Crocus sativus L. produces anti-inflammatory effects and regulates NLRP3–NF-κB pathway

This study aimed to evaluate with local or systemic inflammatory models whether a petal or stamen extraction of the saffron crocus (C. sativus) confers anti-inflammatory effects, and explore the underlying mechanism. Local and systemic inflammatory models were used to explore the anti-inflammatory effects of C. sativus. In vivo, a xylene-induced inflammation model or lipopolysaccharide (LPS)-induced inflammation model was used. C. sativus petal and stamen extracts were each administered to the mice in the xylene and LPS models by gavage for 14 days at doses of 0.1 and 0.4 g/kg, respectively. ELISA was used to measure the concentration of TNF-α and IL-1β in mouse serum. HE staining was used to observe pathological changes in the ear in the xylene-induced inflammation model and spleen in the LPS-induced inflammation model. The level of NLRP3 protein in the NF-κB pathway was evaluated with western blot assay. RAW264.7 cells were treated with LPS (5 μg/mL) and LPS + C. sativus (0.05, 0.1, and 0.2 mg/mL) for 24 h, and Cell Counting Kit-8 was used to measure the cell proliferation. The change of NLRP3 and NF-κB in protein level were evaluated with western blot. Petal and stamen extractions of C. sativus attenuated the anti-inflammatory effects in local or systemic inflammatory models, repaired the pathological changes in the ear in the xylene-induced inflammation model or spleen in the LPS-induced inflammation model, and decreased the concentration of TNF-α and IL-1β in mouse serum in the LPS-induced inflammation model. C. sativus downregulated the protein level of NLRP3 through the NF-κB pathway, and also downregulated LC-3 and beclin-1, in vivo and in vitro. After the addition of CCCP, the effects of C. sativus on the NLRP3–NF-κB pathway were weakened. C. sativus produces anti-inflammatory effects and regulates the NLRP3-NF-κB pathway.