antioxidants

Question 1

what are oxidants

Answer 1

steal an electron
reducing reactive species
oxidsing other molecules

Question 2

oxidative modification - damaging lipids

Answer 2

preoxidation
cell membranes damaged - dysfunction cells
LDL oxidsied - becomes athrogenic, increases CVD

Question 3

oxidative modification - damage to body proteins

Answer 3

carbonylation, can effect metabolism

alter protein function - ageing

Question 4

oxidative modification of DNA

Answer 4

ageing

cancer

Question 5

relevance of oxidative modification on performance

Answer 5

damaged cell membranes - leaky, impaired permability
damaged proteins - altered function of transporters, enzymes, contractile proteins
reduced NO bioavalibilty - decreased perfusion in blood vessels
inflammation - sorness, pain

Question 6

sources of reactive oxygen species

Answer 6

NADPH oxidase - enzyme in cell cytoplasm, produce superoxide
activity of enzymes increases during exercise

mitochondria
B-oxidation of fatty acids

Question 7

important roles of ROS and RNS

Answer 7

signalling molecules 
vasodialation 
immune function - help fight pathogens 
cell communication 
- SR Ca2+ release 
- GLUT 4 translocation 
- increased protein synthesis

Question 8

endogenous antioxidants

Answer 8

present in the system
enzymes
- superoxide dismutase

non enzymatic
- uric acid

Question 9

nutrional antioxidants

Answer 9

vitamins - C,E carotene
minerals - copper, zinc
Phytochemicals - phenolic acid, flavonoids

Question 10

how much do ROS increase with exercise

Answer 10

2-20 fold

Question 11

what are indirect markers of oxidative damage

Answer 11

protein carbonlys and nitrotryosine in blood
F2 - isoprostase
TBARs
MDA

Question 12

what are direct markers of oxidative damage

Answer 12

electron paramagnetic spin resonance
- use chemicals to track them
hard to use

Question 13

effects of ROS in training adaptations

Answer 13

muscle hypertrophy
mitochondrial
increased production of antioxidants

Question 14

what happens if ROS levels are too high

Answer 14

damage occurs

• impairs release of Ca2+ from SR - Ca2+ leak
• reduces sensitivty of muscles to Ca2+
• impaired force production

Question 15

what is N-acetylcystein

Answer 15

direct oxidant scavenger

supports glutathion production (naturally produced antiox)

Question 16

effect of N-acetylcystein on performance (stattery et al 2014)

Answer 16

improvement in 5,10 and 15s cycle sprint
lower levels of ROS
better tolerance to increased training intenisity
lower levels of ROS

Question 17

what is Quercetin

Answer 17

polyphenol
from the flavnid family
widespread presence in fruit and veg

Question 18

what is the habitual intake for Quercetin

Answer 18

5-15mg

Question 19

structure of polyphenols

Answer 19

6 carbon ring and hydroxyl group

Question 20

effect of polyphenols (bowtell et al 2011)

Answer 20

MVC decreased by 40%
recovery significantly better in cherry, returned to 91%
Creatine Kinase increased in both conditions
enhanced functional recovery from intensive exercise after 7 days pre loading with cherry
mediated via reduced exposure to ROS

Question 21

direct antioxidant properties

Answer 21

radical scavengers 
protection 
not hugley bioavailable 
only absorb 5-10% of polyphenols in stomach 
increase about 1hr after ingestion 
90-95% move to gut and further absorbed

Question 22

breakdown of cyanidin pharmacokinetics

Answer 22

increased levels of brekadown of cyanidin
24hrs later hugh peak due to time taken to break down
1 coumpound - produces 17 different molecules

Question 23

oxidants and indirect antioxidant characteristics

Answer 23

poor bioavailibilty

• peak plasma phenolic conc - <10um
• uric acid 150-450um

convereted to a stable radical

• semiquinones and quinones
• trigger increased systhesis of endogenous antiox

inhibit ROS production

Question 24

effect of polypehnols on function recovery

Answer 24

enhance
reduce oxidative damage
reduce inflammation
soreness equivocal