Hypoglycemic, anti-inflammatory, and neuroprotective potentials of crude methanolic extract from Acacia nilotica L. - results of an in vitro study

Acacia nilotica L., also known as babul, belonging to the Fabaceae family and the Acacia genus, is typically used for ornamental purposes and also as a medicinal plant found in tropical and subtropical areas. This plant is a rich source of bioactive compounds. The current study aimed to elucidate the hypoglycemic, anti-inflammatory, and neuroprotective potential of A. nilotica's crude methanolic extract. The results of the in vitro antidiabetic assay revealed that methanolic extract of A. nilotica inhibited the enzyme α-glucosidase (IC50: 33 μg mL-1) and α-amylase (IC50: 17 μg mL-1) in a dose-dependent manner. While in the anticholinesterase enzyme inhibitory assay, maximum inhibition was shown by the extract against acetylcholinesterase (AChE) (637.01 μg mL-1) and butyrylcholinesterase (BChE) (491.98 μg mL-1), with the highest percent inhibition of 67.54% and 71.50% at 1000 μg mL-1, respectively. This inhibitory potential was lower as compared to the standard drug Galantamine that exhibited 82.43 and 89.50% inhibition at the same concentration, respectively. Moreover, the methanolic extract of A. nilotica also significantly inhibited the activities of cyclooxygenase 2 (COX-2) and 5-lipoxygenase (5-LOX) in a concentration-dependent manner. The percent inhibitory activity of 5-LOX and COX-2 ranged from 42.47% to 71.53% and 43.48% to 75.22%, respectively. Furthermore, in silico, in vivo, and clinical investigations must be planned to validate the above-stated bioactivities of A. nilotica.

Isolation, invitro, invivo anti-inflammatory, analgesic and antioxidant potential of Habenaria plantegania Lindl

Habenaira plantaginea belong to orchid family which is native to Asia. Members of this family are commonly famous for the cure of pain and inflammation. To date, no research was found on isolation of compounds from this plant for the treatment of inflammation and analgesia nor has been published to our knowledge. The purpose of this study was to evaluate an analgesic, anti-inflammatory and anti-oxidant activity of the isolated compound from the most potent chloroform sub-fraction and the isolated compounds form the habenaria plantaginea. Anti-inflammatory analgesic and antioxidant potential of the various chloroform sub-fractions and isolated compounds from the most potent sub-fraction (HP-1 & HP-1) were screened for their in vitro enzymatic assays. Furthermore, prior to in-vivo investigation, the isolated compounds were subjected for their toxicity study. The potent compound was then examined for acetic acid-induced writhing, hot plate test, carrageenan-induced inflammation assays. Further various phlogistic agents were used for the evaluation of mechanism. In the COX-2 inhibitory assay the chloroform sub fraction Cf-4 demonstrated excellent activity as compared to the other sub-fraction with 92.15% inhibition. The COX-2 enzyme make prostaglandins which are directly involved in inflammation. Likewise against 5-LOX the Cf-4 was the most potent sub-fraction with IC50 3.77 µg/mL. The 5-LOX catalyzes the biosynthesis of leukotrienes which is a group of lipid mediators of inflammation derived from arachidonic acid. Free radicals can induce inflammation through cellular damage while chronic inflammation generates a large number of free radicals, whose eventually lead to inflammation. In antioxidant assays the Cf-4 fraction was displayed excellent results against ABTS, DPPH and H2O2 free radical with 88.88, 77.44, and 65.52% inhibition at highest concentration. Likewise, the compound HP-1 demonstrated 88.81, 89.34 and 80.43% inhibition while compound HP-2 displayed 84.34, 91.52 and 82.34% inhibition against ABTS, DPPH and H2O2 free radical which were comparable to the standard drug ascorbic acid respectively. This study's findings validate the use of this species as traditional use.

