Fluorinated Kavalactone Inhibited RANKL-Induced Osteoclast Differentiation of RAW264 Cells.

Bone loss and bone-related disease are associated with the deregulation of osteoclast function, and therefore agents that affect osteoclastogenesis have attracted attention. The purpose of the present study was to discover modified kavalactone analogs as potential anti-osteoclastogenic agents. We assessed the effect of 26 analogs on osteoclast differentiation in vitro. The most potent compound, (E)-6-(2-fluorostyryl)-4-methoxy-2H-pyran-2-one (22), suppressed receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenic differentiation of RAW264 cells with IC50 values of 4.3 µM. A partial structure-activity relationship study revealed the importance of fluorine and its position within the 5,6-dehydrokawain skeleton. The results of a pit formation assay suggested that compound 22 prevents osteoclastic bone resorption by inhibiting osteoclastogenesis. Moreover, compound 22 downregulated mRNA expression levels of RANKL-induced nuclear factor of activated T cells c1 (NFATc1) and osteoclastogenesis-related genes. These results suggest that (E)-6-(2-fluorostyryl)-4-methoxy-2H-pyran-2-one scaffold could lead to the identification of new anti-resorptive agents.

Alpinia zerumbet (Pers.): Food and Medicinal Plant with Potential In Vitro and In Vivo Anti-Cancer Activities.

BACKGROUND/AIM: Plants play an important role in anti-cancer drug discovery, therefore, the current study aimed to evaluate the biological activity of Alpinia zerumbet (A. zerumbet) flowers. METHODS: The phytochemical and biological criteria of A. zerumbet were in vitro investigated as well as in mouse xenograft model. RESULTS: A. zerumbet extracts, specially CH2Cl2 and MeOH extracts, exhibited the highest potent anti-tumor activity against Ehrlich ascites carcinoma (EAC) cells. The most active CH2Cl2 extract was subjected to bioassay-guided fractionation leading to isolatation of the naturally occurring 5,6-dehydrokawain (DK) which was characterized by IR, MS, 1H-NMR and 13C-NMR. A. zerumbet extracts, specially MeOH and CH2Cl2 extracts, exhibited significant inhibitory activity towards tumor volume (TV). Furthermore, A. zerumbet extracts declined the high level of malonaldehyde (MDA) as well as elevated the levels of superoxide dismutase (SOD) and catalase (CAT) in liver tissue homogenate. Moreover, DK showed anti-proliferative action on different human cancer cell lines. The recorded IC50 values against breast carcinoma (MCF-7), liver carcinoma (Hep-G2) and larynx carcinoma cells (HEP-2) were 3.08, 6.8, and 8.7 µg/mL, respectively. CONCLUSION: Taken together, these findings open the door for further investigations in order to explore the potential medicinal properties of A. zerumbet.

Methanol Extract of Aerial Parts of Pavetta indica L. Enhances the Cytotoxic Effect of Doxorubicin and Induces Radiation Sensitization in MDA-MB-231 Triple-Negative Breast Cancer Cells.

Pavetta indica L. is used in traditional medicine for the treatment of various diseases including hemorrhoids, headache, urinary conditions, ulcerated nose, and dropsy. However, no study has evaluated the anticancer effect of P. indica L. In this study, we found that a methanol extract of the leaves and branches of P. indica L. (MEPI) caused cellcycle arrest at the sub-G1 phase and induced apoptosis, as indicated by the activation of caspase-8, -3, -7, and c-PARP. Western blotting revealed that MEPI significantly reduced the levels of markers of the epithelial-mesenchymal transition, such as Vimentin, Snail, Slug, and matrix metallopeptidase 9. Notably, the expression of multidrug resistance-associated protein 1 in triple negative breast cancer (TNBC) was significantly decreased by MEPI. Moreover, the co-treatment with MEPI and doxorubicin resulted in a synergistic reduction in cell viability. MEPI also induced radiation sensitization of TNBC cells. Gas chromatography-mass spectrometry analysis revealed that 5,6-dehydrokawain (DK) is the major constituent of MEPI. Interestingly, DK exerted significant anti-invasive and anti-metastatic effects. Our results provide a strong rationale for investigating the molecular mechanisms of action of MEPI in TNBC.

Synthesis of novel 5,6-dehydrokawain analogs as osteogenic inducers and their action mechanisms.

An imbalance between bone resorption by osteoclasts and bone formation by osteoblasts can cause bone loss and bone-related disease. In a previous search for natural products that increase osteogenic activity, we found that 5,6-dehydrokawain (1) from Alpinia zerumbet promotes osteoblastogenesis. In this study, we synthesized and evaluated series of 5,6-dehydrokawain analogs. Our structure-activity relationships revealed that alkylation of para or meta position of aromatic ring of 1 promote osteogenic activity. Among the potential analogs we synthesized, (E)-6-(4-Ethylstyryl)-4-methoxy-2H-pyran-2-one (14) and (E)-6-(4-Butylstyryl)-4-methoxy-2H-pyran-2-one (21) both significantly up-regulated Runx2 and Osterix mRNA expression at 10µM. These osteogenic activities could be mediated by bone morphogenetic protein (BMP) and activation of p38 MAPK signaling pathways. Compounds 14 and 21 also inhibited RANKL-induced osteoclast differentiation of RAW264 cells. These results indicated that novel 5,6-dehydrokawain analogs not only increase osteogenic activity but also inhibit osteoclast differentiation, and could be potential lead compounds for the development of anti-osteoporosis agents.

