Acute toxicity and gastroprotective effect of the Schiff base ligand ¹H-indole-3-ethylene-5-nitrosalicylaldimine and its nickel (II) complex on ethanol induced gastric lesions in rats

Elaboration of novel urea bearing schiff bases as potent in vitro anticancer candidates with low in vivo acute oral toxicity

A novel series of urea Schiff base derivatives were synthesized via the condensation of o-phenylenediamine, naphthyl isocyanate and appropriate aryl aldehyde. The results of the in vitro cytotoxic activities of compounds 5a–h against cancer cells lines PC3, SKOV-3 and HeLa, revealed that almost all compounds exhibited good to moderate activities Compound 5g owing bromine atom at p-position displayed higher activity compared to homolog 5b possessing chlorine atom due to adequate diameter of bromine which is more favourable than chlorine for the inhibition activity. In addition, compound 5h is the best candidate of this series exhibiting excellent activity for three cancer cells lines. Compound 5h demonstrated also an excellent activity with IC50 value of 0.6±0.3μg/mL for prostate cancer cell line PC3 and it is considered more effective than the standard drug doxorubicin Dox (IC50 = 2.6±0.03μg/mL). The most active compound 5h displayed the best activity against ovarian cancer cell line SKOV3 with IC50 = 1.8±0.2μg/mL. This results are higher than clinically used drug Dox (IC50. 2.2±0.02μg/mL). The results of screening activities cytotoxic effect toward cervix cancer cell line HeLa, affirm that compound 5h manifest an activity with IC50 value of 2.2±0.4μg/mL comparable to Dox (IC50. 1.9±0.04μg/mL). In the current study, in vivo acute oral toxicity assessment of urea Schiff base hybrid compounds 5a – h indicated that there was no mortality on treated female mice during 14 days assessment test compared with the vehicle-treated group confirming the safety with LD50 greater than 2000 mg/kg. In the actual study, the results affirmed that compounds 5a–h manifested in vivo no toxicity to saint cells, the compounds 5b, 5g and 5h presented higher anticancer activities against three cancer cells which authorizes promoters to use them as candidate anticancer agents.

Imine or Enamine? Insights and Predictive Guidelines from the Electronic Effect of Substituents in H-Bonded Salicylimines

Imine and enamine bonds decorate the skeleton of numerous reagents, catalysts, and organic materials. However, it is difficult to isolate at will a single tautomer, as dynamic equilibria occur easily, even in the solid state, and are sensitive to electronic and steric effect, including π-conjugation and H-bonding. Here, using as model Schiff bases generated from salicylaldehydes and TRIS in a set of linear free energy relationships (LFER), we disclose how the formation of either imines or enamines can be controlled and provide a comprehensive framework that captures the structural underpinning of this prediction. This work highlights the potentiality of tailor-made designs en route to compounds with desirable functionality.

In vivo acute toxicity and anti-gastric evaluation of a novel dichloro Schiff base: Bax and HSP70 alteration

Chlorine is shown to possess anti-gastric ulcer activity, since it can inactivate Helicobacter pylori, which is regarded as one of the most common risk factors for causing gastric problems. In the current study, the gastroprotective property of a novel dichloro-substituted Schiff base complex, 2, 2'- [-1, 2-cyclohexanediylbis(nitriloethylidyne)] bis(4-chlorophenol) (CNCP), against alcohol-induced gastric lesion in SD rats was assessed. SD rats were divided into four groups, i.e. normal, ulcer control, testing, and reference groups. Ulcer area, gastric wall mucus, and also gastric acidity of the animal stomachs were measured. In addition, antioxidant activity of CNCP was evaluated and its safe dose was identified. Immunohistochemistry staining was also carried to evaluate two important proteins, i.e. Bcl2-associated X protein (Bax) and heat shock protein 70 (HSP70). Moreover, the activities of super oxide dismutase and catalase, as well as the levels of prostaglandin E2 (PGE2) and malondialdehyde (MDA) were also measured. Antioxidant activity of CNCP was approved via the aforementioned experiments. Histological evaluations showed that the compound possesses stomach epithelial defense activity. Additionally, periodic acid-Schiff staining exhibited over-expression of HSP70 and down-expression of Bax protein in the CNCP-treated rats. Moreover, CNCP caused deceased MDA level and elevated PGE2 level, and at the same time increased the activities of the two enzymes.