Evaluation of Habenaria aitchisonii Reichb. for antioxidant, anti-inflammatory, and antinociceptive effects with in vivo and in silico approaches

Habenaria aitchisonii Reichb was analyzed in this research, including its chemical composition and its in vitro antioxidant, anti-inflammatory, acute oral toxicity, and antinociceptive activity. The chloroform and ethyl acetate fractions were found to be the most powerful based on in vitro antioxidant, anti-inflammatory, and analgesic assays. The acute oral toxicity of the crude methanolic extract was determined before in vivo studies. The acetic acid and formalin tests were used to measure the antinociceptive effect, and the potential mechanisms involved in antinociception were explored. The carrageenan-induced paw edema test was used to examine the immediate anti-inflammatory effect, and many phlogistic agents were used to determine the specific mechanism. Furthermore, for ex vivo activities, the mice were sacrificed, the forebrain was isolated, and the antioxidant levels of glutathione (GSH), superoxide dismutase (SOD), thiobarbituric acid reactive substances (TBARS) and catalase (CAT) were estimated using a UV spectrophotometer. No toxicity was seen at oral dosages up to 3,000 mg/kg. The antinociceptive impact was much higher than the standard drug. Both the inflammatory and neurogenic phases of the formalin experiment revealed an analgesic effect in the chloroform and ethyl acetate fractions. In carrageenan anti-inflammatory assays, the chloroform fraction (Ha.Chf) was the most potent fraction. We further studied the GC-MS of crude plant extract and found a total of 18 compounds. In the anti-inflammatory mechanism, it was observed that the Ha.Chf inhibits the COX-2 as well as 5-LOX pathways. The results exhibited that this species is a good source of phytocomponents like germacrone, which can be employed as a sustainable and natural therapeutic agent, supporting its traditional use in folk medicine for inflammatory conditions and pain.

Phenolic phytochemistry, in vitro, in silico, in vivo, and mechanistic anti-inflammatory and antioxidant evaluations of Habenaria digitata

Excessive and imbalance of free radicals within the body lead to inflammation. The objective of the current research work was to explore the anti-inflammatory and antioxidant potential of the isolated compounds from Habenaria digitata. In this study, the isolated phenolic compounds were investigated for in vitro and in vivo anti-inflammatory potential along with the antioxidant enzyme. The anti-inflammatory and antioxidant potential of the phenolic compounds was assayed via various enzymes like COX-1/2, 5-LOX and ABTS, DPPH, and H2O2 free radical enzyme inhibitory assay. These compounds were also explored for their in vivo antioxidant activity like examining SOD, CAT, GSH-Px, and MDA levels in the brain, heart, and liver. The anti-inflammatory potential was evaluated using the carrageenan-induced pleurisy model in mice. On the basis of initial screening of isolated compounds, the most potent compound was further evaluated for the anti-inflammatory mechanism. Furthermore, the molecular docking study was also performed for the potent compound. The phenolic compounds were isolated and identified by GC-MS/NMR analysis by comparing its spectra to the library spectra. The isolated phenolic compounds from H. digitata were 5-methylpyrimidine-24,4-diol (1), 3,5-dihydroxy-6-methyl-2,3-dihydropyran-4-one (2), 2-isopropyl-5-methylphenol (3), 3-methoxy-4-vinylphenol (4), and 2,6-dimethoxy-4-vinylphenol (5). In in vitro antioxidant assay, the most potent compound was compound 1 having IC50 values of 0.98, 0.90, and 5 μg/mL against ABTS, DPPH, and H2O2, respectively. Similarly, against COX1/2 and 5-LOX ,compound 1 was again the potent compound with IC50 values of 42.76, 10.70, and 7.40 μg/mL. Based on the in vitro results, compound 1 was further evaluated for in vivo antioxidant and anti-inflammatory potential. Findings of the study suggest that H. digitata contains active compounds with potential anti-inflammatory and antioxidant effects. These compounds could be screened as drug candidates for pharmaceutical research, targeting conditions associated with oxidative stress and inflammatory conditions in medicinal chemistry and support their ethnomedicinal use for inflammation and oxidative stress.

