Judy Yuet-Wa Chan

Publications of Judy Yuet-Wa Chan

• Photodynamic Therapy of Pheophorbide a Inhibits the Proliferation of Human Breast Tumour via Both Caspase-dependent and -independent Apoptotic Pathways in In Vitro and In Vivo Models.

  Authors: Sandy Wan-Heng Hoi, Hoi Ming Wong, Judy Yuet-Wa Chan, Grace Gar Lee Yue, Gary Man-Kit Tse, Bonita Ka-Bo Law, Wing Ping Fong, Kwok Pui Fung

  Phytotherapy research : PTR. 11/2011;

  Breast cancer is conventionally treated by surgery and radiotherapy, with adjuvant chemotherapy and hormonotherapy as supplementary treatments. However, such treatments are associated with adverseBreast cancer is conventionally treated by surgery and radiotherapy, with adjuvant chemotherapy and hormonotherapy as supplementary treatments. However, such treatments are associated with adverse side effects and drug resistance. In this study, Pheophorbide a (Pa), a photosensitizer isolated from Scutelleria barbata, was analysed for its antiproliferative effect on human breast tumour cells. The IC (inhibitory concentration)(50) of the combined treatment of Pa and photodynamic therapy (Pa-PDT) on human breast tumour MCF-7 cells was 0.5 µm. Mechanistic studies in MCF-7 cells demonstrated that Pa was localized in the mitochondria, and reactive oxygen species were found to be released after Pa-PDT. Apoptosis was the major mechanism responsible for the tumour cell death, and mitochondrial membrane depolarization and cytochrome c release highlighted the role of mitochondria in the apoptotic mechanism. Up-regulation of tumour suppressor protein p53, cleavage of caspase-9 and poly (ADP-ribose) polymerase suggested that the caspase-dependent pathway was induced, while the release of apoptosis-inducing factors demonstrated that the apoptosis was also mediated by the caspase-independent mechanism. In vivo study using the mouse xenograft model showed a significant inhibition of MCF-7 tumour growth by Pa-PDT. Together, the results of this study provide a basis for understanding and developing Pa-PDT as a cure for breast cancer. Copyright © 2011 John Wiley & Sons, Ltd.

• Polyphyllin D, a steroidal saponin from Paris polyphylla, inhibits endothelial cell functions in vitro and angiogenesis in zebrafish embryos in vivo.

  Authors: Judy Yuet-Wa Chan, Johnny Chi-Man Koon, Xiaozhou Liu, Michael Detmar, Biao Yu, Siu-Kai Kong, Kwok-Pui Fung

  Journal of ethnopharmacology. 05/2011; 137(1):64-9.

  Angiogenesis, the process of blood vessel formation, is critical to tumour growth. The importance of angiogenesis in tumour development has lead to the development of anti-angiogenic strategies toAngiogenesis, the process of blood vessel formation, is critical to tumour growth. The importance of angiogenesis in tumour development has lead to the development of anti-angiogenic strategies to inhibit tumour growth. In this study, polyphyllin D (PD), an active component in Chinese herb, Paris polyphylla, was evaluated for its potential anti-angiogenic effects. The inhibitory effects of PD on three important processes involved in angiogenesis, i.e. proliferation, migration and differentiation were examined using human microvascular endothelial cell line HMEC-1 by MTT assay, scratch assay and tube formation assay, respectively. Using zebrafish embryos as an animal model of angiogenesis, the anti-angiogenic effect of PD was further verified in vivo. PD suppressed the growth of HMEC-1 cells at 0.1-0.4 μM without toxic effects. At 0.3 μM and 0.4 μM, PD significantly inhibited endothelial cell migration and capillary tube formation. About 70% of the zebrafish embryos showed defects in intersegmental vessel formation upon treatment with PD at concentrations of 0.156 μM and 0.313 μM. The anti-angiogenic effects of PD have been explored in the study which implied a potential therapeutic development of PD in cancer treatment.

• FHL2 exhibits anti-proliferative and anti-apoptotic activities in liver cancer cells.

  Authors: Chor-Fung Ng, Patrick Kwok-Shing Ng, Vivian Wai-Yan Lui, Jialiang Li, Judy Yuet-Wa Chan, Kwok-Pui Fung, Yuen-Keng Ng, Paul Bo-San Lai, Stephen Kwok Wing Tsui

  Cancer letters. 03/2011; 304(2):97-106.

