Cytotoxic flavonoids from the leaves of Callicarpa nudiflora hook.

A new flavonoid glycoside, luteolin-3'-O-ß-D-6″-acetyl glucopyranoside (1), along with six known flavonoids, were isolated from the leaves of Callicarpa nudiflora Hook. The structures of the isolated compounds were established on the basis of extensive spectroscopic analyses. Compound 6 exhibited potent cytotoxicity and compounds 1 and 7 exhibited moderate cytotoxicity against human hepatocellular carcinoma SMMC-7721 cells.

A new isoflavone glycoside from Abrus cantoniensis.

A new isoflavone glycoside named as 8-O-methylrelusin-7-O-ß-D-apifuranosyl-(1→2)-ß-D-glucopyranoside (1), together with two known compounds, 8-O-methylrelusin-7-O-ß-D-glucopyranoside (2) and isobiflorin (3), were isolated from Abrus cantoniensis. The structure of the new compound was elucidated on the basis of spectroscopic methods including extensive 1D NMR, 2D NMR, and HRESIMS. This is the first report of isoflavone from Abrus cantoniensis. Moreover, all isolated compounds were evaluated for their cytotoxicity against SMMC-7721 and MHCC97-H cell lines.[Formula: see text].

[A new flavonoid with an aryl moiety from Selaginella uncinata].

The present study is to investigate the chemical constituents of the whole plants of Selaginella uncinata. A new flavonoid was isolated from the 75% ethanol extract of Selaginella uncinata by column chromatographies over macroporous resin, silica gel, Sephadex LH-20 and prep-HPLC. The structure was elucidated as 8-[4-(carboxyl)phenoxy]-5,4'-dihydroxy-7-methoxyflavanone (1) and named unciflacone G.

Two new flavonoids from Selaginella uncinata.

Two new flavonoids, uncinataflavones A (1) and B (2), along with one known compound 6-(5-carboxyl-2-methoxyphenyl)-apigenin (3), were isolated from Selaginella uncinata (Desv.) Spring. All these compounds belong to apigenin derivatives with aryl substituents at C-6 position. The structures of new compounds were elucidated on the basis of comprehensive spectroscopic analyses (UV, IR, 1D, and 2D NMR as well as HR-ESI-MS).

[Flavonoids from Selaginella uncinata].

In the current study, nine flavonoids were isolated and purified from 75% ethanol extract of Selaginella uncinata (Desv.) Spring by column chromatographic techniques over macroporous resin, polyamide, silica gel, Sephadex LH-20 and pre-HPLC. On the basis of their physico-chemical properties and spectroscopic data analyses, these compounds were elucidated as cirsimarin (1), nepitrin (2), apigenin-6-C-α-L-arabinopyranosyl-8-C-ß-D-glucopyranoside (3), apigenin-6-C-ß-D-glucopyranosyl-8-C-α-L-arabinopyranoside (4), apigenin-7-O-ß-D-glucopyranoside (5), 2,3-dihydroamentoflavone (6), 4'-O-methylamentoflavone (7), 2,3-dihydro-4'-O-methyl-amentoflavone (8), and 2,3,2",3"-tetrahydron-4'-O-methyl-robustaflavone (9). Compounds 1-5 belong to flavonoid glycosides and were isolated from the genus Selaginella for the first time.

Casticin inhibits epithelial-mesenchymal transition of liver cancer stem cells of the SMMC-7721 cell line through downregulating Twist.

The existence of cancer stem cells (CSCs) is central to the pathogenesis and therapeutic target of human hepatocellular carcinoma. The aim of this study was to investigate the effects of casticin on epithelial-mesenchymal transition (EMT) of liver cancer stem cells (LCSCs) derived from the SMMC-7721 cell line. Our results demonstrated that CD133+ sphere-forming cells (SFCs) sorted from the SMMC-7721 cell line not only possessed a higher capacity to form tumor spheroids in vitro, but also had a greater potential to form tumors when implanted in Balb/c-nu mice, indicating that CD133+ SFCs possessed similar traits to LCSCs. Casticin increased the expression levels of E-cadherin and decreased those of N-cadherin in LCSCs. Treatment of LCSCs with casticin for 48 h also decreased the levels of the EMT-associated transcription factor, Twist. Overexpression of Twist attenuated the casticin-induced regulation of E-cadherin and N-cadherin protein expression, as well as the EMT capacity of LCSCs. In conclusion, CD133+ SFCs of the SMMC-7721 cell line may represent a subpopulation of LCSCs with the characteristics of EMT. Furthermore, casticin targeted LCSCs through the inhibition of EMT by downregulating Twist.