Modification of 4-(4-chlorothiophen-2-yl)thiazol-2-amine derivatives for the treatment of analgesia and inflammation: synthesis and in vitro, in vivo, and in silico studies

Inflammation is a protective response to a variety of infectious agents. To develop a new anti-inflammatory drug, we explored a pharmacologically important thiazole scaffold in this study. In a multi-step synthetic approach, we synthesized seven new thiazole derivatives (5a-5g). Initially, we examined the in vitro anti-inflammatory potentials of our compounds using COX-1, COX-2, and 5-LOX enzyme assays. After in vitro confirmation, the potential compounds were subjected to in vivo analgesic and anti-inflammatory studies. The hot plate method was used for analgesia, and carrageenan-induced inflammation was also assayed. Overall, all our compounds proved to be potent inhibitors of COX-2 compared to celecoxib (IC50 0.05 μM), exhibiting IC50 values in the range of 0.76-9.01 μM .Compounds 5b, 5d, and 5e were dominant and selective COX-2 inhibitors with the lowest IC50 values and selectivity index (SI) values of 42, 112, and 124, respectively. Similarly, in the COX-1 assay, our compounds were relatively less potent but still encouraging. Standard aspirin exhibited an IC50 value of 15.32 μM. In the 5-LOX results, once again, compounds 5d and 5e were dominant with IC50 values of 23.08 and 38.46 μM, respectively. Standard zileuton exhibited an IC50 value of 11.00 μM. Based on the COX/LOX and SI potencies, the compounds 5d and 5e were subjected to in vivo analgesic and anti-inflammatory studies. Compounds 5d and 5e at concentrations of 5, 10, and 20 mg/kg body weight were significant in animal models. Furthermore, we explored the potential role of compounds 5d and 5e in various phlogistic agents. Similarly, both compounds 5d and 5e were also significantly potent in the anti-nociceptive assay. The molecular docking interactions of these two compounds with the target proteins of COX and LOX further strengthened their potential for use in COX/LOX pathway inhibitions.

Investigation of anti-nociceptive, anti-inflammatory potential and ADMET studies of pure compounds isolated from Isodon rugosus Wall. ex Benth

The strong ethnopharmacological utilization of Isodon rugosus Wall. Ex. Benth is evident in the treatment of several types of pain and inflammation, including toothache, earache, abdominal pain, gastric pain, and generalized body pain and inflammation. Based on this background, the antinociceptive effects of the crude extract, various fractions, and essential oil have been reported previously. In this research work, we isolate and characterize pure bioactive compounds from I. rugosus and evaluate possible mechanisms using various in vivo and in vitro models. The pure compounds were analyzed for analgesic and anti-inflammatory activities through various assays. The column chromatography of the chloroform fraction of I. rugosus led to the identification of two pure compounds, i.e., 1 and 2. Compound 1 demonstrated notable inhibition (62% writhing inhibition, 72.77% COX-2 inhibition, and 76.97% 5-LOX inhibition) and anti-inflammatory potential (>50% paw edema inhibition at various intervals). The possible mechanism involved in antinociception was considered primarily, a concept that has already been elucidated through the application of naloxone (an antagonist of opioid receptors). The involvement of adrenergic receptors was investigated using a hot plate model (an adrenergic receptor antagonist). The strong ethnomedicinal analgesic background of I. rugosus, supported by previous reports and current observations, leads to the conclusion that I. rugosus is a potential source of antinociceptive and anti-inflammatory bioactive compounds. It may be concluded from the results that the isolated analgesic compounds of I. rugosus may be a possible alternative remedy for pain and inflammation management with admirable efficacy and safety profiles.

