Superior anticancer activity is demonstrated by total extract of Curcuma longa L. as opposed to individual curcuminoids separated by centrifugal partition chromatography.

Three curcuminoids: bisdemethoxycurcumin, demethoxycurcumin, and curcumin from turmeric were successfully separated by a high capacity solvent system composed of heptane: chloroform: methanol: water mixture (5: 6: 3: 2 v/v/v/v) tailored for centrifugal partition chromatographs at K-values of 0.504, 1.057, 1.644, respectively. These three ferulic acid derivatives obtained at a purity rate exceeding 95% were analysed by an HPLC-MS spectrometer. Turmeric extract inhibited the proliferation/viability of A549 human lung cancer, HT29 colon cancer, and T98G glioblastoma cell lines in (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay (MTT). Single curcuminoids significantly decreased the viability/proliferation of lung cancer cells in a dose-dependent manner. However, total extract displayed the superior anticancer activity in the investigated cell lines. Crude extract in combination with cisplatin augmented the decrease in the viability of cancer cells compared with single compound treatment in A549 lung cancer cells. Total extract of Curcuma longa could be regarded as being more effective against lung cancer cells in vitro than its separated compounds.

9,10-dihydro-2,5-dimethoxyphenanthrene-1,7-diol, from Eulophia ochreata, inhibits inflammatory signalling mediated by Toll-like receptors.

BACKGROUND AND PURPOSE: 9,10-Dihydro-2,5-dimethoxyphenanthrene-1,7-diol (RSCL-0520) is a phenanthrene isolated from Eulophia ochreata, one of the Orchidaceae family, known by local tradition to exhibit medicinal properties. However, no anti-inflammatory activity or any molecular mechanisms involved have been reported or elucidated. Here, for the first time, we evaluate the anti-inflammatory properties of RSCL-0520 on responses induced by lipopolysaccharide (LPS) and mediated via Toll-like receptors (TLRs). EXPERIMENTAL APPROACH: The in vitro anti-inflammatory activities of RSCL-0520 were investigated in LPS-stimulated monocytic cells, measuring activation of cytokine and inflammatory genes regulated by nuclear factor-kappaB (NF-kappaB). Tumour necrosis factor (TNF)-alpha levels in serum following LPS stimulation in mice and carrageenan-induced paw oedema in rats were used as in vivo models. KEY RESULTS: Pretreatment with RSCL-0520 effectively inhibited LPS-induced, TLR4-mediated, NF-kappaB-activated inflammatory genes in vitro, and reduced both LPS-induced TNF-alpha release and carrageenan-induced paw oedema in rats. Treatment with RSCL-0520 reduced LPS-stimulated mRNA expression of TNF-alpha, COX-2, intercellular adhesion molecule-1, interleukin (IL)-8 and IL-1beta, all regulated through NF-kappaB activation. RSCL-0520, however, did not interfere with any cellular processes in the absence of LPS. CONCLUSIONS AND IMPLICATIONS: RSCL-0520 blocked signals generated by TLR4 activation, as shown by down-regulation of NF-kappaB-regulated inflammatory cytokines. The inhibitory effect involved both MyD88-dependent and -independent signalling cascades. Our data elucidated the molecular mechanisms involved, and support the search for plant-derived TLR antagonists, as potential anti inflammatory agents.

Novel synthetic gluco-disaccharide RSCL-0409--a lipopolysaccharide-induced Toll-like receptor-mediated signalling antagonist.

The regulation of cytokines and pro-inflammatory genes is an absolute essentiality to combat inflammatory diseases. The present study investigated the effects of 4-O-chloroacetyl-2,3-di-O-acetyl-6-O-levulinoyl-beta-d-glucopyranosyl]-(1-3)-1-O-(p-methoxyphenyl)-2-deoxy-2-N-trichloroacetyl-4,6-O-benzylidene-alpha-d-glucopyranoside (RSCL-0409), a novel small molecule Toll-like receptor (TLR) signalling antagonist, and its mechanism of action in human monocytic (THP-1) cells stimulated with lipopolysaccharide (LPS). In THP-1 and RAW264.7 cells, RSCL-0409 suppressed LPS-induced production of tumour necrosis factor-alpha (TNF-alpha) with a 50% inhibitory concentration of 10.6 mum and mRNA expression of ICAM-1, Cox-2 and interleukin-8 with no evidence of cytotoxicity. RSCL-0409 also suppressed TNF-alpha production from LPS-stimulated human peripheral blood mononuclear cells. Similar results were obtained in vivo in a murine model of LPS-induced inflammation, where pretreatment with RSCL-0409 resulted in significant inhibition of TNF-alpha. It is also noteworthy that RSCL-0409 suppressed the cytokine production induced by TLR2 and -4 ligands and not for any other TLR ligands. RSCL-0409 significantly inhibited p65 nuclear translocation induced by LPS. In conclusion, RSCL-0409, a novel small molecule, is the first of its kind in the category of carbohydrate-derived TLR signalling antagonists and could definitely be a promising therapeutic agent for inflammatory diseases whose pathogenesis involves TLR2- or TLR4-mediated signalling processes.

Nitric oxide protects against chloroquine resistant Plasmodium yoelii nigeriensis parasites in vitro.

Malaria is a life-threatening disease of global concern. The role of nitric oxide in the clearance of malarial parasites is still under debate. Several reports suggest a possible role for nitric oxide in the protection during initial stages of malarial infection. In the present study, we demonstrate that the nitric oxide in combination with low concentrations of chloroquine controls the parasitaemia in vitro. Activated peritoneal macrophages co-cultured with lipopolysaccharide+interferon-gamma or extracts from Tenospora cordifolia as an immunomodulator promoted nitric oxide production by macrophages. The high concentration of nitric oxide in combination with sub-optimal chloroquine suppressed the parasitaemia in the chloroquine resistant malarial infection. Further, the nitric oxide synthase inhibitor, N(G)-mono-methyl-l-arginine, downregulated nitric oxide production by peritoneal macrophages and the resulting levels of parasitaemia were higher, similar to those of untreated controls. These findings support the proposition that nitric oxide has a crucial role in the control of parasitaemia at the initial periods of blood stage malarial infection.