Mouse Liver Homogenates Research Articles

A New Antioxidant with Natural Origin Characterized by Electron Paramagnetic Resonance Spectroscopy Methods

ABSTRACTFormerly, naturally isolated SQGD exhibited good in vitro radical scavenging capacity towards 1, 1-diphenyl-2-picrylhydrazyl (DPPH). By the present research using EPR in vitro and ex vivomethods we report our further studies on the antioxidant and free radical properties of SQGD. SQGD in powder or in solution form was studied before and after 2 h of UV irradiation by direct EPR in vitro spectroscopy. A single almost symmetrical EPR signal with a g value of 2.0056±0.0002 was registered for the powder form and g=2.0044±0.0002 for the solution form. Based on the calculated g values and the strong EPR signal stability we accept that the radical recorded can be safely ascribed to a semiquinone radical. To study in vivo antioxidant properties of SQGD, white laboratory mice were inoculated i.p.: first group with SQGD (20mg/kg), second with anticancer drug N'-cyclohexyl-N-(2-chloroethyl)-N-nitrosourea (CCNU, 80 mg/kg), third with SQGD plus CCNU and the controls were inoculated with the solvent only. At the 3rd h after treatment mice livers were isolated and homogenates in DMSO solution of the spin trap n-tert-butyl-alpha-phenylnitrone (PBN) were prepared and their EPR spectra were recorded. Statistical significant increased level of ROS production was found in liver homogenates of mice treated by CCNU comparing to those of the controls. ROS production in livers of mice treated by SQGD, or by the combination of SQGD plus CCNU was slightly decreased comparing to the controls.In conclusion, obviously SQGD does not cause oxidative stress in the livers of mice for the followed period and behaves in vivo as an excellent antioxidant and hepatoprotector.

Kinetics of Alloxan-Induced Inhibition on δ-Aminolevulinate Dehydratase Activity in Mouse Liver Homogenates

This study evaluated the effects of alloxan on the kinetics properties of the δ-aminolevulinate dehydratase (δ-ALA-D) using mouse liver homogenates. δ-ALA-D is an important sulfhydryl enzyme that catalyses the second step in heme biosynthesis and is commonly diminished in experimental and human diabetes. Despite the known effects of alloxan in models of experimental diabetes, there are no data in the literature demonstrating the effects of alloxan on the kinetics properties of the δ-ALA-D. The results showed that alloxan (1.25-20 μM) caused a concentration-dependent inhibition of hepatic δ-ALA-D activity. The inhibition constant (K(i)) for alloxan-induced inhibition on δ-ALA-D was 3.64 μM. The alloxan (5 μM) caused a decrease in V(max) (65.8%) and in K(m) (53.1%), which is suggestive of an uncompetitive inhibition of enzyme. In addition, dithiothreitol (700 and 1,000 μM) completely prevented the δ-ALA-D activity inhibition induced by 10 and 20 μM alloxan. Similar protection was obtained in the presence of 2,000 μM glutathione. Therefore, this work showed that the inhibition of hepatic δ-ALA-D activity can be obtained in vitro at low micromolar levels of alloxan, and can also be prevented by reducing agents. Moreover, these results may help to understand the abnormalities in heme pathway found in models of experimental diabetes in vivo.

Assessment of oxidative stress and chromosomal aberration inducing potential of three medical grade silicone polymer materials

Medical expenditures for devices are increasing along with the ageing of human population and the synthesis of materials such as silicone polymers is on upsurge for manufacturing these devices. The International Organization for Standardization (ISO) emphasizes a battery of tests for preclinical assessment of biocompatibility of medical devices. Genotoxicity assays have become an integral component of these test procedures and it employs a set of in vitro and in vivo experiments to detect mutagens. Hence, this study was performed with an intention to investigate the genotoxic potential of the physiological saline extracts of three medical grade silicone polymer materials by the in vitro chromosomal aberration assay using human peripheral blood lymphocytes. Further, the oxidative stress inducing potential of the material extracts was investigated in vivo in mice liver homogenates using cyclophosphamide as positive control. The investigation revealed that none of the three materials were able to produce marked human lymphocyte chromosomal aberration, suggesting the absence of mutagens. The materials also showed negative results in their oxidative stress inducing potential, which was revealed by the normal levels of lipid peroxidation and unaltered levels of glutathione and its metabolizing enzymes in the mice liver tissue homogenates. It was interesting to observe a significant correlation between the genotoxic and antioxidant parameters investigated. Hence, it is suggested that the estimation of antioxidant status would serve as a better preliminary testing procedure prior to evaluating the genetic and molecular toxicity mechanisms of medical devices and/or materials intended for manufacture of such devices.

