Dong-Mei Zhang

Publications of Dong-Mei Zhang

• Cytotoxic dimeric indole alkaloids from Catharanthus roseus.

  Authors: Chun-Hua Wang, Guo-Cai Wang, Ying Wang, Xiao-Qi Zhang, Xiao-Jun Huang, Dong-Mei Zhang, Min-Feng Chen, Wen-Cai Ye

  Fitoterapia. 03/2012;

  Three new dimeric indole alkaloids (1-3), together with five known ones (4-8), were isolated from the whole plants of Catharanthus roseus. The structures and absolute configurations of new compoundsThree new dimeric indole alkaloids (1-3), together with five known ones (4-8), were isolated from the whole plants of Catharanthus roseus. The structures and absolute configurations of new compounds were elucidated by means of NMR and CD analyses. All these compounds were evaluated for their in vitro cytotoxic activities against human breast cancer cell line MDA-MB-231.

• Flueggines A and B, two new dimeric indolizidine alkaloids from Flueggea virosa.

  Authors: Bing-Xin Zhao, Ying Wang, Dong-Mei Zhang, Ren-Wang Jiang, Guo-Cai Wang, Jun-Min Shi, Xiao-Jun Huang, Wei-Min Chen, Chun-Tao Che, Wen-Cai Ye

  Organic letters. 08/2011; 13(15):3888-91.

  Two unprecedented C,C-linked dimeric indolizidine alkaloids, flueggines A (1) and B (2), were isolated from the twigs and leaves of Flueggea virosa. The structures and absolute configurations wereTwo unprecedented C,C-linked dimeric indolizidine alkaloids, flueggines A (1) and B (2), were isolated from the twigs and leaves of Flueggea virosa. The structures and absolute configurations were elucidated by means of NMR, single-crystal X-ray diffraction, and CD analyses. Compound 1 is the first example of Securinega alkaloids bearing an isoxazolidine ring, the plausible biogenetic pathway of which is also proposed. Compound 2 exhibited growth inhibitory activity against MCF-7 and MDA-MB-231 human breast cancer cells.

• Synthesis and antiproliferative evaluation of 23-hydroxybetulinic acid derivatives.

  Authors: Ping Lan, Jiao Wang, Dong-Mei Zhang, Chang Shu, Hui-Hui Cao, Ping-Hua Sun, Xiao-Ming Wu, Wen-Cai Ye, Wei-Min Chen

  European journal of medicinal chemistry. 06/2011; 46(6):2490-502.

  Based on structural modifications of the natural 23-hydroxybetulinic acid, a series of novel its derivatives had been synthesized. The new compounds were screened for in vitro antiproliferativeBased on structural modifications of the natural 23-hydroxybetulinic acid, a series of novel its derivatives had been synthesized. The new compounds were screened for in vitro antiproliferative activity against cancer cell lines HeLa, MCF-7, HepG2, B16 and A375 using doxorubicin as a reference. The vast majority of derivatives had exhibited potent tumor growth inhibitory activity than original compound. The derivatives 4, 5, 7, 20, 23, 26, 43 and 44 with IC50 values lower than 10 μM on all tested cell lines were regarded as the most promising compounds. The structure-activity relationships of 23-hydroxybetulinic acid derivatives were also discussed in the present investigations.

• Two pairs of epimeric indole alkaloids from Catharanthus roseus.

  Authors: Guo-Cai Wang, Xiang-Zhan Zhong, Dong-Mei Zhang, Ying Wang, Xiao-Qi Zhang, Ren-Wang Jiang, Yao-Lan Li, Jiao Wang, Xin-Sheng Yao, Wen-Cai Ye

  Planta medica. 05/2011; 77(15):1739-41.

  Two pairs of epimeric indole alkaloids (1- 4) with a chlorine atom were isolated from the aerial part of Catharanthus roseus. Their structures were established on the basis of the spectroscopic dataTwo pairs of epimeric indole alkaloids (1- 4) with a chlorine atom were isolated from the aerial part of Catharanthus roseus. Their structures were established on the basis of the spectroscopic data including UV, IR, HRESIMS, NMR, and X-ray diffraction analyses. The cytotoxic activities of 1-4 against the HepG2 cell line were evaluated.

