Determination of glycemic index value of Naturo fruit bars.

AIM AND OBJECTIVE: The glycemic response to Naturo fruit bar that is commercially available in India was determined against a glucose sta dard in a non-blind, repeated measure, crossover design trial. METHODS: Eleven healthy subjects (mean age 37.3 (SD 5.5) years and mean BMI 213 (SD 36) kg/m2) were recruited to the study. Subjects were given Naturo fruit bar and a standard food (glucose), on separate occasions, each containing 50 grams carbohydrate. Blood glucose was determined after overnight fasting (0 hours) and at 30, 60, 90 and 120 min after the consumption of each test food. For Naturo fruit bar, the glycemic index (GI) value was calculated geometrically by expressing the incremental area under the blood glucose curve (iAUC) as a percentage of each subject's average iAUC for the standard food. RESULTS: The GI value of Naturo fruit bar was found to be 38.50. As per the Food and Agriculture Organization, GI cut-off values are as follows: low <55; medium 56-69 inclusive, high >70. Therefore Naturo fruit bar could be classified under low glycemic food/nutrient. CONCLUSION: Considering the widespread consumption of fruits/bars in India, this information is valuable for people who prefer to use low glycemic food which offer many beneficial effects because their consumption significantly reduces the GI of the diets of the Indian population.

Effect of Terminalia arjuna extract on adriamycin-induced DNA damage.

The effect of a bark extract of Terminalia arjuna (TAE) was studied on the alteration of adriamycin (ADR)-induced micronuclei formation in cultured human peripheral blood lymphocytes. Exposure of lymphocytes to ADR resulted in a dose-dependent increase in the micronuclei formation indicating DNA damage. Pretreatment of lymphocytes with TAE before ADR treatment resulted in a significant decline in micronuclei formation. Increasing doses of ADR caused a dose-dependent increase in the frequency of lymphocytes bearing one, two and multiple micronuclei. Prior exposure of lymphocytes to 15 microg/mL of TAE significantly reduced the frequency of lymphocytes bearing one, two and multiple micronuclei when compared with ADR-treated control. TAE-inhibited the induction of (*)OH (hydroxyl), O2(*-) (superoxide), DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS(*+) (2,2-azino-bis-3-ethyl benzothiazoline-6-sulphonic acid) radicals in a dose-dependent manner. These results demonstrate that TAE protects DNA against ADR-induced damage.

All-trans-retinoic acid-induced apoptosis in human medulloblastoma: activation of caspase-3/poly(ADP-ribose) polymerase 1 pathway.

Current treatments for childhood brain tumor medulloblastoma (MB), radiation and chemotherapy, lead to undesirable side effects. Identification of antitumor agents that reduce the toxicity will thus have significant therapeutic value. In this study, we investigated all-trans-retinoic acid (ATRA) as an antitumor agent. Although high concentrations (1-10 microM) of retinoic acid derivatives are generally needed for significant antitumor effects in many cancer cells, we observed that pharmacologically relevant concentrations of ATRA were effective in inducing cell death in human MB cells. Using 10-fold lower concentrations (100-500 nM), we found that ATRA inhibits MB (DAOY, D283, D425, and D458) cell proliferation as determined by cell viability [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and bromodeoxyuridine incorporation assays. Furthermore, 100 nM ATRA was potent in inhibiting the anchorage-independent growth of the sensitive cell lines (D283, D425, and D458) in soft agar assays. We also demonstrate that the ATRA-induced decrease in cell viability was due to increased cell death by apoptosis, which was accompanied by a 20-fold induction of caspase-3 activity in the most sensitive cell line, D458. By contrast, induction of caspase-3 was only 2-fold in the relatively insensitive DAOY cells. Furthermore, ATRA-induced cell death in D283, D425, and D458 cells was accompanied by activation of caspase-3, a key executioner of apoptosis. We also demonstrate that activated caspase-3 resulted in cleavage of 116-kDa poly(ADP-ribose) polymerase 1 to its signature fragments (85 and 29 kDa). Pretreatment with a specific caspase-3 inhibitor, DEVD-CHO, significantly reduced ATRA-induced apoptotic cell death. Thus, we demonstrate for the first time that low concentrations of ATRA inhibit MB cell proliferation and induce apoptotic cell death in part by activating caspase-3/poly(ADP-ribose) polymerase 1 effector pathway, and we show that retinoic acids and novel retinoids are potential antitumor agents in MB therapy.