High molecular weight persimmon tannin is a potent antioxidant both ex vivo and in vivo

The antioxidant activities of high molecular weight persimmon condensed tannin (HMWPT) were evaluated in an ex vivo tissue system and in vivo. Addition of HMWPT to mouse liver homogenate protected the samples against auto-peroxidation or H2O2- or Fe2+/ascorbic acid-induced lipid peroxidation. The IC50 values for HMWPT were 4.32±0.20μg/mL (auto-oxidation), 1.36±0.40μg/mL (H2O2-induced peroxidation) or 0.20±0.09mg/mL (Fe2+/ascorbic acid-induced peroxidation). Mice were oxidatively stressed with bromobenzene to test the antioxidant activity of HMWPT in vivo. An oral dose of HMWPT at 200 or 400mg/kg HMWPT significantly (P<0.01) prevented the bromobenzene-induced decrease in serum and liver superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and decreased liver malondialdehyde levels in bromobenzene-treated mice (P<0.01). The results suggest that dietary HMWPT may provide protection from oxidative damage both ex vivo and in vivo.

Hydrogen sulfide mediates the anti-survival effect of sulforaphane on human prostate cancer cells

Hydrogen sulfide (H2S) is a novel gasotransmitter that regulates cell proliferation and other cellular functions. Sulforaphane (SFN) is a sulfur-containing compound that exhibits anticancer properties, and young sprouts of broccoli are particularly rich in SFN. There is consistent epidemiological evidence that the consumption of sulfur-containing vegetables, such as garlic and cruciferous vegetables, may help reduce the occurrence of prostate cancer. Here we found that a large amount of H2S is released when SFN is added into cell culture medium or mixed with mouse liver homogenates, respectively. Both SFN and NaHS (a H2S donor) decreased the viability of PC-3 cells (a human prostate cancer cell line) in a dose-dependent manner, and supplement of methemoglobin or oxidized glutathione (two H2S scavengers) reversed SFN-reduced cell viability. We further found both cystathionine gamma-lyase (CSE) and cystathionine beta-synthase are expressed in PC-3 cells and mouse prostate tissues. H2S production in prostate tissues from CSE knockout mice was only 20% of that from wild-type mice, suggesting CSE is a major H2S-producing enzyme in prostate. CSE overexpression enhanced H2S production and inhibited cell viability in PC-3 cells. In addition, both SFN and NaHS activated p38 mitogen-activated protein kinases (MAPK) and c-Jun N-terminal kinase (JNK). Pre-treatment of PC-3 cells with methemoglobin decreased SFN-stimulated MAPK activities. Suppression of both p38 MAPK and JNK reversed H2S- or SFN-reduced viability of PC-3 cells. Our results demonstrated that H2S mediates the inhibitory effect of SFN on the proliferation of PC-3 cells, which suggests that H2S-releasing diet or drug might be beneficial in the treatment of prostate cancer.

