Citreorosein

Citreorosein inhibits production of proinflammatory cytokines by blocking mitogen activated protein kinases, nuclear factor-kappaB and activator protein-1 activation in mouse bone marrow-derived mast cells.[Pubmed:22687535]

Biol Pharm Bull. 2012;35(6):938-45.

Citreorosein (CIT), an anthraquinone component of Polygoni cuspidati (P. cuspidati) radix, suppressed gene expression of proinflammatory cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-1beta in mouse bone marrow-derived mast cells (BMMCs) stimulated with phorbol 12-myristate 13-acetate (PMA) plus the calcium ionophore A23187. To investigate the molecular mechanisms underlying CIT inhibition of the pro-inflammatory cytokine production, its effects on the activation of both nuclear factor-kappaB (NF-kappaB) and mitogen-activated protein kinases (MAPKs) were assessed. CIT attenuated phosphorylation of the MAPKs including extracellular signal-regulated kinase 1/2 (ERK1/2), p38 MAP kinase and c-Jun NH(2)-terminal kinase (JNK). Furthermore, CIT strongly inhibited DNA binding activity of NF-kappaB through the inhibition of phosphorylation and degradation of inhibitor of kappaB (IkappaB) as well as activator protein-1 (AP)-1 through the reduction of phosphorylation of c-Jun. These results demonstrate that CIT inhibits proinflammatory cytokines production through the inhibition of both MAPKs and AKT-mediated IkappaB kinase (IKK) phosphorylation and subsequent inhibition of transcription factor NF-kappaB activation, thereby attenuating the production of proinflammatory cytokines.

Citreorosein inhibits degranulation and leukotriene C(4) generation through suppression of Syk pathway in mast cells.[Pubmed:22395859]

Mol Cell Biochem. 2012 Jun;365(1-2):333-41.

The aim of this study was to evaluate whether Citreorosein (CIT), a naturally occurring anthraquinone isolated from Polygoni cuspidati (P. cuspidati) radix, modulates degranulation and 5-lipoxygenase (5-LO)-dependent leukotriene C(4) (LTC(4)) generation in mast cells. Cit suppresses both degranulation and the generation of LTC(4) in a dose-dependent manner in stem cell factor (SCF)-mediated mouse bone marrow-derived mast cells (BMMCs). With regard to its molecular mechanism of action, we investigated the effects of CIT on intracellular signaling and mast cell activation employing BMMCs. Binding of SCF to c-Kit on mast cell membranes induced increases in intrinsic tyrosine kinase Syk activity and activation of multiple downstream events including phosphorylation of phospholipase Cgamma (PLCgamma), mobilization of intracellular Ca(2+), phosphatidylinositol 3-kinase (PI3K), Akt, MAP kinases (MAPKs), translocation of phospho-phospholipase A(2) (PLA(2)) and 5-LO. The results from the biochemical analysis demonstrate that CIT attenuates degranulation and LTC(4) generation through the suppression of multiple step signaling and would be beneficial for the prevention of allergic inflammation.

Citreorosein, a naturally occurring anthraquinone derivative isolated from Polygoni cuspidati radix, attenuates cyclooxygenase-2-dependent prostaglandin D2 generation by blocking Akt and JNK pathways in mouse bone marrow-derived mast cells.[Pubmed:22154852]

Food Chem Toxicol. 2012 Mar;50(3-4):913-9.

In this study, we examined the effects of Citreorosein (CIT), an anthraquinone component of Polygoni cuspidati radix (P. cuspidati, Polygonaceae), on cyclooxygenase (COX)-2 dependent prostaglandin (PG)D2 generation in mast cells, central effector cells of allergy and other inflammatory diseases. CIT strongly inhibited COX-2-dependent PGD2 generation in a concentration-dependent manner in mouse bone marrow-derived mast cells (BMMCs) stimulated with stem cell factor (SCF)/IL-10/LPS. In an effort to identify the mechanisms underlying the inhibition of COX-2-dependent PGD2 generation by CIT, we examined the effects of this compound on MAP kinases, Akt and NF-kappaB signaling pathways, which are essential for COX-2 induction. CIT inhibited nuclear translocation of the nuclear factor (NF)-kappaB p65 subunit and its cognate DNA-binding activity, which correlated with its inhibitory effects on the phosphorylation of Akt and IKK and subsequent phosphorylation and degradation of IkappaB. Furthermore, CIT significantly attenuated the DNA binding of activator protein (AP)-1 that regulates COX-2 expression through the reduction of the phosphorylation of c-Jun. Moreover, inhibition of PGD2 generation by CIT was accompanied by a decrease in phosphorylation of cytosolic phospholipase A2alpha. Taken together, the present study suggests that CIT represents a potential therapeutic approach for the treatment of inflammatory diseases.

A facile synthesis of emodin derivatives, emodin carbaldehyde, citreorosein, and their 10-deoxygenated derivatives and their inhibitory activities on mu-calpain.[Pubmed:22477191]

Arch Pharm Res. 2012 Mar;35(3):447-54.

A new procedure for the preparation of emodin carbaldehyde and Citreorosein was described, in which, omega,omega'-dibromomethylemodin triacetate was prepared as a key intermediate by NBSmediated bromination of 1,3,8-triacetylemodin. Reduction of emodin and Citreorosein with SnCl(2) in a 1:1 mixture of HOAc and HCl afforded the corresponding anthrones in 90% and 92% yield, respectively, while the corresponding 10-desoxyemodin carbaldehyde was prepared by MnO(2) oxidation of 10-desoxyCitreorosein. 10-DesoxyCitreorosein and emodin carbaldehyde showed feasible mu-calpain inhibitory activities with IC(50) values of 20.15 and 25.77 M, respectively.