  FHL2 displays tumor promoting or tumor suppressing activities depending on the types of tumor cells. In this study, we demonstrated that FHL2 overexpression inhibits the proliferation of human HCCFHL2 displays tumor promoting or tumor suppressing activities depending on the types of tumor cells. In this study, we demonstrated that FHL2 overexpression inhibits the proliferation of human HCC cells Hep3B through cell cycle regulation by decreasing cyclin D1 expression while increasing the expressions of p21 and p27. FHL2 overexpression also inhibits migration and invasion of Hep3B cells through the regulation of epithelial-mesenchymal transition. Surprisingly, we also demonstrated an antiapoptotic function for FHL2 overexpression with increased resistance to doxorubicin-induced apoptosis, which indicates the separation of anti-proliferative and anti-apoptotic role of FHL2. Taken together, our results indicate FHL2 could exert anti-apoptotic effect independent of tumor growth suppression.

• Gestational and lactational transfer of melamine following gavage administration of a single dose to rats.

  Authors: Judy Yuet Wa Chan, Chau Ming Lau, Tai Lun Ting, Thomas Chung Wai Mak, Michael Ho Ming Chan, Christopher Wai Kei Lam, Chung Shun Ho, Chi Chiu Wang, Tai Fai Fok, Kwok Pui Fung

  Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 03/2011; 49(7):1544-8.

  Melamine contamination in an infant formula manufactured by a firm in China was reported in September 2008. Maternal transfer of melamine during pregnancy and through breast-feeding are possible waysMelamine contamination in an infant formula manufactured by a firm in China was reported in September 2008. Maternal transfer of melamine during pregnancy and through breast-feeding are possible ways of introduction. This study aims to evaluate the maternal transfer of melamine into amniotic fluid and breast milk through oral intake by pregnant and lactating rats, respectively. The quantity of melamine in the dam's sera, amniotic fluid, breast milk as well as in fetal whole body extract was measured. Our results showed that, after administration of single dose of 21.4 mg/kg per body weight of melamine to pregnant rats (16-18 days of gestation) by gavage, about 80% of melamine was found in dam's serum in 0.5 h. Melamine further reached the fetuses through placental transfer as it was found that peak melamine level of 7.15 ppm (∼30%) was detected in the fetuses after 2h and 4.36 ppm (∼20%) was shown in amniotic fluid after 3h of maternal intake. In the lactating rats, about 40% of maternal intake of melamine was transferred to breast milk and peaked at 3h. The results of this study confirmed the maternal transfer of melamine to fetuses in utero and infants through breast feeding.

• P-glycoprotein enhances radiation-induced apoptotic cell death through the regulation of miR-16 and Bcl-2 expressions in hepatocellular carcinoma cells.

  Authors: Tsun Yee Tsang, Wan Yee Tang, Judy Yuet Wa Chan, Ngai Na Co, Chi Lam Au Yeung, Pak Lun Yau, Siu Kai Kong, Kwok Pui Fung, Tim Tak Kwok

  Apoptosis : an international journal on programmed cell death. 02/2011; 16(5):524-35.

  P-glycoprotein (Pgp), an efflux pump, was confirmed the first time to regulate the expressions of miR/gene in cells. Pgp is known to be associated with multidrug resistance. RHepG2 cells, theP-glycoprotein (Pgp), an efflux pump, was confirmed the first time to regulate the expressions of miR/gene in cells. Pgp is known to be associated with multidrug resistance. RHepG2 cells, the multidrug resistant subline of human hepatocellular carcinoma HepG2 cells, expressed higher levels of Pgp as well as miR-16, and lower level of Bcl-2 than the parental cells. In addition, RHepG2 cells were more radiation sensitive and showed more pronounced radiation-induced apoptotic cell death than the parental cells. Mechanistic analysis revealed that transfection with mdr1 specific antisense oligos suppressed radiation-induced apoptosis in HepG2 cells. On the other hand, ectopic mdr1 expression enhanced radiation-induced apoptosis in HepG2 cells, SK-HEP-1 cells, MiHa cells, and furthermore, induced miR-16 and suppressed its target gene Bcl-2 in HepG2 cells. Moreover, the enhancement effects of Pgp and miR-16 on radiation-induced apoptosis were counteracted by overexpression of Bcl-2. The Pgp effect on miR-16/Bcl-2 was suppressed by Pgp blocker verapamil indicating the importance of the efflux of Pgp substrates. The present study is the first to reveal the role of Pgp in regulation of miRNA/gene expressions. The findings may provide new perspective in understanding the biological function of Pgp.

