Arctium lappa Extract Suppresses Inflammation and Inhibits Melanoma Progression

Abstract

Background: Arctium lappa has been used as popular medicinal herb and health supplement in Chinese societies. Bioactive components from A. lappa have attracted the attention of researchers due to their promising therapeutic effects. In this study, we investigated the effects of A. lappa hydroalcoholic extract (Alhe) during different models of inflammation, in vivo. Methods: The anti-inflammatory activity was evaluated through the air pouch model. For this, mice received an inflammatory stimulus with lipopolysaccharide (LPS) and were later injected with Alhe. To assess anti-tumoral activity, the animals were inoculated with B16F10 cells and injected with Alhe every 5 days, along the course of 30 days. Controls were submitted to the same conditions and injected with the vehicle. Peritoneal or air pouch fluids were collected to evaluate leukocyte counting or cellular activation via quantification of cytokines and nitric oxide. Results: Alhe injection reduced the neutrophil influx and production of inflammatory mediators in inflammatory foci after LPS or tumor challenges. Furthermore, Alhe injection reduced tumor growth and enhanced mice survival. Conclusions: Collectively, these data suggest that Alhe regulates immune cell migration and activation, which correlates with favorable outcome in mouse models of acute inflammation and melanoma progression.

Keywords: Arctium lappa; inflammation; melanoma; natural product; phytomedicine.

Figure 1

Alhe induces leukocyte accumulation into the peritoneal cavity and peripheral blood. Total leukocytes and neutrophils were evaluated after injection of 300 μL of Alhe at different concentrations (50, 300, and 500 mg/kg) in the peritoneal cavity (A,B) or peripheral blood (C,D). The experiment was conducted twice using five mice per group (n = 10); the error bars denote ± SEM. * indicates control PBS versus different doses. These differences were considered significant when p < 0.05, according to ANOVA with Tukey’s post-test.

Figure 2

A. lappa extract suppresses inflammation in lipopolysaccharide (LPS)-inflamed air pouches. After 1 h of injection of phosphate-buffered saline (PBS) (PBS/1 mL/pouch) or LPS (1 μg/mL/1 mL/pouch) into air pouches, mice were injected with Alhe (300 mg/kg/1 mL/pouch) or PBS (PBS/1 mL/pouch). Total and differential leukocyte numbers were determined in the lavage fluid, after 4 h. (A) Total leukocytes, (B) neutrophils, (C) mononuclear cell counts, and (D) total protein quantification. (E) IL-6, (F) TNF-α, and (G) IL-1β were quantified by ELISA. The experiment was conducted twice using five mice per group (n = 5), and error bars denote mean ± SEM. * PBS (control) versus LPS; # LPS versus LPS + A. lappa. Differences were considered significant if p < 0.05 according to ANOVA with Tukey’s post-test.

Figure 3

A. lappa extract reduced inflammation induced by tumor implantation. (A,C) Total leukocytes and (B,D) neutrophil accumulation was evaluated in the peritoneal cavity after 30 days of the B16F10 melanoma implantation. The animals received Alhe (50 mg/kg/300 μL) or PBS (300 μL) via i.p. every 5 days for 30 days. (E) Total protein, (F) NO₂⁻, (G) IL-6; (H) TNF-α, and (I) IL-1β were quantified in the peritoneal fluid. The experiment was conducted twice using five mice per group (n = 5). Data represents mean ± SEM. * control versus tumor or tumor + A. lappa; ^# tumor versus A. lappa. Differences were considered significant with p < 0.05 according to ANOVA with Tukey’s post-test.

Figure 4

A. lappa extract reduces tumor growth and rescues animal mortality. (A) For assessment of tumor size and (B) mice survival, B16F10 melanoma cells were implanted and the animals received Alhe (50 mg/kg/300 μL) or PBS (300 μL) every 5 days for 30 days. (A) Tumors were measured with a Vernier caliper, and tumor volume was calculated with the equation—tumor length × height × width/2. (B) Animal survival was monitored for 30 days. The experiment was conducted twice using five mice per group (n = 5). Data denote mean ± SEM. * Tumor versus tumor + A. lappa. Differences were considered significant with p < 0.05, according to ANOVA with Tukey’s post-test (tumor growth) or the log-rank test (mice survival).