Aim:
To evaluate blackcurrant anthocyanin-rich extract (BAE) consumption on time- and dose-dependent plasma anthocyanin bioavailability and conduct a pilot study to explore the potential effect of BAE in promoting recovery from exercise-induced oxidative stress, and maintenance of circulating neutrophil function.
Methods:
Time- and dose-dependent blackcurrant anthocyanin bioavailability was assessed using LC-MS in 12 participants over 6 h after the ingestion of a placebo or BAE containing 0.8, 1.6, or 3.2 mg/kg total anthocyanins. In a separate pilot intervention exercise trial, 32 participants consumed either a placebo or 0.8, 1.6, or 3.2 mg/kg BAE (8 individuals per group), and then 1 h later performed a 30 min row at 70% VO
2
max. Blood was collected during the trial for oxidative, antioxidant, inflammatory, and circulating neutrophil status.
Results:
Consumption of BAE caused a time- and dose-dependent increase in plasma anthocyanins, peaking at 2 h after ingestion of 3.2 mg/kg BAE (217 ± 69 nM). BAE consumed 1 h prior to a 30 min row had no effect on plasma antioxidant status but hastened the recovery from exercise-induced oxidative stress: By 2 h recovery, consumption of 1.6 mg/kg BAE prior to exercise caused a significant (
P
< 0.05) 34 and 32% decrease in post-exercise plasma oxidative capacity and protein carbonyl levels, respectively, compared to placebo. BAE consumption prior to exercise dose-dependently attenuated a small, yet significant (
P
< 0.01) transient 13 ± 2% decline in circulating neutrophils observed in the placebo group immediately post-exercise. Furthermore, the timed consumption of either 1.6 or 3.2 mg/kg BAE attenuated a 17 ± 2.4% (
P
< 0.05) decline in neutrophil phagocytic capability of opsonised FITC-
Escherichia coli
observed 6 h post-exercise in the placebo group. Similarly, a dose-dependent increase in neutrophil surface expression of complement receptor-3 complex (CR3, critical for effective phagocytosis of opsonised microbes), was observed 6 h post-exercise in both 1.6 and 3.2 mg/kg BAE intervention groups.
Conclusions:
Consumption of BAE (>1.6 mg/kg) 1 h prior to exercise facilitated recovery from exercise-induced oxidative stress and preserved circulating neutrophil function. This study provides data to underpin a larger study designed to evaluate the efficacy of timed BAE consumption on post-exercise recovery and innate immunity.
Skeletal muscle damage can result from disease and unaccustomed or excessive exercise. Muscle dysfunction occurs via an increased level of reactive oxygen species and hence there is potential in antioxidants as amelioration strategies. We explored the putative benefit of fruit polyphenolic extracts in reducing the susceptibility of skeletal muscle cells to oxidative stress. Muscle myotubes were simultaneously challenged with fruit extracts (1-50 microg/mL) and calcium ionophore (A23187), hydrogen peroxide, or 2,4-dinitrophenol and damage monitored by release of cytosolic enzymes. A blueberry fruit extract displayed a potent and significant dose-dependent protective capacity. Evaluation of the protective capacity of anthocyanin sub-extracts of blueberry fruit and pure individual glycosides, with identification of extract polyphenolic components using MS, suggested that malvidin galactoside and/or glucoside were the active compounds. These in vitro data support the concept that blueberry fruits or derived foods rich in malvidin glycosides may be beneficial in alleviating muscle damage caused by oxidative stress. More research on the benefits of blueberry fruit consumption in human intervention studies is warranted.
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