Comparative evaluation of the anticancer effects of Echium amoenum and Valeriana officinalis on U87-MG glioblastoma cells

Abstract

Objectives: Glioblastoma (GBM) is one of the most aggressive and treatment-resistant types of brain cancer, and conventional therapies such as surgery, chemotherapy, and radiotherapy have limited effectiveness in controlling it. In this context, the use of natural compounds with anticancer properties has been explored as a complementary strategy. The purpose of the current study was to assess the cytotoxic and pro-apoptotic potential of the plant extracts Echium amoenum and Valeriana officinalis in U87-MG glioblastoma cells.

Materials and methods: The Maceration technique was used to prepare the plant extracts. U87-MG cells and L-929 cell lines were cultured and treated with various concentrations (31.25, 62.5, 125, 250, 500 and 1000μg/mL) of the extracts upon reaching optimal confluence. An MTT assay was performed to evaluate the cytotoxicity at 24, 48 and 72hours. To investigate the expression of apoptosis-related genes (Bax, Bcl-2 and Caspase-3, Caspase-9 and puma), RNA was extracted and converted to cDNA and then the expression of these genes was analyzed by real-time PCR.

Results: MTT assay results showed that both extracts inhibited cancer cell growth in a dose- and time-dependent manner. At 72hours and a concentration of 1000μg/mL, E. amoenum extract exhibited the highest inhibition rate (96%), while V. officinalis extract showed 95% inhibition under the same conditions. At the molecular level, E. amoenum extract significantly upregulated Caspase-3 expression by more than 20-fold (P<0.0001) indicating a strong activation of the apoptotic pathway, while V. officinalis extract did not cause a significant change in the expression of this gene. Additionally, Bcl-2 expression was significantly elevated in the E. amoenum-treated group (P<0.001). However, the upregulation of Bcl-2-a gene associated with cell survival-was considerably weaker compared to the robust induction of Caspase-3. Also, E. amoenum significantly upregulated Caspase-9 expression (P<0.0001), indicating activation of the intrinsic apoptotic pathway.

Conclusion: The results demonstrated that extracts from V. officinalis and E. amoenum have anticancer effects on U87-MG cells, possibly through the induction of apoptosis. E. amoenum was more effective in raising Caspase-3 and initiating pathways leading to programmed cell death, whereas V. officinalis did not change the expression levels of apoptotic genes. Our finding suggests that this plant may exert its anticancer effects through non-apoptotic or alternative apoptotic mechanisms, rather than the classical intrinsic or mitochondrial pathway. These findings imply that more research should be done on the application of natural substances as a supplemental approach to GBM therapy.

Keywords: Apoptose; Apoptosis; Caspase-3; Echium amoenum; Glioblastoma; Glioblastome; Valeriana officinalis.