2-Hydroxybenzohydrazide as a novel potential candidate against nociception, inflammation, and pyrexia: in vitro, in vivo, and computational approaches

The current study was designed to evaluate the 2-hydroxybenzohydrazide (HBH) as a drug having efficacy against pyrexia, inflammation, and nociception. Besides, the therapeutic effects of HBH on oxidative stress and C-reactive proteins were also evaluated. The pharmacological studies on HBH (20-60 mg/kg) were conducted using nociception, inflammation, and pyrexia standard models. Naloxone antagonism was performed to assess the possible involvement of opioidergic mechanisms. The antioxidant study was conducted on ABTS and DPPH assays using gallic acid as a standard. Moreover, the binding capability of HBH with enzymes cyclooxygenase-I/II (COX-I/II) was determined using molecular modeling analysis. The findings indicated that the HBH dose-dependently inhibited pain, inflammation, and pyrexia. The HBH has significant anti-nociceptive and anti-inflammatory activities at 60 mg/kg (***p < 0.001), similar to the lower doses of diclofenac sodium (50 mg/kg) and tramadol (30 mg/kg). The HBH at 60 mg/kg reduced pyrexia as paracetamol (150 mg/kg). The HBH at 20-60 mg/kg doses declined the plasma C-reactive protein concentration. The mechanistic studies showed that the anti-nociceptive effect of HBH was antagonized by naloxone, indicating that the opioidergic mechanisms are involved. Furthermore, computational studies showed that the HBH exhibited an affinity for COX-I/II target receptors. The HBH significantly inhibited ABTS and DPPH radicals (IC50 = 33.81 and 26.74 μg/ml). These results proposed that the HBH has significant antipyretic, anti-inflammatory, and anti-nociceptive activities involving opioidergic mechanism.

Drug repurposing of FDA-approved anti-viral drugs via computational screening against novel 6M03 SARS-COVID-19

OBJECTIVE

The COVID-19 pandemic has been recognized as severe acute respiratory syndrome, one of the worst and disastrous infectious diseases in human history. Until now, there is no cure to this contagious infection although some multinational pharmaceutical companies have synthesized the vaccines and injecting them into humans, but a drug treatment regimen is yet to come.

AIM

Among the multiple areas of SARS-CoV-2 that can be targeted, protease protein has significant values due to its essential role in viral replication and life. The repurposing of FDA-approved drugs for the treatment of COVID-19 has been a critical strategy during the pandemic due to the urgency of effective therapies. The novelty in this work refers to the innovative use of existing drugs with greater safety, speed, cost-effectiveness, broad availability, and diversity in the mechanism of action that have been approved and developed for other medical conditions.

METHODS

In this research work, we have engaged drug reprofiling or drug repurposing to recognize possible inhibitors of protease protein 6M03 in an instantaneous approach through computational docking studies.

RESULTS

We screened 16 FDA-approved anti-viral drugs that were known for different viral infections to be tested against this contagious novel strain. Through these reprofiling studies, we come up with 5 drugs, namely, Delavirdine, Fosamprenavir, Imiquimod, Stavudine, and Zanamivir, showing excellent results with the negative binding energies in Kcal/mol as - 8.5, - 7.0, - 6.8, - 6.8, and - 6.6, respectively, in the best binding posture. In silico studies allowed us to demonstrate the potential role of these drugs against COVID-19.

CONCLUSION

In our study, we also observed the nucleotide sequence of protease protein consisting of 316 amino acid residues and the influence of these pronouncing drugs over these sequences. The outcome of this research work provides researchers with a track record for carrying out further investigational procedures by applying docking simulations and in vitro and in vivo experimentation with these reprofile drugs so that a better drug can be formulated against coronavirus.