Upper gastrointestinal pathophysiology due to mouse malaria Plasmodium berghei ANKA infection

Background

Epigastric pain, vomiting, and other gastrointestinal problems are among the most important symptoms of malaria infection as they suggest the possibility that the condition is serious. Pathophysiologies such as gastric mucosal changes and delayed gastric emptying have been reported in serious cases of malaria infection. However, it is unclear whether or not pathophysiological involvement of the upper gastrointestinal tract occurs in Plasmodium berghei ANKA (PbA)-infected mice.

Methods

PbA-infective Anopheles mosquitoes were used to infect mice via the natural route of infection. Fifteen PbA-C57BL/6 mice were used as a cerebral malaria model and the same numbers of PbA-BALB/c mice were used as a cerebral malaria-resistant model, and then we investigated the pathophysiological involvement of the stomach and small intestine.

Results

On day 8 post infection, six PbA-C57BL/6 mice showed cerebral malaria and nine others had uncomplicated infection. All the PbA-C57BL/6 mice on that same day showed severe weight loss with multiple, red gastric patches and changes to the course of the small intestine with villus goblet cell enlargement. In addition, cerebral malaria cases showed gastric gas retention with submucosal edema and small intestinal shortening. In PbA-BALB/c mice, overextension of the stomach and gas retention were evident from week 2 after PbA infection, as well as changes to the course of the small intestine and mesenteric thinning with fragility.

Conclusions

We described the upper gastrointestinal pathophysiology representing new findings directly linked to malarial severity and subsequent death in PbA-infected mice as a mouse model of malaria infection.

New transition metal complexes with a pendent indole ring: insights into the antifungal activity and mode of action

Development of new chemotherapeutic agents to treat multidrug-resistant fungal infections to augment the current treatment options is a must. In this direction, a series of mixed ligand complexes was synthesized from a Schiff base (L) obtained by the condensation of 2-hydroxynapthaldehyde and tryptamine, and 1,10-phenanthroline (1,10-phen) as a secondary ligand. Based on spectral characterization and physical measurements an octahedral geometry was assigned to [Co(phen)LClH₂O] (C2), [Ni(phen)LClH₂O](C3), and [Zn(phen)LClH₂O](C4) complexes while a distorted octahedral geometry was assigned to the [Cu(phen)LClH₂O](C1) complex. All the synthesized compounds were tested for antifungal activity against 11 Candida albicans isolates, including fluconazole (FLC) resistant isolates, by determining minimum inhibitory concentrations and studying growth curves. MIC results suggest that all the newly synthesized compounds have potent antifungal activity at varying levels. The rapid action of these compounds on fungal cells suggested a membrane-located target for their action.

Mixed ligand complexes containing a pendent indole showed significant proton pump ATPase targeted antifungal activity.

Synthesis, biological evaluation and corrosion inhibition studies of transition metal complexes of Schiff base

Background

The transition metal complexes formed from Schiff base is regarded as leading molecules in medicinal chemistry. Because of the preparative availability and diversity in the structure of central group, the transition metals are important in coordination chemistry. In the present work, we have designed and prepared Schiff base and its metal complexes (MC₁–MC₄) and screened them for antimicrobial, anticancer and corrosion inhibitory properties.

Methodology

The synthesized metal complexes were characterized by physicochemical and spectral investigation (UV, IR, ¹H and ¹³C-NMR) and were further evaluated for their antimicrobial (tube dilution) and anticancer (SRB assay) activities. In addition, the corrosion inhibition potential was determined by electrochemical impedance spectroscopy (EIS) technique.