• [Anti-angiogenetic effect of arenobufagin in vitro and in vivo].

  Authors: Jun-shan Liu, Dong-mei Zhang, Min-feng Chen, Man-mei Li, Qing-dao Luo, Hiroshi Kurihara, Wen-cai Ye

  Yao xue xue bao = Acta pharmaceutica Sinica. 05/2011; 46(5):527-33.

  This study is to investigate the anti-angiogenetic effect of arenobufagin in vitro and in vivo. The anti-proliferation effect of arenobufagin on CNE-2, Hep2, SH-SY5Y, LOVO, PC-3 and DU145 cells asThis study is to investigate the anti-angiogenetic effect of arenobufagin in vitro and in vivo. The anti-proliferation effect of arenobufagin on CNE-2, Hep2, SH-SY5Y, LOVO, PC-3 and DU145 cells as well as human umbilical vein endothelial cells (HUVECs) was determined by MTT assay. Cell morphological changes of LOVO and HUVECs after arenobufagin treatment were observed by microscopy. Arenobufagin inhibited the proliferation of CNE-2, Hep2, SH-SY5Y, LOVO, PC-3, DU145 and HUVECs in a dose-dependent manner. Furthermore, it was obviously observed that the subcytotoxic concentration of arenobufagin in human carcinoma cells induced a marked decrease in the viability of HUVECs. Chick embryo chorioallantoic membrane (CAM) model was used to detect the anti-angiogenetic effect of arenobufagin in vivo. Arenobufagin significantly suppressed the angiogenesis of CAM. Cell cycle analysis demonstrated that G2/M phase was arrested and the sub-G1 peak appeared with the increase of arenobufagin concentration. PI/Annexin V double staining assay further demonstrated that arenobufagin could induce apoptosis in a dose- and time-dependent manner. Mitochondrial potential collapse detected by flow cytometric analysis was increased after arenobufagin treatment. It also observed that PARP was cleaved to p85 active form by Western blotting. Taken together, arenobufagin has significant anti-angiogenetic effect in vitro and in vivo, and the action mechanisms behind its anti-angiogenesis may be associated with cell cycle arrest and apoptosis of vein endothelial cells.

• Five new C21 steroidal glycosides from Periploca sepium.

  Authors: Lei Wang, Zhi-Qi Yin, Qing-Wen Zhang, Xiao-Qi Zhang, Dong-Mei Zhang, Kang Liu, Yao-Lan Li, Xin-Sheng Yao, Wen-Cai Ye

  Steroids. 02/2011; 76(3):238-43.

  Five new C(21) steroidal glycosides, named periseosides A-E (1-5), along with six known analogues, were isolated from the root barks of Periploca sepium. Their structures were elucidated on the basisFive new C(21) steroidal glycosides, named periseosides A-E (1-5), along with six known analogues, were isolated from the root barks of Periploca sepium. Their structures were elucidated on the basis of spectroscopic analysis and chemical evidence. All compounds were evaluated for their immunosuppressive activities.

• Triterpenoids with neurotrophic activity from Ganoderma lucidum.

  Authors: Xiao-Qi Zhang, Fanny C F Ip, Dong-Mei Zhang, Li-Xin Chen, Wei Zhang, Yao-Lan Li, Nancy Y Ip, Wen-Cai Ye

  Natural product research. 01/2011; 25(17):1607-13.

  A new triterpenoid, 4,4,14α-trimethyl-5α-chol-7,9(11)-dien-3-oxo-24-oic acid (1), together with seven known triterpenoids, were isolated from the dried fruiting bodies of Ganoderma lucidum. TheirA new triterpenoid, 4,4,14α-trimethyl-5α-chol-7,9(11)-dien-3-oxo-24-oic acid (1), together with seven known triterpenoids, were isolated from the dried fruiting bodies of Ganoderma lucidum. Their structures were elucidated by extensive spectroscopic analyses. Bioassay results revealed that compounds 1 and methyl ganoderic acid B (5) had nerve growth factor-like neuronal survival-promoting effects, whereas compounds 1, and 4-7 showed brain-derived neurotrophic factor-like neuronal survival-promoting activities.

• New bufadienolides and C(23) steroids from the venom of Bufo bufo gargarizans.