In vivo radioprotective potential of thymol, a monoterpene phenol derivative of cymene

The radioprotective and anticlastogenic potential of a phenol derivative monoterpene thymol(TOH), against whole-body gamma radiation was studied in Swiss albino mice. Acute toxicity of TOH, with an LD50(14) of 1134.03mg/kgbwt., was observed when administered intra-peritoneally (i.p.). The radioprotective potential of TOH was evaluated using the optimal dose of 10mg/kgbwt. TOH, which increased the LD50/30 by 2.17Gy and resulted in a dose reduction factor (DRF) of 1.25. A significant (p<0.01) reduction in micronucleated, polychromatic erythrocytes (PCE), normochromatic erythrocytes (NCE), and an increased PCE/NCE ratio was also observed after administration of 10mg/kg.b.wt. TOH prior to gamma radiation, indicating its antigenotoxic effect. TOH pre-treatment significantly (p<0.01) elevated reduced glutathione, glutathione-S-transferase, catalase, and superoxide dismutase levels and decreased lipid peroxidation levels in mouse liver homogenates at 24 and 48h after exposure to 4.5Gy of radiation. Further, TOH treatment before exposure to 7.5Gy of gamma radiation resulted in a significant (p<0.01) increase in hematological parameters at various post-treatment time points, with increased numbers of endogenous spleen colonies as well. The histological observations indicated a decline in villus heights and crypt numbers in mouse jejunum and were accompanied by a significant decrease in bone marrow nucleated cells in the irradiated group, which was almost normalized by pre-treatment with TOH. Our study clearly documents the antioxidant, anticlastogenic and radioprotective potentials of TOH, which may be attributed to several possible mechanisms, such as normalization of intracellular antioxidant levels and free radical scavenging activities by TOH.

Evaluation of hydroxyapatite–bioglass and hydroxyapatite–ethyl vinyl acetate composite extracts on antioxidant defense mechanism and genotoxicity: An in vitro study

Hydroxyapatite–bioglass (HA BG) and hydroxyapatite–ethyl vinyl acetate (HA EVA) are two composite materials that have been developed for bone substitution. Their activity on antioxidant defense mechanism and genotoxicity has not been investigated before. To further confirm its biocompatibility, the present study was undertaken to investigate the effect of HA BG and HA EVA on mice liver antioxidant mechanism along with chromosomal aberrations in human lymphocytes. Physiological saline extract of HA BG and HA EVA showed no adverse effect on liver antioxidant mechanism compared to the cyclophosphamide (CP)-induced toxicity on mice liver homogenate. The results were judged from the in vitro studies made on reduced glutathione, glutathione reductase and lipid peroxidation. These results were well supported by CP- and mytomycin C (MC)-induced genotoxicity studies on human lymphocytes in the presence and absence of a metabolic activator (S9). Hence, it was suggested that these tests could be considered for preliminary toxicological screening of materials intended for clinical applications ahead of in vivo animal model evaluation.

Evaluation of physicochemical properties, skin permeation and accumulation profiles of salicylic acid amide prodrugs as sunscreen agent

Various amide prodrugs of salicylic acid were synthesised, and their physicochemical properties including lipophilicity, chemical stability and enzymatic hydrolysis were investigated. In vivo skin permeation and accumulation profiles were also evaluated using a combination of common permeation enhancing techniques such as the use of a supersaturated solution of permeants in an enhancer vehicle, a lipophilic receptor solution, removal of the stratum corneum and delipidisation of skin. Their capacity factor values were proportional to the degree of carbon–carbon saturation in the side chain. All these amides were highly stable in acetonitrile and glycerine. Amide prodrugs were converted to salicylic acid both in hairless mouse liver and skin homogenates. N-dodecyl salicylamide (C12SM) showed the lowest permeation of salicylic acid in skin compared to the other prodrugs, probably due to its low aqueous solubility. It had a high affinity for the stratum corneum and its accumulation was restricted to only the uppermost layer of skin. Thus, this amide prodrug could be a safer topical sunscreen agent with minimum potential for systemic absorption.