Overexpression of cyclooxygenase-2 (COX-2) in human primitive neuroectodermal tumors: effect of celecoxib and rofecoxib.

In this study the role of cyclooxygenase-2 (COX-2) in primitive neuroectodermal tumor (PNET) the most malignant brain tumors of childhood was investigated. COX-2 expression in human brain tumor biopsy samples (seven/seven) was about 6-8-fold higher than normal brain tissue and several PNET cell lines also express COX-2. The effect of selective COX-2 inhibitors, celecoxib and rofecoxib on the growth of two PNET cell lines (DAOY and PFSK) was determined. Celecoxib was more potent than rofecoxib in suppressing cell growth. Growth inhibition by celecoxib and rofecoxib was independent of Bcl-2 expression. Celecoxib suppressed the expression of Akt and activated the caspase-3 in DAOY and PFSK, whereas rofecoxib did not have such an effect.

Anti-proliferative effects of 20-epi-vitamin-D3 analogue, KH1060 in human neuroblastoma: induction of RAR-beta and p21(Cip1).

We determined the in vitro biological activities of 1 alpha, 25-dihdroxyvitamin D(3) (1,25-D(3)) and its analogue, 20-epi-22-oxa-24a, 26a, 27a-trihomo-1 alpha, 25 (OH)(2) vitamin D(3) (KH1060) in six human neuroblastoma (NB) cell lines (SH-SY5Y, NB69, SK-N-AS, IMR5, CHP-134, NGP). The ability of these compounds to inhibit cell growth and DNA synthesis was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and BrdU incorporation, respectively. The induction of cell death was monitored by caspase-3 activity. Their antineoplastic effect was assessed by clonal proliferation in soft agar. KH1060 was more effective than 1,25 D(3) in inhibiting cell growth and DNA synthesis. The IC-(50) (inhibition of 50% cell viability) indicated that KH1060 was about 10-20-fold more potent than 1,25 D(3). This growth inhibition was also accompanied by induction of caspase-3 activity, indicating that these compounds induce cell death in a caspase-dependent fashion. Moreover, KH1060 exerted potent antineoplastic activity by suppressing the clonal proliferation of the six NB cells. For the first time we demonstrate that KH1060 induces the expression of retinoic acid receptor-beta and p21(Cip1) suggesting that these proteins in part mediate the growth inhibitory effects. Taken together, all the six NB cells were more susceptible to growth inhibition by KH1060 than 1,25-D(3), suggesting its possible use in NB to potentiate the action of retinoids, which are in clinical use for this disease.

Effect of 20-epi-1alpha,25-dihydroxyvitamin D3 on the proliferation of human neuroblastoma: role of cell cycle regulators and the Myc-Id2 pathway.

