A systematic review and meta-analysis of the anti-tumor effects of Paeoniae Radix Rubra in animal models

Paeoniae Radix Rubra (PRR) is the dried root of Paeonia lactiflora Pall, which has been widely used to anti-thrombotic, lipid-lowering, anti-spasmodic, antioxidant, antibacterial, hepatoprotective, and anti-tumor in Chinese clinical practice. Recent research has demonstrated that PRR plays a significant anti-tumor role in animal models of tumor-bearing. There has not been the evaluation of the anti-tumor effects of PRR. This study conducts a meta-analysis to assess the anti-tumor efficacy of PRR on animal models, providing scientific evidence for clinical application of PRR in the adjuvant therapy of tumors. English databases (PubMed, The Cochrane Library, Embase, and Web of Science) and Chinese databases (CNKI, WanFang, SinoMed, CTSJ-VIP) were used to search all pertinent animal studies investigating the anti-tumor effects of PRR and its extracts. The quality of the included studies was evaluated using the SYRCLE animal experiment risk assessment tool, and statistical analysis was carried out using Revman 5.3 software. Egger's test and funnel plots were used to assess potential publication bias in the studies. The initial search produced a total of 3905 potentially pertinent studies, and 24 studies met the inclusion criteria. These studies included animal tumor models of hepatocellular carcinoma, lung cancer, sarcoma, bladder cancer, leukemia, colon cancer, glioblastoma, and pancreatic cancer. The meta-analysis findings demonstrated that both PRR and its extracts significantly inhibited tumor growth in animals. Compared with the control group, PRR substantively inhibited tumor volume (SMD, −3.09; 95% CI, [-4.05, −2.13]; P < 0.0001), reduced tumor weight (SMD, −1.08; 95% CI, [-1.37, −0.78]; P < 0.0001), decreased tumor number (SMD, −2.16; 95% CI, [-3.45, −0.86]; P = 0.001), and prolonged the survival duration time (SMD, 0.97; 95% CI, [0.23, 1.71]; P = 0.01) on the experimental animals. PRR displayed a potential therapeutic efficacy on eight tumors in animal models including hepatocellular carcinoma, lung cancer, sarcoma, bladder cancer, leukemia, colon cancer, glioblastoma, and pancreatic cancer. However, the quality and quantity of included studies may affect the accuracy of positive results. In the future, more high-quality randomized controlled animal experiments are need for meta-analysis.