BCL2 and central nervous system cancer: Most alkaloids act in a concentration-dependent manner by (1) reducing glioma cell viability, (2) suppressing proliferation, (3) inhibiting migration and invasion, (4) inducing cell death, (5) downregulating Bcl-2 and key signaling pathways, (6) exhibiting antiangiogenic effects, (7) reducing tumor weight, and (8) improving survival rates.