Acanthus ilicifolius var. xiamenensis is a traditional herbal medicine in China. In this study, the anti-inflammatory activities of active ingredients of A. ilicifolius var. xiamenensis were investigated in RAW 264.7 cells and Freund's complete adjuvant-induced arthritic rats. Results showed that n-butanol extract exerted antiarthritic potential by reducing paw edema, arthritis score, and altered hematological and biochemical parameters in experimental rats. Phytochemical studies on n-butanol extract resulted in the isolation of five alkaloids (1-5) and five phenylethanoids (6-10). The anti-inflammatory assay of compounds 1-10 on lipopolysaccharide (LPS)-treated RAW 264.7 cells indicated that phenylethanoids 9 and 10 exhibited notable inhibitory activities. The result indicated that compounds 9 and 10 attenuated inflammation by decreasing the production of nuclear factor kappa-B (NF-κB) p65, inhibitory subunit of NF kappa B alpha, Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), and inducible nitric oxide synthase in LPS-mediated RAW 264.7 macrophages. Phenylethanoids 9 and 10 increased the expression of interleukin-10 and endothelial nitric oxide synthase. Therefore, compounds 9 and 10 showed anti-inflammatory activity by regulation of NF-κB and JAK/STAT signaling pathways. © Copyright 2023, Mary Ann Liebert, Inc., publishers, and Korean Society of Food Science and Nutrition 2023.