FT-IR, FT-Raman, SERS and computational study of 5-ethylsulphonyl-2-(o-chlorobenzyl)benzoxazole

FT-IR, FT-Raman and surface-enhanced Raman scattering spectra of 5-ethylsulphonyl-2-(o-chlorobenzyl)benzoxazole were recorded and analyzed. The vibrational wavenumbers were examined theoretically using the Gaussian09 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution calculations. The presence of CH(2), SO(2) and CH(3) modes in the SERS spectrum indicates the nearness of the methyl group to the metal surface which affects the orientation and metal molecule interaction. The synthesis, NMR spectra and antibacterial properties are reported. The title compound shows more inhibitory effect against Pseudomonas aeruginosa than ampicillin and found to be more potent against Klebsiella pneumoniae and drug-resistant Bacillus subtilis than the other microorganisms. A computation of the first hyperpolarizability indicates that the compound may be a good candidate as a NLO material. The RMS errors of the observed Raman and IR bands are found to be 30.93, 29.77 for HF and 9.57, 6.75 for DFT methods, respectively.

Spectroscopic investigations and computational study of 4-(3-bromopropyl)-4-azatricyclo [5.2.2.0(2,6)]undecane-3,5,8-trione

Fourier-transform (FT)-Raman and FT-infrared spectrum of 4-(3-bromopropyl)-4-azatricyclo [5.2.2.0(2,6)]undecane-3,5,8-trione were recorded and analyzed. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. The first hyperpolarizability, predicted infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with reported values of similar structures which makes this compound an attractive object for future studies of nonlinear optics. The calculated first hyperpolarizability was found to be very high and it is due to the pi-electron cloud movement from donor to acceptor which makes the molecule highly polarized and the intermolecular charge transfer interaction which is justified by the FT-IR spectrum due to the presence of strong broad bands in the region 2873-2000cm(-1). Optimized geometrical parameters of the compound are in agreement with similar reported structures.

Quantum chemical DFT study of 4-azatricyclo [5.2.2.0(2,6)] undecane-3,5,8-trione

Fourier-transform-Raman and infrared spectrum of 4-azatricyclo [5.2.2.0(2,6)] undecane-3,5,8-trione were recorded and analyzed. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. The first hyperpolarizability, predicted infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with reported values of similar structures which makes this compound an attractive object for future studies of nonlinear optics. Optimized geometrical parameters of the compound are in agreement with similar reported structures. The red shift of the NH stretching wavenumber in the infrared spectrum from the computational wavenumber indicates the weakening of NH bond.

Hepatoprotective and toxicological assessment of an ethnomedicinal plant Euphorbia fusiformis Buch.-Ham.ex D.Don

AIM OF THE STUDY

The tubers of Euphorbia fusiformis Buch.-Ham.ex D.Don (Euphorbiaceae) are traditionally used in India by the Malayali tribes of Chitteri hills, Eastern Ghats, Tamil Nadu to treat liver disorders. The objective of the present study was to assess the hepatoprotective potential and biosafety of Euphorbia fusiformis tuber upon administration thereby justifying the traditional claims.

MATERIALS AND METHODS

The hepatoprotective potential of the ethanol extract of Euphorbia fusiformis tuber against rifampicin induced hepatic damage was investigated in Wistar albino rats. The acute and subchronic toxicity were assessed in mice and rats, respectively.

RESULTS

The ethanol extract of tubers (250 mg/kg p.o.) showed remarkable hepatoprotective effect against rifampicin induced hepatic damage in Wistar albino rats. The degree of protection was measured using the biochemical parameters serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), gamma glutamyl transpeptidase (GGTP), alkaline phosphatase (ALP), total bilirubin and total protein. Treatment with ethanolic extract prior to the administration of rifampicin significantly (P<0.05 to P<0.001) restored the elevated levels of the said parameters on a par with the control group. The single dose LD(50) was found to be 10,000 mg/kg bw when administered orally in mice. Subchronic toxicity studies in rats with oral doses of 125, 250 and 500 mg/kg exhibited no significant changes in body weight gain, general behavior, hematological and biochemical parameters. The histological profile of liver and kidney also indicated the non-toxic nature of this drug.