Chlorella vulgaris extract ameliorates carbon tetrachloride-induced acute hepatic injury in mice

The possible protective effects of Chlorella vulgaris extract (CVE) on carbon tetrachloride (CCl(4))-induced acute hepatic injury in mice and the mechanism underlying these effects was investigated. CCl(4) administration caused a marked increase in the levels of serum aminotransferases, lipid peroxidation and cytochrome P450-2E1 (CYP450) expression. Also, decreased glutathione (GSH) content and activities of cellular antioxidant defense enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase and glutathione-S-transferase (GST) were found after CCl(4) exposure. All of these phenotypes were markedly reversed by preadministration of the mice with CVE. In addition, CVE exhibited antioxidant effects on FeCl(2)-ascorbate induced lipid peroxidation in mouse liver homogenates, and on superoxide radical scavenging activity. Taken together, these results suggest that CVE produced a protective action on CCl(4)-induced acute hepatic injury in mice, presumably through blocking CYP-mediated CCl(4) bioactivation, inducing the GSH levels, antioxidant enzyme activities and free radical scavenging effect. Therefore, CVE may be an effective hepatoprotective agent and viable candidate for treating hepatic disorders and other oxidative stress-related diseases.

The antiplasmodial activity of Anogeissus leiocarpus and its effect on oxidative stress and lipid profile in mice infected with Plasmodium bergheii

Methanolic extracts of Anogeissus leiocarpus has been considered locally to have the same antimalarial activities as artemisinin derivatives. This work studied the in vivo antiplasmodial activity of methanolic extracts of A. leiocarpus and its effect on oxidative stress and lipid profile in mice infected with Plasmodium bergheii. Mice used for this study were divided into five groups; four of the groups were infected with P. bergheii. The first group was not infected with the parasite. The second group was infected with parasite but not treated with antimalarial drugs (negative control). The third group was infected and treated with artesunat at 5mg/kg body weight (positive control), while the fourth and fifth groups were infected and treated with 100 and 200mg/kg body weight of extract of stem bark of A. leiocarpus, respectively. The rate of parasite clearance was higher in the group treated with 200mg/kg body weight of extract of A. leiocarpus when compared with the groups treated with artesunat. Malondialdehyde (MDA) level was significantly higher (P < 0.05) in the serum of negative control as compared with other groups which have received treatment. MDA level was moderately higher in the liver homogenates of infected mice treated with artesunat than in other groups. There were significant increases (P < 0.05) in the levels of serum and liver superoxide dismutase of infected mice treated with 200mg/kg body weight of A. leiocarpus when compared with other groups. Serum low density lipoprotein, total triglyceride, and total cholesterol were moderately higher in the group treated with artesunat than other groups, while high density lipoprotein (HDL) level was higher in the two groups treated with A. leiocarpus as compared with the group treated with artesunat. This study shows that the methanolic extract of A. leiocarpus has high antimalarial activities, high antioxidant property, and capable of boosting HDL level in malaria-infected organisms.

Key genomic changes necessary for an in vivo lethal mouse marburgvirus variant selection process.

Marburgvirus (MARV) infections are generally lethal in humans and nonhuman primates but require in vivo lethal mouse variant selection by the serial transfer (passage) of the nonlethal virus into naïve mice to propagate a lethal infection. The passage of progenitor (wild-type) MARV or Ravn virus (RAVV) from infected scid BALB/c mouse liver homogenates into immunocompetent BALB/c mice results in the selection of lethal mouse viruses from within the quasispecies sufficient to establish lethality in immunocompetent mice. Genomic analysis in conjunction with the passage history of each mutation detailed the altered primary and secondary structures of the viral genomic RNA throughout the process. Key findings included the following: (i) a VP40:D184N mutation previously identified in the lethal guinea pig MARV genome was the first mutation to occur during the passage of both the MARV and RAVV variants; (ii) there was biased hypermutagenesis in the RAVV variant genome; (iii) there were two identical mutations in lethal mouse MARV and RAVV variants, VP40:Y19H in the PPPY motif and VP40:D184N in a loop structure between the two VP40 domains; (iv) the passage of wild-type MARV and RAVV in mice resulted in the selection of viral variants from among the quasispecies with different genotypes than those of the wild-type viruses; and (v) a lethal mouse RAVV variant had different tissue tropisms distinct from those of its wild-type virus. These studies provide insights into how marburgviruses manipulate the host for enzymes, metabolites, translation regulators, and effectors of the innate immune response to serve as potential viral countermeasures.

