cDNA cloning and 1.75 A crystal structure determination of PPL2, an endochitinase and N-acetylglucosamine-binding hemagglutinin from Parkia platycephala seeds

Parkia platycephala lectin 2 was purified from Parkia platycephala (Leguminosae, Mimosoideae) seeds by affinity chromatography and RP-HPLC. Equilibrium sedimentation and MS showed that Parkia platycephala lectin 2 is a nonglycosylated monomeric protein of molecular mass 29 407+/-15 Da, which contains six cysteine residues engaged in the formation of three intramolecular disulfide bonds. Parkia platycephala lectin 2 agglutinated rabbit erythrocytes, and this activity was specifically inhibited by N-acetylglucosamine. In addition, Parkia platycephala lectin 2 hydrolyzed beta(1-4) glycosidic bonds linking 2-acetoamido-2-deoxy-beta-D-glucopyranose units in chitin. The full-length amino acid sequence of Parkia platycephala lectin 2, determined by N-terminal sequencing and cDNA cloning, and its three-dimensional structure, established by X-ray crystallography at 1.75 A resolution, showed that Parkia platycephala lectin 2 is homologous to endochitinases of the glycosyl hydrolase family 18, which share the (betaalpha)8 barrel topology harboring the catalytic residues Asp125, Glu127, and Tyr182.     

Purification, chemical, and immunochemical properties of a new lectin from Mimosoideae (Parkia discolor)

A glucose/mannose-binding lectin was isolated from seeds of Parkia discolor (Mimosoideae) using affinity chromatography on Sephadex G-100 gel. The protein presented a unique component in SDS-PAGE corresponding to a molecular mass of 58,000 Da, which is very similar to that of a closely related lectin from Parkia platycephala. Among the simple sugars tested, mannose was the best inhibitor, but biantennary glycans, containing the trimannoside core, present in N-glycoproteins, also seem to be powerful inhibitors of the haemagglutinating activity induced by the purified lectin. The protein was characterised by high content of glycine and proline and absence of cysteine. Rabbit antibodies, anti-P. platycephala seed lectin, recognised the P. discolor lectin. However, no cross-reaction was observed when a set of other legume lectins from sub-family Papilionoideae and others from families Moraceae and Euphorbiaceae were assayed with the Parkia lectins. This suggests that Parkia lectins comprise a new group of legume lectins exhibiting distinct characteristics.     

The first crystal structure of a Mimosoideae lectin reveals a novel quaternary arrangement of a widespread domain

The crystal structures of the apo and mannose-bound Parkia platycephala seed lectin represent the first structure of a Mimosoideae lectin and a novel circular arrangement of beta-prism domains, and highlight the adaptability of the beta-prism fold as a building block in the evolution of plant lectins. The P.platycephala lectin is a dimer both in solution and in the crystals. Mannose binding to each of the three homologous carbohydrate-recognition domains of the lectin occurs through different modes, and restrains the flexibility of surface-exposed loops and residues involved in carbohydrate recognition. The planar array of carbohydrate-binding sites on the rim of the toroid-shaped structure of the P.platycephala lectin dimer immediately suggests a mechanism to promote multivalent interactions leading to cross-linking of carbohydrate ligands as part of the host strategy against phytopredators and pathogens. The cyclic structure of the P.platycephala lectin points to the convergent evolution of a structural principle for the construction of lectins involved in host defense or in attacking other organisms.     

The amino-acid sequence of the glucose/mannose-specific lectin isolated from Parkia platycephala seeds reveals three tandemly arranged jacalin-related domains.

