NUTR 3330 > Flavonoids > Flashcards

Flavonoids Flashcards

Exam 3 (57 cards)

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1
Q

What are phytochemicals?

A
  • chemicals found in plants
  • generally non-nutritive substances
  • physiologically active components
  • proposed to contribute toward disease prevention
  • more than 900 classes have been identified and many more continue to be discovered
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2
Q

What are some examples of phytochemicals?

A
  • flavonoids
  • phytoestrogens
  • phytosterols
  • allyl sulfur phytiochemicals
  • glucosinolates
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3
Q

What are plant polyphenols

A
  • Plant metabolites
    -present in all plant organs
  • largest category of phytochemicals
  • range from simple phenolic molecules (simple phenols) to highly polymerized compounds (tannins)
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4
Q

Where do plant polyphenols occur?

A
  • naturally occurring compounds found in plants (fruits and veg, grains)
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5
Q

Do phytochemicals have sub-types

A
  • yes they usually have sub-types
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6
Q

What is essential to plant physiology?

A
  • Plant polyphenols
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7
Q

What do plant polyphenols contribute to in plants

A
  • Plant pigmentation
  • plant growth and reproduction
  • provides plants with resistance to pathogens and predators
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8
Q

Where are plant polyphenols derived from

A
  • derived from a common intermediate phenylalanine or a close precursor shikimic acid
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9
Q

What is the common structural feature of plant polyphenols?

A
  • Aromatic ring with at least one hydroxyl group
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10
Q

What are the 4 classes of plant polyphenols

A
  1. Phenolic acids
  2. Flavonoids
  3. Stilbenes
  4. Lignans
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11
Q

What are the classes of plant polyphenols and how are they determined?

A
  • based on the number of phenol rings and on the structural elements that bind these rings to one another
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12
Q

What influences the amount of polyphenols in plants

A
  • Light
  • genetic factors
  • environmental conditions
  • degree of ripeness
  • variety
  • processing
  • storage
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13
Q

can the amount of polyphenols in plants vary even within a plant species?

A
  • Yes
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14
Q

What do polyphenols in food contribute to?

A
  • bitterness
  • astringency
  • colour
  • flavour
  • odor
  • oxidative stability
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15
Q

What were polyphenols traditionally considered?

A
  • “anti-nutrients”
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16
Q

Why would polyphenols be considered “anti-nutrients”?

A
  • they can interfere with bioavailability
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17
Q

How do polyphenols interfere with macronutrients?

A
  • they can bind protein to reduce absorption
  • polyphenol must be highly polymerized and most low molecule weight polyphenols do not do this
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18
Q

What happens when polyphenols bind and reduce absorption

A
  • increase fecal nitrogen
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19
Q

How do polyphenols affect micronutrients?

A
  • form complexes with minerals and may decrease absorption
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20
Q

How have polyphenols evolved?

A
  • historically understood as compounds that could interfere with bioavailability of nutrients
  • however now are renewed and know as antioxidant capacities, potential beneficial human health effects
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21
Q

What are flavonoids?

A

-Low molecular weight polyphenolic substances
- most common group of plant polyphenols
- most of the research on polyphenols and health focused on flavonoids
- present in most plants

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22
Q

What were flavonoids originally called?

A
  • vitamin P
  • P=pigment
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23
Q

What did Nobel prize winning biochemists Rusznyak ad Szent-Gyorgyi discover about flavonoids?

Study These Flashcards
A
  • they discovered that flavonoids enhanced the function of vitamin C, improving absorption and protecting it from oxidation
24
Q

What is the basic flavonoid structure?

