates, scopolin, quinic acid, sesquiterpenoids,
solanine, chaconine
Solanine (Glycoalkaloid)Sunburned spuds or growth shoots (periderm)10-50 ppm is normal, increases 7-fold during stress Natural pesticide (cholinesterase inhibitor)
Acetylcholine is a neurotransmitterExtremely bitter, not soluble in waterHeat stable
TomatoStress MetabolitesCinnamates, rishitin, falcarindiol, tomatine
Tomatine (Alkaloid)High in immature fruitRipe tomato contains ~30-40 ppmNatural pesticideHeat labile
CarrotStress MetabolitesCinnamates, falcarinol, falcarindiol, isocoumarin
Isocoumarin (neutral phenolic)Anti-microbial (~10 ppm)Extremely bitter, not soluble in waterHeat stableEthylene sensitive synthesis
“Natural” Carcinogens in Coffee Acetaldehyde Benzaldehyde Benzene Benzofuran Benzo[a]pyrene Caffeic acid Catechol 1,2,5,6 Dibenzanthracene Ethanol
Ethylbenzene Formaldehyde Furan Furfural Hydrogen peroxide Hydroquinone Limonine Styrene Toluene Xylene
Other Commodities
Peppers- Capsidiol
Sweet potato- Ipomeamarone
Celery, parsnips, parsley- Psoralens (furanocoumarins)
Grapes- Resveratrol, stilbene
Alfalfa- Medicarpin (Isoflavonoid)
Soybean roots- Glyceollin
Peas- Pisatin
Bean pods- Phaseollin
Plant vs Man: “Xenobiotic” Metabolism
Cytochrome P-450 system In body: liver, lung, skin, nasal mucosa, GI tractEnzyme system to solubilize chemicalsSubstrate (xenobiotics) must be somewhat
lipophilic to reach active sites for metabolismPlants did not want to become food for people or
animals….but we fought back !!
“Antioxidant” Enzyme Systems
Active Oxygen Detoxification Enzymes SOD (superoxide dismutase) GSH (glutathione) POD (peroxidase) CAT (catalase)
Cytochrome P-450 systemInduction of Phase I and Phase II Enzymes
Phase IOxidation/Reduction– Add/Remove O, Add/Remove H.
ie. alcohol dehydrogenaseHydrolysis.– Add water
Phase IIConjugation reactions.-Enzyme catalyzed reactions.-Tend to increase size and polarity for excretion.
Phytochemicals
Current trend: Increased consumer interest in nutraceuticals…..which are phytochemicals
Nutraceuticals
Dietary compounds, foods, or supplements used to promote
health life or prevent some disease
Phytochemical
Components in a plant based diet other than traditional
nutrients that can potentially reduce the risk of degenerative diseases
Vit K and E Polyhenolic Sterols Prebiotics Probiotics
Phyto= plant…chemicals Organosulfides Isothiocynates Indoles Carotenoids Saponins Tocopherols Amino acids/Proteins Lipids Carbohydrates
Polyphenols Flavonoids Tannins Isoflavones
Vitamins/Minerals Coumarins Dietary Fiber Enzymes
Mechanisms of ActionMany antioxidant effects Increased activity of enzymes that detoxify
carcinogensEffect on cell differentiationBlock formation of carcinogens (ie. nitrosamines)Alter estrogen metabolismDecrease cell proliferationMaintenance of normal DNA repair
How Did They Get There ??
Selective Biosynthesis
How are Phytoalexins Formed?The “-noids” Shikimic acid pathway (phenylpropanoids)
Hydroxycinnamic acids Coumarins Hydroxybenzoic acids
Mevalonic acid pathway (Isoprenoids) Carotenoids Terpenoids
Combination of Pathways
(Shikimic-Polymalonic) Flavonoids and anthocyanins
OOH
OH O
OH
OH
OH
OH
HOOC
OH
OH
OOCCH CH
OH
OH
Shikimic Acid Pathway-Phenolics
PEP from glycolysis + erythrose 4-P from PP-pathway forms skikimic acid which are the precursor to phenylalanine and tyrosine.