A mannose/glucose-specific lectin was isolated from seeds of Parkia platycephala, the most primitive subfamily of Leguminosae plants. The molecular mass of the purified lectin determined by mass spectrometry was 47 946 +/- 6 Da (by electrospray ionization) and 47 951 +/- 9 Da (by matrix-assisted laser-desoption ionization). The apparent molecular mass of the lectin in solutions of pH in the range 4.5-8.5 determined by analytical ultracentrifugation equilibrium sedimentation was 94 +/- 3 kDa, showing that the protein behaved as a non-pH-dependent dimer. The amino-acid sequence of the Parkia lectin was determined by Edman degradation of overlapping peptides. This is the first report of the primary structure of a Mimosoideae lectin. The protein contained a blocked N-terminus and a single, nonglycosylated polypeptide chain composed of three tandemly arranged homologous domains. Each of these domains shares sequence similarity with jacalin-related lectin monomers from Asteraceae, Convolvulaceae, Moraceae, Musaceae, Gramineae, and Fagaceae plant families. Based on this homology, we predict that each Parkia lectin repeat may display a beta prism fold similar to that observed in the crystal structure of the lectin from Helianthus tuberosus. The P. platycephala lectin also shows sequence similarity with stress- and pathogen-upregulated defence genes of a number of different plants, suggesting a common ancestry for jacalin-related lectins and inducible defence proteins.     

Gastroprotective potential of risperidone, an atypical antipsychotic, against stress and pyloric ligation induced gastric lesions

Risperidone has been used in some stress disorders and may be potentially protective against stress-induced gastric lesions. Thus, the aim of the present study is to investigate, whether risperidone, a D(2) receptor and 5-HT(2A) receptor antagonist, would be able to result in gastroprotective effect in stress-induced lesions and also explore the possible mechanism of action behind its gastroprotective activity. Gastroprotective activity of risperidone was evaluated both by single treatment and 21 days repeated (0.03, 0.1, 0.3 and 1mg/kg, p.o.) treatment in the cold restraint stress (CRS) model and 21 days repeated treatment in the pyloric ligation (PL) model and compared with that of sulpiride (D(2) receptor antagonist) and ketanserin (5-HT(2) receptor antagonist) as standard. Histopathological assessment was done to evaluate the gastroprotective activity of risperidone in CRS model. The roles of nitric oxide (NO), sulfhydryl (SH) group, ATP-sensitive K(+) channels (K(ATP) channels) and prostaglandins (PGs) in the gastroprotective effect of risperidone against CRS were also investigated. PGE(2), hexosamine as a marker of mucus barrier and microvascular permeability were also estimated. Results show that repeated treatment of risperidone, sulpiride and ketanserin exhibited a gastroprotective effect against CRS-induced lesions while single administration of risperidone was found to be ineffective. Moreover, repeated treatment of risperidone and ketanserin was found to be ineffective in case of PL in contrast to sulpiride. Risperidone pretreatment reverses the stress induced alteration in hexosamine, PGE(2) and microvascular permeability. Pretreatment with l-NAME, NEM, glibenclamide and indomethacin reversed the gastroprotective effect of risperidone. The results suggest that risperidone has significant gastroprotective effects in CRS-induced gastric lesions models, which appears to be mediated by endogenous NO, SH, PGs and K(ATP) channel opening.     

Gastroprotective and Ulcer Healing Effects of Essential Oil of Hyptis martiusii Benth. (Lamiaceae)

Hyptis martiusii Benth. is an aromatic plant found in abundance in northeastern Brazil that is used in ethnomedicine to treat gastric disorders. The aim of this study was to elucidate the mechanisms of action involved in the gastroprotection of the essential oil of Hyptis martiusii (EOHM) and to evaluate its healing capacity. Wistar rats were exposed to different protocols and subsequently were treated with 1% Tween-80 aqueous solution (negative control), pantoprazole, carbenoxolone, N-acetylcysteine (depending on the specificity of each model) or EOHM. The antisecretory activity (basal or stimulated) was determined using the pyloric ligature method. The gastroprotective action of nitric oxide and sulphydryl groups (–SH groups), as well as the quantification of adherent mucus and the levels of malondialdehyde and –SH groups in gastric mucosa, were evaluated using ethanol-induced gastric ulcer model. The healing ability was evaluated using the acetic acid-induced gastric ulcer model and histological and immunohistochemical analysis (HE, PAS and PCNA). EOHM (400 mg/kg) reduced the volume and acidity of gastric secretion stimulated by histamine and pentagastrin. The gastroprotective effect of EOHM involves the participation of endogenous sulfhydryl groups. EOHM increased mucus production (54.8%), reduced levels of MDA (72.5%) and prevented the depletion of –SH groups (73.8%) in the gastric mucosa. The treatment with EOHM reduced in 70.3% the gastric lesion area, promoting significant regeneration of the gastric mucosa, as confirmed by histological analysis and analysis of proliferating cell nuclear antigen. The results show that gastroprotective effect of EOHM is mediated by cytoprotective and antioxidant mechanisms and by their antisecretory activity, and suggest that the essential oil of Hyptis martiusii is a promising candidate for the treatment of gastric ulcers.     

