Isolation and cytotoxic activity of selaginellin derivatives and biflavonoids from Selaginella tamariscina

Five selaginellin derivatives, including two new selaginellins termed selaginellins M (1) and N (2), and three previously identified compounds, selaginellin (3), selaginellin A (4), and selaginellin C (5), were isolated from the Selaginella tamariscina (Beauv.) Spring plant. In addition, four known biflavonoids, namely neocryptomerin ( 6), hinokiflavone (7), pulvinatabiflavone (8), and 7'- O-methylamentoflavone (9), were also isolated. The structures of new compounds 1 and 2 were elucidated by spectroscopic analysis. The cytotoxic activity of compounds 1- 9 was evaluated against a small panel of human cancer cell lines, including U251 (human glioma cells), HeLa (human cervical carcinoma cells), and MCF-7 (human breast cancer cells). The two new selaginellins, selaginellins M (1) and N (2), showed medium activity against the human cancer cell lines.     

新型6,7-二甲氧基-4-(2-氟苯氧基)喹啉类c-Met抑制剂的设计、合成及生物活性研究

基于卡博替尼(cabozantinib)和foretinib的化学结构,通过改变中间链,设计合成了一系列含有哌嗪酰胺的6,7-二甲氧基-4-(2-氟苯氧基)喹啉类c-Met抑制剂。这些化合物未见文献报道,其结构通过MS和NMR确证。采用酶联免疫吸附测定(ELISA)法和MTT法测定了目标化合物对c-Met的抑制活性和对人结肠癌细胞(HT-29)、人肺癌细胞(H460)、人非小细胞肺癌细胞(A549)和人胃癌细胞(MKN-45)的细胞毒性。结果表明,4-(4-氯苯基)-N-[4-[(6,7-二甲氧基-4-喹啉)氧基]-3-氟苯基]哌嗪-1-甲酰胺(1b)、4-(3-氯苯基)-N-[4-[(6,7-二甲氧基-4-喹啉)氧基]-3-氟苯基]哌嗪-1-甲酰胺(1h)和4-(2-氯苯基)-N-[4-[(6,7-二甲氧基-4-喹啉)氧基]-3-氟苯基]哌嗪-1-甲酰胺(1j)对HT-29、H460、A549和MKN-45细胞的抑制活性明显优于对照药卡博替尼。其中,化合物1h和1j对c-Met具有较强的抑制活性,其IC50值分别为0.007 2和0.009 8 μmol/L。     

1,1-Bis(3'-indolyl)-1-(p-substitutedphenyl)methanes are peroxisome proliferator-activated receptor gamma agonists but decrease HCT-116 colon cancer cell survival through receptor-independent activation of early growth response-1 and nonsteroidal anti-inflammatory drug-activated gene-1

1,1-Bis-(3'-indolyl)-1-(p-substitutedphenyl)methanes containing p-trifluoromethyl (DIM-C-pPhCF3), p-t-butyl (DIM-C-pPhtBu), and phenyl (DIM-C-pPhC6H5) substituents decrease survival of HCT-116 colon cancer cells and activate peroxisome proliferator-activated receptor (PPAR) gamma in this and other cancer cell lines. These PPARgamma-active compounds had minimal effects on expression of cell cycle proteins and did not induce caveolin-1 in HCT-116 cells. However, these compounds induced nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1) and apoptosis in HCT-116 cells, and in time-course studies, the PPARgamma agonists maximally induced early growth response-1 (Egr-1) protein within 2 h, whereas a longer time course was observed for induction of NAG-1 protein. These data, coupled with deletion and mutation analysis of both the Egr-1 and NAG-1 gene promoters, indicate that activation of NAG-1 by these compounds was dependent on prior induction of Egr-1, and induction of these responses was PPARgamma-independent. Results of kinase inhibitor studies also demonstrated that activation of Egr-1/NAG-1 by methylene-substituted diindolylmethanes (C-DIMs) was phosphatidylinositol 3-kinase-dependent, and this represents a novel receptor-independent pathway for C-DIM-induced growth inhibition and apoptosis in colon cancer cells.     