Novel Coumarin Derivatives as Potential Urease Inhibitors for Kidney Stone Prevention and Antiulcer Therapy: From Synthesis to In Vivo Evaluation

The presence of ammonium ions in urine, along with basic pH in the presence of urease-producing bacteria, promotes the production of struvite stones. This causes renal malfunction, which is manifested by symptoms such as fever, nausea, vomiting, and blood in the urine. The involvement of urease in stone formation makes it a good target for finding urease enzyme inhibitors, which have the potential to be developed as lead drugs against kidney stones in the future. The documented ethnopharmacology of coumarin 2-one against bacterial, fungal and viral strains encouraged us to synthesize new derivatives of coumarins by reacting aromatic aldehydes with 4-aminocoumarin. The synthesized compounds (2a to 11a) were evaluated for their antimicrobial, in vitro, and in silico properties against the urease enzyme. The study also covers in vivo determination of the synthesized compounds with respect to different types of induced ulcers. The molecular docking study along with extended MD simulations (100 ns each) and MMPBSA study confirmed the potential inhibitory candidates as evident from computed ∆Gbind (3a = -11.62 and 5a = -12.08 Kcal/mol) against the urease enzyme. The in silico analyses were augmented by an enzymatic assay, which revealed that compounds 3a and 5a had strong inhibitory action, with IC50 of 0.412 µM (64.0% inhibition) and 0.322 µM (77.7% inhibition), respectively, compared to standard (Thiourea) with 82% inhibition at 0.14 µM. Moreover, the most active compound, 5a, was further tested in vivo for antiulcer activity by different types of induced ulcers, including pyloric ligation-, ethanol-, aspirin-, and histamine-induced ulcers. Compound 5a effectively reduced gastric acidity, lipid peroxidation, and ulceration in a rat model while also inhibiting gastric ATPase activity, which makes it a promising candidate for ulcer treatment. As a result of the current research, 3a and 5a may be used as new molecules for developing potent urease inhibitors. Additionally, the compound 3a showed antibacterial activity against Staphylococcus aureus and Salmonella typhimurium, with zones of inhibition of 41 ± 0.9 mm and 35 ± 0.9 mm, respectively. Compound 7a showed antibacterial activity against Staphylococcus aureus and Salmonella typhimurium, with zones of inhibition of 30 ± 0.8 mm and 42 ± 0.8 mm, respectively. These results prove that the synthesized compounds also possess good antibacterial potential against Gram-positive and Gram-negative bacterial strains.

Synthesis, in-vitro inhibition of cyclooxygenases and in silico studies of new isoxazole derivatives

Isoxazole belongs to the class of five-membered heterocyclic compounds. The process of developing new drugs has significantly gained attention due to inadequate pharmacokinetic and safety attributes of the available drugs. This study aimed to design a new diverse array of ten novel isoxazole derivatives via Claisen Schmidt condensation reaction. In vitro COX-1/2 anti-inflammatory assay, in silico molecular docking of potent compounds, Molecular docking simulation, and SwissADME pharmacokinetic profile were investigated in this research. The in vitro COX-1 and COX-2 enzyme inhibitory assay showed that almost all the tested compounds exhibited anti-inflammatory effects whereas C6, C5, and C3 were found to be the most potent COX-2 enzyme inhibitors among the tested compounds and are good candidates for selective COX-2 inhibitors. In silico molecular docking studies coupled with molecular dynamic simulation has been done to rationalize the time-evolved mode of interaction of selected inhibitor inside the active pockets of target COX-2. The binding orientations and binding energy results also showed the selectivity of compounds towards COX-2. Physicochemical properties, pharmacokinetic profile, lipophilicity, water solubility, drug metabolism, drug-likeness properties, and medicinal chemistry of the synthesized isoxazole derivatives were assessed. The SwissADME (absorption, distribution, metabolism, and excretion) database was used to assess the physicochemical properties and drug-likeness properties of the synthesized isoxazole derivatives. All the compounds were shown high GI absorption except Compound 7 (C7). Compound 1 (C1) and Compound 2 (C2) were found to cross the blood-brain barrier (BBB). Lipinski's rule of five is not violated by any of the ten synthesized isoxazole derivatives. It was predicted with the SwissADME database that C2, C5, C6, C7, and C8 are potent inhibitors of cytochrome (CYP) subtype CYP-2C19. A subtype of CYP-2C9 was inhibited by C4 and C7. The medicinal chemistry of all the compounds C1-C10 showed no PAIN (Pan assay interference compounds) alerts. The improved gastrointestinal (GI) absorption and BBB permeability of C1 and C2 can provide a future prospective for new researchers in the medicinal field to investigate the compounds for the management of chronic diseases. The synthesized isoxazole compounds showed excellent in vitro COX-1/2 enzymes anti-inflammatory investigations, in silico studies, good physicochemical properties, and improved pharmacokinetic profile which will be further investigated via in vivo anti-inflammatory activities. Moreover, to further support our findings of the computational research and in vitro studies, an in-vivo pharmacokinetic profile is suggested in the future.

