Cacao extracts suppress tryptophan degradation of mitogen-stimulated peripheral blood mononuclear cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The fruits of Theobroma cacao L. (Sterculiaceae) have been used as food and a remedy for more than 4000 years. Today, about 100 therapeutic applications of cacao are described involving the gastrointestinal, nervous, cardiovascular and immune systems. Pro-inflammatory cytokine interferon-gamma and related biochemical pathways like tryptophan degradation by indoleamine 2,3-dioxygenase and neopterin formation are closely associated with the pathogenesis of such disorders. AIM OF THE STUDY: To determine the anti-inflammatory effect of cacao extracts on interferon-gamma and biochemical consequences in immunocompetent cells. MATERIALS AND METHODS: Effects of aqueous or ethanolic extracts of cacao were examined on mitogen-induced human peripheral blood mononuclear cells (PBMC) of healthy donors and on lipopolysaccharide-stimulated myelomonocytic THP-1 cells. Antioxidant activity of extracts was determined by oxygen radical absorption capacity (ORAC) assay. RESULTS: In mitogen-stimulated PBMC, enhanced degradation of tryptophan, formation of neopterin and interferon-gamma were almost completely suppressed by the cacao extracts at doses of > or = 5 microg/mL. Cacao extracts had no effect on tryptophan degradation in lipopolysaccharide-stimulated THP-1 cells. CONCLUSIONS: There is a significant suppressive effect of cacao extracts on pro-inflammatory pathways in activated T-cells. Particularly the influence on indoleamine 2,3-dioxygenase could relate to some of the beneficial health effects ascribed to cacao.

PADMA 28 modulates interferon-gamma-induced tryptophan degradation and neopterin production in human PBMC in vitro.

Tibetan herbal remedy PADMA 28 revealed promising results to support treatment of intermittent claudication, atherosclerosis and chronic hepatitis. The remedy was confirmed to be closely linked with anti- and pro-oxidative properties in vitro. In this study, effect of PADMA 28 was investigated in stimulated and unstimulated human peripheral blood mononuclear cells (PBMC) in vitro. Neopterin production and tryptophan degradation were measured in supernatants of PBMC in the presence or absence of mitogens phytohaemagglutinin (PHA) and concanavalin A (Con A). Stimulation of PBMC induced neopterin formation and tryptophan degradation (p<0.001 compared to unstimulated PBMC), and PADMA 28 inhibited both immunobiochemical effects (p<0.001) in a concentration-dependent manner. Higher concentrations of PADMA 28 were more effective and were able to completely block the pathways induced upon mitogenic stimulation. Data allow to conclude that PADMA 28 is able to inhibit immunobiological effects in stimulated PBMC in vitro. The suppression of neopterin production and tryptophan degradation suggests a specific influence on biochemical pathways induced by Th1-type cytokine interferon-gamma.

The protein kinase C inhibitor ilmofosine (BM 41 440) arrests cells in G2 phase and suppresses CDC2 kinase activation through a mechanism different from that of DNA damaging agents.

The thioether phospholipid derivative ilmofosine (BM41440), a selective inhibitor of protein kinase C, is a new anticancer drug presently undergoing Phase II clinical trials. We have examined the influence of the compound on cell cycle progression. Ilmofosine was found to induce a dose-dependent accumulation of CA46 cells in G2-phase of the cell cycle. G2-arrest correlated with suppression of cdc2 kinase activation. Ilmofosine did not affect cdc2 kinase activity in vitro, consistent with an indirect locus of action. Ilmofosine treated CA46 cells failed to accumulate hyperphosphorylated-cdc2/cyclin B1 complexes that are observed when G2-arrest is induced by either nitrogen mustard or ionizing radiation. Indeed, cdc2 became dephosphorylated and cyclin B1 protein levels decreased as ilmofosine treated cells became arrested in G2. Our findings suggest that ilmofosine down-regulates cdc2 kinase activation through a mechanism that affects the formation of cdc2/cyclin B1 complexes.

B-859-35, a new drug with anti-tumor activity reverses multi-drug resistance.

It has previously been shown that B-859-35 ((-)-3-methyl-5- 3-(4,4-diphenyl-l-piperidinyl)-propyl-l,4-dihydro- 2,6-dimethyl-4-(3-nitrophenyl)-pyridine-3,5-dicarboxylate-hydrochloride) exerts a selective carcinostatic effect on some tumors. In order to evaluate whether the anti-cancer activity of B-859-35 can be modulated, we combined the new drug with several established anti-tumor drugs. A combination of B-859-35 with VP-16 (etoposide) in MDR(multi-drug-resistant-gene)-expressing Walker rat carcinoma cells shows synergism. A combination of B-859-35 with doxorubicin results in stronger synergism than verapamil/doxorubicin, especially at low concentrations of B-859-35. The resistance of mdrl(human multi-drug-resistance-gene)-expressing human HeLa KB-8-5 cells to doxorubicin can be reversed with non-toxic or weakly toxic concentrations of B-859-35 to the sensitivity of the parent KB-3-l cells. The finding that an anti-tumor drug is able to reverse multi-drug resistance makes B-859-35 an interesting drug for cancer treatment.

Synergistic enhancement of the antiproliferative activity of cis-diamminedichloroplatinum(II) by the ether lipid analogue BM41440, an inhibitor of protein kinase C.

The new phospholipid analogue 3-hexadecylmercapto-2-methoxy-methyl-propyl-1-phosphocholine inhibits the phospholipid-calcium-dependent protein kinase, partially purified from Walker carcinoma cells with a Ki value of 0.56 microM. The compound inhibits the phorbol ester stimulated phosphorylation of the ribosomal protein S6 indicating that the depression of Ca2+-phospholipid-dependent protein kinase by the alkyl phospholipid also occurs in intact cells. The dose effect curve for the inhibition of cell proliferation by 3-hexadecylmercapto-2-methoxy-methyl-propyl-1-phosphocholine in Walker cells exhibits a close correlation to the dose effect curve for the depression of Ca2+-phospholipid-dependent protein kinase activity. Although alternative mechanisms cannot be excluded, the data suggest that the growth inhibitory activity of 3-hexadecylmercapto-2-methoxy-methyl-propyl-1-phosphocholine correlates with the inhibition of Ca2+-phospholipid-dependent protein kinase. The antiproliferative activity of 3-hexadecylmercapto-2-methoxy-methyl-propyl-1-phosphocholine is synergistically enhanced by cis-diamminedichloroplatinum(II).