  Authors: Hai-Yan Tian, Lei Wang, Xiao-Qi Zhang, Dong-Mei Zhang, Ying Wang, Jun-Shan Liu, Ren-Wang Jiang, Wen-Cai Ye

  Steroids. 12/2010; 75(12):884-90.

  Six new bufadienolides (1-6) and two new C(23) steroids (7 and 8), together with three known compounds (9-11) were isolated from the venom of Bufo bufo gargarizans. Their structures were elucidatedSix new bufadienolides (1-6) and two new C(23) steroids (7 and 8), together with three known compounds (9-11) were isolated from the venom of Bufo bufo gargarizans. Their structures were elucidated by spectroscopic analysis and single-crystal X-ray diffraction. In vitro cytotoxicities of all compounds were evaluated in A549 cancer cell line. Compounds 2, 3 and 10 showed significant cytotoxic activities.

• [Advances in the study of structural modifications and biological activities of betulinic acids].

  Authors: Ping Lan, Dong-Mei Zhang, Wei-Min Chen, Wen-Cai Ye

  Yao xue xue bao = Acta pharmaceutica Sinica. 11/2010; 45(11):1339-45.

  Betulinic acids are lupine-type pentacyclic triterpenoid saponins commonly found in some plants of Betulaceae family, especially in the bark of betula alba (birch). The potent anti-HIV and anti-tumorBetulinic acids are lupine-type pentacyclic triterpenoid saponins commonly found in some plants of Betulaceae family, especially in the bark of betula alba (birch). The potent anti-HIV and anti-tumor activities of betulinic acids have been greatly concerned. The natural betulinic acids include betulinic acid, 23-hydroxy betulinic acid, betulin and so on. Some investigations on the structural modifications of betulinic acids were carried out, and many derivatives with excellent biological activity have been obtained nowadays. In this paper, the research advances of the structural modification of betulinic acids, as well as their anti-HIV and anti-tumor activities are reviewed.

• Anemoside A3-induced relaxation in rat renal arteries: role of endothelium and Ca2+ channel inhibition.

  Authors: Dong-Mei Zhang, Shun-Ming Lin, Chi-Wai Lau, Anita Yiu, Jiao Wang, Yong Li, Chun-Lin Fan, Yu Huang, Wen-Cai Ye

  Planta medica. 11/2010; 76(16):1814-9.

  Anemoside A(3), a lupane-type triterpenoid saponin, exists in the roots of Pulsatilla chinensis, but its pharmacological properties are largely unknown. The present study aimed to investigate theAnemoside A(3), a lupane-type triterpenoid saponin, exists in the roots of Pulsatilla chinensis, but its pharmacological properties are largely unknown. The present study aimed to investigate the mechanisms underlying anemoside A(3)-induced relaxation in rat renal arteries. Changes of isometric force were determined on arteries with a myograph. Anemoside A(3) caused concentration-dependent relaxation in precontracted aortas, mesenteric, left coronary, and renal arteries. Removal of endothelium or treatment with charybdotoxin plus apamin slightly but significantly attenuated the relaxation in renal arteries. TEA(+) inhibited the relaxation caused by anemoside A(3) in renal arteries with and without endothelium while glibenclamide, BaCl(2), or capsaicin had no effect on it. Anemoside A(3) produced less relaxation in rings contracted by 60 mM KCl compared with rings contracted by receptor-dependent constrictors. It further inhibited contractions induced by Ca(2+) influx through nifedipine-sensitive voltage-gated Ca(2+) channels, nifedipine-insensitive receptor-operated Ca(2+) channels, and by intracellular Ca(2+) release. Pretreatment with nifedipine attenuated anemoside A(3)-induced relaxation. Taken together, the present results indicate that anemoside A(3) produces relaxation in rat renal arteries through multiple mechanisms. The release of CTX/apamin-sensitive endothelium-derived hyperpolarizing factor, stimulation of TEA(+)-sensitive K(+) channel, and inhibition of Ca(2+) influx jointly contribute to the relaxation.

• Two pairs of enantiomeric neolignans from Lobelia chinensis.

  Authors: Jian-Xin Chen, Shen-Hui Huang, Lei Wang, Wei-Li Han, Ying Wang, Dong-Mei Zhang, Wen-Cai Ye

  Natural product communications. 10/2010; 5(10):1627-30.

