Improved antioxidant and anti-tubercular potential of liquiritigenin grafted on low molecular weight chitosan from gladius of Sepioteuthis lessoniana.

Chitosan (CH) is natural abundant biopolymer present on earth after cellulose. CH can be functionalized by numerous functional groups such as amino and carboxyl groups, potential biologically active compounds. The functionalization of CH with polyphenols had a greater biological than non-grafted CH. In the present study, the polyphenolic compound liquiritigenin (LTG) is chemically functionalized on the low molecular weight chitosan (LMW-CH) (693.09 Da). This was extracted and irradiated with gamma radiation from the gladius of Sepioteuthis lessoniana. The grafted compound was to in vitro anti-oxidant employing physicochemical methods and characterization was made by spectroscopic methods. The degree of deacetylation (DDA) of the LMW-CH was detected in 74 % of the samples, and at higher concentrations (100 g/mL). LMW-CH grafted with LTG had improved water solubility (5 mg/mL), and was thermally stable upto 143.58 °C. Its molecular weight was 855.1 Da. In conclusion the in vitro antioxidant and the anti-tuberculosis (anti-TB) properties of the grafted samples were significantly (P < 0.001) increased compared to the unconjugated LMW-CH and LTG. Overall, functionalization of LTG with LMW-CH improved the anti-tuberculosis activity. Further studies are needed to explore the possibilities of its use in vivo models.

Haemodynamic responses to angiotensin II in conscious lambs: role of nitric oxide and prostaglandins.

It was hypothesized that nitric oxide (NO) and prostaglandins (PGs) play a synergistic role in modulating haemodynamic responses to angiotensin II (ANG II) in an age-dependent manner. To this end, experiments were carried out in conscious, chronically instrumented lambs aged ∼1 week (N = 9) and ∼6 weeks (N = 10) to evaluate the haemodynamic responses to ANG II, before and after treatment with the L: -arginine analogue, N-nitro-L: -arginine methyl ester (L: -NAME), as well as the cyclooxygenase inhibitor, indomethacin (INDO). Pressor and renal blood flow responses to ANG II were measured before (control) and after administration of L: -NAME (20 mg kg(-1)), following pretreatment with either vehicle (VEH) (experiment 1) or INDO (1 mg kg(-1), experiment 2). The two experiments were carried out at minimum intervals of 48 h. In both age groups, the pressor and renal vasoconstrictor responses to ANG II were augmented by pretreatment with INDO, the effects being similar at 1 and 6 weeks. The haemodynamic responses to ANG II were, however, not altered after L: -NAME following pretreatment with either VEH or INDO. These data provide new evidence that soon after birth, endogenously produced PGs, but not endogenously produced NO, balance the vasoconstrictor actions of ANG II. There is, however, no apparent interaction between PGs and NO in modulating the responses to ANG II postnatally.

Structural characterization, teratogenicity and in vitro avian antimicrobial activity of posterior salivary gland (PSG) toxin from cuttlefish, Sepia prashadi.

A low molecular weight posterior salivary gland (PSG) toxin was isolated and purified from the cuttlefish Sepia prashadi by Reverse Phase High Performance Liquid Chromatography (RP-HPLC). The protein and neutral sugar content of the PSG toxin was determined to be 1.033 mg/g and 282 µg/g. Fourier Transform Infrared (FT-IR) spectroscopy revealed the presence of υ-OH, υ-CO and δ-NH functional groups. Circular Dichroism (CD) spectroscopy and K2D2 analysis quantified the presence of 38.39% α-helix and 9.25% ß-sheet and 52.36% of ß-turn. Matrix Assisted Laser Desorption/Ionization-Time-of Flight/Mass Spectrometry (MALDI-TOF/MS) and MASCOT analysis revealed the amino acid sequence of MEMQSKQQNSKAPANRKIFPWMKTSAVATASKRVEMASLLNLQERQIKIWFQNRMKQKSQQPQTR (1.92 kDa) homologous to homeobox protein H4 of pufferfish, T. rubripes. The PSG toxin showed differential stability with pH and induced premature hatching in Zebrafish eggs and dose dependant developmental malformations in embryos with a Maximum tolerated dose of 1.85 µM. The PSG toxin exhibited significant antibacterial activity with pronounced zone of inhibition against S. typhimurium (12.94 mm) and inhibited avian RBC binding of Newcastle Disease virus (NDV) at a titre value of 1/4. The present study strongly advocates the biomedical potential of the PSG toxin from S. prashadi and illustrates its promise as a potential avian antimicrobial agent of the future.

In vitro and in vivo anticancer activity of posterior salivary gland toxin from the cuttlefish Sepia pharaonis, Ehrenberg (1831).

