Effects of <i>Phyllanthus niruri</i> L. Extract on CTL, VEGF, and COX-2 Expression in a DMH-Induced Colorectal Cancer Rat Model

Abstract

Background: Colorectal cancer is one of the leading causes of cancer-related morbidity and mortality worldwide. Tumor development is strongly influenced by the tumor microenvironment, including mechanisms such as antitumor cellular immunity, angiogenesis, and chronic inflammation. This study aimed to evaluate the effects of Phyllanthus niruri L. extract on colorectal cancer through immunological, angiogenic, and inflammatory pathways. Methods: This in vivo laboratory-based experimental study employed a post-test-only control group design. Fifty male Sprague-Dawley rats were randomly allocated into three groups: (1) healthy control, (2) colorectal cancer without treatment, and (3) colorectal cancer treated with P. niruri L. extract. Colorectal carcinogenesis was induced using 1,2-dimethylhydrazine (DMH) for 12 consecutive weeks. The extract was administered orally at a dose of 13.5 mg/kg body weight once daily from weeks 13 to 16, indicating a therapeutic post-induction model rather than a preventive concurrent-induction model. Biomarker analysis included cytotoxic T lymphocytes (CTLs) to assess cellular immunity, vascular endothelial growth factor (VEGF) as an angiogenesis marker, and cyclooxygenase-2 (COX-2) as an inflammatory marker. Pairwise p-values reported in the Results correspond to adjusted post hoc comparisons, and effect sizes were estimated to reflect the magnitude of between-group differences. Results: Administration of P. niruri L. extract significantly increased CTL expression compared with the untreated colorectal cancer group (P < 0.01), indicating enhanced adaptive cellular immune response. In contrast, VEGF expression was significantly reduced (P < 0.01), suggesting suppression of angiogenesis. Similarly, COX-2 expression decreased significantly (P < 0.01), reflecting reduced inflammatory activity within the tumor microenvironment. Conclusions: Phyllanthus niruri L. demonstrated multiple anticancer effects by enhancing cellular immunity, inhibiting angiogenesis, and attenuating inflammatory responses. These findings support its potential role as a complementary therapeutic agent in colorectal cancer management.