Three new species of Parkia (Leguminosae: Mimosoideae) from tropical South America

Parkia cachimboensis andP. bahiae are described from central and eastern Brazil respectively. The third new species,P. panurensis, which is widespread in central and western Amazonia, has passed hitherto under the incorrect nameP. pectinata (Willd.) Benth.     

Role of polyamines in gastroprotection induced by epidermal growth factor.

Polyamines have been shown to stimulate cellular growth and differentiation, though their role in the prevention of acute gastric lesion induced by various noxious agents has been little studied. Epidermal growth factor (EGF) exhibits gastroprotective and ulcer healing properties due to its potent mitogenic and growth promoting action. This study was designed to compare the gastroprotective effects of spermine and EGF against gastric damage induced by absolute ethanol, acidified aspirin and stress and to determine the role of endogenous polyamines in EGF-induced gastroprotection. Spermine and EGF significantly reduced the lesions induced by all three ulcerogens. Oral administration of spermine or subcutaneous infusion of EGF in 24 h fasted rats with chronic gastric fistula resulted in similar inhibition of gastric acid and pepsin secretion. Pretreatment with difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase (ODC), a key enzyme in the biosynthesis of polyamines, did not affect ethanol lesions, but reversed the protective effect EGF but not spermine against ethanol. This finding indicates that polyamines mediate, at least in part, EGF-induced gastroprotection. In tests with oral administration of aminoguanidine that is known to suppress the activity of diamino-oxidase (DAO) and to inhibit the degradation of polyamines, EGF showed a markedly enhanced gastroprotective activity against ethanol damage. Since indomethacin failed to affect the gastroprotective effects of spermine and EGF and neither of these agents influenced the mucosal generation of PGE2 in intact or injured gastric mucosa, we conclude that prostaglandins are not the major factors in spermine- and EGF-induced gastroprotection. This study demonstrates that polyamines are highly effective against gastric lesions induced by various ulcerogens and that they act as primary mediators of EGF-induced gastroprotection.     

Effect of menthol in experimentally induced ulcers: Pathways of gastroprotection

Based on ethnopharmacological indications that Mentha species may be used in the treatment of gastrointestinal diseases, this study aimed to characterize the gastroprotective mechanisms of menthol (ME), the major compound of the essential oil from species of the genus Mentha. The gastroprotective action of ME was analyzed in gastric ulcers that were induced by ethanol or indomethacin in Wistar male rats. The mechanisms responsible for the gastroprotective effect were assessed by analyzing the amount of mucus secreted, involvement of non-protein sulfhydryl (NP-SH) compounds, involvement of calcium ion channels and NO/cGMP/K⁺_ATP pathway, gastric antisecretory activity and the prostaglandin E₂ (PGE₂) production. The anti-diarrheal activity and acute toxicity of ME were also evaluated. Oral treatment with ME (50 mg/kg) offered 88.62% and 72.62% of gastroprotection against ethanol and indomethacin, respectively. There was an increased amount of mucus and PGE₂ production. The gastroprotective activity of ME involved NP-SH compounds and the stimulation of K⁺_ATP channels, but not the activation of calcium ion channels or the production of NO. The oral administration of ME induced an antisecretory effect as it decreased the H⁺ concentration in gastric juice. ME displayed anti-diarrheal and antiperistaltic activity. There were no signs of toxicity in the biochemical analyses performed in the rats’ serum. These results demonstrated that ME provides gastroprotective and anti-diarrheal activities with no toxicity in rats.     

