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Gambogic acid (GA) is the major active ingredient of gamboge, a brownish to orange resin exuded from Garcinia hanburryi tree in Southeast Asia. The present study aims to demonstrate that gambogic acid (GA) has potent anticancer activity for glioblastoma by in vitro and in vivo study. Rat brain microvascular endothelial cells (rBMEC) were used as an in vitro model of the blood-brain barrier (BBB). To reveal an involvement of the intrinsic mitochondrial pathway of apoptosis, the mitochondrial membrane potential and the western blot evaluation of Bax, Bcl-2, Caspase-3, caspase-9 and cytochrome c released from mitochondria were performed. Angiogenesis was detected by CD31 immunochemical study. The results showed that the uptake of GA by rBMEC was time-dependent, which indicated that it could pass BBB and represent a possible new target in glioma therapy. GA could cause apoptosis of rat C6 glioma cells in vitro in a concentration-dependent manner by triggering the intrinsic mitochondrial pathway of apoptosis. In vivo study also revealed that i.v. injection of GA once a day for two weeks could significantly reduce tumor volumes by antiangiogenesis and apoptotic induction of glioma cells. Collectively, the current data indicated that GA may be of potential use in treatment of glioblastoma by apoptotic induction and antiangiogenic effects.

LYG-202 is a newly synthesized flavonoid with a piperazine substitution. We investigated the antitumor effect of LYG-202 in vivo and in vitro. We show that, LYG-202 significantly decreases tumor growth in mice inoculated with S180 sarcoma cells, compared with the control group. Meanwhile, the viabilities of various kinds of tumor cells were inhibited by LYG-202 with IC(50) values in the range of 4.80 to 27.70 microM. Then apoptosis induced by LYG-202 in HepG2 cells was characterized by DAPI staining and Annexin V/PI double staining and degradation of PARP was observed. Activation of the caspase cascade for both the extrinsic and intrinsic pathways was demonstrated, including caspase-8, -9, and -3. The results also showed that the expression of Bcl-2 protein decreased whereas that of Bax protein increased, leading to an increase of the Bax/Bcl-2 ratio. Our results demonstrated that LYG-202 exhibited strong antitumor effect in vivo and in vitro, involving with apoptosis induction.

Oroxylin A is a flavonoid that is found in the roots of Scutellaria baicalensis Georgi. Here, we investigated the antitumor effect of oroxylin A in human cervical cancer HeLa cell line in vitro and in vivo. We found that after inoculated with the HeLa cells the mice treated with oroxylin A showed a significant decrease of tumor volumes and tumor weight compared with the control. Meanwhile, the growth inhibition of oroxylin A on HeLa cells were observed by MTT assay and the value of IC50 was 19.4 ± 0.7 μM after treatment for 48 h. Upon our previous research, the inhibition by oroxylin A might be through apoptosis. Then apoptosis induced by oroxylin A in HeLa cells was characterized by DAPI staining and Annexin V/PI double staining, and degradation of PARP (poly-ADP–ribose polymerase) was both found in HeLa cells and tumor tissue. Next, activation of the caspase cascade for both the extrinsic and intrinsic pathways were demonstrated in vivo and in vitro, including caspase-8, -9 and -3. We also found that the expression of Bcl-2 protein decreased, which leading to an increase of the Bax/Bcl-2 ratio. Our results showed that oroxylin A exhibited strong antitumor effect in HeLa cell line and apoptosis induction involved in it.

Gambogic acid (GA) is the major active ingredient of gamboge, a brownish resin exuded from Garcinia hanburryi tree in Southeast Asia. In this study, we compared the different apoptotic induction of GA on human normal embryonic hepatic L02 cells and human hepatoma SMMC-7721 cells by detecting growth inhibition, observing morphological changes, and the expressions of the relative apoptotic proteins (Bax, Bcl-2 and caspase-3). The results indicated that GA could selectively induce apoptosis of SMMC-7721 cells, while had relatively less effect on L02 cells. To illustrate the distinct selective antitumor mechanism of GA, we further study its distribution in cultured cells and in tumor-bearing mice. The results indicated that SMMC-7721 cells have higher GA binding activity than L02 cells. The retention time of GA in grafted tumor was longer than in liver, renal and other organs. Collectively, the selective anticancer activity of GA could be due to its significant apoptotic inducing effects as well as its higher distribution and longer retention time in tumor cells compared to the normal cells. So GA might be a kind of highly effective anticancer drug candidate with low toxicity to normal tissue.