Effects of purslane supplementation on C‐reactive protein levels and biomarkers of oxidative stress as marks for metabolic syndrome: A systematic review and meta‐analysis of randomized controlled trials

The antioxidant and antiinflammatory properties of purslane (Portulaca oleracea L.) are known in preclinical studies but further examination is needed to expand their potential into the clinical scenario. A systematic review and meta‐analysis of randomized controlled trials were performed to elucidate the effects of purslane supplementation on C‐reactive protein (CRP) levels and biomarkers of oxidative stress in metabolic syndrome, its related complications, and other diseases. PubMed/MEDLINE, Web of Science, SCOPUS, and Embase were the databases searched. Heterogeneity was examined using the I‐squared (I2) statistic, in which the source of heterogeneity was determined if the I2‐value was >50%. After all the screening processes, 10 studies met the eligibility criteria and were analyzed. Following purslane supplementation, CRP levels decreased significantly (weighted mean difference [WMD]: −0.33 mg/dl, 95% confidence interval [CI]: −0.66, −0.004, p = .047) but with significant heterogeneity (I2 = 87.4%, p = .001). Purslane supplementation did not significantly change serum levels of malondialdehyde (MDA) (WMD: −0.353 μm/L; 95% CI: −0.920, 0.213; I2 = 50.7%), total antioxidant capacity (TAC) (WMD: 0.090 mm/L, 95% CI: −0.081, 0.262; I2 = 47.1%), and superoxide dismutase (SOD) (WMD: 6.54 U/ml, 95% CI: −22.150, 35.236; I2 = 70.7%). Thus, this meta‐analysis showed a positive effect of purslane supplementation as a tool to decrease CRP levels, but not to MDA, TAC, and SOD levels.