PAL and TAL (ammonia lyases) Cinnamic acid Coumarin p-Coumaric acid Caffeic acid Ferulic acid Sinapic acid
COOHOH
COOHOH
OH
COOHOH
MeO
COOHOH
MeO
MeO
O
OH
OH
OH
OH
OH
D-glucose
O3PO
H
OOH
OH
O3PO
COO-
+
erythrose 4-phosphate phosphoenolpyruvate
O
O3POH2COH
OH
OH
COOH
deoxy-arabino-heptulosonate-7-phosphate
DAHP synthetase
OH
OH
O
OH COOH
dehydroquinatesynthase
3-dehydroquinic acid
OH
OH
O
COOH
dehydroquinatedehydratase
3-dehydroshikimic acid
OH
OH
OH OH
COOH
quinic acid
quinatedehydrogenase
OH
OH
OH
COOH
shikimic acid
NADPH NADP+
shikimatedehydrogenase OH
OH
O3PO
COOH
shikimate kinase
ATP
3-phosphoshikimic acid
ADPO3PO COOH
PEP
EPSP synthase
OH
O COOH
COOH
chorismatesynthetase
chorismic acid
The Shikimic Acid Pathway Leading to Phenylpropanoid and Flavonoid SynthesisThe Shikimic Acid Pathway Leading to Phenylpropanoid and Flavonoid Synthesis
OH
OH3OPO OH
COOH
3-phosphoquinic acid
O3PO
OH
O
HHH
OPO3
COOH
COOH O3PO
OH
O
COOH
COOH
5-enolpyruvyl shikimic acid 3-phosphate
O
COOH
COO-
NH3+H
CH2
OH H
HOOCCH
COOH
NH2
prephenatedehydratase
Phenylalanine (phe)
Phenylpyruvic acid
Arogenic acid
arogenatedehydratase
OH
COOH
HOOC
chorismatemutase
prephenic acid
OH
COOH
cinnamate-4-hydroxylase
p-coumaric acid
OH
OH COOH
Caffeic acid
p-comuarate3-mono-oxygenaseOH
MeO COOH
Ferulic acid
caffeate methyl-3-O-transferase
S-adenosyl-methionineOH
MeO
OMe
COOH
Sinnapic acid
Caffeic acid 3-O-methyltransferase
2-oxoglutaric acid glutamic acid
glutamine 2-oxoglutarateamidotransferase (GOGAT)
glutamine glutamic acid
NH4+ from PAL
COOH
L-phenylalanineammonia lyase (PAL)Cinnamic acid
NH4+
NH2
OH
COOH
arogenatedehydrogenase
NADP+
NADPH
tyrosine ammonia-lyase (TAL)
NH4+
tyrosine
OH
OH
OMe
COOH
5-hydroxyferulic acid
Ferululate-5-hydroxylase
OH
OH
OH OH
COOH
OH
OH
OO
OHOH
OH
COOH
quinic acid
Chlorogenic acid(5 cafeoylquinic acid)
OH
OH
OO
OH OH
OH COOH
OH
OH
OO
O OH
OH COOH
OHOH
O
Chlorogenic acid(4 cafeoylquinic acid)
Isochlorogenic acid(4,5 cafeoylquinic acid)
OH
OH
O
OH
OH
OO
O OH
OH
COOH
Isochlorogenic acid(3,5 cafeoylquinic acid)
COS-CoA
OH
hydroxycinnamate:CoA ligase(4-coumaroyl:CoA ligase)
p-coumaryl-CoAOH
COOH
OH
OH
CHO
OH
COOH
p-hydroxybenzaldehydep-hydroxybenzoic acid
NADP+NADPH
OH
OOH
OH
OH
Me SCoA
O
SCoA
O
HOOC
chalconesynthase
Chalcone
-3CO2
acetyl CoAcarboxylase
Malonyl CoA
O
O
OH
OH
OH
R2
R1
chalconeisomerase
Flavanone
O
OOH
OH
OH
OH
R2
R1
Dihydroflavonol
flavanone3-hydrolase
O
OOH
OH
OH
OH
R1
R2
Flavonol
flavonolsynthase
O
OOH
OH
OH
R1
R2
Flavone
flavonesynthase I & II
O
OHOH
OH
OH
OH
R2
R1
Flavan-3,4-diol(leucoanthocyanidin)
dihydroflavonol4-reductase
NADPHNADP+
O+
OH
OH
OH
OH
R2
R1
Anthocyanidin
anthocyanidinsynthase
O2 & alpha-ketoglutarate
2H2OCO2
succinateO
+
OH
OH
OH
Gly
R2
R1
Anthocyanidin-3-O-glycosides
flavonoidglucosyltransferase
UDP-D-glucose
UDP
O
OH
OH
OH
OH
R1
R2
Flav-3-nol
leucoanthocyanidinreductase
O
OHOH
OH
OH
R
Flavan-4-ol
flavanone4-reductase
R1 = R2 = H; DihydrokaempferolR1 = H, R2 =OH; Dihydroquercetin
R1 = R2 = OH; Dihydromyricetin
R1 = R2 = H; KaempferolR1 = H, R2 =OH; Quercetin
R1 = R2 = OH; Myricetin
R1 = R2 = H; LeucopelargonidinR1 = H, R2 =OH; LeucocyanidinR1 = R2 = OH; Leucodelphinidin
R1 = R2 = H; PelargonidinR1 = H, R2 =OH; CyanidinR1 = R2 = OH; Delphinidin