Casticin induces breast cancer cell apoptosis by inhibiting the expression of forkhead box protein M1.

Casticin is an active ingredient derived from Fructus Viticis, a traditional Chinese medicine. This study aimed to investigate the role of forkhead box O3 (FOXO3a) in breast cancer cells and examine the regulatory mechanisms of FOXO3a in response to casticin treatment of the cells by ELISA, flow cytometry, small interfering RNA (siRNA) transfection and western blot analysis. Casticin treatment induced apoptosis and reduced the expression of the transcription factor forkhead box protein M1 (FOXM1). In addition, FOXM1 repression induced by casticin treatment was associated with the activation of FOXO3a via increased dephosphorylation. Notably, silencing FOXO3a expression by siRNA-mediated gene knockdown attenuated casticin-mediated apoptosis. Collectively, these findings suggest that FOXO3a is a critical mediator of the inhibitory effects of casticin on apoptosis in breast cancer cells.

Casticin induces ovarian cancer cell apoptosis by repressing FoxM1 through the activation of FOXO3a.

Casticin, a polymethoxyflavone, is reported to have anticancer activities. The aim of the present study was to examine the molecular mechanisms by which casticin induces apoptosis in ovarian cancer cells. The human ovarian cancer cell lines SKOV3 and A2780 were cultured in vitro. Various molecular techniques, including histone/DNA enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR), western blot analysis and gene transfection, were used to assess the expression of FOXO3a and forkhead box protein M1 (FoxM1) in casticin-treated ovarian cancer cell lines. Casticin-induced apoptotic cell death was accompanied by the activation of transcription factor FOXO3a, with a concomitant decrease in the expression levels of FoxM1 and its downstream target factors, namely survivin and polo-like kinase 1 (PLK1), and an increase in p27KIP1. A small inhibitory RNA (siRNA) knockout of FoxM1 potentiated casticin-induced apoptosis in ovarian cancer cells. Silencing FOXO3a expression using siRNA increased FoxM1 expression levels and clearly attenuated the induction of apoptosis by casticin treatment. These results show that casticin-induced apoptosis in ovarian cancer may be caused by the activation of FOXO3a, leading to FoxM1 inhibition.

Casticin-induced apoptosis involves death receptor 5 upregulation in hepatocellular carcinoma cells.

AIM: To investigate the apoptotic activities of casticin in hepatocellular carcinoma (HCC) cells and its molecular mechanisms. METHODS: PLC/PRF/5 and Hep G2 cell lines were cultured in vitro and the inhibitory effect of casticin on the growth of cells was detected by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolim bromide (MTT) assay. The apoptotic cell death was examined using the cell apoptosis enzyme linked immunosorbent assay (ELISA) detection kit, flow cytometry (FCM) after propidium iodide (PI) staining and DNA agarose gel electrophoresis. The caspase activities were measured using ELISA. Reactive oxygen species (ROS) production was evaluated by FCM after dichlorodihydrofluorescein diacetate (DCFH-DA) probe labeling. Intracellular glutathione (GSH) content was measured using a glutathione assay kit. The expression of death receptor (DR)4 and DR5 proteins was analyzed by Western blotting and FCM. RESULTS: Casticin significantly inhibited the growth of human HCC (PLC/PRF/5 and Hep G2) cells in a dose-dependent manner (P < 0.05). Casticin increased the percentage of the sub-G1 population in HCC cells in a concentration-dependent manner. The potency of casticin to PLC/PRF/5 cells was higher than that of 5-flurouracil (26.8% ± 4.8% vs 17.4% ± 5.1%) at 10 µmol/L for 24 h. Casticin increased the levels of Histone/DNA fragmentation and the levels of active caspase-3, -8 and -9 in a concentration-dependent manner (P < 0.05). Treatment with 30 µmol/L casticin for 24 h resulted in the formation of a DNA ladder. Casticin reduced the GSH content (P < 0.05), but did not affect the level of intracellular ROS in PLC/PRF/5 and Hep G2 cells. The thiol antioxidants, acetylcysteine (NAC) and GSH restored GSH content and attenuated casticin-induced apoptosis. In contrast, the nonthiol antioxidants, butylated hydroxyanisole and mannitol failed to do so. In the HCC cells treated with casticin for 24 h, DR5 protein level was increased. The expression of DR5 protein induced by casticin was inhibited by NAC. Pretreatment with DR5/Fc chimera protein, a blocking antibody, effectively attenuated the induction of apoptosis by casticin. CONCLUSION: Casticin-induced apoptosis of HCC cells is involved in GSH depletion and DR5 upregulation.