Posterior salivary gland (PSG) toxins are high molecular weight toxins secreted by cephalopods and gastropods which possess immense potentials in biomedical applications. In the present study, the biomedical potentials of the PSG toxin from the cuttlefish, S. pharaonis was determined in vitro and in vivo. The cytostatic potentials of the PSG toxin was determined by the lymphocyte migration inhibition assay. The PSG toxin (50 µg/ml) effectively inhibited the migration of lymphocytes across the agarose gel matrix under the presence of lipopolysaccharide mitogen. The cytotoxicity of the PSG toxin against cancer cell lines was determined using the MTT assay. The PSG toxin exhibited highest cytotoxicity against the MCF-7 breast cancer cells (IC50-10.64 µM) followed by KB, HeLa and A549 cells. The PSG toxin also exhibited proportional release of LDH leakage by mitochondrial damage with an IC50-13.85 µM against MCF-7 breast cancer cells. Flow cytometry analysis revealed that the PSG toxin induced apoptosis in MCF-7 cells by cell cycle arrest at G0/G1 phase. The PSG toxin (80 mg/kg b.w.) exhibited pronounced reduction (29%) in tumor growth in experimentally induced breast carcinoma in female Balb/C mice, in vivo. Hematological analysis illustrated the restoration of blood and biochemical parameters by the PSG toxin in mice induced with tumor. Histopathology studies also revealed the restitution of morphological features in the mammary tumor and vital organs in mice treated with the PSG toxin without any observed toxicity and adverse effects. The PSG toxin further exhibited commendable potentials in the prevention of tumor metastasis into immediate organs viz lungs, thus functioning as an anti-metastatic agent. The results of the present study showed that the PSG toxin exhibited immense promise as a potential peptide based anticancer agent, in future.

Multivariate analysis and molecular interaction of curcumin with PPARγ in high fructose diet induced insulin resistance in rats.

To investigate the effect of curcumin on the multivariate and docking analysis on peroxisome proliferator activated receptor-γ, the rats were fed with high fructose diet (Group 2) to induce insulin resistance and curcumin was co-administered orally (Group 4) for a period of 8 weeks and measured the biochemical parameters in blood, kidney and liver tissues. The results showed a significant (p ≤ 0.05) increase in the level of creatinine, glucose, insulin, low density lipoprotein, total cholesterol, triglyceride, urea, uric acid, very low density lipoprotein and decreased albumin, high density lipoprotein and total protein level in the blood of Group 2 when compared with Group 1 control rats. Further, analysis on liver and kidney tissues showed a significant decrease in antioxidants, hexokinase and increased glucose 6-phosphatase and fructose 1,6-bisphosphatase, hydroperoxides and TBARS in Group 2 rats. Furthermore, the multivariate and loading coefficient analysis showed that albumin, HDL, catalase, glutathione reductase, hexokinase and vitamin E are the most contributing factors in blood, liver and kidney. Subsequently, molecular docking was carried out to determine the binding efficiency of curcumin as agonist of PPARγ showed high affinity compared to pioglitazone. The histology of liver and kidney were also studied and the administration of curcumin along with fructose protects the organs from the abnormal changes and also prevents the fat accumulation. Overall, these results demonstrate the preventive role of curcumin on diet induced insulin resistant in rats by ameliorating the altered levels of metabolic changes and potential binding of curcumin with PPARγ as agonist in the treatment of insulin resistance.

Synergistic effect of nicorandil and amlodipine on lysosomal hydrolases during experimental myocardial infarction in rats.

The synergistic effect of nicorandil (K(ATP) channel opener) and amlodipine (calcium channel blocker) on lysosomal hydrolases in serum and heart was examined by determining the activity of beta-glucuronidase, beta-N-acetyl glucosaminidase, beta-galactosidase, cathepsin-D and acid phosphatase on isoproterenol-induced myocardial infarction in rats. The rats given isoproterenol (150 mg kg(-1) daily, i.p.) for 2 d showed significant increase in serum and heart lysosomal hydrolases activity. Isoproterenol administration to rats resulted in decreased stability of the membranes, which was reflected by the lowered activity of cathepsin-D and beta-glucuronidase in mitochondrial, nuclear, lysosomal and microsomal fractions. Pretreatment with nicorandil (2.5 mg kg(-1) daily, p.o.) and amlodipine (5.0 mg kg(-1) daily, p.o.) for 3 d significantly prevented these alterations and restored the enzyme activity to near normal. These findings demonstrate that the pretreatment with nicorandil and amlodipine could preserve lysosomal integrity and hence establish the cardioprotective effect of the combination.

Synergistic effect of nicorandil and amlodipine on mitochondrial function during isoproterenol-induced myocardial infarction in rats.