Results and discussion

Antimicrobial screening results found complexes (MC₁–MC₄) to exhibit less antibacterial activity against the tested bacterial species compared to ofloxacin while the complex MC₁ exhibited greater antifungal activity than the fluconazole. The anticancer activity results found the synthesized Schiff base and its metal complexes to elicit poor cytotoxic activity than the standard drug (5-fluorouracil) against HCT116 cancer cell line. Metal complex MC₂ showed more corrosion inhibition efficiency with high R_ct values and low C_dl values.

Conclusion

From the results, we can conclude that complexes MC₁ and MC₂ may be used as potent antimicrobial and anticorrosion agents, respectively.

New applied pharmacological approach/trend on utilization of agro-industrial wastes

This study aimed to transform the locally available lignocellulosic residual palm frond (PF) and rice straw (RS) wastes into multifunction added products like methylated cellulose and sulfated and phosphorylated hemicelluloses by simple processes. Hydrolysis with 2 N sulfuric acid was the most suitable reaction for microcrystalline cellulose production. The characteristics of the prepared products were studied to obtain the optimum reaction conditions. Palm frond hemicellulose (PFHC) recorded the highest antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans (22, 22, 26 mm), respectively, and phosphorylated palm frond hemicellulose (PPFHC) exhibited the highest potential antioxidant activity of approximately 60%, suggesting a possible correlation between the two bioactivities. Most of extracted celluloses and their derivatives had a variety of promising probiotic activities which are expected to reduce the side effects of the gastric mucosa and possibly play a role in curing the gastric ulcer. Accordingly, the determination of anti-inflammatory and gastroprotective activity results revealed that methylcellulose, sulfated and phosphorylated hemicelluloses showed anti-inflammatory and gastroprotective activities and the capability of all tested compounds to ameliorate the ethanol-induced gastric ulcer in rats' stomach. All results recommended PF and RS and their derivatives to be used as a medicinal food.

The antiulcer effect of Cibotium barometz leaves in rats with experimentally induced acute gastric ulcer

Cibotium barometz is a pharmaceutical plant customarily used in traditional medicine in Malaysia for the treatment of different diseases, such as gastric ulcer. The gastroprotective effect of C. barometz leaves against ethanol-induced gastric hemorrhagic abrasions in Sprague Dawley rats has been evaluated in terms of medicinal properties. Seven groups of rats (normal control and ulcerated control groups, omeprazole 20 mg/kg, 62.5, 125, 250, and 500 mg/kg of C. barometz correspondingly) were used in antiulcer experiment and pretreated with 10% Tween 20. After 1 hour, the normal group was orally administered 10% Tween 20, whereas absolute alcohol was fed orally to ulcerated control, omeprazole, and experimental groups. Gastric's homogenate were assessed for endogenous enzymes activities. Stomachs were examined macroscopically and histologically. Grossly, the data demonstrated a significant decrease in the ulcer area of rats pretreated with plant extract in a dose-dependent manner with respect to the ulcerated group. Homogenates of the gastric tissue exhibited significantly increased endogenous enzymes activities in rats pretreated with C. barometz extract associated with the ulcerated control group. Histology of rats pretreated with C. barometz extract group using hematoxylin and eosin staining exhibited a moderate-to-mild disruption of the surface epithelium with reduction in submucosal edema and leucocyte infiltration in a dose-dependent manner. In addition, it showed heat shock protein70 protein up-expression and BCL2-associated X protein downexpression. These outcomes might be attributed to the gastroprotective and antioxidative effects of the plant.

