Cultivar-dependent immunometabolic effects of pigmented rice extracts in immunosuppressed obese mice

Pigmented rice (Oryza sativa L.) contains diverse bioactive compounds with reported antioxidant, metabolic, and immunomodulatory properties. This study investigated the cultivar-dependent immunometabolic effects of three Korean pigmented rice extracts in a cyclophosphamide- and high-fat diet (CPA-HFD)-induced immunosuppressed obese mouse model. Administration of pigmented rice extracts was associated with favorable changes in metabolic parameters, including reduced fasting blood glucose and triglyceride levels, increased HDL-cholesterol levels, and attenuation of hepatic steatosis. Immune-related parameters were also modulated, including white blood cell counts, lymphocyte proportions, serum IgG levels, natural killer cell activity, and mitogen-induced T- and B-cell proliferation. Among the cultivars, JM showed the most prominent overall immunometabolic effects. Pancreatic endocrine markers were not markedly altered by CPA treatment, but variations in insulin- and glucagon-positive staining were observed among pigmented rice groups, reflecting changes at the level of marker expression rather than functional endocrine activity. Together with previously reported phytochemical properties of pigmented rice, the present findings support the cultivar-specific potential of pigmented rice extracts to modulate metabolic and immune responses under CPA-HFD-induced immunometabolic stress. Further phytochemical profiling is needed to clarify the bioactive compounds associated with these effects and to strengthen cultivar-dependent interpretation.