Efficacy and safety of plant-derived bioactive compounds in the treatment of psoriasis vulgaris: a systematic review and network meta-analysis

BACKGROUND: Long-term use of conventional therapy (CT) for psoriasis vulgaris (PV) is often constrained by adverse effects and costs. While oral plant-derived bioactive compounds show clinical promise as adjunctive treatments, the relative efficacy and safety of these compounds and their combination regimens remain poorly defined due to a lack of head-to-head comparisons. This systematic review and network meta-analysis aimed to compare and rank the efficacy and safety of different oral plant-derived bioactive compounds and their combination regimens for PV. METHODS: Randomized controlled trials investigating the effects of plant-derived bioactive compounds, such as compound glycyrrhizin (CG), tripterygium glycosides (TG), and total glucosides of paeony (TGP), on PV were retrieved from Chinese and English databases via computer searches. The main outcome measures included the Psoriasis Area and Severity Index (PASI), CD4+/CD8+ ratio, IL-23, IL-17, and TNF-α. Network meta-analysis was performed using Stata 16.0 software. RESULTS: We included 84 randomized controlled trials comprising 7,544 patients across 15 treatment regimens. Most combination therapies significantly outperformed monotherapy in PASI reduction. TG combined with topical therapy (TOP) produced the greatest reduction in PASI scores [mean difference (MD) = -13.96, 95% confidence interval (CI) (-16.88, -11.03)], with the highest surface under the cumulative ranking curve (SUCRA) value of 99.80%. Individual compounds showed distinct advantages for specific therapeutic targets. CG + TOP proved most effective for reducing IL-23 levels (SUCRA = 97.30%), while CG + NB-UVB achieved the greatest IL-17 reduction (SUCRA = 91.20%). CG + CT best restored CD4+/CD8+ ratio balance (SUCRA = 94.70%), and TGP + TOP led all regimens in TNF-α suppression (SUCRA = 92.40%). Adverse events were predominantly mild, consisting of gastrointestinal symptoms or skin dryness. No serious or irreversible events were recorded. CONCLUSION: Combining plant-derived compounds with CT may enhance short-term, outcome-specific efficacy. TG + TOP showed the greatest PASI reduction. Immunologically, CG-based regimens optimized IL-23/IL-17 suppression and CD4+/CD8+ normalization, while TGP + TOP maximized TNF-α inhibition. These distinct profiles inform individualized treatment and warrant long-term confirmation. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261304681, identifier (CRD420261304681).