• Pheophorbide a: a photosensitizer with immunostimulating activities on mouse macrophage RAW 264.7 cells in the absence of irradiation.

  Authors: Ngoc-Ha Bui-Xuan, Patrick Ming-Kuen Tang, Chun-Kwok Wong, Judy Yuet-Wa Chan, Karen Ka Yan Cheung, Jonney Lei Jiang, Kwok-Pui Fung

  Cellular immunology. 01/2011; 269(1):60-7.

  Pheophorbide a (Pa) has been proposed to be a potential photosensitizer for the photodynamic therapy of human cancer. However, the immunomodulatory effect of Pa, in the absence of irradiation, hasPheophorbide a (Pa) has been proposed to be a potential photosensitizer for the photodynamic therapy of human cancer. However, the immunomodulatory effect of Pa, in the absence of irradiation, has not yet been investigated. The present study revealed that Pa possessed immunostimulating effect on a murine macrophages cell line RAW 264.7. Pa could significantly stimulate the growth of RAW 264.7 cells with the maximum effect at 1.0μM after 24, 48 and 72 h of treatment (all p<0.05). Besides, intracellular mitogen activated protein kinases (MAPK) including extracellular signal-regulated kinase (ERK) and p38 MAPK were activated by Pa treatment in a dose-dependent manner. The activation of ERK and p38 MAPK was found to be related to the Pa-induced intracellular reactive oxygen species. Furthermore, Pa could significantly induce the release of interleukine-6 and tumour necrosis factor-α, and enhance the phagocytic activity of RAW 264.7 cells (all p<0.05). The present work is the first report to demonstrate the potential immunomodulatory effect of Pa on macrophages, apart from its well-studied anti-tumour activity.

• Ursolic acid induces doxorubicin-resistant HepG2 cell death via the release of apoptosis-inducing factor.

  Authors: Lu Yang, Xiaozhuo Liu, Zengbing Lu, Judy Yuet-Wa Chan, Linli Zhou, Kwok-Pui Fung, Ping Wu, Shihua Wu

  Cancer letters. 12/2010; 298(1):128-38.

  Ursolic acid (UA), a triterpenoid compound isolated previously from Oldenlandia diffusa, which is a Traditional Chinese Medicine used to treat cancer, was found to inhibit the proliferation ofUrsolic acid (UA), a triterpenoid compound isolated previously from Oldenlandia diffusa, which is a Traditional Chinese Medicine used to treat cancer, was found to inhibit the proliferation of doxorubicin-resistant human hepatoma cell line (R-HepG2) through apoptosis as shown by externalization of phosphatidyl serine, morphological changes and loss of mitochondrial membrane potential. UA could activate Bak but not Bax, which implied that Bak may play an important role in UA-induced apoptosis. Furthermore, the death of R-HepG2 cells induced by UA was found to be mainly through the caspase-independent apoptosis-inducing factor (AIF) signaling pathway which was evidenced by: (a) the pan-caspase inhibitor and the specific caspase inhibitor had only modest protective effect against UA; (b) UA treatment caused the nuclear translocation of AIF, which is retained in the mitochondria in untreated R-HepG2 cells; (c) cells that had been treated with human AIF-specific siRNA could resist cell death induced by UA. In addition, a further animal study showed that UA was effective against R-HepG2 cells in vivo with negligible body weight loss and damage towards the liver, heart and spleen. Most importantly, immunohistochemical staining in animal tissues also suggested that UA also significantly inhibited the growth of R-HepG2 cells in nude mice through the AIF signaling pathway.

• Transcriptional analysis of doxorubicin-induced cytotoxicity and resistance in human hepatocellular carcinoma cell lines.