The synergistic effects of nicorandil (KATP-channel opener) and amlodipine (calcium-channel blocker) on heart mitochondrial enzymes and the mitochondrial antioxidant defence system was examined on isoproterenol-induced myocardial infarction in rats. The rats given isoproterenol (150 mg kg(-1) daily, i.p.) for two days showed significant changes in marker enzymes, mitochondrial enzymes and the mitochondrial defence system. Pre-co-treatment with nicorandil (2.5 mg kg(-1) daily, p.o.) and amlodipine (5.0 mg kg(-1) daily, p.o.) for 3 days significantly prevented these alterations and restored enzyme activity to near normal. These findings demonstrate the protective and synergistic effect of nicorandil and amlodipine in combination against isoproterenol-induced cardiac damage.

Effects of indomethacin on systemic and renal haemodynamics in conscious lambs.

Both prostaglandins (PGs) PGE(2) and PGI(2) can act as renal vasodilators, these effects being exacerbated when the renin-angiotensin system is activated. Therefore, we hypothesized that PGs would play a more predominant role in modulating renal haemodynamics in the newborn period, when the renin-angiotensin system is activated. To this end, the role of endogenously produced PGs in modulating systemic and renal haemodynamics was investigated in two groups of conscious lambs aged approximately 1 and approximately 6 weeks. Arterial pressure, venous pressure and renal blood flow were measured for 5 min before (control) and for 20 min after intravenous injection of vehicle (experiment 1). Twenty-four hours later, this protocol was repeated with intravenous injection of the non-selective cyclo-oxygenase inhibitor indomethacin (1 mg kg(-1), experiment 2). Heart rate was calculated from the systolic peak of the arterial pressure waveform, and renal vascular resistance (RVR) was calculated from the measured variables. In response to indomethacin but not vehicle, in both age groups of lambs there was an increase in mean arterial pressure and pulse interval, as well as a marked increase in RVR. These responses to indomethacin were, however, transient, with baseline levels being resumed within minutes. Although the hypothesis that PGs play a greater role in modulating renal haemodynamics early in life is not supported, these data do provide evidence that endogenously produced PGs modulate systemic and renal haemodynamics during postnatal maturation. It is apparent, however, that other vasoactive factors must be rapidly recruited in order to buffer the circulatory responses to removal of vasodilatory PGs in the developing newborn.

Biochemical changes on the cardioprotective effect of nicorandil and amlodipine during experimental myocardial infarction in rats.

The synergistic protective effect of nicorandil (KATP channel opener) and amlodipine (calcium channel blocker) on mitochondrial respiration and mitochondrial lipid contents were examined on isoproterenol-induced myocardial infarction in rats. The rats given isoproterenol (150 mg kg(-1) daily, i.p.) for 2 days showed significant changes in mitochondrial respiration and mitochondrial lipid profile levels. Pretreatment with nicorandil (2.5 mg kg(-1) daily, p.o.) and amlodipine (5.0 mg kg(-1) daily, p.o.) for 3 days significantly prevented these alterations and restored the mitochondrial respiration and mitochondrial lipid contents to near normal. Histopathological observations were also in correlation with the biochemical parameters. These findings indicate the synergistic protective effect of nicorandil and amlodipine on mitochondrial respiration and its membrane integrity during isoproterenol-induced cardiac damage.

Synergistic effect of Nicorandil and Amlodipine on tissue defense system during experimental myocardial infarction in rats.

The synergistic protective effect of Nicorandil (K(ATP) channel opener) and Amlodipine (calcium channel blocker) on heart tissue antioxidant defense system and lipid profile were examined on isoproterenol induced myocardial infarction in rats. The rats given isoproterenol (150 mg kg(-1) daily, i.p.) for 2 days showed significant changes in antioxidant defense system and lipid profile levels. Pretreatment with Nicorandil (2.5 mg kg(-1) daily, p.o.) and Amlodipine (5.0 mg kg(-1) daily, p.o.) for 3 days significantly prevented these alterations and restored the enzyme activities to near normal. These findings indicate the synergistic protective effect of Nicorandil and Amlodipine on tissue defense system and lipid metabolism during isoproterenol induced cardiac damage.

Effect of L-arginine and L-lysine on lysosomal hydrolases and membrane bound phosphatases in experimentally induced myocardial infarction in rats.

The protective effect of L-arginine and L-lysine on lysosomal enzymes and membrane bound ATPases was examined on isoproterenol induced myocardial infarction in rats. Lysosomal enzymes play an important role in the inflammatory process. The rats given isoproterenol (150 mg kg(-1) daily) intraperitoneally for 2 days showed significant changes in the marker enzymes, lysosomal enzymes and membrane bound phosphatases. Histopathological studies also confirmed the induction of myocardial infarction in isoproterenol administered rats. Prior oral treatment with L-arginine (250 mg kg(-1) daily) and L-lysine (5 mg kg(-1) daily) for 5 days significantly prevented these alterations and restored the enzyme activities to near normal. These findings demonstrate the protective effect of L-arginine and L-lysine in combination against isoproterenol induced cardiac damage.