Ulcer Prevention Effect Of 3,4,5-Tihydroxy-N0-[(2-Methyl-1H-Indol-3yl)Methylidene]Benzohydrazide In HCl/Ethanol-Induced Gastric Mucosal Damage In Rats

The newly synthesized, 3,4,5-Trihydroxy-N 0-[(2-methyl-1H-indol-3-yl)-methylidene] benzohydrazide (TIBH), is an indole and gallic acid derivative. The aim of this research investigation was to evaluate the acute toxicity and the ulcer prevention potential of TIBH in HCl/Ethanol-induced gastric ulcer rat model. Six groups of rats were orally received 5ml/kg of vehicle (1 % Carboxy methyl cellulose) for the normal and ulcer control groups each, Omeprazole (20mg/kg) for positive control, 50 mg/kg, 100 mg/kg and 200 mg/kg of TIBH for experimental groups, respectively. After one hour, instead of rats in the normal group which received 5ml/kg of 1% CMC, other groups received 5ml/kg of HCl/Ethanol. All rats were sacrificed after one additional hour. Gastric juice, gastric mucosa, morphologies of gastric ulcers and protein expressions of both control and treatment groups were evaluated. TIBH showed a ulcer prevention potential by increase of the mucus secretion, decrease of the gastric acidity, up-regulation of HSP70 protein, down-regulation of Bax protein, decrease of the lipid peroxidation and the increase of the Superoxide dismutase (SOD) activity in gastric tissue homogenate. Acute toxicity assay exposed valuable information on the safety of this compound. TIBH had a dose dependent ulcer prevention potential against HCl/Ethanol-triggered gastric ulcer.

Underlying mechanism for the modulation of apoptosis induced by a new benzoindole derivative on HT-29 colon cancer cells

DBID compound induced LDH leakage in HT-29 cells when compared to untreated cells.

Dhiyaaldeen S, Abdulaziz Bardi D, M. Salama S, Rouhollahi E, Karimian H, Abdolmalaki R, Azizan AHS, Mohd Ali H, Mohd Noor S, Abdulla MA. The Gastroprotective Effect of Vitex pubescens Leaf Extract against Ethanol-Provoked Gastric Mucosal Damage in Sprague-Dawley Rats

Vitex pubescens is a Malaysian therapeutic plant employed in traditional drug to remedy a variety of disorders. The purpose of this research is to assess the gastroprotective efficiency of V. pubescens leaves against ethanol-induced gastric hemorrhagic laceration in rats. Animals were randomly allocated into seven groups and pre-treated, separately, with 10% Tween 20 (normal and ulcer control groups), 20 mg/kg omeprazole (reference group), and 62.5, 125, 250, and 500 mg/kg of V. pubescens extract (experimental groups). All animals were sacrificed after another hour. Histological evaluation of the ulcer control group revealed significant injury to the gastric mucosa with edema and leucocyte infiltration of the submucosal layer. PAS staining, showed remarkably intense magenta color, remarkable increase of HSP70 and decrease of Bax proteins in rats pre-treated with plant extracts compared to the ulcer control group. Gastric homogenates revealed a remarkable increase in endogenous antioxidant enzyme activities (CAT, SOD, GSH) and a decrease in the lipid peroxidation level (MDA) in animals pre-treated with V. pubescens extract compared with the ulcer control group. The gastroprotective activity of this plant might be related to increased antioxidant enzymes and decrease lipid peroxidation upsurge of HSP70 and reduced expression of Bax proteins.

Synthesis, X-ray structure, spectroscopic properties and DFT studies of a novel Schiff base

A series of Schiff bases, salicylideneaniline derivatives 1-4, was synthesized under mild conditions and characterized by 1H NMR, HRMS, UV-Vis and fluorescence spectra, and single-crystal X-ray diffraction. In solid and aprotic solvents 1-4 exist mainly as E conformers that possess an intramolecular six-membered-ring hydrogen bond. A weak intramolecular C-H···F hydrogen bond is also observed in fluoro-functionalized Schiff base 4, which generates another S(6) ring motif. The C-H···F hydrogen bond further stabilizes its structure and leads it to form a planar configuration. Compounds 1-3 exhibit solely a long-wavelength proton-transfer tautomer emission, while dipole-functionalized Schiff base 4 shows remarkable dual emission originated from the excited-state intramolecular charge transfer (ESICT) and excited-state intramolecular proton transfer (ESIPT) states. Furthermore, the geometric structures, frontier molecular orbitals (MOs) and the potential energy curves for 1-4 in the ground and the first singlet excited state were fully rationalized by density functional theory (DFT) and time-dependent DFT calculations.

