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The present study aims at the isolation and identification of diverse phenolic polyketides from Aloe vera (L.) Burm.f. and Aloe plicatilis (L.) Miller and includes their 5-LOX/COX-1 inhibiting potency. After initial Sephadex-LH20 gel filtration and combined silica gel 60- and RP18-CC, three dihydroisocoumarins (nonaketides), four 5-methyl-8- C -glucosylchromones (heptaketides) from A. vera, and two hexaketide-naphthalenes from A. plicatilis have been isolated by means of HSCCC. The structures of all polyketides were elucidated by ESI-MS and 2D 1 H/ 13 C-NMR (HMQC, HMBC) techniques. The analytical/preparative separation of 3 R -feralolide, 3'- O -β-d-glucopyranosyl- and the new 6- O -β-d-glucopyranosyl-3 R -feralolide into their respective positional isomers are described here for the first time, including the assignment of the 3 R -configuration in all feralolides by comparative CD spectroscopy. The chromones 7- O -methyl-aloesin and 7- O -methyl-aloeresin A were isolated for the first time from A. vera, together with the previously described aloesin (syn. aloeresin B) and aloeresin D. Furthermore, the new 5,6,7,8-tetrahydro-1- O -β-d-glucopyranosyl- 3,6 R -dihydroxy-8 R -methylnaphtalene was isolated from A. plicatilis, together with the known plicataloside. Subsequently, biological-pharmacological screening was performed to identify Aloe polyketides with anti-inflammatory potential in vitro. In addition to the above constituents, the anthranoids (octaketides) aloe emodin, aloin, 6'-( E )-p-coumaroyl-aloin A and B, and 6'-( E )-p-coumaroyl-7-hydroxy-8- O -methyl-aloin A and B were tested. In the COX-1 examination, only feralolide (10 µM) inhibited the formation of MDA by 24%, whereas the other polyketides did not display any inhibition at all. In the 5-LOX-test, all aloin-type anthranoids (10 µM) inhibited the formation of LTB 4 by about 25-41%. Aloesin also displayed 10% inhibition at 10 µM in this in vitro setup, while the other chromones and naphthalenes did not display any activity. The present study, therefore, demonstrates the importance of low molecular phenolic polyketides for the known overall anti-inflammatory activity of Aloe vera preparations. more...

3-Indolyl and 3-azaindolyl-4-aryl maleimide derivatives, called moguntinones (MOG), have been selected for their ability to inhibit protein kinases associated with angiogenesis and induce apoptosis. Here, we characterize their mode of action and their potential clinical value in human colorectal cancer in vitro and in vivo. MOG-19 and MOG-13 were characterized in vitro using kinase, viability, and apoptosis assays in different human colon cancer (HT-29, HCT-116, Caco-2, and SW480) and normal colon cell lines (CCD-18Co, FHC, and HCoEpiC) alone or in combination with topoisomerase I inhibitors. Intracellular signaling pathways were analyzed by Western blotting. To determine their potential to inhibit tumor growth in vivo, the human HT-29 tumor xenograft model was used. Moguntinones prominently inhibit several protein kinases associated with tumor growth and metastasis. Specific signaling pathways such as GSK3β and mTOR downstream targets were inhibited with IC(50) values in the nanomolar range. GSK3β signaling inhibition was independent of KRAS, BRAF, and PI3KCA mutation status. While moguntinones alone induced apoptosis only in concentrations >10 μmol/L, MOG-19 in combination with topoisomerase I inhibitors induced apoptosis synergistically at lower concentrations. Consistent with in vitro data, MOG-19 significantly reduced tumor volume and weight in combination with a topoisomerase I inhibitor in vivo. Our in vitro and in vivo data present significant proapoptotic, antiangiogenic, and antiproliferative effects of MOG-19 in different human colon cancer cells. Combination with clinically relevant topoisomerase I inhibitors in vitro and xenograft mouse model demonstrate a high potency of moguntinones to complement and improve standard chemotherapy options in human colorectal cancer., (©2014 American Association for Cancer Research.) more...

