Impact of quercetin on systemic levels of inflammation: a meta-analysis of randomised controlled human trials

Knowledge regarding the anti-inflammatory capability of quercetin remains inconclusive and controversial due to the heterogeneous methods and inconsistent results of RCTs. We performed a series of meta-analyses of RCTs to evaluate the impact of quercetin supplementation on inflammatory biomarkers. Three cytokines (CRP, IL-6, TNF-α) with enough eligible studies (<i>n</i> = 6, 5 and 4, respectively) were selected for further meta-analyses. Data from these RCTs were pooled, and both overall effect and stratified subgroup analyses were performed. No relevant overall effects on peripheral CRP, IL-6 and TNF-α were observed. Subgroup analyses revealed a significant reduction in circulating CRP in participants with diagnosed diseases (SMD: –0.24, 95% CI: –0.49, 0.00) and IL-6 in females (SMD: –1.37, 95% CI: –1.93, –0.81), subjects with diagnosed diseases (SMD: –1.37, 95% CI: –1.93, –0.81) and with high-dose interventions (SMD: –0.69, 95% CI: –1.10, –0.38). In conclusion, consumption of quercetin is a promising therapeutic strategy for chronic disease management.

由于随机对照试验（Randomized Controlled Trials, RCTs）方法存在异质性且研究结果不一致，目前学界关于槲皮素（quercetin）抗炎能力的认知仍不明确且存在争议。本研究针对RCTs开展了一系列荟萃分析（meta-analysis），以评估槲皮素补充干预对炎症生物标志物（inflammatory biomarkers）的影响。我们选取了符合纳入标准且研究数量充足的三种细胞因子：C反应蛋白（C-reactive protein, CRP）、白细胞介素6（Interleukin 6, IL-6）与肿瘤坏死因子α（Tumor Necrosis Factor α, TNF-α），对应合格研究数量分别为6项、5项与4项，进而开展进一步荟萃分析。本研究合并了上述RCTs的相关数据，同时进行了整体效应分析与分层亚组分析。结果显示，未观察到槲皮素补充对外周血CRP、IL-6及TNF-α产生显著整体效应。亚组分析结果表明：在确诊疾病的受试者中，循环CRP水平显著降低（标准化均数差（Standardized Mean Difference, SMD）：–0.24，95%置信区间（95% Confidence Interval, 95% CI）：–0.49, 0.00）；在女性受试者、确诊疾病的受试者以及接受高剂量干预的受试者中，循环IL-6水平显著降低，具体为：女性组（SMD：–1.37，95% CI：–1.93, –0.81）、确诊疾病组（SMD：–1.37，95% CI：–1.93, –0.81）、高剂量干预组（SMD：–0.69，95% CI：–1.10, –0.38）。综上，槲皮素摄入有望成为慢性疾病管理的潜在治疗策略。