Two novel lectins from Parkia biglandulosa and Parkia roxburghii: isolation, physicochemical characterization, mitogenicity and anti-proliferative activity

Two mannose/glucose specific seed lectins were isolated from Parkia biglandulosa and Parkia roxburghii and were characterized w.r.t various physicochemical properties. Unlike other Parkia lectins a comparison of native and subunit molecular mass showed that both Parkia lectins were heterotetramers. Parkia biglandulosa lectin was found to be T-cell mitogen as revealed by IL-2 bioassay. These lectins showed anti-proliferative effect on two murine macrophage cancer cell lines i.e. P 388DI (50%) and J774 (70%). In addition Parkia roxburghii also inhibited proliferation of HB98 (65.47%), a B-cell hybridoma cell line.     

New polycyclic pyrimidine derivatives with antiplatelet in vitro activity: synthesis and pharmacological screening

The preparation and the pharmacological screening of novel anti-aggregatory/antiphlogistic polycyclic pyrimidine derivatives are described. The compounds were developed starting from bioactive 2-aminobenzopyranopyrimidine derivatives in order to assess the importance of the benzopyrano[4,3-d]pyrimidine structure and the role of an amino basic moiety in position 2. Antiplatelet activity was assessed in vitro against ADP and arachidonic acid-induced aggregation in guinea-pig plasma. Anti-inflammatory/analgesic/antipyretic activities were studied in rat paw oedema, mouse writhing test and E. coli-induced rat fever. Ulcerogenic and gastroprotective effects were also investigated in vivo on rat gastric mucosa. Among the tested compounds, the 5-substituted benzopyranopyrimidine derivatives 3d and 4d proved to be the most active antiplatelet agents as potent as acetylsalicylic acid against arachidonic acid-stimulated aggregation. Furthermore the 2-methylthio derivative 4d was endowed with greater efficacy against ADP aggregation suggesting that additional non-TXA2 dependent mechanisms are involved in its biological activity. Orally administered at 100 mg kg(-1) in rats this latter compound displayed antiphlogistic acitivity comparable to indomethacin (10 mg kg(-1)) coupled with an unusual gastroprotective effect on ethanol-induced ulcers. In conclusion, these findings indicate that the 5-pyrrolidino-2-methylthiobenzopyrano[4,3-d]pyrimidine 4d fulfils the chemical requirements to exhibit antiplatelet activity associated with gastroprotective effect.     

Tryptamine-gallic acid hybrid prevents non-steroidal anti-inflammatory drug-induced gastropathy: correction of mitochondrial dysfunction and inhibition of apoptosis in gastric mucosal cells

We have investigated the gastroprotective effect of SEGA (3a), a newly synthesized tryptamine-gallic acid hybrid molecule against non-steroidal anti-inflammatory drug (NSAID)-induced gastropathy with mechanistic details. SEGA (3a) prevents indomethacin (NSAID)-induced mitochondrial oxidative stress (MOS) and dysfunctions in gastric mucosal cells, which play a pathogenic role in inducing gastropathy. SEGA (3a) offers this mitoprotective effect by scavenging of mitochondrial superoxide anion (O(2)(·-)) and intramitochondrial free iron released as a result of MOS. SEGA (3a) in vivo blocks indomethacin-mediated MOS, as is evident from the inhibition of indomethacin-induced mitochondrial protein carbonyl formation, lipid peroxidation, and thiol depletion. SEGA (3a) corrects indomethacin-mediated mitochondrial dysfunction in vivo by restoring defective electron transport chain function, collapse of transmembrane potential, and loss of dehydrogenase activity. SEGA (3a) not only corrects mitochondrial dysfunction but also inhibits the activation of the mitochondrial pathway of apoptosis by indomethacin. SEGA (3a) inhibits indomethacin-induced down-regulation of bcl-2 and up-regulation of bax genes in gastric mucosa. SEGA (3a) also inhibits indometacin-induced activation of caspase-9 and caspase-3 in gastric mucosa. Besides the gastroprotective effect against NSAID, SEGA (3a) also expedites the healing of already damaged gastric mucosa. Radiolabeled ((99m)Tc-labeled SEGA (3a)) tracer studies confirm that SEGA (3a) enters into mitochondria of gastric mucosal cell in vivo, and it is quite stable in serum. Thus, SEGA (3a) bears an immense potential to be a novel gastroprotective agent against NSAID-induced gastropathy.     