Nrf2 Induces Interleukin-6 (IL-6) Expression via an Antioxidant Response Element within the IL-6 Promoter

IL-6 gene expression is controlled by a promoter region containing multiple regulatory elements such as NF-κB, NF-IL6, CRE, GRE, and TRE. In this study, we demonstrated that TRE, found within the IL-6 promoter, is embedded in a functional antioxidant response element (ARE) matching an entire ARE consensus sequence. Further, point mutations of the ARE consensus sequence in the IL-6 promoter construct selectively eliminate ARE but not TRE activity. Nrf2 is a redox-sensitive transcription factor which provides cytoprotection against electrophilic and oxidative stress and is the most potent activator of ARE-dependent transcription. Using Nrf2 knock-out mice we demonstrate that Nrf2 is a potent activator of IL-6 gene transcription in vivo. Moreover, we show evidence that Nrf2 is the transcription factor that activates IL6 expression in a cholestatic hepatitis mouse model. Our findings suggest a possible role of IL-6 in oxidative stress defense and also give indication about an important function for Nrf2 in the regulation of hematopoietic and inflammatory processes.

Evaluation of salicylic acid fatty ester prodrugs for UV protection

The purpose of this study was to investigate the physicochemical properties and in vitro evaluation of fatty ester prodrugs of salicylic acid for ultraviolet (UV) protection. The physicochemical properties such as lipophilicity, chemical stability and enzymatic hydrolysis were investigated with the following fatty ester prodrugs of salicylic acid: octanoyl (C8SA), nonanoyl (C9SA), decanoyl (C10SA), lauroyl (C12SA), myristoyl (C14SA) and palmitoyl oxysalicylate (C16SA). Furthermore, their skin permeation and accumulation were evaluated using a combination of common permeation enhancing techniques such as the use of a lipophilic receptor solution, removal of stratum corneum and delipidization of skin. Their k′ values were proportional to the degree of carbon–carbon saturation in the side chain. All these fatty esters were highly stable in 2-propanol, acetonitrile and glycerin, but unstable in methanol and ethanol. They were relatively unstable in liver and skin homogenates. In particular, C16SA was mostly hydrolyzed to its parent compound in hairless mouse liver and skin homogenates, suggesting that it might be converted to salicylic acid after its topical administration. In the skin permeation and accumulation study, C16SA showed the poorest permeation in all skins, suggesting that it could not be permeated in the skin. Furthermore, C14SA and C16SA were less accumulated in delipidized skin compared with normal skin or stripped skin, suggesting that these esters had relatively strong affinities for lipids compared with the other prodrugs in the skin. C16SA showed significantly higher dermal accumulation in all skins compared with its parent salicylic acid. Thus, the palmitoyl oxysalicylate (C16SA) might be a potential candidate for UV protection due to its absence of skin permeation, smaller uptake in the lipid phase and relatively lower skin accumulation.

Piperine, an active ingredient of black pepper attenuates acetaminophen–induced hepatotoxicity in mice

Objective To explore the hepatoprotective and antioxidant effects of piperine against acetaminophen-induced hepatotoxicity in mice. Methods In mice, hepatotoxicity was induced by a single dose of acetaminophen (900 mg/kg b.w. i.p.). Piperine (25 mg/kg b.w. i.p.) and standard drug silymarin (25 mg/kg b.w. i.p.) were given to mice, 30 min after the single injection of acetaminophen. After 4 h, the mice were decapitated. Activities of liver marker enzymes [(aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP)] and inflammatory mediator tumour necrosis factor-alpha (TNF-α) were estimated in serum, while lipid peroxidation and antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-s-transferase and glutathione) were determined in liver homogenate of control and experimental mice. Results Acetaminophen induction (900 mg/kg b.w. i.p.) significantly increased the levels of liver marker enzymes, TNF-α, and lipid peroxidation, and caused the depletion of antioxidant status. Piperine and silymarin treatment to acetaminophen challenged mice resulted in decreased liver marker enzymes activity, TNF-α and lipid peroxidation levels with increase in antioxidant status. Conclusions The results clearly demonstrate that piperine shows promising hepatoprotective effect as comparable to standard drug silymarin.