FLT3 kinase has become an attractive drug target in AML with up to 30% of cases harboring internal-tandem-duplication (ITD) mutations. For these, conferring a worse prognosis and decreased overall survival, several FLT3 tyrosine kinase inhibitors (TKIs) are currently being tested in clinical trials. However, when using these drugs as monotherapy, the problem of short duration of remissions and high incidence of TKI resistance has emerged. Here, we investigated two members of a novel class of tyrosine kinase inhibitors, 3,4-diarylmaleimides, for their efficacy on mutated FLT3 kinase. These compounds inhibit FLT3 kinase in an ATP-competitive manner and effectively inhibit phosphorylation of downstream targets. 3,4-Diarylmaleimides (DHF125 and 150) induce apoptosis in FLT3-ITD-dependent cells lines and patient blasts at low micromolar concentrations. They are retained in the cytoplasm of exposed cells for more than 24 h and synergize with chemotherapy and midostaurin. Both 3,4-diarylmaleimides show inhbition of FLT3-ITD-related kinase autophosphorylation at distinct tyrosine residues when compared to midostaurin. In conclusion, this novel group of compounds shows differential inhibition patterns with regard to FLT3 kinase and displays a promising profile for further clinical development. Currently, experiments evaluating toxicity in murine models and unraveling the exact binding mechanism are under way to facilitate a potential clinical application. more...

Background: The invasion of cancer cells is critical for metastasis. The effects of Eclipta prostrata, a Thai medicinal plant, on invasion, migration and adhesion of cancer cells were investigated and the anti-angiogenic activity in vivo was evaluated., Materials and Methods: In vitro invasion and migration assays were performed in modified Boyden chambers. In vivo anti-angiogenic activity was determined using the chick chorioallantoic membrane (CAM) assay., Results: E. prostrata juice inhibited cancer invasion and migration, without affecting cell adhesion. Cell migration was inhibited in a variety of cancer cell types and in endothelial cells, with IC50 values of 31-70 microg/ml, much lower than the IC50 values for cytotoxicity of 203-1,217 microg/ml for cancer cells and >4,000 microg/ml for endothelial cells. Fifty percent inhibition of angiogenesis by E. prostrata juice was observed at 200 microg/egg., Conclusion: E. prostrata juice inhibited cancer and endothelial cell migration in vitro and also showed in vivo anti-angiogenic activity. more...

We report on a facile and rapid computerized in-vitro assay for the quantification of leukocyte adhesion to endothelial cells under static conditions using bovine polymorphonuclear neutrophils (PMN) or human leukaemic Mono Mac 6 cells (MM6) and bovine aorta endothelial cells (BAEC). Images of leukocytes adherent to BAEC monolayers grown in microtiter plates were obtained by a digital camera attached to a conventional microscope and transferred to the public domain NIH ImageJ program for analysis. Using individually adapted program routines adherent leukocytes are easily discriminated and reproducibly quantified. The results obtained with our assay correspond to previous findings and demonstrate the suitability of the described procedure, which can easily be adapted to further standards as proven by the use of two different leukocyte species. This assay lends itself to the screening of pharmacological substances with different mechanism of action that might act on either leukocytes or endothelial cells. more...

A number of pathological events in humans such as solid tumour growth and metastasis have been found to be associated with angiogenesis, the formation of new blood vessels front pre-existing vasculature. A novel approach in cancer treatment consists of blocking or delaying the progression of neovascularisation to dysplastic cells in order to stop delivery of nutrients and oxygen. Thus, agents with antiangiogenic activity may be useful to treat cancer with potentially less systemic toxicity than conventional cytotoxic therapeutics. In this study we report the development and validation of a modified quantitative and objective in vivo chick embryo assay with Digital Image Analysis to screen compounds for antiangiogenic activity. The evaluation of vascular responses was optimised to less than one minute per sample in order to make this automatic method suitable for larger experimental series. Significant activity of the known antiangiogenic compounds thalidomide and captopril was determined, which resulted in approximately 50% inhibition of the vessel area compared to the control. The stability and release of thalidomide and captopril within 48 h after application to the extraembryonic vessel system was monitored by HPLC analysis. In conclusion, this multiple target test system will be complementary to existing angiogenesis assays and may be useful to quantify the antiangiogenic activity of compounds. more...