水杨柳根的化学成分

本文的目的是对水杨柳的根部进行化学成分研究， 采用硅胶柱色谱的方法分离和纯化化合物， 根据理化性质和波谱方法鉴定化合物结构。从水杨柳的根部分离得到了13个化合物， 包括1-羰基-油桐酸(1)， 油桐酸(2)， 3-乙酰氧基-油桐酸(3)， 蒲公英赛酮(4)， 蒲公英赛醇(5)， 3-乙酰氧基-12-齐墩果烯-28-酸甲酯(6)， 3-乙酰氧基-12-齐墩果烯-28-醇(7)， 熊果酸(8)， 羽扇豆醇(9)， 乙酰氧羽扇豆醇酯(10)， 臭矢菜素A(11)， 大黄酚(12)和没食子酸(13)。化合物1为新的蒲公英赛烷三萜类化合物， 化合物2～12均为首次从该植物中分离得到。并用MTT法测定了化合物1～3对AGZY 83-a和SMMC-7721细胞的抑制作用。证明化合物2对AGZY 83-a细胞有弱抑制作用(IC50 33.055 μg·mL^-1)。     

Cytotoxic activities of trichothecenes isolated from an endophytic fungus belonging to order hypocreales

Bioassay-guided fractionation of the extract of the endophytic fungus KLAR 5 belonging to order Hypocreales, which was isolated from the twig of Knema laurina (Blume) Warb., resulted in the isolation of brefeldin A (1), 8-deoxy-trichothecin (2), trichothecolone (3), 7alpha-hydroxytrichodermol (4), and 7alpha-hydroxyscirpene (5). Compound 5 was isolated from natural source for the first time. Compound 1 was very highly active against human epidermoid carcinoma of the mouth, human breast cancer (BC-1), and human small cell lung cancer (NCI-H187) cells whereas compounds 2 and 4 were selectively active against BC-1 and NCI-H187 cells. Compounds 3 and 5 were moderately active against these three cancer cell lines.     

Isolation,characterization and anticancer activity of secondary metabolites from Verbascum speciosum

Herein, two iridoid glucosides aucubin (1) and ajugol (2), and two phenyl ethanoids, verbascoside (3) and poliumoside (4) were isolated from the methanol extract of the aerial parts of Verbascum speciosum and used to study about their anticancer activity for the first time. The structures of all compounds were elucidated using spectroscopic data (IR, 1D and 2D NMR, LC-TOF/MS). Antiproliferative activities of Aucubun ( 1 ) and Verbascoside (3) were tested against A-549 (human colon cancer), MDA-MD-453 (human breast cancer) and 3T3-L1 (mouse fibroblast)cell lines by XTT assay. In addition, the anticarcer mechanism of action of aucubin (1) was investigated on MDA-MB-453 cells for the first time. XTT result showed that both applied compounds exhibited antiproliferative effect at different dose ranges depending on the cancer type, as well as selectivity between cancer and healty cell lines. Flow cytometry analyzes revealed that aucubin (1) exerts its cytotoxic effect in MDA-MB-453 cells by directing cells to early apoptosis and inhibiting the P13K/AKT signaling pathway.     

Synthesis, DNA-binding affinity and cytotoxicity of the dinuclear platinum(II) complexes with berenil and amines ligands

A series of platinium(II) complexes of formula [Pt2L4(berenil)2]Cl4.4HCl.2H2O where L is piperidine (1), 4-picoline (2), 3-picoline (3) or isopropylamine (4) was prepared and their cytotoxicity have been tested against the growth of human breast cancer cells. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more active than cisplatin. Data from the ethidium displacement assay indicated that these compounds show moderate specificity for AT base pairs of DNA. Compounds 1-4 were also potent topoisomerase II inhibitors, with 50% inhibitory concentrations (IC50) ranging from 5 to 50 microM.     

Isolation and identification of novel selective antitumor constituents,sidrin and sidroside,from Zizyphus spina-christi