  Authors: Jin Wang, Judy Yuet-Wa Chan, Chi-Chun Fong, Chi-Hung Tzang, Kwok-Pui Fung, Mengsu Yang

  Liver international : official journal of the International Association for the Study of the Liver. 08/2009;

  Abstract Background/Aims: Hepatoma is either intrinsically resistant to chemotherapy or response to it but later develop resistance. The aim of this study was to clarify the relationship of treatmentAbstract Background/Aims: Hepatoma is either intrinsically resistant to chemotherapy or response to it but later develop resistance. The aim of this study was to clarify the relationship of treatment with doxorubicin (Dox) in hepatoma HepG2 cells and drug resistance developed by Dox. Methods: We have analysed the bioactivities and gene expression profiles of multidrug resistant (MDR) HepG2/DR cell line and its parental HepG2 cell, which were exposure to Dox. Results: We confirmed that Dox-induced apoptosis of HepG2 cells in a time-dependent manner; cDNA microarray and hierarchical cluster analysis demonstrate that the features of the transcriptional programme of the later response to Dox in HepG2 cells and MDR HepG2/DR cells have a common character, which is upregulation of stress response, cytoskeleton, ubiquitin-proteasome pathway and repressed G-protein signal transduction system; differentially expressed genes in MDR HepG2/DR such as drug transporters and tumour-associated antigens were verified at the levels of mRNA by semiquantitative reverse transcriptase-polymerase chain reaction. Conclusions: These results reveal novel co-ordinated changes that occurred in resistant HepG2 cells to survive from cell apoptosis elicited by Dox treatment.

• Antihyperglycemic and antioxidative effects of a herbal formulation of Radix Astragali, Radix Codonopsis and Cortex Lycii in a mouse model of type 2 diabetes mellitus.

  Authors: Judy Yuet-Wa Chan, Fung-Chun Lam, Ping Chung Leung, Chun-Tao Che, Kwok-Pui Fung

  Phytotherapy research : PTR. 12/2008;

  There is emerging evidence that the generation of reactive oxygen species (ROS), which leads to dysfunction of pancreatic beta-cells, is a major factor in the development of type 2 diabetes mellitus.There is emerging evidence that the generation of reactive oxygen species (ROS), which leads to dysfunction of pancreatic beta-cells, is a major factor in the development of type 2 diabetes mellitus. Antioxidation is one of the therapeutic strategies to overwhelm the imbalance in ROS production. In this study, a herbal formulation SR10, comprising Radix Astragali, Radix Codonopsis and Cortex Lycii, was examined for its antidiabetic and antioxidative effects using the diabetic +db/+db mouse model. The results showed that SR10 was effective in decreasing the blood glucose level in chronic treatment by improving beta-cell function. The activities and expression of antioxidant enzymes, catalase and superoxide dismutase, were up-regulated when treated with SR10. Moreover, SR10 treatment did not exhibit any toxic effect to the host. Copyright (c) 2008 John Wiley & Sons, Ltd.

• Protective effects of an herbal formulation of Radix Astragali, Radix Codonopsis and Cortex Lycii on streptozotocin-induced apoptosis in pancreatic beta-cells: an implication for its treatment of diabetes mellitus.

  Authors: Judy Yuet-Wa Chan, Ping Chung Leung, Chun-Tao Che, Kwok-Pui Fung

  Phytotherapy research : PTR. 03/2008; 22(2):190-6.

  Hyperglycemia is one of the main causes of oxidative stress in type 2 diabetes mellitus. During hyperglycemia, the increased level of various reducing sugars in the blood enhances the production ofHyperglycemia is one of the main causes of oxidative stress in type 2 diabetes mellitus. During hyperglycemia, the increased level of various reducing sugars in the blood enhances the production of reactive oxygen species (ROS) and triggers tissue damage, especially in pancreatic beta-cells. Streptozotocin (STZ) is a diabetogen that causes diabetes mellitus via ROS-induced apoptosis in beta-cells. In this study, SR10, an herbal formulation consisting of the aqueous extracts of Radix Astragali, Radix Codonopsis and Cortex Lycii was examined for its antidiabetic effects in vitro. SR10 treatment resulted in significant enhancement of survival rate of rat pancreatic beta-cells which were treated by streptozotocin. SR10 apparently reduced apoptosis of streptozotocin-treated beta-cells by decreasing DNA fragmentation, sub-G(1) peak area and percentage of apoptotic cells. Nitric oxide (NO) production in streptozotocin-treated cells was inhibited by SR10 via the suppression of the expression of inducible nitric oxide synthase (iNOS). The implication of SR10 in treating type 2 diabetes mellitus was discussed.

• Leachianone A as a potential anti-cancer drug by induction of apoptosis in human hepatoma HepG2 cells.