5,6-Dehydrokawain from Alpinia zerumbet promotes osteoblastic MC3T3-E1 cell differentiation.

Bone homeostasis is maintained by balancing bone formation and bone resorption, but an imbalance between them is associated with various bone-related diseases such as osteoporosis and rheumatoid arthritis. We found that 5,6-dehydrokawain (DK) and dihydro-5,6-dehydrokawain (DDK), which were isolated as promising compounds from Alpinia zerumbet rhizomes, promote differentiation of osteoblastic MC3T3-E1 cells. DK and DDK increased the alkaline phosphatase activity and matrix mineralization of MC3T3-E1 cells. DK exerts larger effects than DDK. The gene expression of runt-related transcription factor 2 and osterix, which are essential transcription factors in the early period of osteoblast differentiation, was significantly increased by DK treatment. The mRNA level of distal-less homeobox 5 was also enhanced by DK treatment, and DK activated the p38 mitogen-activated protein kinase pathway. Therefore, DK may have clinical potential for preventing osteoporosis, and could be considered as a potential anabolic therapeutic agent.

Advanced glycation end products inhibitors from Alpinia zerumbet rhizomes.

Advanced glycation end products (AGEs) are major factors responsible for the complication of diabetes. The present study was carried out to investigate the inhibitory activities on fructosamine adduct and α-dicarbonyl formations by hexane extracts of various parts of Alpinia zerumbet. Furthermore, we isolated two previously known compounds, namely 5,6-dehydrokawain (DK) and dihydro-5,6-dehydrokawain (DDK). 8(17),12-Labdadiene-15,16-dial (labdadiene) was isolated for the first time from the rhizome of A. zerumbet. The results showed that labdadiene (IC50=51.06µg/mL) had similar activity to rutin and quercetin against fructosamine adduct. The inhibition of α-dicarbonyl compounds formation by labdadiene was significantly higher than that of DK and DDK. Our results indicate that labdadiene is a potent antiglycation agent which was found to inhibit AGEs formation in three different steps in the pathway. These data indicate that labdadiene could be used to prevent glycation-associated complications in diabetes.

5,6-dehydrokawain from the rhizome of Alpinia mutica Roxb. induced proangiogenic tumour-derived VEGF of HT-29 colorectal cancer.

Vascular endothelial growth factor (VEGF) is a glycoprotein vital to the regulation of vascular endothelial cells proliferation, migration and angiogenesis. The expression of VEGF is required for the formation of new blood vessels critical in supplying oxygen and nutrition in the course of tumorigenesis. The present study investigated the effect of 5,6-dehydrokawain isolated from the rhizomes of Alpinia mutica on VEGF expression in vitro using HT-29 cell line. The results revealed that 5,6-dehydrokawain induced the expression of proangiogenic tumour-derived VEGF of HT-29 cells, which may explain the inability of 5,6-dehydrokawain in suppressing cancer cells proliferation.

Synthesis and anti-neuroinflammatory activity of lactone benzoyl hydrazine and 2-nitro-1-phenyl-1h-indole derivatives as p38α MAPK inhibitors.

Inhibition of p38 mitogen-activated protein kinases (MAPKs) would allow significant modulation of the neuroinflammation condition associated with Alzheimer's disease (AD). Inspired from the pharmacophore of natural NF-κB and p38α MAPK inhibitor 5,6-dehydrokawain and p38α MAPK inhibitors 1a, 1-pyrazolyl-3-(4-((2-anilinopyrimidin-4-yl)oxy)napththalen-1-yl)ureas, and 1b, a class of indole-pyrimidinyl compounds which were patented respectively, we designed, de novo synthesized, and evaluated two kinds of novel series of lactone benzoyl hydrazine derivatives and 2-nitro-1-phenyl-1H-indole derivatives in an effort to develop pharmacologically tractable agents to alleviate the progression of AD. Fourteen of the seventeen synthesized compounds exhibit significant inhibitory effect on the nitric oxide (NO) production induced by lipopolysaccharide (LPS)-induced microglia activation with IC50 less than the control 5,6-dehydrokawain. Notably, compound 27, 6-methoxy-2-nitro-1-(1H-1, 2, 3-triazol-1-yl)-1H-indole, with IC50 values of 1.6 µm can markedly inhibit p38α MAPK and NO release in BV-2 microglial cells. The molecular dynamic (MD) simulations demonstrate that compound 27 inhibits p38α MAPK through binding to the Glu71 and Asp168 residues. Moreover, in vitro study shows that all compounds can easily cross the blood-brain barrier (BBB) and did not exhibit any acute cellular toxicity checked by MTT assay. These investigations provide promising chemical lead candidate as anti-neuroinflammatory agents for AD.