BackgroundThe leaves of Zizyphus spina-christi (L.) Willd contain several compounds exhibiting different pharmacologic activities. However, studies on the cytotoxic activity of these compounds are limited.ObjectivesWe aimed to investigate and isolate cytotoxic compounds with selective antitumor effects from the leaves of Z. spina-christi using bioassay-guided fractionation of methanol extract.MethodsPowdered, dried leaves were subjected to methanol extraction and fractionated using n-hexane, chloroform, ethyl acetate, and n-butanol. Fractions with positive cytotoxicity against HeLa and THP-1 cell lines were further fractionated and eluted using various concentrations of organic solvents. Active compounds were isolated using different chromatographic methods and their chemical structures were determined using extensive spectroscopic methods, such as 1D NMR (¹H NMR, ¹³C NMR, and DEPT), 2D NMR (COSY, HMBC, and HMQC), HRFAB-MS, and IR. Furthermore, the cytotoxic effects of the isolated compounds were evaluated against 62 tumor cell lines (including HeLa and THP-1) in addition to normal bone marrow cells.ResultsThe chloroform and aqueous methanol fractions of the leaves showed cytotoxic activity. Two compounds were successfully isolated and named “sidrin” (13-β-hydroxy-lup-20(30)-ene-2,3-β-epoxy-28-carboxylate) and “sidroside” (3-O-β-D-glucopyranosyl-(1–3)-α-L-arabinopyranosyl-jujubogenin-20-O-α-L-rhamnopyranoside). Sidrin exhibited cytotoxic activity against the human leukemia (Hl-60, RPMI-8226), lung cancer (A549, EKVX), breast cancer (BT-549, MDA-MB-231/ATCC), colon cancer (KM12), melanoma (M14, SK-MEL-5), and central nervous system (CNS) cancer (SF-295) cell lines, and selectivity was observed against the Hl-60, EKVX, BT-549, KM12, and SF-295 cell lines. In addition, sidrin was more active than sidroside and doxorubicin against the Hl-60 and EKVX cell lines. In contrast, sidrin had a similar effect to doxorubicin against the BT-549 and renal cancer (UO-31) cell lines. Sidroside was more selective against the leukemia (CCRF-CEM, MOLT-4), lung cancer (HOP-92, NCI-H322M), breast cancer (MDA-MB-468), melanoma (LOX IMVI), CNS cancer (SNB-19), ovarian cancer (OVCAR-8), renal cancer (UO-31, RXF 393), and prostate cancer (PC-3) cell lines. Both compounds exhibited similar activity against the breast cancer (MDA-MB-231, T-47D), colon cancer (HCC-2998, HCT-116), ovarian cancer (OVCAR-3), renal cancer (UO-31, 786–0, and SN 12C) cell lines. Normal bone marrow cells were unaffected at the same concentrations of sidrin and sidroside applied to tumor cells.ConclusionsThese results suggest tumor-selective cytotoxicity of sidrin and sidroside.     

Cytotoxicity and mode of action of four naturally occuring flavonoids from the genus Dorstenia: gancaonin Q, 4-hydroxylonchocarpin, 6-prenylapigenin, and 6,8-diprenyleriodictyol

Several flavonoid-like compounds were found to possess good antiproliferative properties. Herein, we examined the ability of four naturally occuring and biologically active flavonoids from the genus Dorstenia, gancaonin Q (1), 6-prenylapigenin (2), 6,8-diprenyleriodictyol (3), and 4-hydroxylonchocarpin ( 4), to inhibit the proliferation of a panel of fourteen cancer cell lines including leukemia and solid cancer cells, as well as AML12 normal hepatocytes. The study was extended to the analysis of cell cycle distribution, apoptosis induction, and caspase 3/7 activity and the antiangiogenic properties of the four compounds. The results of the cytotoxicity assays showed that more than 50?% inhibition of proliferation was obtained with compound 1 on all the fourteen studied cancer cell lines, with IC (50) values below 20?μg/mL. Compounds 2, 4, and 3 showed selective activity, with IC (50) values below 20?μg/mL being noted on 57.15?%, 71.42?%, and 85.71?% of the fourteen cancer cell lines, respectively. None of the compounds exhibited more than 50?% inhibition against AML12 normal hepatocytes cells at 20?μg/mL. IC (50) values below or around 4?μg/mL were recorded on 28.57?% of the tested cell lines for both compound 1 and 4 and 21.43?% for compound 3, which appeared to be the best cytotoxic compounds. This study indicates that caspase 3/7 activation is one of the modes of induction of apoptosis for compounds 1, 3, and 4 in CCRF-CEM cells. The results of the antiangiogenic assay indicated that compounds 1, 3, and 4 were also able to inhibit the growth of blood capillaries on the chorioallantoic membrane of quail eggs, the best effect being noted for compound 4 (54.1?% inhibition). The results of the present work provide evidence of the cytotoxic potential of the four studied flavonoids and supportive data for further investigations.     

