Abstract
Background Propolis is rich in polyphenols, especially flavonoids and phenolic acids, and has significant antioxidant activity, shown mainly in “in vitro” studies. Objective The aim of this study was to evaluate the antioxidant efficacy and safety of a standardized propolis extract in healthy volunteers. Design A two-phase sequential, open-label, nonrandomized, before and after clinical trial. Methods Healthy participants received two EPP-AF® doses (375 and 750 mg/d, P.O, tid) during 7 ± 2 days, starting with the lower doses. Immediately before starting EPP-AF® administration and at the end of each 7-day dosing schedule, blood and urine samples were collected for quantification of 8-OHDG (8-hydroxydeoxyguanosine) and 8-ISO (8-isoprostanes) in urine and GSH (reduced glutathione), GSSG (oxidized glutathione), SOD (superoxide dismutase), FRAP (Ferric Reducing Antioxidant Power), vitamin E, and MDA (malondialdehyde) in plasma. Results In our study, we had 34 healthy participants (67.7% women, 30 ± 8 years old, 97% white). The 8-ISO, a biomarker of lipid peroxidation, decreased with both doses of EPP-AF® compared to baseline (8-ISO, 1.1 (0.9–1.3) versus 0.85 (0.75–0.95) and 0.89 (0.74–1.0), ng/mg creatinine, P < 0.05, for 375 and 750 mg/d EPP-AF® doses versus baseline, mean and CI 95%, respectively). 8-OHDG, a biomarker of DNA oxidation, was also reduced compared to baseline with 750 mg/d doses (8-OHDG, 15.7 (13.2–18.1) versus 11.6 (10.2–13.0), baseline versus 750 mg/d, respectively, ng/mg creatinine, P < 0.05). Reduction of biomarkers of oxidative stress damage was accompanied by increased plasma SOD activity (68.8 (66.1–73.3) versus 78.2 (72.2–80.5) and 77.7 (74.1–82.6), %inhibition, P < 0.0001, 375 and 750 mg/d versus baseline, median and interquartile range 25–75%, respectively) and by increased GSH for 375 mg/d EPP-AF® doses (1.23 (1.06–1.34) versus 1.33 (1.06–1.47), μmol/L, P < 0.05). Conclusion EPP-AF® reduced biomarkers of oxidative stress cell damage in healthy humans, with increased antioxidant enzymatic capacity, especially of SOD. This trial is registered with the Brazilian Registry of Clinical Trials (ReBEC, RBR-9zmfs9).
Highlights
Maintaining cell viability requires a continuous process of energy production, which is largely accomplished by mitochondria
Excess production of oxygen free radicals, defined as oxidative stress, can lead to cell damage and be part of a number of some chronic degenerative diseases observed in humans, such as cancer, inflammatory and cardiovascular diseases, diabetes mellitus, atherosclerosis, and Alzheimer’s disease [2,3,4]
Antioxidant defenses are composed of enzymatic mechanisms such as glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD) [5] and dozens of substances that play a role in binding and neutralizing free radicals. ese substances may be endogenous or offered from diet or supplements [6,7,8]
Summary
Propolis is rich in polyphenols, especially flavonoids and phenolic acids, and has significant antioxidant activity, shown mainly in “in vitro” studies. Healthy participants received two EPP-AF doses (375 and 750 mg/d, P.O, tid) during 7 ± 2 days, starting. 8-OHDG, a biomarker of DNA oxidation, was reduced compared to baseline with 750 mg/d doses (8-OHDG, 15.7 (13.2–18.1) versus 11.6 (10.2–13.0), baseline versus 750 mg/d, respectively, ng/mg creatinine, P < 0.05). Reduction of biomarkers of oxidative stress damage was accompanied by increased plasma SOD activity (68.8 (66.1–73.3) versus 78.2 (72.2–80.5) and 77.7 (74.1–82.6), %inhibition, P < 0.0001, 375 and 750 mg/d versus baseline, median and interquartile range 25–75%, respectively) and by increased GSH for 375 mg/d EPP-AF doses (1.23 (1.06–1.34) versus 1.33. EPP-AF reduced biomarkers of oxidative stress cell damage in healthy humans, with increased antioxidant enzymatic capacity, especially of SOD. EPP-AF reduced biomarkers of oxidative stress cell damage in healthy humans, with increased antioxidant enzymatic capacity, especially of SOD. is trial is registered with the Brazilian Registry of Clinical Trials (ReBEC, RBR-9zmfs9)
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