Allicin induces apoptosis through activation of both intrinsic and extrinsic pathways in glioma cells.

Allicin is an extract purified from Allium sativum (garlic), and previous research has indicated that Allicin has an inhibitory effect on many kinds of tumor cells. The aim of the present study was to explore the anticancer activity of Allicin on human glioma cells and investigate the underlying mechanism. MTT and colony-formation assays were performed to detect glioma cell proliferation, and explore the effect of Allicin at various doses and time-points. The apoptosis of glioma cells was measured by fluorescence microscopy with Hoechst 33258 staining, and then flow cytometry was used to analyzed changes in glioma cell apoptosis. Reverse transcription‑quantitative polymerase chain reaction and western blot analysis were used to detect the effect of Allicin on the expression levels of Fas/Fas ligand (FasL), caspase‑3, B‑cell lymphoma 2 and Bcl‑2‑associated X protein. Allicin suppressed the proliferation and colony formation ability of U251 cells in a dose‑ and time‑dependent manner. A cytotoxic effect of Allicin was observed in glioma cells in a dose‑dependent manner. Changes in nuclear morphology were observed in U251 cells with Hoechst 33258 staining. The activity of caspases were significantly elevated and Fas/FasL expression levels were increased following treatment with Allicin, at both the mRNA and protein level. These results demonstrated that Allicin suppresses proliferation and induces glioma cell apoptosis in vitro. Both intrinsic mitochondrial and extrinsic Fas/FasL‑mediated pathways react in glioma cell after treating with Allicin, which then activate major apoptotic cascades. These results implicate Allicin as a novel antitumor agent in treating glioma.