Pimaradienoic acid (PA) inhibits carrageenan-induced nitric oxide (NO) production.

<p>Mice were treated per oral (p.o.) with PA (10 mg/kg) or vehicle (DMSO 2% diluted in saline) 30 minutes before the intraperitoneal (i.p.) injection of carrageenan (300 μg/paw). Nitrite production in peritoneal exudates was determined 3 hours after carrageenan injection. Results are means ± SEM of six mice per group per experiment, and are representative of two separate experiments. [*p<0.05 compared with the saline group, and #p< 0.05 compared to the vehicle group (One-way ANOVA followed by Tukey’s test)].</p

Pimaradienoic acid (PA) inhibits carrageenan-induced oxidative stress.

<p>Mice were treated per oral (p.o.) with PA (10 mg/kg) or vehicle (DMSO 2% diluted in saline) 30 minutes before the intraplantar (i.pl.) injection of carrageenan (300 μg/paw). Paw skin (A) GSH levels, (B) ABTS⁺ scavenging activity, (C) the ability to reduce iron (FRAP), and (D) superoxide anion production were determined 3 hours after carrageenan injection. Results are means ± SEM of six mice per group per experiment, and are representative of two separate experiments. [*p<0.05 compared to the saline group; #p<0.05 compared to inflammatory stimulus group. (One-way ANOVA followed by Tukey’s test)].</p

Pimaradienoic acid (PA) inhibits carrageenan-induced paw edema and myeloperoxidase (MPO) activity.

<p>Mice were treated per oral (p.o.) with PA (10 mg/kg) or vehicle (DMSO 2% diluted in saline) 30 minutes before the intraplantar (i.pl.) injection of carrageenan (300 μg/paw). The evaluation of (A) paw edema was at 1–5 hours and (B) MPO activity at 5 hours after carrageenan injection. Results are means ± SEM of six mice per group per experiment, and are representative of two separate experiments. [*p< 0.05 compared with the saline group, #p <0.05 compared to the vehicle group (One-way ANOVA followed by Tukey’s test)].</p

Pimaradienoic acid (PA) inhibited carrageenan-induced superoxide anion production.

<p>Mice were treated per oral (p.o.) with PA (10 mg/kg) or vehicle (DMSO 2% diluted in saline) 30 minutes before the intraperitoneal (i.p.) injection of carrageenan (500 μg/cavity). (A) Superoxide anion production and (B) NBT reaction positive cells (presence of formazan crystals) were determined in peritoneal cavity exudates 3 hours after carrageenan injection. Results are means ± SEM of six mice per group per experiment, and are representative of two separate experiments. [*p< 0.05 compared with the saline group, and #p< 0.05 compared to the vehicle group (One-way ANOVA followed by Tukey’s test)].</p

Pimaradienoic acid (PA) inhibits carrageenan-induced peritoneal cytokine production.

<p>Mice were treated per oral (p.o.) with PA (10 mg/kg) or vehicle (DMSO 2% diluted in saline) 30 minutes before the intraperitoneal (i.p.) injection of carrageenan (500 μg/cavity). Peritoneal exudate samples were harvested 6 hours after carrageenan injection for (A) TNF-α and (B) IL-1β determination by ELISA. Results are means ± SEM of six mice per group per experiment, and are representative of two separate experiments. [*p<0.05 compared with the saline group, #p<0.05 compared to vehicle group (One-way ANOVA followed by Tukey’s test)].</p

Pimaradienoic acid (PA) structure.

<p>Chemical structure of PA[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0149656#pone.0149656.ref029" target="_blank">29</a>].</p

Pimaradienoic acid (PA) inhibits carrageenan-induced total leukocyte and neutrophil recruitment in the peritoneal cavity.

<p>Mice were treated per oral (p.o.) with PA (0.1–10 mg/kg) or vehicle (DMSO 2% diluted in saline) 30 minutes before carrageenan (500 μg/ cavity) intraperitoneal (i.p.) injection. The (A) total number of leukocytes, (B) neutrophils and (C) mononuclear cells was evaluated 6 hours after carrageenan injection. Results are means ± SEM of six mice per group per experiment and are representative of two separate experiments. [*p < 0.05 compared to the saline group; #p < 0.05 compared to the vehicle group (One-way ANOVA followed by Tukey’s test)].</p

Hesperidin Methylchalcone Suppresses Experimental Gout Arthritis in Mice by Inhibiting NF-κB Activation

Gout arthritis is a painful inflammatory disease induced by monosodium urate (MSU) crystals. We evaluate the therapeutic potential of the flavonoid hesperidin methylchalcone (HMC) in a mouse model of gout arthritis induced by intra-articular injection of MSU (100 μg/10 μL). Orally given HMC (3–30 mg/kg, 100 μL) reduced in a dose-dependent manner the MSU-induced hyperalgesia (44%, <i>p</i> < 0.05), edema (54%, <i>p</i> < 0.05), and leukocyte infiltration (70%, <i>p</i> < 0.05). HMC (30 mg/kg) inhibited MSU-induced infiltration of LysM-eGFP⁺ cells (81%, <i>p</i> < 0.05), synovitis (76%, <i>p</i> < 0.05), and oxidative stress (increased GSH, FRAP, and ABTS by 62, 78, and 73%, respectively; reduced O₂^– and NO by 89 and 48%, <i>p</i> < 0.05) and modulated cytokine production (reduced IL-1β, TNF-α, IL-6, and IL-10 by 35, 72, 37, and 46%, respectively, and increased TGF-β by 90%, <i>p</i> < 0.05). HMC also inhibited MSU-induced NF-κB activation (41%, <i>p</i> < 0.05), gp91^phox (66%, <i>p</i> < 0.05) and NLRP3 inflammasome components mRNA expression in vivo (72, 77, 71, and 73% for NLRP3, ASC, pro-caspase-1, and pro-IL-1 β, respectively, <i>p</i> < 0.05), and induced Nrf2/HO-1 mRNA expression (3.9- and 5.1-fold increase, respectively, <i>p</i> < 0.05). HMC (30, 100, and 300 μM) did not inhibit IL-1β secretion by macrophages primed by LPS and challenged with MSU (450 μg/mL), demonstrating that the anti-inflammatory effect of HMC in gout arthritis depends on inhibiting NF-κB but not on direct inhibition of inflammasome. The pharmacological effects of HMC indicate its therapeutic potential for the treatment of gout