CONCLUSION

The ethanol extract of Euphorbia fusiformis tubers may have potential therapeutic value in the treatment of liver disorders and is safer to use even at higher doses when taken orally.

IR, Raman and SERS spectra of 2-phenoxymethylbenzothiazole

The FT-IR and FT-Raman spectra of 2-phenoxymethylbenzothiazole were recorded and analyzed. The surface enhanced Raman scattering (SERS) spectrum was recorded in a silver colloid. The vibrational wavenumbers of the compound have been computed using the Hartree-Fock/6-31G* basis and compared with the experimental values. The appearance of the Ag-O stretching mode at 237cm(-1) in the SERS spectrum along with theoretically calculated atomic charge density, leads us to suggest that the molecule is adsorbed through the oxygen atom with the molecular plane tilted on the colloidal silver surface. The direction of charge transfer contribution to SERS has been discussed from the frontier orbital theory.

Effect of Clausena dentata (Willd.) M. Roem. against paracetamol induced hepatotoxicity in rats

Ethanol extract of Clausena dentata (Willd.) M. Roem (Rutaceae) was evaluated for hepatoprotective activity in rats. The plant extract (250 mg/kg, p.o.) showed a remarkable hepatoprotective activity against acetaminophen-induced hepatotoxicity as judged from the serum markers for liver damage. Acetaminophen induced a significant rise in aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), total bilirubin, gamma glutamate transpeptidase (GGTP) and decrease in total protein. Treatment of rats with ethanol extract (250 mg/kg) significantly (P<0.001) altered serum marker enzymes levels to near normal against acetaminophen treated rats. The activity of the extract was comparable to the standard drug, silymarin (50 mg/kg, p.o.). Histopathological changes of liver sample were compared with respective control. Results indicate that Clausena dentata possesses hepatoprotective effect on acetaminophen-induced hepatotoxicity in rats.

A central role for IL-2 in fate determination of mature T cells--I: role in determining the Th1/Th2 profile in primary T cell cultures

IL-2 signaling appears to play a significant role in enabling the synthesis of T(h)2 cytokines in an in vitro system for studying primary T cell responses. When T cells from C57BL/6J or BALB/c strains of mice were activated in vitro and re-stimulated through their TCR complex 48 h later, CD4(+) T cells producing the T(h)2 cytokines IL-4 and IL-10 were found only when IL-2 was present. IL-2 also enhanced IFN-gamma synthesis in C57BL/6J cells but not in BALB/c cells. By up-regulating production of anti-inflammatory T(h)2 cytokines during a primary response, IL-2 may play a critical role in limiting T(h)1-mediated responses.

Long-term persistence of IL-2-unresponsive allogeneic T cells in sublethally irradiated SCID mice

Donor T cells that are activated by host alloantigens initiate graft versus host disease (GVHD) but their long-term fate is poorly understood. The behavior of alloreactive donor T cells was studied in sublethally irradiated SCID mice. Intravenous injection of 10(6) allogeneic lymphocytes caused a severe form of GVHD, characterized by host hematopoietic atrophy. Fifty-fold fewer donor cells did not induce disease and were not simply rejected by radioresistant host mechanisms. Instead, low numbers of allogeneic T cells expanded 20- to 50-fold and remained for >1 year without causing evidence of GVHD. Persistent non-cycling donor cells with an activated phenotype were mainly found in the spleen. Tolerance was inferred by the recovery of host hematopoiesis, despite the presence of donor allogeneic T cells, and the inability of long-term persisting donor T cells to mediate cellular cytotoxicity or proliferate in response to exogenous IL-2 or antigenic stimulation in vitro. The TCR density of long-term persisting donor T cells was down-regulated. These findings suggest that the development of GVHD depends on the magnitude of the initial anti-host response. Subsequently donor cells differentiate, over several months, into a senescent-like state. This behavior questions the rationale for current treatment approaches to GVHD and is of relevance to any clinical situation where chronic T cell activation takes place in the absence of thymic development.