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A
  • A ring usually arises from the acetate pathway
  • B ring usually arises from the shikimate pathway
  • Both A and B rings have OH groups attached
  • C ring determines the major class of flavonoid
25
What is flavonoid classification based on?
- Based on six major sub classes of variations of the C-ring
26
What are the six major subclasses of flavonoids?
1. Flavones 2. Flavonols 3. Flavanones 4. Flavanols 5. AnthocyaniNS 6. Isoflavones
27
Where are flavonoids distributed in plants?
- Located mainly in leaves, flowers, and outer parts of the plants (skin, peel) - decreased concentrations towards the central core - Only trace amounts found in plant parts below the soil surface
28
What foods are flavonoids in?
- widely distributed in foods and beverages of plant origin
29
Can the amount of flavonoids in food vary
- yes, it can vary a lot
30
Is there challenges with flavonoid intake
- yes there are challenges in quantifying dietary intake related to determination of flavonoid content in plant
31
What are some variation factor of content of flavonoids in foods?
- variety - crop year - location - genetic variation - light amount - environmental conditions - degree of ripeness processing and storage - amount of skin surface area
32
What are some challenges with quantifying dietary intake of flavonoids also related to?
- Analytical methodology
33
What is analytical methodology?
- lack of standardization in methodology for quantifying flavonoids - quantifiable data in literature is therefore inconsistent
34
Why do we need to care about accurately quantifying dietary intake of flavonoids?
We need to accurately quantify dietary intake of flavonoids because flavonoids are bioactive compounds that can influence human health, and understanding how much people consume helps researchers and policymakers make better dietary recommendations.
35
What can studies do with the flavonoid database?
- relate intake to health outcomes
36
Explain the study of flavonoid intake and all cause mortality
- Objective was to explore the association between flavonoid intake and risk of 5 year mortality from all causes by using 2 comprehensive food consumption databases to assess flavonoid intake - N=1063 women in western Austria - USDA database and Phenol-Explorer database - low (<547 mg) - high > or equal to (813) flavonoid intake - moderate (547-<813 mg) - RR= 0.37 (0.22,0.58)
37
What is the main idea of the study done on the comparison of flavonoid intake assessment methods using USDA and Phenol Explorer Databases: Subcohort diet, Cancer and health-next generations- max study
- Databases are needed and with advance of multiple databases come another source of variation
38
What is flavonoid intake related to?
- Related to many aspects of health
39
What do studies involve related to flavonoid intake
- Studies involve a dietary assessment and an analysis of the foods and beverages consumed for flavonoid content using a database - There are many factors that cause variation in these numbers - These studies do not consider if the flavonoids are absorbed
40
What are flavonoid glycosides?
- Flavonoids are typically attaches/conjugated to carbohydrate in the food matrix - Terminology reflects if the carbohydrate attachment is there or not -
41
What do majority of flavonoids appear in plants as and how does it help
- appear in plants as glycosides - helps with storage in the plant
42
What does flavonoid glycoside mean?
- There is carbohydrate attachment
43
- What does flavonoid aglycone mean?
- There is no carbohydrate attachment
44
Explain flavonoid bioavailability
- Intimately thought to be negligible since they are bound to glycosides, but now known that glycosides can be metabolized to aglycones and absorbed - Flavonoids are absorbed and reach concentrations of varying magnitudes in our biological fluids
45
What have numerous kinetic studies found with bioavailability of specific flavonoids
- Present in blood and urine
46
What is essential to consider before considering impact on health outcomes of flavonoids and why?
- Essential to consider bioavailability - Relies on clear knowledge of intake and if absorption occurred (bioavailability)
47
What is the best biological marker is the best for flavonoids?
- Flavonoid Metabolism
48
Explain what the study orange juice (poly)phenols studied showed
- That organ juice (poly)phenols are highly bioavailable in humans - In order for orange flavanone to exert their health effects in vivo, it is essential that they are bioavailable and absorbed from the gastrointestinal tract into the circulatory system - Examined urinary flavanone and colonic metabolites - Collected urine over 24 hours and used GCMS and HPLC-MS - Identified 14 metabolites
49
What are flavonoid biological effects
1. Antioxidant effects 2. Hormonal/Anti-hormonal effects 3. Anti-proliferative effects
50
Explain the antioxidant effects of flavonoids
- direct free radical scavenger (OH) groups - chelate metals involved in the initiation of lipid per oxidation, namely IRON - protect vitamin E that has been oxidized - Increases glutathione levels
51
Explain the hormonal/anti-hormonal effects of flavonoids
- primarily estrogenic and anti-estrogenic - relation to hormone-dependent cancers - isoflavones main flavonoid in this area
52
Explain anti-proliferative effects of flavonoids
- Inhibition of cellular transformation and proliferation - Relevant for existing cancer cells - Inhibit growth of cancer cell in vitro - Interact with enzymes associated with DNA - inhibit topoisomerase II - reduce stability of cancer cells - facilitates apoptosis (death of cancer cells)
53
What are other biologic effects of flavonoids
- All involved in plant culture - All intuitive based on their role in the plant itself - All of these biological effects have potential relevance to human health and disease
54
What are some health effects from flavonoids
- Research is evaluating the role of various flavonoids in reducing the risk of several diseases including: * Cancer * Cardiovascular Disease * Any other condition associated with oxidative stress
55
How does flavonoids eliminate the risk of Cancer
-Antioxidant - Anti-estrogenic - Anti-proliferative
56
How does flavonoids eliminate the risk of CVD
- Antioxidant - Estrogenic - Anti-inflammatory
57
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