Biological activities of Eugenia uniflora L. (pitangueira) extracts in oxidative stress-induced pathologies: A systematic review and meta‐analysis of animal studies

Background

Eugenia uniflora L. (EU) is widely distributed geographically and has been used in traditional medicine owing to its range of therapeutic properties associated with antioxidant action. To determine the viability of this species as an herbal with promising pharmaceutical applications, we assessed the evidence from preclinical studies about the antioxidant potential of EU extracts as a natural source for prevention and treatment of diseases associated with oxidative stress.

Methods

The search was conducted in the electronic databases: PubMed, ScienceDirect, and SciELO. In vivo studies related to the antioxidant properties and preclinical assays of this species were included. The risk of bias was assessed in all studies and meta-analysis was carried to summarize effect size of EU extracts.

Results

From 738 reports, 7 studies were included in qualitative synthesis and 4 in meta-analysis. Studies using extracts or fractions, and different pharmacological activities were reported. Meta-analysis showed positive effects of EU versus control on superoxide dismutase levels in hippocampus (MD=6.59; 95% CI=4.56–8.63) and on cortex (MD=7.57; 95% CI=5.92–9.21); and glutathione peroxidase (GPx) on hippocampus (MD = 11.85; 95%CI = 10.42–13.29). However, EU extracts did not show significant effects on GPx levels on cortex (p = 0.56); on acetylcholinesterase on cortex (p = 0.05), and hippocampus (p = 0.66); and glutathione levels on liver (p = 0.38).

Conclusion

In general, the studies have heterogeneity and some concerns about risk of bias, specially about randomization and blind outcome assessment. Current evidence of in vivo studies supports antioxidant action of EU extracts in brain tissue by increase of endogenous antioxidant molecules.