In Vitro Evaluation of Amritabhallataka Paka on Cell Viability and Apoptosis in U87MG Glioblastoma Cells and Cytocompatibility in L929 Fibroblasts

Abstract

Background: Glioblastoma is an aggressive primary brain tumour with poor prognosis due to recurrence and treatment resistance. Amritabhallataka Paka (AP), an Ayurvedic formulation containing Semecarpus anacardium L.f. (Bhallataka), has limited experimental evidence in glioblastoma models. Objective: To evaluate the effects of AP on U87MG glioblastoma cell viability and apoptosis, assess its cytocompatibility in L929 mouse fibroblasts, and compare its effects with temozolomide (TMZ) and their combination. Methods: U87MG cells were treated with AP, TMZ and AP+TMZ, while L929 fibroblasts received AP and TMZ. Cell viability was assessed using the MTT assay at six concentrations in three independent experiments with technical replicates. IC₅₀ values were estimated using nonlinear dose-response regression. Apoptosis in U87MG cells was evaluated using Annexin V-FITC/propidium iodide flow cytometry in three independent experiments. Cellular morphology was examined using phase-contrast microscopy. Results: AP produced a concentration-dependent reduction in U87MG cell viability. The IC₅₀ values were 334.85 µg/mL for AP, 249.42 µg/mL for TMZ and 327.20 µg/mL for AP+TMZ. In L929 fibroblasts, AP maintained 71–87% viability across tested concentrations. TMZ-treated L929 cells showed 99.5% viability at 15.6 µg/mL, with reduced viability at concentrations ≥31.25 µg/mL. Total apoptosis in U87MG cells was highest with AP+TMZ (25.15 ± 1.80%), followed by TMZ (14.71 ± 1.20%), AP (11.85 ± 1.75%) and untreated controls (3.26 ± 0.50%). Conclusion: AP reduced U87MG cell viability while maintaining comparatively high L929 fibroblast viability under the tested conditions. AP+TMZ produced higher total apoptosis than either treatment alone. However, synergistic or enhanced combination efficacy cannot be established without formal drug-interaction analysis.