Ethanol-Induced Gastric Injury: Microscopic Analysis of the Protective Effect of Frutalin

Obtained from breadfruit seeds (Artocarpus incisa), frutalin (FTL) has a range of important pharmacological properties. FTL activates and modulates lymphocytes and neutrophils and possesses gastroprotective effects. The purpose of this study was to evaluate the ability of FTL to protect the gastric mucosa of mice submitted to ethanol-induced gastric injury. The gastroprotective effect of frutalina was evaluated using a murine model of ethanol-induced gastric injury. Damage of the gastric mucosa was assessed morphologically by light, scanning electron and atomic force microscopy. Lymphocyte infiltration, necrosis, disruption of the mucosal structures and epithelial desquamation were observed in the control group. In the group pretreated with frutalina at 0.5 mg/kg, gastroprotection, reduced tissue damage and preserved submucosal and mucosal structures were observed. In conclusion, FTL displayed gastroprotective activity against ethanol-induced gastric injury, preventing the formation of gastric ulcer and reducing epithelial desquamation, glandular damage, mucosal necrosis and infiltration. The observed effects appear to be due to mechanisms previously described for frutalin.     

Gastroprotective action of Cissus quadrangularis extract against NSAID induced gastric ulcer: role of proinflammatory cytokines and oxidative damage

The objective of this research was to analyse the gastroprotective effect of Cissus quadrangularis extract (CQE) along with its mechanism underlying the therapeutic action against the gastric mucosal damage induced by aspirin. In this study, we investigated the effect of CQE on the course of experimentally induced gastric ulcer by analyzing the levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), microvascular permeability, activity of nitric oxide synthase-2 (NOS-2), mitochondrial antioxidants, lipid peroxidation and DNA damage. A significant increase in vascular permeability, NOS-2 activity, TNF-alpha, IL-1beta levels and oxidative damage were noted in aspirin administered rats. Pretreatment with CQE (500 mg/kg bw/day) by oral gavage for 7 days significantly attenuated these biochemical changes caused by aspirin in rats. Tissue damage was showed by decreased levels of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) and an associated rise in lipid peroxidation (LPO) in mitochondria, which were reversed by CQE. In addition, CQE prevents oxidative damage of DNA by reducing DNA fragmentation indicating its block on cell death. Ulcer protection in CQE treated rats was confirmed by histoarchitecture, which was comprised of reduced size of ulcer crater and restoration of mucosal epithelium. Thus, reduced neutrophil infiltration, antiapoptotic and antioxidant action have a pivotal role in the gastroprotective effect of CQE.     

Gastroprotective Mechanisms of the Monoterpene 1,8-Cineole (Eucalyptol)