  A pair of new enantiomeric neolignans, ethyl 3-[(2R,3S)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl] propanoate (+) (1) and ethylA pair of new enantiomeric neolignans, ethyl 3-[(2R,3S)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl] propanoate (+) (1) and ethyl 3-[(2S,3R)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl] propanoate (-) (1), together with a pair of known enantiomeric neolignans (+) (2) and (-) (2), as well as five known lignans (3-7) were isolated from the ethanol extract of Lobelia chinensis. Their structures were elucidated on the basis of extensive spectroscopic analyses, including 1D and 2D NMR, HR-ESI-MS and CD spectra.

• Psiguadials A and B, two novel meroterpenoids with unusual skeletons from the leaves of Psidium guajava.

  Authors: Meng Shao, Ying Wang, Zhong Liu, Dong-Mei Zhang, Hui-Hui Cao, Ren-Wang Jiang, Chun-Lin Fan, Xiao-Qi Zhang, He-Ru Chen, Xin-Sheng Yao, Wen-Cai Ye

  Organic letters. 10/2010; 12(21):5040-3.

  Psiguadials A (1) and B (2), two novel sesquiterpenoid-diphenylmethane meroterpenoids with unusual skeletons, along with a pair of known epimers, psidial A (3) and guajadial (4), were isolated fromPsiguadials A (1) and B (2), two novel sesquiterpenoid-diphenylmethane meroterpenoids with unusual skeletons, along with a pair of known epimers, psidial A (3) and guajadial (4), were isolated from the leaves of Psidium guajava. Their structures with absolute configurations were elucidated by means of NMR, X-ray diffraction, and quantum chemical CD calculation. Compounds 1, 2, and 4 exhibited potent inhibitory effects on the growth of human hepatoma cells.

• Bufogargarizins A and B: two novel 19-norbufadienolides with unprecedented skeletons from the venom of Bufo bufo gargarizans.

  Authors: Hai-Yan Tian, Lei Wang, Xiao-Qi Zhang, Ying Wang, Dong-Mei Zhang, Ren-Wang Jiang, Zhong Liu, Jun-Shan Liu, Yao-Lan Li, Wen-Cai Ye

  Chemistry (Weinheim an der Bergstrasse, Germany). 09/2010; 16(36):10989-93.

• Photodynamic therapy inhibits p-glycoprotein mediated multidrug resistance via JNK activation in human hepatomacellular carcinoma using the photosensitizer pheophorbide a.

  Authors: Patrick Ming-Kuen Tang, Dong-Mei Zhang, Ngoc-Ha Bui-Xuan, Stephen Kwok-Wing Tsui, Mary Miu-Yee Waye, Siu-Kai Kong, Wing-Ping Fong, Kwok-Pui Fung

  Molecular cancer. 08/2009; 8(1):56.

  ABSTRACT: BACKGROUND: Multidrug resistance (MDR) is frequently observed after prolonged treatment in human hepatoma with conventional anti-tumor drugs, and photodynamic therapy (PDT) is a recentlyABSTRACT: BACKGROUND: Multidrug resistance (MDR) is frequently observed after prolonged treatment in human hepatoma with conventional anti-tumor drugs, and photodynamic therapy (PDT) is a recently suggested alternative to overcome MDR. The therapeutic potential of PDT was evaluated in a multidrug resistance (MDR) human hepatoma cell line R-HepG2 with photosensitizer pheophorbide a (Pa). RESULTS: Our results demonstrated that intracellular accumulation of Pa was not reduced by the overexpression of p-glycoprotein. Pa-based PDT (Pa-PDT) significantly inhibited the growth of R-HepG2 cells with an IC50 value of 0.6 microM. Mechanistic study demonstrated that genomic DNA fragmentation and phosphatidylserine externalization were occurred where increase of intracellular singlet oxygen level triggers the phosphorylation of c-Jun N-terminal Kinase (JNK) and leads to activation of intrinsic apoptotic caspases cascade during the Pa-PDT treatment. The cytotoxicity of Pa-PDT, accumulation of sub-G1 population, and depolarization of mitochondrial membrane could be inhibited by JNK inhibitor in the Pa-PDT treated cells. Interestingly, the Pa-PDT induced JNK activation showed inhibitory effect on MDR by the down-regulation of p-glycoprotein in R-HepG2 cells in a dose-dependent manner. In addition, significant reduction of tumor size was obtained in Pa-PDT treated R-HepG2-bearing nude mice with no significant damages in liver and heart. CONCLUSION: In summary, our findings provided the first evidence that PDT could inhibit the MDR activity by down-regulating the expression of p-glycoprotein via JNK activation using pheophorbide a as the photosensitizer, and our work proved that Pa-PDT inhibit the growth of MDR hepatoma cells by mitochondrial-mediated apoptosis induction.

