Coix seed oil improves the inflammatory response in mice with phlegm-dampness collagen-induced arthritis by inhibiting the differentiation of Th17 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: As documented in traditional Chinese medicine, Coix lacryma-jobi L. is known to invigorate the spleen, eliminate dampness, reduce rheumatism, and resolve purulent discharge. It is widely used clinically, particularly for rheumatoid arthritis (RA) characterized by dampness. Coix seed oil (CSO), the main active extract from it, has demonstrated significant anti-inflammatory effects in the treatment of RA.

AIM OF THE STUDY: Coix seed oil (CSO), a bioactive compound derived from Coix lacryma-jobi L., is utilized in the treatment of rheumatoid arthritis (RA), obesity, diabetes, and related disorders. However, its anti-inflammatory mechanisms in RA remain incompletely understood.

MATERIALS AND

METHODS

In this study, we collected indicators from different participants to analyze the impact of dampness-phlegm on RA. In vivo experiments were conducted to validate the therapeutic effects of CSO on inflammatory responses, phlegm-dampness syndrome, and pathological damage in RA and phlegm-dampness models. We further identified that Th17 cell differentiation plays a critical role in the therapeutic action of CSO. Using flow cytometry, Th17 differentiation was assessed both in vivo and in vitro. The interaction between leptin and PPARγ was examined via immunohistochemistry, immunofluorescence, and co-immunoprecipitation.

RESULTS

Mechanistically, CSO inhibited Th17 cell differentiation by reducing the interaction between leptin and PPARγ, thereby attenuating the induction and proliferation of synovial fibroblasts and exerting anti-inflammatory effects.

CONCLUSIONS

These findings provide new mechanistic insights into the immunomodulatory function of CSO in RA, supporting its ethnopharmacological use in dampness-phlegm dominated RA.