Recently, our research group identified and reported 1,8-cineole (CIN), a monoterpene that naturally occur in many aromatic plants, as one of the major constituent of the essential oil from leaves of Hyptis martiusii (EOHM), as well as characterized the gastroprotective action of this oil. The aim of this study was to investigate the mechanisms of action involved in the antiulcer and healing activity of CIN, in order to confirm its correlation with the gastroprotective effect of EOHM. Wistar rats were exposed to different protocols (acute ulceration, gastrointestinal motility and antisecretory activity). In addition, were determinated the involvement of nitric oxide and sulphydryl groups; the levels of gastric mucus, lipid peroxidation, sulphydryl groups and myeloperoxidase activity. The healing ability was evaluated by acetic acid-induced chronic ulcer and histological and immunohistochemical analysis (PCNA, Ki-67 and BrdU). The treatment with CIN inhibited ethanol-, ethanol/HCl- and indomethacin-induced gastric lesions. The highest doses of CIN inhibited gastric emptying, but did not affect intestinal transit. CIN (100 mg/kg) reduced the volume of basal but not stimulated acid secretion. CIN increased levels of mucus (89.3%), prevented depletion of –SH groups (62.6%) and reduced the level of lipid peroxidation (55.3%) and myeloperoxidase activity (59.4%) in the gastric mucosa. In chronic ulcer model, CIN reduced in 43.1% the gastric area lesion, promoted significant regeneration and restoration of the levels of mucus in glandular cells as confirmed by histological analysis; and promoted increase in cell proliferation as evidenced by reactivity for PCNA, Ki-67 and BrdU. This findings demonstrate the role of 1,8-cineole as an important ulcer healing agent and indicate the involvement of antioxidant and cytoprotective mechanisms in the gastroprotective effect of compound. This study also provides evidence that 1,8-cineole is related to the gastroprotective effect of the essential oil of Hyptis martiusii.     

Effect of the method of preparation on the composition and cytotoxic activity of the essential oil of Pituranthos tortuosus

The aerial parts of Pituranthos tortuosus (Desf.) Benth and Hook (Apiaceae), growing wild in Egypt, yielded 0.8%, 0.6%, and 1.5% (v/w) of essential oil when prepared by hydrodistillation (HD), simultaneous hydrodistillation-solvent (n-pentane) extraction (Lickens-Nickerson, DE), and conventional volatile solvent extraction (preparation of the "absolute", SE), respectively. GC-MS analysis showed that the major components in the HD sample were beta-myrcene (18.81%), sabinene (18.49%), trans-iso-elemicin (12.90%), and terpinen-4-ol (8.09%); those predominent in the DE sample were terpinen-4-ol (29.65%), sabinene (7.38%), gamma-terpinene (7.27%), and beta-myrcene (5.53%); while the prominent ones in the SE sample were terpinen-4-ol (15.40%), dill apiol (7.90%), and allo-ocimene (4E,6Z) (6.00%). The oil prepared in each case was tested for its cytotoxic activity on three human cancer cell lines, i.e., liver cancer cell line (HEPG2), colon cancer cell line (HCT116), and breast cancer cell line (MCF7). The DE sample showed the most potent activity against the three human cancer cell lines (with IC50 values of 1.67, 1.34, and 3.38 microg/ml against the liver, colon, and breast cancer cell lines, respectively). Terpinen-4-ol, sabinene, gamma-terpinene, and beta-myrcene were isolated from the DE sample and subjected to a similar evaluation of cytotoxic potency; significant activity was observed.     

Evaluation of in vivo biological activity profile of isoorientin

Anti-nociceptive, anti-inflammatory and gastroprotective activities of the known C-glycosyl flavonoid, isoorientin, were studied in rats and mice. For the anti-nociceptive activity assessment the p-benzoquinone-induced writing test, for the anti-inflammatory activity the carrageenan-induced hind paw edema model in mice, and for the gastroprotective activity the EtOH-induced ulcerogenesis model in rats were used. Isoorientin was shown to possess significant anti-nociceptive and anti-inflammatory activities at 15 mg/kg and 30 mg/kg doses, without inducing any apparent acute toxicity as well as gastric damage. However, the compound did not possess any significant gastroprotective activity against EtOH-induced ulcerogenesis.     

Gastroprotective and ulcer-healing activity of oleanolic acid derivatives: in vitro-in vivo relationships