Effect of biological matrix and sample preparation on qPCR quantitation of siRNA drugs in animal tissues

Introduction Quantitative pharmacokinetic measurement of short nucleotide sequences in animal tissues is critical to the successful development of siRNA-based drugs. Stem-loop qRT-PCR is a sensitive and precise methodology, but the effect of biological matrix and purity of the input sample has yet to be investigated. Results The impact of lipid encapsulation, siRNA chemical modification and purity of the biological matrix on the stem-loop qRT-PCR assay was investigated. A comparison of siRNA standard curves in mouse liver homogenates before and after isolation of total RNA uncovered the potential for erroneous measurement due to significant loss of siRNA on purification columns. Recovery of chemically stabilized siRNA was improved by omission of the DNAse I digestion during RNA isolation. The stem-loop qRT-PCR method demonstrated excellent sensitivity and efficiency in mouse liver homogenates, plasma and whole blood. An optimized protocol based on these findings was used to quantitate siRNA in tissues after dosing mice with two different lipid nanoparticle formulations containing siRNA payloads. Conclusions Assay of crude homogenates, whole blood or plasma is more accurate, less resource intensive and more amenable to clinical translation than measurement of column-purified total RNA.

Novel Flavonoids from the Leaves ofActinidia valvataDunn: Structural Elucidation and Antioxidant Activity

Two novel flavonoids, kaempferol 3- O- α-L-rhamnopyranosyl (1-3) (2,4-di- O-acetyl-α-L-rhamnopyranosyl) (1-6) β-D-galactopyranoside (1) and kaempferol 3- O-α-L-rhamnopyranosyl (1-3) (4-O-acetyl-α-L-rhamnopyranosyl) (1-6) β-D-galactopyranoside (2), along with three known ones, kaempferol-3- O-β-D-galactopyranoside (3), kaempferol (4), and 7-hydroxychromone (5), have been isolated from the leaves of Actinidia valvata Dunn, and their structures were elucidated based on spectroscopic methods. Compounds 1-3 exhibited dose-dependent activity in scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, superoxide anion radicals, and hydroxyl radicals, and inhibited lipid peroxidation of mouse liver homogenate IN VITRO.

Selenocysteine abundance was decreased in the hepatic GPX1 protein of SOD1−/− mice

We previously reported a 40% loss of specific activity in the GPX1 protein purified from the SOD1−/− mouse liver homogenate compared to that of the wild type mice. This study was to explore structural modifications for that GPX1 activity loss. After liver homogenates (200 μg of protein) of both SOD1−/− and wild type mice were pre‐cleared and incubated with the anti‐GPX1 antibody (Abfrontier, Seoul, South Korea) and the protein G agarose beads, the precipitates were subjected to SDS‐PAGE for separating the GPX1 protein band that was excised and digested in situ. The in‐gel‐extracted tryptic peptides were reconstituted for nanoLC‐MS/MS analysis. The identified peptides covered over 90% GPX1 protein sequence for both genotype samples. Notably, the 47th residue in the tryptic peptide (residues 37–52) of GPX1 exhibited two forms: the projected native selenocysteine and the Se‐lost dehydra‐alanine. Using extracted ion chromatogram and multiple reaction monitoring analyses, we found the ratio between the SOD1−/− and the wild type for selenocysteine and the dehydra‐alanine substitute was 0.65 and 1.3, respectively. There were no genotype differences in several other peptide modifications on the hepatic GPX1 protein. In conclusion, the relative abundance change of the selenocysteine residue into the dehydra‐alanine form in the hepatic GPX1 protein of the SOD1−/− mice matched closely to the decrease of the enzyme specific activity. Likely, the physiological level of SOD1 activity plays an important role in maintaining the integrity of selenocysteine in the hepatic GPX1 protein in vivo. (NIH DK 53018 TO XGL).