Pharmacological evaluations of amide carboxylates as potential anti-Alzheimer agents: anti-radicals, enzyme inhibition, simulation and behavioral studies in animal models

Alzheimer's disease (AD) is a neurological disorder that progresses gradually but irreversibly leading to dementia and is difficult to prevent and treat. There is a considerable time window in which the progression of the disease can be intervened. Scientific advances were required to help the researchers to identify the effective methods for the prevention and treatment of disease. This research was designed to investigate potential mediators for the remedy of AD, five new carboxylate amide zinc complexes (AAZ9-AAZ13) were synthesized and characterized by spectroscopic and physicochemical techniques. The biological evaluation was carried out based on the cholinesterase inhibitory mechanism. The preparation methodology provided the effective synthesis of targeted moieties. The in vitro pharmacological activities were evaluated involving AChE/BChE inhibition and antioxidant potential. All synthesized compounds displayed activity against both enzymes in higher or comparable to the standard drug Galantamine, a reversible inhibitor but the results displayed by compound AAZ10 indicated IC50 of 0.0013 µM (AChE) and 0.061 µM (BChE) as high values for dual AChE/BChE inhibition with potent anti-oxidant results. Structure activity relationship (SAR) indicated that the potent activity of compound AAZ10 appeared due to the presence of nitro clusters at the ortho position of an aromatic ring. The potent synthesized compound AAZ10 was also explored for the in-vivo Anti-Alzheimer activity and anti-oxidant activity. Binding approaches of all synthesized compounds were revealed through molecular docking studies concerning binding pockets of enzymes that analyzed the best posture interaction with amino acid (AA) residues providing an appreciable understanding of enzyme inhibitory mechanisms. Results indicate that synthesized zinc (II) amide carboxylates can behave as an effective remedy in the treatment of Alzheimer's disease.Communicated by Ramaswamy H. Sarma.

In-vitro and in-vivo assessment of the anti-diabetic, analgesic, and anti-inflammatory potenstials of metal-based carboxylates derivative