The triterpene oleanolic acid 1 and its semisynthetic derivatives 2-7 were assessed for gastroprotective and ulcer-healing effect using human epithelial gastric cells (AGS) and human lung fibroblasts (MRC-5). The ability of the compounds to protect the AGS cells against the damage induced by sodium taurocholate (NaT), to stimulate the cellular reduced glutathione (GSH) and prostaglandin E(2) content, to enhance AGS and MRC-5 cell proliferation and to scavenge superoxide anion in vitro was studied. The cytotoxicity of the compounds was assessed towards MRC-5 and AGS cells. In addition, the gastroprotective activity of the compounds was assessed in vivo using the HCl/EtOH-induced ulcer model in mice. All the assayed compounds displayed a significant reduction of AGS cells damage after incubation with NaT. None of the studied compounds was active as a superoxide anion scavenger nor stimulated the GSH content in AGS cell cultures. Compounds 1, 2, 4 and 6 were able to increase the prostaglandin content in AGS cell cultures. Concerning the proliferation assays, a significant stimulating effect was observed for compounds 3 and 7 on AGS cells and for 1 and 7 on MRC-5 fibroblasts. Regarding cytotoxicity, derivatives 2, 4, 6 and 7 were less toxic than the parent compound oleanolic acid. Our results strongly support the predictive capacity of the in vitro assessment of gastroprotective activity allowing the reduction of experimental animals.     

Unusual mitochondrial genome structure of the freshwater goby Odontobutis platycephala: rearrangement of tRNAs and an additional non-coding region

Mitochondrial DNA was isolated from the Korean freshwater gobioid fish Odontobutis platycephala by long-polymerase chain reaction with conserved primers and this mtDNA was sequenced by primer walking using flanking sequences as sequencing primers. The resultant O. platycephala mtDNA sequence was found to be 17 588 bp in size with a mostly conserved structural organization when compared with that of other teleost fish. Rearrangements of tRNAs (tRNA-Ser, tRNA-Leu, tRNA-His) and an additional non-coding region (533 bp) were present between the ND4 and ND5 genes. In the present paper, the basic characteristics of the O. platycephala mitochondrial genome is reported, including its structural organization, base composition of rRNAs, tRNAs and protein-encoding genes, characteristics of mitochondrial tRNAs and the peculiar rearrangement features of some parts of the mtDNA. Phylogenetic analysis performed using the cytochrome b gene sequences of 16 Korean freshwater fishes (15 gobioids) with the Bayesian algorithm showed that O. platycephala forms a clade (1·00 of posterior probability) with other species of Odontobutis . This suggests that the observed rearrangement between the ND4 and ND5 genes in the O. platycephala mitogenome reflects independent events.     

Protective role of ellagitannins from Eucalyptus citriodora against ethanol-induced gastric ulcer in rats: Impact on oxidative stress,inflammation and calcitonin-gene related peptide

The gastroprotective activity of an ellagitannin-rich fraction obtained from Eucalyptus citriodora (ECF) was investigated against ethanol-induced gastric ulceration in rats. The rats were pretreated with ECF (25, 50 and 100 mg/kg) 1 h before the administration of absolute ethanol to induce acute gastric ulceration. The gastric lesions were significantly reduced by all doses of ECF. Notably, pre-treatment with ECF (100 mg/kg) conferred 99.6% gastroprotection, which is significantly higher than that produced by omeprazole. Moreover, ECF administration markedly increased the mucin content in a dose-dependent manner. The potent gastroprotective effect of ECF could be partly mediated by attenuating ethanol-induced oxidative stress. ECF-pre-treatment markedly increased the depleted GSH and SOD levels in a dose-dependent manner. Moreover, ECF significantly decreased the elevated MDA tissue levels induced by ethanol administration. The results demonstrated that ECF administration exerted a powerful anti-inflammatory activity as evidenced by the reduction in the pro-inflammatory markers; IL-1β, TNF-α, 5-LO and COX-2. Additionally, the caspase-3 tissue levels were significantly reduced in the groups pre-treated with ECF. These results suggest that ECF could exert a beneficial gastroprotective effect through their antioxidant, anti-inflammatory and anti-apoptotic properties. Furthermore, ECF pre-treatment significantly attenuated the ethanol-induced decrease in CGRP expression, which has a protective role against gastric ulceration. Histopathological examination revealed intact mucosal layer, absence of hemorrhage and necrosis in groups treated with ECF. Ellagitannins were identified as the major active constituents responsible for the marked antioxidant and gastroprotective properties of ECF. The HPLC–PDA–ESI/MS/MS technique was employed to identify the ellagitannins of E. citriodora.