  Authors: Crystal Sao-Fong Cheung, Karen Ka-Wing Chung, Julian Chun-Kin Lui, Ching-Po Lau, Po-Ming Hon, Judy Yuet-Wa Chan, Kwok-Pui Fung, Shannon Wing-Ngor Au

  Cancer letters. 09/2007; 253(2):224-35.

  The Chinese herbal medicine Radix Sophorae is widely applied as an anti-carcinogenic/ anti-metastatic agent against liver cancer. In this study, Leachianone A, isolated from Radix Sophorae, possessedThe Chinese herbal medicine Radix Sophorae is widely applied as an anti-carcinogenic/ anti-metastatic agent against liver cancer. In this study, Leachianone A, isolated from Radix Sophorae, possessed a profound cytotoxic activity against human hepatoma cell line HepG2 in vitro, with an IC(50) value of 3.4microg/ml post-48-h treatment. Its action mechanism via induction of apoptosis involved both extrinsic and intrinsic pathways. Its anti-tumor effect was further demonstrated in vivo by 17-54% reduction of tumor size in HepG2-bearing nude mice, in which no toxicity to the heart and liver tissues was observed. In conclusion, this is the first report describing the isolation of Leachianone A from Radix Sophorae and the molecular mechanism of its anti-proliferative effect on HepG2 cells.

• Pheophorbide a, an active component in Scutellaria barbata, reverses P-glycoprotein-mediated multidrug resistance on a human hepatoma cell line R-HepG2.

  Authors: Patrick Ming-Kuen Tang, Judy Yuet-Wa Chan, Dong-Mei Zhang, Shannon Wing-Ngor Au, Wing-Ping Fong, Siu-Kai Kong, Stephen Kwok-Wing Tsui, Mary Mui-Yee Waye, Thomas Chung-Wai Mak, Kwok-Pui Fung

  Cancer biology & therapy. 05/2007; 6(4):504-9.

  Scutellaria barbata, a Traditional Chinese Medicine native in southern China, has been widely used for treating liver diseases. In this study, the anti-proliferative effect of Pheophorbide a (Pa), anScutellaria barbata, a Traditional Chinese Medicine native in southern China, has been widely used for treating liver diseases. In this study, the anti-proliferative effect of Pheophorbide a (Pa), an active component from S. barbata, was examined on a multi-drug resistant (MDR) human hepatoma cell line R-HepG2. Our study showed that Pa could significantly inhibit the growth of R-HepG2 cells with an IC50 value at 25.0 microM after 48 hours treatment. When compared with the parental HepG2 cells, Pa showed weak resistance to R-HepG2. Efflux of Pa out of R-HepG2 cells was not observed as its cellular uptake level showed no significant difference comparing with HepG2 cells. Interestingly, significant reduction of P-glycoprotein expression on Pa-treated R-HepG2 cells was found at both transcriptional and translational levels, leading to reduction of P-glycoprotein activity. In addition, mechanistic study elucidated that Pa induced cell cycle arrest at G2/M phase and inhibited the expressions of G2/M phase cell cycle regulatory proteins, cyclin-A1 and cdc2 in a dose-dependent manner.

• Pheophorbide a, an active compound isolated from Scutellaria barbata, possesses photodynamic activities by inducing apoptosis in human hepatocellular carcinoma.

  Authors: Patrick Ming-Kuen Tang, Judy Yuet-Wa Chan, Shannon Wing-Ngor Au, Siu-Kai Kong, Stephen Kwok-Wing Tsui, Mary Mui-Yee Waye, Thomas Chung-Wai Mak, Wing-Ping Fong, Kwok-Pui Fung

  Cancer biology & therapy. 10/2006; 5(9):1111-6.

  Photodynamic therapy (PDT) is an effective treatment for cancer by inducing apoptosis or necrosis in the target cells. Pheophorbide a (Pa), a chlorophyll derivative, is a photosensitzier which canPhotodynamic therapy (PDT) is an effective treatment for cancer by inducing apoptosis or necrosis in the target cells. Pheophorbide a (Pa), a chlorophyll derivative, is a photosensitzier which can induce significant anti-proliferative effects in a number of human cancer cell lines. This study investigated the action mechanism of Pa-mediated photodynamic therapy (Pa-PDT) on the human hepatocellular carcinoma, Hep3B cells. Pa-PDT significantly inhibited the growth of Hep3B cells with an IC50 value of 1.5 microM. Intracellular ROS level was increased in Pa-PDT treated cells and the cytotoxic effect could be reversed when ascorbic acid was applied. Pa was found to be localized in the mitochondria and then induced the target cells to undergo apoptosis, which was confirmed by propidium iodide staining and DNA fragmentation assay. Pa-PDT treatment also led to the depolarization of mitochondrial membrane potential (Deltapim) and a release of cytochrome c from mitochondria to the cytosol. The caspase cascade was activated as shown by a significant decrease of procaspase-3 and -9 in Pa-PDT treated cells in a dose-dependent manner. Furthermore, in nude mice model, Pa-PDT treatment could reduce the tumor size by 57% after 14 days treatment.

