Caesalpinia Crista Linn. Induces Protection against DNA and Membrane Damage.

BACKGROUND: Caesalpinia crista is a medicinal herb used to cure various ailments in subtropical and tropical regions of Southeast Asia. OBJECTIVE: The objective of this evaluation of C. crista against free radical induced DNA and erythrocyte damage. MATERIALS AND METHODS: The profiles of polyphenol and flavonoid were quantified through reversed-phase high-performance liquid chromatography. Free radical induced DNA and membrane damage were performed using H2O2 as oxidative agent. RESULTS: The total polyphenol content of C. crista leaf ethyl acetate extract (CcEA) was 94.5 ± 3.8 mg/gGAE, CcME (C. crista leaf methanol extract) was 52.7 ± 2.8 mg/gGAE, and CcWE (C. crista leaf Water extract) was 31.84 ± 1.8 mg/gGAE. Total flavonoid content of CcEA was 60.46 ± 2.3 mg/gQE, CcME was 46.26 ± 1.8 mg/gQE, and CcWE was 20.47 ± 1.1 mg/gQE. The extracts also exhibited good antioxidant activity as confirmed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), hydroxyl scavenging, reducing power, and total antioxidant assays. Among the three extracts, CcEA and CcME showed better protection against red blood cell (RBC) hemolysis and DNA damage as confirmed by electrophoretic study. Further, Scanning electron micrograph data showed that CcEA revealed the free radical induced structural alterations in RBC. CONCLUSION: These findings suggest that C. crista contains bioactive molecules and can inhibit oxidative stress and can be source of further study to use this in herbal medicine. SUMMARY: ROS are generated under normal biological systems. These ROS generated can be scavenged by endogenous and exogenous cellular mechanisms. Environmental stress, radiation, smoke etc. elevates ROS dramatically. This leads to significant damage to cellular biomolecules like DNA and cell structures. Plants as a large reservoir of drugs for protecting DNA and cell structures from oxidative stress. Polyphenols present in the C. crista extracts acts through several mechanisms to quench free radicals. Extracts exhibited potent antioxidant properties and also protected DNA and cell membrane from oxidative damage. Hence this can be used in herbal medicine for treating oxidative stress mediated diseases. Abbreviations used: ABTS: 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid); CcEA: C. crista leaf ethyl acetate extract; CcME: C. crista leaf methanol extract; CcWE: C. crista leaf Water extract; DPPH: 2,2-diphenyl-1-picrylhydrazyl; GAE: Gallic acid Equivalent; H2O2: Hydrogen Peroxide; QE: Quercetin Equivalent; RNS: Reactive Nitrogen Spevcies; ROS: Reactive Oxygen Species; SEM: Scanning Electron Microscope.

Evaluation of Cassia tora Linn. against Oxidative Stress-induced DNA and Cell Membrane Damage.

OBJECTIVE: The present study aims to evaluate antioxidants and protective role of Cassia tora Linn. against oxidative stress-induced DNA and cell membrane damage. MATERIALS AND METHODS: The total and profiles of flavonoids were identified and quantified through reversed-phase high-performance liquid chromatography. In vitro antioxidant activity was determined using standard antioxidant assays. The protective role of C. tora extracts against oxidative stress-induced DNA and cell membrane damage was examined by electrophoretic and scanning electron microscopic studies, respectively. RESULTS: The total flavonoid content of CtEA was 106.8 ± 2.8 mg/g d.w.QE, CtME was 72.4 ± 1.12 mg/g d.w.QE, and CtWE was 30.4 ± 0.8 mg/g d.w.QE. The concentration of flavonoids present in CtEA in decreasing order: quercetin >kaempferol >epicatechin; in CtME: quercetin >rutin >kaempferol; whereas, in CtWE: quercetin >rutin >kaempferol. The CtEA inhibited free radical-induced red blood cell hemolysis and cell membrane morphology better than CtME as confirmed by a scanning electron micrograph. CtEA also showed better protection than CtME and CtWE against free radical-induced DNA damage as confirmed by electrophoresis. CONCLUSION: C. tora contains flavonoids and inhibits oxidative stress and can be used for many health benefits and pharmacotherapy.

Enzyme dimension of the ribosomal protein S4 across plant and animal kingdoms.