• Pheophorbide a based photodynamic therapy induces apoptosis via mitochondrial-mediated pathway in human uterine carcinosarcoma.

  Authors: Patrick Tang, Xiao-Zhuo Liu, Dong-Mei Zhang, Wing-Ping Fong, Kwok-Pui Fung

  Cancer biology & therapy. 04/2009; 8(6).

  Uterine carcinosarcoma is an aggressive neoplasm with low survival rates because of the lack of very effective chemotherapy protocol. Photodynamic therapy (PDT) is recently suggested to be anUterine carcinosarcoma is an aggressive neoplasm with low survival rates because of the lack of very effective chemotherapy protocol. Photodynamic therapy (PDT) is recently suggested to be an efficient protocol for this cancer. Pheophorbide a (Pa) is a chlorophyll degradation product in the green plant cells, its antitumor effect was reported on a number of human cancer cells with PDT approach. This study demonstrated that using Pa in PDT (Pa-PDT) significantly inhibited the human uterine sarcoma cell line MES-SA with an IC(50) value of 0.5 muM at 24 h. Induction of apoptosis was found on the Pa-PDT treated cells according to the results of propidium iodide (PI) staining, annexin-V staining and DNA fragmentation assay. Pa was found to be localized in the mitochondria that lead to the depolarization of mitochondrial membrane potential by the rapid generation of singlet oxygen during light irradiation, where release of cytochrome c was detected and lead to the activation of intrinsic apoptotic pathway in MES-SA cells. Our findings revealed the therapeutic potential of Pa-PDT on the human uterine cancer.

• Photodynamic therapy inhibits p-glycoprotein mediated multidrug resistance via JNK activation in human hepatocellular carcinoma using the photosensitizer pheophorbide a

  Authors: Patrick Tang, Dong-Mei Zhang, Ngoc-Ha Xuan, Stephen Tsui, Mary Waye, Siu-Kai Kong, Wing-Ping Fong, Kwok-Pui Fung

  Molecular Cancer. 01/2009;

  Abstract Background Multidrug resistance (MDR) is frequently observed after prolonged treatment in human hepatoma with conventional anti-tumor drugs, and photodynamic therapy (PDT) is a recentlyAbstract Background Multidrug resistance (MDR) is frequently observed after prolonged treatment in human hepatoma with conventional anti-tumor drugs, and photodynamic therapy (PDT) is a recently suggested alternative to overcome MDR. The therapeutic potential of PDT was evaluated in a multidrug resistance (MDR) human hepatoma cell line R-HepG2 with photosensitizer pheophorbide a (Pa). Results Our results demonstrated that intracellular accumulation of Pa was not reduced by the overexpression of P-glycoprotein. Pa-based PDT (Pa-PDT) significantly inhibited the growth of R-HepG2 cells with an IC50 value of 0.6 μM. Mechanistic study demonstrated that genomic DNA fragmentation and phosphatidylserine externalization occurred where increase of intracellular singlet oxygen level triggers the phosphorylation of c-Jun N-terminal Kinase (JNK) and leads to activation of intrinsic apoptotic caspases cascade during the Pa-PDT treatment. The cytotoxicity of Pa-PDT, accumulation of sub-G1 population, and depolarization of mitochondrial membrane could be inhibited by JNK inhibitor in the Pa-PDT treated cells. Interestingly, the Pa-PDT induced JNK activation showed inhibitory effect on MDR by the down-regulation of P-glycoprotein in R-HepG2 cells in a dose-dependent manner. In addition, significant reduction of tumor size was obtained in Pa-PDT treated R-HepG2-bearing nude mice with no significant damages in liver and heart. Conclusion In summary, our findings provided the first evidence that PDT could inhibit the MDR activity by down-regulating the expression of P-glycoprotein via JNK activation using pheophorbide a as the photosensitizer, and our work proved that Pa-PDT inhibited the growth of MDR hepatoma cells by mitochondrial-mediated apoptosis induction.