• Effect of arsenic trioxide on multidrug resistant hepatocellular carcinoma cells.

  Authors: Judy Yuet-Wa Chan, Katy Pak-Yan Siu, Kwok-Pui Fung

  Cancer letters. 06/2006; 236(2):250-8.

  Our previous study showed that arsenic trioxide (As2O3) was effective in inhibiting the growth of human hepatocellular carcinoma (HepG2) cells via induction of apoptosis. In the present study, weOur previous study showed that arsenic trioxide (As2O3) was effective in inhibiting the growth of human hepatocellular carcinoma (HepG2) cells via induction of apoptosis. In the present study, we examined the effect of As2O3 on multidrug resistant human hepatocellular carcinoma (R-HepG2) cells which are characterized with overexpression of mdr1 gene and P-glycoprotein. The anti-proliferation of R-HepG2 by As2O3 was examined by MTT assay. For the induction of apoptosis, DNA fragmentation and Annexin V-PI staining were performed after treatment with arsenic trioxide. To study the effect of arsenic trioxide on P-glycoprotein, Western analysis probing anti-P-glycoprotein antibody was used to monitor the change of its expression. Results showed that As2O3 was effective in inhibiting the cell proliferation of R-HepG2 cells in a dose- and time-dependent manner via induction of apoptosis without affecting the cell cycle. The sensitivity of R-HepG2 cells toward As2O3 was found to be similar to that of the parental HepG2 cells. The Western analysis showed that As2O3 was probably not the substrate to be bound and extruded by P-glycoprotein in R-HepG2 cells because it could not maintain the cellular P-glycoprotein expression.

• Pheophorbide a, a major antitumor component purified from Scutellaria barbata, induces apoptosis in human hepatocellular carcinoma cells.

  Authors: Judy Yuet-Wa Chan, Patrick Ming-Kuen Tang, Po-Ming Hon, Shannon Wing-Ngor Au, Stephen Kwok-Wing Tsui, Mary Mui-Yee Waye, Siu-Kai Kong, Thomas Chung-Wai Mak, Kwok-Pui Fung

  Planta medica. 02/2006; 72(1):28-33.

  Scutellaria barbata has long been used as a Chinese medicine for the treatment of liver diseases such as hepatitis and hepatocellular carcinoma. In the present study, a bioassay-guided method wasScutellaria barbata has long been used as a Chinese medicine for the treatment of liver diseases such as hepatitis and hepatocellular carcinoma. In the present study, a bioassay-guided method was used to isolate the most active components from Scutellaria barbata. The anti-proliferative effects on human hepatoma HepG2 and Hep3B cells of each fraction at every stage of the purification were monitored. An active component, which is 97% pure by high performance liquid chromatographic analysis, was isolated. Based on nuclear magnetic resonance (NMR) and mass spectrophotometric (MS) analysis, this active component was identified to be pheophorbide a (C35H36N4O5). Mechanistic studies showed that pheophorbide a induced apoptosis in Hep3B cells, a viral-induced hepatoma cell line. However, it was found to be non-toxic in normal human liver cells WRL-68. DNA fragmentation, sub-G1 cell cycle arrest, as well as suppression of the anti-apoptotic protein Bcl-2, release of cytochrome c to the cytosol, and activation of pro-caspase 3 and pro-caspase 9 were observed when Hep3B cells were treated with 40 microg/mL (i. e., 67.5 microM) pheophorbide a for 48 hours. In conclusion, this is the first report describing the isolation of pheophorbide a from Scutellaria barbata using a bioassay-guided isolation method. The anti-proliferative activity and possible mechanisms of action of pheophorbide a on hepatoma Hep3B cells are also discussed.