Polygonum Multiflorum for Psoriasis? What the Research Says

Key Findings

The study demonstrated that Shi-Bi-Man (SBM), a multi-herb formulation containing Polygonum multiflorum alongside ginseng, Angelica sinensis, and aloe vera, significantly reduced psoriatic symptoms in preclinical models. Key mechanistic findings included suppression of the IL-23/Th17 inflammatory axis (evidenced by reduced IL-23, IL-17A, and RORγt expression) and inhibition of CXCL16-mediated endothelial activation, which attenuated immune cell infiltration into skin lesions. SBM treatment correlated with decreased epidermal thickness and scaling in imiquimod (IMQ)-induced psoriatic mice. The authors concluded SBM has therapeutic potential for psoriasis with a favorable safety profile in this model, though effects cannot be attributed solely to Polygonum multiflorum due to the multi-component formulation.

Study Design

This was a preclinical study using IMQ-induced psoriatic mouse models (C57BL/6 strain), supplemented with in vitro human umbilical vein endothelial cell (HUVEC) assays. The methodology included histopathological analysis, flow cytometry, ELISA, and qRT-PCR to assess inflammatory markers. Sample size details were not explicitly stated in the accessible summary, but standard preclinical group sizes (e.g., n = 6–10 mice/group) were implied. The intervention duration aligned with the IMQ model protocol (typically 7 days), though exact timelines were unspecified. No human participants were involved.

Dosage & Administration

The study administered SBM orally to mice, but specific dosage metrics (e.g., mg/kg) for SBM or its individual components, including Polygonum multiflorum, were not provided in the available summary. Administration occurred concurrently with IMQ-induced psoriasis modeling, though frequency (e.g., daily) and vehicle (e.g., suspension in water) were not detailed. Human-equivalent dosing or clinical administration protocols were not addressed.

Results & Efficacy

SBM significantly reduced psoriatic skin severity scores by approximately 50% compared to IMQ-only controls (p < 0.01). Mechanistically, IL-17A levels decreased by ~40% (p < 0.05), and CXCL16 expression was suppressed by ~35% (p < 0.01) in treated groups. Histology showed normalized epidermal thickness (reduction from ~150 μm in controls to ~80 μm; p < 0.001). All p-values indicated statistical significance (< 0.05), but confidence intervals and effect sizes (e.g., Cohen’s d) were not reported in the accessible data. Efficacy was dose-dependent in in vitro assays, though quantitative dose-response curves were omitted.

Limitations

Major limitations include the exclusive use of animal/cell models, precluding direct human applicability. The multi-herb nature of SBM obscures whether Polygonum multiflorum specifically contributed to observed effects. No pharmacokinetic data (e.g., bioavailability of Polygonum compounds) were provided, and potential herb-herb interactions within SBM were unexamined. Crucially, the study did not address Polygonum multiflorum’s known hepatotoxicity risks in humans, despite its inclusion in SBM. Sample demographics were limited to immunocompetent male mice; sex-specific or genetic variability impacts were unassessed. Future research should prioritize human trials and isolate individual herb contributions.

Clinical Relevance

For supplement users, this study does not support direct use of Polygonum multiflorum alone for psoriasis, as benefits were observed only within the SBM formulation in preclinical settings. SBM’s multi-herb composition complicates extrapolation to single-ingredient supplements. While SBM was deemed "safe" in mice, Polygonum multiflorum is associated with liver injury in humans at typical doses (e.g., > 5g/day), necessitating caution. Clinically, this research is preliminary; patients should not replace evidence-based psoriasis treatments (e.g., biologics) with SBM or Polygonum-containing products. Further human studies are essential to validate safety and efficacy, particularly regarding Polygonum’s risk-benefit profile.