Abstract: Dysfunction of sarcoplasmic reticulum (SR)
Ca^{2+}-ATPase induced by oxidative stress may be a
contributing factor to the development of serious age related diseases.
Incubation of sarcoplasmic reticulum (SR) vesicles of rabbit skeletal muscles
with
Fe^{2+}/H_2O_2/ascorbate
decreased the SH group content of SR approximately to 35% and
Ca^{2+}-ATPase activity to 50% of control not oxidized
sample. Protein carbonyls increased twofold, lipid peroxidation was also
significantly elevated. The antioxidant effects of trolox, the pyridoindole derivative
stobadine and of the standardized extracts from bark of Pinus Pinaster
Pycnogenol® (Pyc) and from leaves of Ginkgo biloba (EGb 761) were studied
on oxidatively injured SR. All antioxidants exerted preventive effects against
the oxidized lipids and protein SH groups of SR vesicles. Trolox and stobadine
did not influence protein carbonyl formation, while flavonoid extracts
prevented carbonyl generation, probably by binding to protein. The preventive
effects of the antioxidants studied on lipids and protein SH groups were
however not associated with protection of Ca^{2+}-ATPase
activity. Stobadine and trolox exerted no effect on enzyme activity, Pyc and
EGb 761 enhanced the inhibitory effect of Ca^{2+}-ATPase
activity in oxidatively injured SR. Concluding, under the conditions of
oxidative stress induced by
Fe^{2+}/H_2O_2/ascorbate
against SR of rabbit skeletal muscle, the agents studied demonstrated
antioxidant effects yet failed to protect Ca^{2+}-ATPase
activity.