The antiproliferative effects of 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] and its epimer, 20-epi-1alpha,25-dihydroxyvitamin D(3) [20-epi-1,25(OH)(2)D(3)], in six human neuroblastoma (NB) cell lines (SH-SY5Y, NB69, SK-N-AS, IMR5, CHP134, and NGP) were investigated. We determined the ability of 1,25(OH)(2)D(3) and 20-epi-1,25(OH)(2)D(3) to influence cell viability by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell proliferation by bromodeoxyuridine (BrdU) incorporation, and their antineoplastic effect on colony formation in a soft agar assay. A concentration-dependent decrease in cell viability, inhibition of DNA synthesis, and suppression of clonal proliferation was observed with both compounds. 20-epi-1,25(OH)(2)D(3) was more potent in suppressing the proliferation of all six NB cell lines. To understand the mechanisms of action, we examined the effect of 20-epi-1,25(OH)(2)D(3) on the Myc-Id2 cell proliferative network and also on key regulators of the cell cycle. For the first time, we show that 20-epi-1,25(OH)(2)D(3) down-regulated Myc and Id2 expression by western blot analysis. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that 20-epi-1,25(OH)(2)D(3) induced the expression of retinoic acid receptor-beta and p21(Cip1), and down-regulated the expression of cyclin D1 resulting in decreased phosphorylation of retinoblastoma protein (pRB). In sum, we show that 20-epi-1,25(OH)(2)D(3) exerts strong antiproliferative effects by regulating key growth control networks (Myc-Id2-pRB) in NB cells.

Anticancer effects of the novel 1alpha, 25-dihydroxyvitamin D3 hybrid analog QW1624F2-2 in human neuroblastoma.

Vitamin D3 analogs are potential anti-cancer agents with theoretically wide therapeutic index, but there have been limited studies directed towards human neuroblastoma. The antiproliferative ability of the novel vitamin D3 hybrid analog QW-1624F2-2 (QW, 1-hydroxymethyl-16-ene-24, 24-F2-26, 27-bishomo-25-hydroxyvitamin D3) was examined in two human neuroblastoma-derived cell-lines. Analog QW inhibited cell-cycle progression of IMR5 cells with accumulation in G1 phase. QW induced the differentiation of CHP134 as evidenced by increased neurite length. These effects were accompanied by decreased expression of MYCN in both the cell-lines treated with QW. Furthermore, QW inhibited the migration of CHP134 cells in matrigel invasion assays, indicating its anti-invasive ability. In athymic nude mice, we found that QW was less calcemic than EB1089 (1alpha, 25-dihydroxy-22, 24-diene-24, 26,27-trishomovitamin D3). Systemic administration of QW in a mouse xenotransplantation model revealed that it is more effective than EB1089 in suppressing the growth of CHP134 flank tumors. In summary, the low-calcemic hybrid analog QW showed significant anti-tumor activity in vivo and thus exhibits potential as a novel cancer therapeutic.

Mitogen-activated protein kinase pathway mediates DBP-maf-induced apoptosis in RAW 264.7 macrophages.

Vitamin D-binding protein-macrophage-activating factor (DBP-maf) is derived from serum vitamin D binding protein (DBP) by selective deglycosylation during inflammation. In the present study, we investigated the effect of DBP-maf on RAW 264.7 macrophages and the underlying intracellular signal transduction pathways. DBP-maf increased proapoptotic caspase-3, -8, and -9 activities and induced apoptosis in RAW 264.7 cells. However, DBP, the precursor to DBP-maf did not induce apoptosis in these cells. Cell cycle analysis of DBP-maf-treated RAW 264.7 cells revealed growth arrest with accumulation of cells in sub-G(0)/G(1) phase. We also investigated the role of mitogen-activated protein kinase (MAPK) pathways in the DBP-maf-induced apoptosis of RAW264.7 cells. DBP-maf increased the phosphorylation of p38 and JNK1/2, while it decreased the ERK1/2 phosphorylation. Treatment with the p38 MAPK inhibitor, SB202190, attenuated DBP-maf-induced apoptosis. PD98059, a MEK specific inhibitor, did not show a significant inhibition of apoptosis induced by DBP-maf. Taken together, these results suggest that the p38 MAPK pathway plays a crucial role in DBP-maf-mediated apoptosis of macrophages. Our studies indicate that, during inflammation DBP-maf may function positively by causing death of the macrophages when activated macrophages are no longer needed at the site of inflammation. In summary, we report for the first time that DBP-maf induces apoptosis in macrophages via p38 and JNK1/2 pathway.