Caesalpinia spinosa extract selectively affects mouse colorectal cancer cells

A standardized extract derived from Caesalpinia spinosa reduced the viability of mouse colorectal adenocarcinoma cells in laboratory experiments, with the response accompanied by increased intracellular reactive oxygen species and activation of caspase-3/7. The extract, called P2Et, showed no significant cytotoxicity in two human colorectal cancer cell lines under the conditions tested. This selective activity was observed in an in vitro study and does not establish that P2Et is safe or effective as a treatment for colorectal cancer in people.

The research evaluated P2Et in SW480 and SW620 human colorectal cancer cells and CT26 murine colorectal adenocarcinoma cells. Investigators measured cell viability with a colorimetric assay and normalized the results to untreated controls. Nonlinear regression was used to estimate half-maximal inhibitory concentration values. Selectivity was calculated by comparing responses in the cancer cell lines with the response in a non-malignant cell line. Fluorescence-based assays were also used to assess antiproliferative activity and intracellular reactive oxygen species, while caspase-3/7 activation, nuclear staining and mitochondrial permeability transition pore opening were examined with additional fluorescence-based measurements and microscopy.

The two human lines, SW480 and SW620, produced comparable responses to P2Et and showed no significant cytotoxicity under the tested conditions. In CT26 cells, by contrast, P2Et reduced cell viability after 48 hours of exposure. The treatment was also associated with greater production of intracellular reactive oxygen species and increased caspase-3/7 activity. These measurements linked the treatment response with oxidative stress and activation of a pathway used to assess apoptosis, but the study did not determine whether those processes caused the loss of viability or resulted from it. For the fluorescence-based comparisons, the researchers used two-way analysis of variance followed by Dunnett’s post hoc test, with a p value of 0.05 or lower treated as statistically significant.

Apoptosis was evaluated through caspase-3/7 activation and fluorescence microscopy of nuclear staining. The investigators also tested whether P2Et altered mitochondrial permeability transition pore opening, another cellular endpoint included in their analysis. No change in pore opening was detected in the tested cells. Accordingly, the reported results do not demonstrate that alteration of mitochondrial permeability transition pore opening explains the reduction in CT26 cell viability. The absence of a measured effect on that endpoint does not identify which other cellular processes may have contributed to the response.

The authors described the findings as preliminary evidence of cellular responses to P2Et and called for further research to clarify the mechanisms behind P2Et-induced cell death and its relationship to oxidative stress and caspase activation. The scope of the evidence is limited to cultured human and mouse cell lines, and the most pronounced response occurred in the murine CT26 line while the two human lines showed no significant cytotoxicity under the tested conditions. The study therefore supports further mechanistic investigation of this standardized phytochemical extract, not a conclusion that it constitutes an alternative or adjuvant colorectal cancer therapy. The research was published in BMC Complementary Medicine and Therapies as an open-access, peer-reviewed article.

Subject of Research: In vitro effects of a standardized Caesalpinia spinosa extract on human and mouse colorectal cancer cell lines

Article Title: Biological activity of P2Et extract from Caesalpinia spinosa on colorectal cancer cell lines

Article References: Cardona, L. M., Correa, E., Lasso, P., Fiorentino, S., & Naranjo, T. W. (2026). Biological activity of P2Et extract from Caesalpinia spinosa on colorectal cancer cell lines. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05628-4

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05628-4

Keywords: Caesalpinia spinosa, P2Et extract, colorectal cancer cells, CT26 cells, cell viability, reactive oxygen species, caspase-3/7 activation, apoptosis, mitochondrial permeability, phytochemicals, Biological, activity