R1 = R2 = H; Pelargonidin-3-glycosideR1 = H, R2 =OH; Cyanidin-3-glycosideR1 = R2 = OH; Delphinidin-3-glycoside
R1 = R2 = H; AfzelechinR1 = H, R2 =OH; Catechin
R1 = R2 = OH; Gallocatechin
OOH
OH
OH
R3
R4
O
OH
OH
OH
OH
R1
R2
Procyanidins
leucoanthocyanidinreductase
R1 = OH, R2 = H; NaringeninR1 = OCH3, R2 =H; Isosakuranetin
R1 = R2 = OH; EriodictyolR1 = OCH3, R2 = OH; Hesperitin
R1 = OH, R2 = H; ApigininR1 = OCH3, R2 = H; Fortuneletin
R1 = R2 = OH; LuteolinR1 = OCH3, R2 = OH; Diosmetin R = H; Apiferol
R = OH; Luteoferol
OH
O
OH
OH
OH
chalconeisomerase
Isoliquiritigenin
chalconereductase
O
OOH
OH
OH
isoflavonesynthase
2-hydroxyisoflavanone
NADPHO2
NADP+
H2O
O
OOH
OH
OH
2-hydroxyisolflavanonedehydratase
H2O
Daidzein
O
O
OH
OH
OH
Naringenin
O
OOH
OH
OH
OH
2-hydroxyisoflavanone naringenin
isoflavonesynthase
NADPHO2
NADP+
H2O
OH
O
O
OH
isoflavonesynthase
Liquiritigenin
O
O
O
OH
o-methyltransferase
S-adenosyl-homocysteine
S-adenosyl-methionine
2,7-dihydroxy-4'-methoxyisoflavanone
O
OOH
OH
OMe
H2O
Formononetin
S-adenosyl-homocysteine
S-adenosyl-methionine
o-methyl transferase
O
OOH
OH
OHgenistein
isoflavonedehydratase
H2O
O
OOH
OH
O
OH
H
2,5,7-trihydroxy-4'-methoxyisoflavanone
isoflavonemethyl transferase
S-adenosyl-methionine
S-adenosyl-homocysteine
O
OOH
OH
OBiochinan A
methoxyisoflavonedehydratase
H2O
S-adenosyl-methionine
S-adenosyl-homocysteine
O
OOH
O
OHPrunetin
isoflaveone methyltransferase
S-adenosyl-methionine
S-adenosyl-homocysteine
O
OOH
OH
O
OH
Pratensein
isoflavonehydrolase
NADPHO2
NADP+
H2O
Flavonoids
Phenylpropanoids
OH
COOH
OH
protocatechuic acid
O2
NADP+
H2ONADPH
p-hydroxybenzoicacid hydroxylaseOH
COOH
OHOH
gallic acid
O2
NADP+
H2ONADPH
protocatechuicacid hydroxylase
Phenolics
Plants produce a variety of compounds that contain one or more phenol groups - called phenolics
Thousands of phenolics occur in plants
PhenolicsLarge group of diverse compoundsMany serve as defense compounds against
herbivores and pathogensSome attract pollinatorsSome absorb UV lightSome reduce growth of competitors
BackgroundFlavonoids are non-nutrients1936-Szent-Gyorgyi, called flavonoids Vitamin P.1950’s disproved the theoryLate seventies-mutagenecity of quercetinRecent research-anticarcinogenic
O
OH
O R2
R1
HO
HO
Structure of flavonoids
X
7
6
5
3
2
4
8
6151
41
31
21
A
B
C
FLAVONOLSKaempferolQuercetinMyrcetin
O
OH
Kaempferol
O
OH
HO
HO
O
OH
Quercetin
O OH
OH
HO
HO
O
OH
Myricetin
O
OH
HO
HO
OH
OH
Two Specific Polyphenolics
Ellagic acid
Isoflavonoids
Ellagic acid Derivatives
Ref. Mullen et.al. 2003
Ellagic acid Conversion
OOH
OOH
OH
Isoflavones share several features in common with estradiol
1. Presence of a phenolic (benzene) ring: Prerequisite for binding to the
estrogen receptors.
2. Pair of OH- groups separated by a similar distance
3. Common compounds: genestein/genestin and diadzein/diadzin
Isoflavone
CH3
OH
OH
17 - estradiol
Isoflavones: Free- and “Conjugated” Forms
OR1
OOH
OH
R2
OR1
OO
OH
R2
OCH2
HH
OHH
OHOH
H H
HOH
OR1
OO
OH
R2
OCH2
HH
OHH
OHOH
H H
HO
R3
Acetyl COCH3
Malonyl COCH2COOH
Aglycone
Glycoside
Phytochemicals
Carotenoids
Mevalonic Acid Pathway-Carotenoids
Pyruvate from glycolysis is decarboxylated to form acetate which combines with coenzyme A to form acetyl CoA.