A role for perforin in activation-induced T cell death in vivo: increased expansion of allogeneic perforin-deficient T cells in SCID mice

Despite defective granule exocytosis, T cells from mice whose perforin gene was ablated by homologous recombination (pko mice) caused a similar degree of graft-vs-host disease as normal T cells after injection into sublethally irradiated C.B-17 SCID mice. Moreover host spleens contained significantly greater numbers of T cells from pko mice than from wild-type mice following their i.v. injection. This increase could not be explained by persistence of host APCs that were not cleared by defective donor cytotoxic effector cells. The absence of functional perforin-dependent suppressor cells or an altered cytokine profile of donor T cells could also not account for the behavior of pko cells. Spontaneous and Fas-mediated apoptosis of in vivo activated donor T cells were independent of donor origin. However, pko T blasts exhibited less growth inhibition and cell death after reactivation in vitro. The results are compatible with a model of a defective activation-induced cell death (AICD) pathway, controlled by perforin, accounting for the increased expansion of alloreactive pko T cells.

Impaired TCR-mediated apoptosis and Bcl-XL expression in T cells lacking the stress kinase activator SEK1/MKK4

The dual specificity kinase SEK1 (MKK4) is a direct activator of stress-activated protein kinases (SAPK/JNK) in response to environmental stresses or mitogenic factors. We show in Sek1(-/-)Rag(-/-) chimeric mice that a Sek1 null mutation augments the susceptibility of peripheral T cells to TCR/CD3 religation-induced apoptosis. Sek1(-/-) T cells failed to induce expression of the death suppressor Bcl-XL in response to Ag receptor activation. The Sek1 mutation did not alter the induction of apoptosis in response to etoposide, cisplatinum, Adriamycin, and gamma-irradiation. Moreover, we show that CD3epsilon activation alone leads to SEK1 activation in Sek1(+/+) T cells. These results suggest that SEK1 transduces cellular survival signals during T cell stimulation.

A role for perforin in activation-induced cell death

The granule exocytosis pathway of T cell cytotoxicity is absent in mice whose perforin gene has been ablated by targeted mutagenesis. The ability of activated naive T cells to undergo apoptosis in vitro following reaggregation of the TCR complex with anti-TCR mAbs via a Fas-independent pathway was found to be defective in the absence of perforin. Protection from death was most marked in CD8+ T cells. In wild-type cells, perforin was expressed at the same time that apoptosis occurred, and blockade of perforin expression by either incubation with perforin antisense oligonucleotides or with anti-IL-2 Abs resulted in increased viability of activated T cells. The role of perforin was not via perforin-dependent fratricidal killing. The results suggest a model in which perforin acts internally to cause a form of activation-induced T cell death distinct from that caused by members of the TNFR superfamily.

Interleukin-2 reverses the defect in activation-induced apoptosis in T cells from autoimmune lpr mice

Activated T cells from MRLlpr/lpr (lpr) mice have been shown to be resistant to TCR-induced apoptosis (activation-induced cell death) in vitro. We have found that this resistance is related to a defect in IL-2R alpha (CD25) expression and IL-2 signaling. Following primary activation, splenic T cells from 8-week old lpr mice failed to undergo apoptosis after the TCR was religated upon reculture with plate-bound anti-CD3 mAb. These cells had markedly reduced levels of IL-2 secretion and CD25 expression during primary activation in vitro; however, the cells still progressed through the cell cycle and were capable of cell division following TCR religation. Addition of exogenous IL-2 during the primary activation of 8-week-old lpr T cells overcame the defect in CD25 expression. Strikingly, these cells also became sensitive to apoptosis induction and died when the TCR was religated with anti-CD3 mAb. Viable cell recovery of both the lpr CD4+ and CD8+ subsets, as well as the CD4-CD8- subsets, was dramatically reduced under these conditions. Further investigation also revealed that the defect in activation-induced apoptosis in T cells from lpr mice was age-related. Activated T cells from young lpr mice (5 weeks old) underwent apoptosis in response to TCR ligation; these cells also expressed normal levels of CD25 following primary activation. However, as the mice aged from 5 to 8 weeks, susceptibility to TCR-mediated apoptosis in vitro was progressively lost together with the ability to express CD25. Our results suggest that before the onset of severe lymphoaccumulation, activated T cells from young lpr mice possess the capability to undergo TCR-induced apoptosis despite defective fas expression; IL-2 participates in sensitizing the cells to this death pathway. In older mice, this pathway breaks down and, together with the lack of fas-induced apoptosis, may account for the onset of severe lymphoaccumulation and autoimmunity.