Cytotoxic terpene hydroperoxides from the aerial parts ofAster spathulifolius

Three new sesquiterpene hydroperoxides, 1-[3-(2-hydroperoxy-3-methylbut-3-en)-4-hydroxyphenyl]ethanone (2), 7beta-hydroperoxy-eudesma-11-en-4-ol (3), and 7alpha-hydroperoxymanool (4), together with three known compounds, germacrone (1), ent-germacra-4(15),5,10(14)-trien-1alpha-ol (5) and teucdiol A (6) were isolated from the aerial parts of Aster spathulifolius (Compositae). Their structures were characterized using chemical and spectroscopic methods. The isolated compounds were tested for their cytotoxicity against five human tumor cell lines in vitro using a SRB method. The two new compounds, 3 and 4, showed moderate cytotoxicity against human cancer cells with ED50 values ranging from 0.24 to 13.27 microg/mL.     

A new elemanolide sesquiterpene lactone from Elephantopus scaber

A new elemanolide sesquiterpene lactone, named elescaberin (1), together with two known compounds, namely, isodeoxyelephantopin (2) and deoxyelephantopin (3), was isolated from the whole plant of Elephantopus scaber. The structure of 1 was elucidated on the basis of spectroscopic analysis. All three compounds exhibited significant inhibitory activities against human SMMC-7721 liver cancer cells in vitro (IC(50) 8.18-14.08 micromol/l).     

Cytotoxic Compounds from Brucea mollis

Ten compounds, including soulameanone (1), isobruceine B (2), 9-methoxy-canthin-6-one (3), bruceolline F (4), niloticine (5), octatriacontan-1-ol (6), bombiprenone (7), α-tocopherol (8), inosine (9), and apigenin 7-O-β-D-glucopyranoside (10), were isolated from the leaves, stems, and roots of Brucea mollis Wall. ex Kurz. Their structures were determined using one-and two-dimensional NMR spectroscopy and mass spectrometry. All compounds were evaluated for their cytotoxic activity against KB (human carcinoma of the mouth), LU-1 (human lung adenocarcinoma), LNCaP (human prostate adeno-carcinoma), and HL-60 (human promyelocytic leukemia) cancer cell lines. Compound 2 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC₅₀ values of 0.39, 0.40, 0.34, and 0.23 μg/mL, respectively. In addition, compounds 3 and 5 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC₅₀ values around 1–4 μg/mL. Compounds 9-methoxycanthin-6-one (3) and niloticine (5) have been discovered for the first time from the Brucea genus.     

Cytotoxic oleane-type triterpene saponins from Glochidion eriocarpum

The anticancer activity of ten compounds from the aerial parts of Glochidion eriocarpum were evaluated on two human cancer cell lines, HL-60 and HCT-116. Compounds 1-4 displayed highly potent cytotoxic activity on the HCT-116 cancer cell line with IC(50) values ranging of 0.41～1.16 μM. Compounds 1-4 significantly inhibited the HL-60 cell line with IC(50) values ranging of 4.51～6.33 μM. These results suggested that the benzoyl group at the C-22 position in oleane-type triterpene saponins was essential for cytotoxicity towards tumor cells. Moreover, compounds 2 and 3 showed more potent cytotoxicity than compounds 1 and 4 against HL-60 and HCT-116 cells. With respect to the mechanism underlying cytotoxicity, compounds 1-4 increased chromatin condensation, a typical apoptotic characteristic in HL-60 and HCT-116 cells. In the mechanism of apoptosis induction, compounds 1-4 reduced Bcl-2 expression, whereas the expression of Bax was increased compared to controls in HCT-116 cells. In addition, compounds 1-4 decreased the level of procaspase-3. The cleavage of poly (ADP-ribose) polymerase (PARP), a vital substrate of effector caspase, was observed in HCT-116 cells. Furthermore, the induction of apoptosis was also accompanied by an activation of extracellular signal-regulated kinase (ERK) and p38 kinase in HCT-116 cells. These findings provide evidence demonstrating that the pro-apoptotic effects of compounds 1-4 are mediated through the activation of ERK and p38 in HCT-116 cells.     

Isolation and characterization of new lactam compounds that inhibit lung and colon cancer cells from adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) bran

Five active compounds that inhibit cancer cells were isolated from adlay bran (Coix lachryma-jobi L. var. ma-yuen Stapf), and their structures and activities in vitro were characterized. The ethyl acetate-soluble fraction of methanol extracts of adlay bran (ABM-EtOAc) exhibited a stronger anti-proliferative effect on human lung cancer cell A549, human colorectal carcinoma cell HT-29, and COLO 205 than other fractions by MTT (3-4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide) assay. Assay-guided isolation gave five lactams including three that were previously undocumented; coixspirolactam A (1), coixspirolactam B (2), and coixspirolactam C (3); one isolated from the natural plant for the first time, coixlactam (4); and one known compound, methyl dioxindole-3-acetate (5). Pure active compounds were identified by spectral analysis including IR, ¹H and ¹³C NMR, UV–vis, MS and 2D NMR techniques. All the compounds were tested for their anti-proliferative effect on A549, HT-29 and COLO 205 cells. These compounds showed anti-cancer activities with IC₅₀ values between 28.6 and 72.6 μg/mL.     