BACKGROUND: The protein S4 of the smaller ribosomal subunit is centrally important for its anchorage role in ribosome assembly and rRNA binding. Eubacterial S4 also facilitates synthesis of rRNA, and restrains translation of ribosomal proteins of the same polycistronic mRNA. Eukaryotic S4 has no homolog in eubacterial kingdom, nor are such extraribosomal functions of S4 known in plants and animals even as genetic evidence suggests that deficiency of S4X isoform in 46,XX human females may produce Turner syndrome (45,XO). METHODS: Recombinant human S4X and rice S4 were used to determine their enzymatic action in the cleavage of synthetic peptide substrates and natural proteins. We also studied autoproteolysis of the recombinant S4 proteins, and examined the growth and proliferation of S4-transfected human embryonic kidney cells. RESULTS: Extraribosomal enzyme nature of eukaryotic S4 is described. Both human S4X and rice S4 are cysteine proteases capable of hydrolyzing a wide spectrum of peptides and natural proteins of diverse origin. Whereas rice S4 also cleaves the -XXXD↓- consensus sequence assumed to be specific for caspase-9 and granzyme B, human S4 does not. Curiously, both human and rice S4 show multiple-site autoproteolysis leading to self-annihilation. Overexpression of human S4 blocks the growth and proliferation of transfected embryonic kidney cells, presumably due to the extraribosomal enzyme trait reported. CONCLUSIONS: The S4 proteins of humans and rice, prototypes of eukaryota, are non-specific cysteine proteases in the extraribosomal milieu. GENERAL SIGNIFICANCE: The enzyme nature of S4 is relevant toward understanding not only the origin of ribosomal proteins, but also processes in cell biology and diseases.

Cysteine endoprotease activity of human ribosomal protein S4 is entirely due to the C-terminal domain, and is consistent with Michaelis-Menten mechanism.

BACKGROUND: It is known that tandem domains of enzymes can carry out catalysis independently or by collaboration. In the case of cysteine proteases, domain sequestration abolishes catalysis because the active site residues are distributed in both domains. The validity of this argument is tested here by using isolated human ribosomal protein S4, which has been recently identified as an unorthodox cysteine protease. METHODS: Cleavage of the peptide substrate Z-FR↓-AMC catalyzed by recombinant C-terminal domain of human S4 (CHS4) is studied by fluorescence-monitored steady-state and stopped-flow kinetic methods. Proteolysis and autoproteolysis were analyzed by electrophoresis. RESULTS: The CHS4 domain comprised of sequence residues 116-263 has been cloned and ovreexpressed in Escherichia coli. The purified domain is enzymatically active. Barring minor differences, steady-state kinetic parameters for catalysis by CHS4 are very similar to those for full-length human S4. Further, stopped-flow transient kinetics of pre-steady-state substrate binding shows that the catalytic mechanism for both full-length S4 and CHS4 obeys the Michaelis-Menten model adequately. Consideration of the evolutionary domain organization of the S4e family of ribosomal proteins indicates that the central domain (residues 94-170) within CHS4 is indispensable. CONCLUSION: The C-terminal domain can carry out catalysis independently and as efficiently as the full-length human S4 does. SIGNIFICANCE: Localization of the enzyme function in the C-terminal domain of human S4 provides the only example of a cysteine endoprotease where substrate-mediated intramolecular domain interaction is irrelevant for catalytic activity.

Umbilical hemorrhage as first manifestation in a case of cirrhosis.

Portal hypertension is often associated with an extensive collateral circulation. The paraumbilical vein is a relatively common collateral pathway recognized in these patients but cutaneous bleeding from the umbilicus is rare; the same as first manifestation of cirrhosis is exceptional. We report a case of umbilical venous bleed causing hemodynamic compromise, which turned out to be a case of alcoholic cirrhosis with portal hypertension. The patient was managed with suture ligation of the vessels.

An update on cyclic nucleotide phosphodiesterase (PDE) inhibitors: phosphodiesterases and drug selectivity.

In recent years, there has been a prodigious expansion of knowledge about cyclic nucleotide phosphodiesterases (PDEs). This isozyme superfamily has now become a major focus of drug discovery efforts owing to its diversity, molecular nature, differential regulation and expression in different cell types, and the range of biological functions. Inhibition of these isozymes can lead to an increase in cAMP and cGMP levels, which can affect a variety of physiological responses. Selective inhibitors for each of the multiple forms of PDE can offer an opportunity for desired therapeutic intervention and would be an extremely useful tool in drug discovery efforts for a medicinal chemist. This review details many key aspects of multiple forms of PDEs and their inhibitors with diversified chemical structures, which can act as leads for synthesis of novel drugs.