Correlation between mutation in P53, p53 expression, cytogenetics, histologic type, and survival in patients with B-cell non-Hodgkin's lymphoma

In the biology of a cell, the central role of p53 in controlling functions such as G1/S transition (check point) and DNA damage repair, and as a trigger of apoptosis, is well established. Somatic mutations or other changes in P53 have been reported in numerous tumor types, and in some of these, they are associated with poor prognosis. In this study, we examined 237 cytogenetically characterized B-cell non-Hodgkin's lymphomas (B-NHLs) for somatic changes in P53 by Southern blot analysis, by single-strand conformation polymorphism analysis (SSCP) of exon 5 through 9, and by direct sequencing of SSCP variants to determine the frequency and types of mutations and their clinical significance. In a portion of these (173 tumors), we also studied p53 expression by immunostaining. On Southern blots, no gross change was identified in P53 and no mutation was identified in exon 9. In exons 5 through 8, 27 different mutations were identified in 25 patients (23 single-base substitutions, 3 deletions, 1 duplication). Mutations in P53 were identified in 25 of 237 tumors (10.5%), which included 1 of 45 small lymphocytic lymphomas (SLLs), 2 of 38 follicular small cleaved-cell lymphomas (FSCCs), 2 of 35 follicular mixed small cleaved-cell and large-cell lymphomas (FMxs), 1 of 4 follicular large-cell lymphomas (FLCs), 1 of 14 diffuse small cleaved-cell lymphomas (DSCCs), 2 of 17 diffuse mixed small- and large-cell lymphomas (DMxs), and 16 of 84 diffuse large-cell lymphomas (DLCCs); the difference between the histologic groups was significant (P < .01). Among mantle-cell lymphoma (MC) patients, 3 of 10 had mutations. In 16 patients, the mutation was identified in specimens obtained at diagnosis. Mutation of transition type and transversion type occurred at a relative frequency of 2:1. Thirty percent occurred at CpG dinucleotide sequences and the codon for arginine was most frequently affected. Nineteen of 99 tumors with complex cytogenetic abnormalities, but none of 69 tumors with simple cytogenetic abnormalities, had mutations (P < .001). Similarly, 11 of 25 tumors with an abnormality of 17p and 8 of 143 tumors with apparently normal 17p had mutations (P < .0001). Positive correlations were found between a mutation and p53 expression (P < .001), between missense type mutations and p53 expression (P < .005), and between 17p abnormalities and p53 expression (P < .05). Twenty-two of 49 patients without mutation and 14 of 17 patients with mutations died (P < .05), but there was no significant difference in median survival. Similarly, 21 of 26 p53 positive patients died, whereas only 1 of 24 p53-negative patients died on-study (P < .001). Among p53-negative patients, mutation (P < .01) was positively associated with a fatal outcome. These findings indicate that in B-NHL, somatic changes in P53 were present in diagnostic specimens of all histologic types, but at a higher frequency in DLC and MC tumors. P53 mutation and/or expression has a negative influence on survival, and therefore can serve as prognostic indicators. Immunostaining for p53 is an effective way to screen for P53 changes in these tumors.