Coenzyme Q0 induces apoptosis and modulates the cell cycle in estrogen receptor negative breast cancer cells

We postulated that methoxy-substituted cyclic compounds could inhibit estrogen receptor (ER) negative breast cancer growth in vitro. Therefore, this study assessed the cytotoxic potential of various methoxy-substituted cyclic compounds [7,8-dimethoxyflavone, 4-methoxyphenylacetic acid, 2-methoxyphenylacetic acid, 4-methoxybenzophenone, 5-methoxy-1-indanone, and coenzyme Q0 (CoQ0)] toward ER-negative human breast cancer cells (MDA-MB-231 and SKBr3). Cytotoxicity was assessed using the sulforhodamine B assay. CoQ0 demonstrated the strongest cytotoxicity toward MDA-MB-231 and SKBr3 cells with IC50 values of 1.7 micromol/l and 3.1 micromol/l, respectively, whereas the other compounds were either much less potent or completely lacked cytotoxicity toward both breast cancer cell lines. Therefore, only CoQ0 was examined for its ability to modulate cell cycle progression and induce apoptosis. Cell cycle experiments, using propidium iodide staining and flow cytometry, demonstrated that CoQ0 at 7.5 micromol/l increased the proportion of MDA-MB-231 cells in G1/G0-phase by 16.6+/-0.6% of control (P<0.05), and increased in the proportion of S-phase SKBr3 cells by 37.8+/-5.8% over control (P<0.05). Induction of apoptosis was determined using propidium iodide/Annexin-V-FLUOS staining followed by flow cytometry. The results demonstrated that treatment with CoQ0 (7.5 micromol/l) increased the proportion of apoptotic MDA-MB-231 and SKBr3 cells by 12-fold and 4-fold over control (P<0.05), respectively. Thus, CoQ0 is a potent cytotoxic drug that induces apoptosis and modulates cell cycle progression in ER-negative breast cancer cells. Therefore, CoQ0 is an appropriate candidate for further study and development as a potential drug for ER-negative breast cancer.     

Metabolism of [6]-shogaol in mice and in cancer cells

Ginger has received extensive attention because of its antioxidant, anti-inflammatory, and antitumor activities. However, the metabolic fate of its major components is still unclear. In the present study, the metabolism of [6]-shogaol, one of the major active components in ginger, was examined for the first time in mice and in cancer cells. Thirteen metabolites were detected and identified, seven of which were purified from fecal samples collected from [6]-shogaol-treated mice. Their structures were elucidated as 1-(4'-hydroxy-3'-methoxyphenyl)-4-decen-3-ol (M6), 5-methoxy-1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M7), 3',4'-dihydroxyphenyl-decan-3-one (M8), 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-ol (M9), 5-methylthio-1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M10), 1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-one (M11), and 5-methylthio-1-(4'-hydroxy-3'-methoxyphenyl)-decan-3-ol (M12) on the basis of detailed analysis of their (1)H, (13)C, and two-dimensional NMR data. The rest of the metabolites were identified as 5-cysteinyl-M6 (M1), 5-cysteinyl-[6]-shogaol (M2), 5-cysteinylglycinyl-M6 (M3), 5-N-acetylcysteinyl-M6 (M4), 5-N-acetylcysteinyl-[6]-shogaol (M5), and 5-glutathiol-[6]-shogaol (M13) by analysis of the MS(n) (n = 1-3) spectra and comparison to authentic standards. Among the metabolites, M1 through M5, M10, M12, and M13 were identified as the thiol conjugates of [6]-shogaol and its metabolite M6. M9 and M11 were identified as the major metabolites in four different cancer cell lines (HCT-116, HT-29, H-1299, and CL-13), and M13 was detected as a major metabolite in HCT-116 human colon cancer cells. We further showed that M9 and M11 are bioactive compounds that can inhibit cancer cell growth and induce apoptosis in human cancer cells. Our results suggest that 1) [6]-shogaol is extensively metabolized in these two models, 2) its metabolites are bioactive compounds, and 3) the mercapturic acid pathway is one of the major biotransformation pathways of [6]-shogaol.     