• Saxifragifolin B from Androsace umbellata induced apoptosis on human hepatoma cells.

  Authors: Dong-Mei Zhang, Ying Wang, Ming-Kuen Tang, Yuet Wa Chan, Hung-Ming Lam, Wen-Cai Ye, Kwok-Pui Fung

  Biochemical and biophysical research communications. 11/2007; 362(3):759-65.

  Bioassay-guided phytochemical study of Androsace umbellata led to the successful isolation of saxifragifolin B (SB) for the first time. The anti-tumor effect of SB was firstly reported that it wasBioassay-guided phytochemical study of Androsace umbellata led to the successful isolation of saxifragifolin B (SB) for the first time. The anti-tumor effect of SB was firstly reported that it was shown to have potent cytotoxicity on human hepatoma HepG2 cells with IC50 value of 11.9 microM at 24 h. Mechanistic studies were conducted, the accumulation of sub-G1 population and the externalization of phosphatidylserine suggested that SB exerted its cytotoxic effect by induction of programmed cell death, which was confirmed by activation of PARP and caspase-3. Furthermore, SB-induced apoptosis on HepG2 cells was mediated by activation of caspase-8 and -9, mitochondrial membrane potential (Deltapsim) collapse and the leakage of cytochrome c. In summary, this study provided evidence that SB isolated from A. umbellata could induce apoptosis on human hepatoma HepG2 cells and described the molecular mechanism. Our finding revealed the potential of SB as new chemotherapeutic agent for human hepatoma.

• 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.

• New bufadienolides and C23 steroids from the venom of Bufo bufo gargarizans

  Authors: Hai-Yan Tian, Lei Wang, Xiao-Qi Zhang, Dong-Mei Zhang, Ying Wang, Jun-Shan Liu, Ren-Wang Jiang, Wen-Cai Ye

  Steroids.

  Six new bufadienolides (1–6) and two new C23 steroids (7 and 8), together with three known compounds (9–11) were isolated from the venom of Bufo bufo gargarizans. Their structures were elucidated bySix new bufadienolides (1–6) and two new C23 steroids (7 and 8), together with three known compounds (9–11) were isolated from the venom of Bufo bufo gargarizans. Their structures were elucidated by spectroscopic analysis and single-crystal X-ray diffraction. In vitro cytotoxicities of all compounds were evaluated in A549 cancer cell line. Compounds 2, 3 and 10 showed significant cytotoxic activities.

• Saxifragifolin B from Androsace umbellata induced apoptosis on human hepatoma cells

  Authors: Dong-Mei Zhang, Ying Wang, Ming-Kuen Tang, Yuet-Wa Chan, Hung-Ming Lam, Wen-Cai Ye, Kwok-Pui Fung

  Biochemical and Biophysical Research Communications.

  Bioassay-guided phytochemical study of Androsace umbellata led to the successful isolation of saxifragifolin B (SB) for the first time. The anti-tumor effect of SB was firstly reported that it wasBioassay-guided phytochemical study of Androsace umbellata led to the successful isolation of saxifragifolin B (SB) for the first time. The anti-tumor effect of SB was firstly reported that it was shown to have potent cytotoxicity on human hepatoma HepG2 cells with IC50 value of 11.9 μM at 24 h. Mechanistic studies were conducted, the accumulation of sub-G1 population and the externalization of phosphatidylserine suggested that SB exerted its cytotoxic effect by induction of programmed cell death, which was confirmed by activation of PARP and caspase-3. Furthermore, SB-induced apoptosis on HepG2 cells was mediated by activation of caspase-8 and -9, mitochondrial membrane potential (Δψm) collapse and the leakage of cytochrome c. In summary, this study provided evidence that SB isolated from A. umbellata could induce apoptosis on human hepatoma HepG2 cells and described the molecular mechanism. Our finding revealed the potential of SB as new chemotherapeutic agent for human hepatoma.