antioxidants Flashcards
what are oxidants
steal an electron
reducing reactive species
oxidsing other molecules
oxidative modification - damaging lipids
preoxidation
cell membranes damaged - dysfunction cells
LDL oxidsied - becomes athrogenic, increases CVD
oxidative modification - damage to body proteins
carbonylation, can effect metabolism
alter protein function - ageing
oxidative modification of DNA
ageing
cancer
relevance of oxidative modification on performance
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
sources of reactive oxygen species
NADPH oxidase - enzyme in cell cytoplasm, produce superoxide
activity of enzymes increases during exercise
mitochondria
B-oxidation of fatty acids
important roles of ROS and RNS
signalling molecules vasodialation immune function - help fight pathogens cell communication - SR Ca2+ release - GLUT 4 translocation - increased protein synthesis
endogenous antioxidants
present in the system
enzymes
- superoxide dismutase
non enzymatic
- uric acid
nutrional antioxidants
vitamins - C,E carotene
minerals - copper, zinc
Phytochemicals - phenolic acid, flavonoids
how much do ROS increase with exercise
2-20 fold
what are indirect markers of oxidative damage
protein carbonlys and nitrotryosine in blood
F2 - isoprostase
TBARs
MDA
what are direct markers of oxidative damage
electron paramagnetic spin resonance
- use chemicals to track them
hard to use
effects of ROS in training adaptations
muscle hypertrophy
mitochondrial
increased production of antioxidants
what happens if ROS levels are too high
damage occurs
- impairs release of Ca2+ from SR - Ca2+ leak
- reduces sensitivty of muscles to Ca2+
- impaired force production
what is N-acetylcystein
direct oxidant scavenger
supports glutathion production (naturally produced antiox)
effect of N-acetylcystein on performance (stattery et al 2014)
improvement in 5,10 and 15s cycle sprint
lower levels of ROS
better tolerance to increased training intenisity
lower levels of ROS
what is Quercetin
polyphenol
from the flavnid family
widespread presence in fruit and veg
what is the habitual intake for Quercetin
5-15mg
structure of polyphenols
6 carbon ring and hydroxyl group
effect of polyphenols (bowtell et al 2011)
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
direct antioxidant properties
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
breakdown of cyanidin pharmacokinetics
increased levels of brekadown of cyanidin
24hrs later hugh peak due to time taken to break down
1 coumpound - produces 17 different molecules
oxidants and indirect antioxidant characteristics
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
effect of polypehnols on function recovery
enhance
reduce oxidative damage
reduce inflammation
soreness equivocal