Effects of nontoxic heat shock protein 90 inhibitor peptide derivatives on reversal of MDR of tumor cells

Novel heat shock protein 90 inhibitor peptide derivatives [D- Trp-Phe-D- Trp-Leu-AMB (1), p-HOPA-D- TrpPhe-D-Trp-Leu-psi(CH2NH)-Leu-NH2 (2), D-Trp-Phe-D-Trp-OH (3), Suc-D-Trp-Phe-D-Trp-Leu-AMB (4), D-Tyr-Phe-D-Trp-Leu-AMB (5), D-Arg-D-Trp-Phe-D-Trp-Leu-Leu-NH2 (6), Leu-psi(CH2NH)-Leu-NH2x2HCl (7), Phe-Trp-Phe-Trp-Leu-Leu-NH2 (8), Tyr-Trp-Phe-Trp-Leu-Leu-NH2 (9) and Tyr-D- Trp-Phe-D-Trp-Leu-Leu-NH2 (10)] were synthetized, and their ability to reverse multidrug resistance (MDR) was studied. Peptide derivatives 1, 4 and 5, with D-Trp or D-Tyr residues in the N-terminal position caused a marked inhibition of MDR in cancer cells. These MDR inhibitor compounds and epirubicin were demonstrated to have additive and synergistic antiproliferative effects in checkerboard experiments on human MDR1 gene-transfected mouse lymphoma cells in vitro. It is suggested that the MDR reversal effects of these anticancer peptide derivatives, together with their antiproliferative effects on lung cancer cells, may open up new horizons in cancer chemotherapy.     

Inhibition of phospholipase Cγ1 and cancer cell proliferation by lignans and flavans from<Emphasis Type="Italic">Machilus thunbergii</Emphasis>

Thirteen compounds were isolated from the CH2Cl2 fraction of Machilus thunbergii as phospholipase Cgamma1 (PLCgamma1) inhibitors. These compounds were identified as nine lignans, two neolignans, and two flavans by spectroscopic analysis. Of these, 5,7-di-O-methyl-3',4'-methylenated (-)-epicatechin (12) and 5,7,3'-tri-O-methyl (-)-epicatechin (13) have not been reported previously in this plant. In addition, seven compounds, machilin A (1), (-)-sesamin (3), machilin G (5), (+)-galbacin (9), licarin A (10), (-)-acuminatin (11) and compound 12 showed dose-dependent potent inhibitory activities against PLCgamma1 in vitro with IC50 values ranging from 8.8 to 26.0 microM. These lignans, neolignans, and flavans are presented as a new class of PLCgamma1 inhibitors. The brief study of the structure activity relationship of these compounds suggested that the benzene ring with the methylene dioxy group is responsible for the expression of inhibitory activities against PLCgamma1. Moreover, it is suggested that inhibition of PLCgamma1 may be an important mechanism for an antiproliferative effect on the human cancer cells. Therefore, these inhibitors may be utilized as cancer chemotherapeutic and chemopreventive agents.     

Cardiac glycosides from the seeds of Thevetia peruviana and their pro-apoptotic activity toward cancer cells

Phytochemical investigation of the seeds of Thevetia peruviana resulted in the isolation of seven cardiac glycosides (1–7), including two new compounds (1 and 2). Cytotoxicity of them toward cancer cell lines P15 (human lung cancer cell), MGC-803 (human gastric cancer cells), SW1990 (human pancreatic cancer cells), and normal hepatocyte cell LO2 suggested that compound 1 could selectively inhibit the proliferation of cancer cell lines with IC₅₀ from 0.05 to 0.15 μM. Pro-apoptotic activity revealed that it induced the apoptosis of MGC-803 cancer cells in a dose-dependent manner. Meanwhile, treatment of MGC-803 cancer cells with 1 resulted in diminution of pro-caspases 3 and 9 and activation of caspases 3 and 9, while it increased the Bax/Bcl-2 ratio in a dose-dependent manner. These meant that 1 induced the apoptosis of cancer cells by involving the intrinsic apoptotic pathway. In addition, the cell cycle distribution of MGC-803 cancer cells treated by 1 revealed that it could lead to cell cycle arrest at the G2/M phase. Altogether, this study suggested that compound 1 may exhibit anticancer activity by its capability of induction of intrinsic apoptosis and cell cycle arrest at G2/M phase.