Acetate + Acetyl CoA = Acetoacetyl CoA Acetoacetyl CoA + Acetyl CoA = Mevalonic acid
Phytoene Lycopene ß-carotene Lutein
O
COOH
H OPO3
OH
OH TPP
2-
Pyruvate
Glyceraldehyde 3-phosphate
thiaminepyrophosphate CO2
1-deoxy-D-xylulose5-phosphate synthase
The Mevalonic Acid Pathway for Carotenoid SynthesisThe Mevalonic Acid Pathway for Carotenoid Synthesis
OPO3
OHO
OPO3
OH
OH
OH
2-
1-deoxy-D-xylulose5-phosphate
NADPH + H+ NADP+
2-
2-C-methyl-D-erythriol4-phosphate
OPO3PO3
metabolitesunknown Isopentyl
diphosphate (IPP)
OPO3PO3
Dimethallylpyrophosphate
IPP Isomerase
OPO3PO3
OPO3PO3
Farnesyldiphosphate (FPP)
IPP Isomerase
Geranyldiphosphate (GPP)
IPP Isomerase
OPO3PO3
Geranylgeranyl diphosphate (GGPP)
IPPIsomerase
Prephytoene pyrophosphate
phytoenesynthase
Phytoene
phytoenesynthase
Phytofluene
phytoenedesaturase
Zetacarotene
zetacarotenedesaturase
Neurosporene
phytoenedesaturase
Lycopene
zetacarotenedesaturase
Delta-carotene
lycopene epsilon cyclase
Gamma-carotene
lycopene beta cyclase
Alpha-carotene
lycopene beta cyclase
Beta-carotene
lycopene beta cyclase
OH
Zeinoxanthin
beta-carotene hydrolasee
OH Beta-cryptoxanthin
beta-carotene hydrolase
OH
OH Lutein
alpha-carotenehydrolase
OH
OH Zeaxanthin
beta-carotene hydrolase
caroteneisomerase
Nomenclature and Structure
OH Beta-Cryptoxanthin
LuteinOH
OH
Beta-Carotene
Metabolism of Dietary Carotenoids
Breeding Fruits and Vegetables for Functionality
Phytochemicals for Improved Human Health
Crops containing or that can be developed with: Anthocyanins Carotenes Phenolic acids Quercetin Vitamins C, D, and E
Blueberry Antioxidants
Blackberry Antioxidants
Total Soluble Phenolics and ORACTotal Soluble Phenolics and ORAC
0
1500
3000
4500
6000
7500
0 20 40 60 80 100 120 140
ORAC (µM Trolox equivalents)
Tot
al P
heno
lics
(mg/
kg C
hlor
ogen
ic a
cid)
Blueberry (9)Blackberry (13)
Grape (10)Peach-Nectar. (10)Tomato (10)
R2 = 0.62
Anthocyanins and ORACAnthocyanins and ORAC
0
400
800
1200
1600
2000
0 20 40 60 80 100 120 140
ORAC (µM Trolox equivilents)
Ant
hocy
anin
(mg/
kg M
alvi
din
3-G
lu)
Blackberry (13)Blueberry (9)Grape (4)Nectarine (1)
R2 = 0.51
Structure-Based Antioxidant Activity of Phytochemicals
p-OH-benzoicp-coumaric
ProtocatechuicCaffeic
VanillicFerulic
0.08 2.22
1.19 1.26
1.43 1.90
Structurally Similar Compounds
OOH
OH O
OH
OH
OH
OOH
OH
OH
OH
OH
OOH
OH
OH
OH
OH
+
QuercetinAOX = 4.7
CatechinAOX = 2.4
CyanidinAOX = 4.4
Importance of the 3-OH group
OOH
OH O
OH
OH
OH
OO
O
OO
O
OOH
OH O
OH
OH
QuercetinAOX = 4.7
Quercetin-3-glucosideAOX ~ 2.5
OOH
OH O
OH
OH
LuteolinAOX = 2.1
Importance of the 2-3 db
OOH
OH O
OH
OH
OH
QuercetinAOX = 4.7
TaxifolinAOX = 1.9
OOH
OH O
OH
OH
OH
Summation
OOH
OH O
OH
OH
OH
QuercetinAOX = 4.7
OOH
OH O
OH
OH
Rutinoside
OOH
OH O
OH
OH
OOH
OH O
OH
OH
OOH
OH O
OH
OH
OH
RutinAOX = 2.4
KaempferolAOX = 1.3
LuteolinAOX = 2.1
TaxifolinAOX = 1.9