Abstract

Background: Rheum khorasanicum is a medicinal plant that belongs to the Polygonaceae family. This family is well-known for its anticancer activities.

Objective: Due to the limited studies on the anticancer activity of R. khorasanicum, the present study aimed to evaluate the apoptotic effect of this medicinal plant on MDA-MB-231 cells as a model for an aggressive triple-negative breast cancer that has a lower treatment option.

Methods: R. khorasanicum root was collected in April, 2021 from Neyshabur, Iran, and its hydroalcoholic extract was prepared using the maceration method. The High-Performance Thin-Layer Chromatography (HPTLC) assay was used to determine the main ingredients of the extract. The viability and apoptosis of the cells were evaluated by WST-1 and the annexin-V/PI dual staining assay, respectively. The scratch assay was used to assess the migratory potential of cancer cells, and the Western blotting test was employed for determining the expression of Bcl-2, Bax, cleaved caspase- 3, cleaved caspase-7, and procaspase-7 proteins involved in the apoptotic pathway.

Results: The yield of extract from R. khorasanicum root was 56.8 ± 11.1%. The HPTLC analysis indicated that emodin, gallic acid, and epigallocatechin were pharmacologically active compounds isolated from the hydroalcoholic extract of R. khorasanicum root. The extract showed a significant toxic effect on MDA-MB-231 cells up to 60 μg/mL concentration. R. khorasanicum root extracts also inhibited the migratory potential of MDA-MB-231 at concentrations ≥ 60 μg/mL. The plant root extract at concentrations of 60 and 100 μg/mL significantly increased the Bax/Bcl-2 ratio cleaved caspase-3, cleaved caspase-7/ procaspase-7 protein levels compared to the nontreated cells.

Conclusion: Our findings demonstrated that the hydroalcoholic extract of R. khorasanicum efficiently triggered the apoptosis of MDA-MB-231 cells as a suitable model for aggressive triple-negative breast cancer, possibly by decreasing their migratory potential and stimulating the apoptotic signaling pathway.

Keywords: Breast cancer, Rheum khorasanicum, apoptosis, MDA-MB231, cytotoxicity, HPTLC.