Gastroprotective activity of ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylidene) amino]benzoate against ethanol-induced gastric mucosal ulcer in rats

BACKGROUND

The study was carried out to determine the cytotoxic, antioxidant and gastro-protective effect of ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylid ene)amino] benzoate (ETHAB) in rats.

METHODOLOGY/PRINCIPAL FINDINGS

The cytotoxic effect of ETHAB was assessed using a MTT cleavage assay on a WRL68 cell line, while its antioxidant activity was evaluated in vitro. In the anti-ulcer study, rats were divided into six groups. Group 1 and group 2 received 10% Tween 20 (vehicle). Group 3 received 20 mg/kg Omeprazole. Groups 4, 5 and 6 received ETHAB at doses of 5, 10, and 20 mg/kg, respectively. After an hour, group 1 received the vehicle. Groups 2-6 received absolute ethanol to induce gastric mucosal lesions. In the WRL68 cell line, an IC50 of more than 100 µg/mL was observed. ETHAB results showed antioxidant activity in the DPPH, FRAP, nitric oxide and metal chelating assays. There was no acute toxicity even at the highest dosage (1000 mg/kg). Microscopy showed that rats pretreated with ETHAB revealed protection of gastric mucosa as ascertained by significant increases in superoxide dismutase (SOD), pH level, mucus secretion, reduced gastric lesions, malondialdehyde (MDA) level and remarkable flattened gastric mucosa. Histologically, pretreatment with ETHAB resulted in comparatively better gastric protection, due to reduction of submucosal edema with leucocyte infiltration. PAS staining showed increased intensity in uptake of Alcian blue. In terms of immunohistochemistry, ETHAB showed down-expression of Bax proteins and over-expression of Hsp70 proteins.

CONCLUSION/SIGNIFICANCE

The gastroprotective effect of ETHAB may be attributed to antioxidant activity, increased gastric wall mucus, pH level of gastric contents, SOD activity, decrease in MDA level, ulcer area, flattening of gastric mucosa, reduction of edema and leucocyte infiltration of the submucosal layer, increased PAS staining, up-regulation of Hsp70 protein and suppressed expression of Bax.

Schiff base metal derivatives enhance the expression of HSP70 and suppress BAX proteins in prevention of acute gastric lesion

Schiff base complexes have appeared to be promising in the treatment of different diseases and disorders and have drawn a lot of attention to their biological activities. This study was conducted to evaluate the regulatory effect of Schiff base metal derivatives on the expression of heat shock proteins (HSP) 70 and BAX in protection against acute haemorrhagic gastric ulcer in rats. Rats were assigned to 6 groups of 6 rats: the normal control (Tween 20 5% v/v, 5 mL/kg), the positive control (Tween 20 5% v/v, 5 mL/kg), and four Schiff base derivative groups named Schiff_1, Schiff_2, Schiff_3, and Schiff_4 (25 mg/kg). After 1 h, all of the groups received ethanol 95% (5 mL/kg) but the normal control received Tween 20 (Tween 20 5% v/v, 5 mL/kg). The animals were euthanized after 60 min and the stomachs were dissected for histology (H&E), immunohistochemistry, and western blot analysis against HSP70 and BAX proteins. The results showed that the Schiff base metal derivatives enhanced the expression of HSP70 and suppressed the expression of BAX proteins during their gastroprotection against ethanol-induced gastric lesion in rats.