Protection of DNA and membrane from γ-radiation induced damage by the extract of Acorus calamus Linn.: An in vitro study

Acorus calamus, an ethnomedicinally important plant, was investigated for its protecting activity against radiation induced DNA and membrane damage. The in vitro free radical scavenging activity of the extract (water:ethanol, 1:1) of A. calamus was studied by parameters viz DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical scavenging activity, hydroxyl radical scavenging activity, and superoxide radical scavenging activity. Membrane damage due to radiation exposure was measured as the peroxidation of lipids in terms of thiobarbituric acid reacting substance (TBARS). The in vitro DNA damage was monitored by assessing the radiation induced relaxation of supercoiled plasmid DNA (pBR322). Damage to cellular DNA induced by γ-radiation (6 Gy) was monitored by alkaline single cell gel electrophoresis or comet assay in murine cells and human peripheral blood leukocytes. Enhancement of DNA repair mechanism was also monitored. The extract effectively scavenged free radicals in a concentration dependent manner. Presence of A. calamus extract during irradiation prevented peroxidation of membrane lipids in mouse liver homogenate. It helped to reduce the disappearance of the covalently closed circular (ccc) form of plasmid DNA following exposure to γ-radiation. Also the A. calamus extract effectively protected DNA from radiation induced strand breaks and enhanced the DNA repair process. Hence A. calamus extract can be used as a good source of natural radioprotecting agent.

Isosorbide-based cholinesterase inhibitors; replacement of 5-ester groups leading to increased stability

Isosorbide-2-carbamate-5-esters are highly potent and selective butyrylcholinesterase inhibitors with potential utility in the treatment of Alzheimer’s Disease (AD). They are stable in human plasma but in mouse plasma they undergo hydrolysis at the 5-ester group potentially attenuating in vivo potency. In this paper we explore the role of the 5-position in modulating potency. The focus of the study was to increase metabolic stability while preserving potency and selectivity. Dicarbamates and 5-keto derivatives were markedly less potent than the ester class. The 2-benzylcarbamate-5-benzyl ether was found to be potent (IC 50 52 nM) and stable in the presence of mouse plasma and liver homogenate. The compound produces sustained moderate inhibition of mouse butyrylcholinesterase at 1 mg/kg, IP.

Potent hepatoprotective effect in CCl4-induced hepatic injury in mice of phloroacetophenone from Myrcia multiflora

Background: This study investigated the hepatoprotective effect and antioxidant properties of phloroacetophenone (2′,4′,6′-trihydroxyacetophenone – THA), an acetophenone derived from the plant Myrcia multiflora.Material & Method: The free radical scavenging activity in vitro and induction of oxidative hepatic damage by carbon tetrachloride (CCl4) (0.5 ml/kg, i.p.) were tested in male Swiss mice (25±5 g).Results: This compound exhibited in vitro antioxidant effects on FeCl2–ascorbate-induced lipid peroxidation (LPO) in mouse liver homogenate, scavenging hydroxyl and superoxide radicals, and 2,2-diphenyl-1-picrylhydrazyl. The in vivo assays showed that THA significantly (p<0.01) prevented the increases of hepatic LPO as measured by the levels of thiobarbituric acid-reactive substances, mitochondrial swelling. It also protected hepatocytes against protein carbonylation and oxidative DNA damage. Consistent with these observations, THA pre-treatment normalized the activities of antioxidant enzymes, such as catalase, glutathione peroxidase, and superoxide dismutase, and increased the levels of reduced glutathione (GSH) in CCl4-treated mice. In addition, THA treatment significantly prevented the elevation of serum enzymatic activities of alanine amino transferase, aspartate amino transferase, and lactate dehydrogenase, as well as histological alterations induced by CCl4. Silymarin (SIL) (24 mg/kg), a known hepatoprotective drug used for comparison, led to a significant decrease (p<0.01) in activities of theses enzymes in way very similar to that observed in pre-treatment with THA.Conclusion: These results suggest that the protective effects are due to reduction of oxidative damage induced by CCl4 resulting from the antioxidant properties of THA.