In the current research work, an amide based metal carboxylate chemical ([((5-((5-(2-hydroxyethyl)-4-methylthiazol-3-ium-3-yl)methyl)-2-methylpyrimidin-4-yl)amino)bis((4-((4-methoxy-2-nitrophenyl)amino)-4-oxobutanoyl)oxy)zinc]) was identified as anti-diabetic analgesic and anti-inflammatory. The identified chemical(MT-1) was tested for acute toxicity (the MT-1 was fund safe), antidiabetic analgesic, and anti-inflammatory potentials. The in-vitro study was conducted for antidiabetic enzyme inhibition (α-amylase and α-glucosidase) and the in-vivo studies included analgesic (acetic acid-induced writing and hot plate model) and anti-inflammatory (carrageenan etc induced edema) effects. The tested compound showed 88.63% (IC50 = 3.23 μg/ml) and 89.10%(IC50 = 5.10 μg/ml) againstα-amylase and α-glucosidase respectively. A significant (p < 0.001) analgesic effect was noted by MT-1 in acetic acid-induced animal models with a percent effect of 86.00, 60.,06, and 55.29 at the tested doses of 20, 1,0, and 5 mg/kg respectively. In the case of the hot plate model, the MT-1 showed a significant (p < 0.001) effect with maximum percent prolongation in latency observed after 60 min.08, 22.2,9, and 11.61) against 20, 1,0, and 5 mg/kg. The analgesic effect in the hot plate model was significantly (p < 0.01) reversed by the injection of naloxone (0.125 mg/kg). The paw edema induced by carrageenan, histamine, bradykinin, arachidonic acid, and PGE2 was significantly antagonized with percent attenuation of 34.09, 33.57, 34.60, 34.14, and 48.04 respectively. Furthermore, to predict the interactions between the MT-1 compound and COX-2 molecular docking was carried out and the result was compared with the standard compound. The docking score of MT-1 was predicted as -6.30 while that of Diclofenac was predicted as -6.82. Both compounds made several hydrogen bond interactions with the active site of the COX-2 enzyme. The docking study revealed the potent inhibitory potential of the compound MT-1 against the COX-2 receptor.

SAR and lead optimization of (Z)-5-(4-hydroxy-3-methoxybenzylidene)-3-(2-morpholinoacetyl)thiazolidine-2,4-dione as a potential multi-target antidiabetic agent

In case of metabolic disorder like Diabetes mellitus (DM), a number of key enzymes are abnormally expressed and hence they might be excellent targets for antidiabetic drug design. Multi-target design strategy has recently attracted great attention to treat challenging diseases. We have previously reported a vanillin-thiazolidine-2,4-dione hybrid 3 as multitarget inhibitor of α-glucosidase, α-amylase, PTP-1B and DPP-4. The reported compound predominantly exhibited good in-vitro DPP-4 inhibition only. Current research describes the goal to optimize an early lead compound. The efforts were focused on enhancing the capability of manipulating multiple pathways at the same time for the treatment of diabetes. The central 5-benzylidinethiazolidine-2,4-dione for Lead compound (Z)-5-(4-hydroxy-3-methoxybenzylidene)-3-(2-morpholinoacetyl)thiazolidine-2,4-dione (Z-HMMTD) was left unchanged. While East and West moieties were altered by the introduction of different building blocks conceived by using a number of rounds of predictive docking studies performed on X-ray crystal structures of four target enzymes. This systematic SAR led to the syntheses of new potent multi-target antidiabetic compounds 47-49 and 55-57 with many fold increase in the in-vitro potency compared to Z-HMMTD. The potent compounds showed good in-vitro and in-vivo safety profile. Compound 56 emerged excellent as glucose-uptake promotor via hemi diaphragm of the rat. Moreover, the compounds demonstrated antidiabetic activity in STZ-induced diabetic animal model.

Exploration of Succinimide Derivative as a Multi-Target, Anti-Diabetic Agent: In Vitro and In Vivo Approaches

Diabetes mellitus (DM) is counted among one of the leading challenges in the recent era, and it is a life-threatening disorder. Compound 4-hydroxy 3-methoxy phenylacetone (compound 1) was previously isolated from Polygonum aviculare. This compound was reacted with N-benzylmaleimide to synthesize the targeted compound 3. The purpose of this research is to exhibit our developed compound 3's ability to concurrently inhibit many targets that are responsible for hyperglycemia. Compound 3 was capable of inhibiting α-amylase, α-glucosidase, and protein tyrosine phosphatase 1 B. Even so, outstanding in vitro inhibition was shown by the compound against dipeptidyl peptidase-4 (DPP-4) with an IC₅₀ value of 0.07 µM. Additionally, by using DPPH in the antioxidant activity, it exhibited good antioxidant potential. Similarly, in the in vivo activity, the experimental mice proved to be safe by treatment with compound 3. After 21 days of examination, the compound 3 activity pattern was found to be effective in experimental mice. Compound 3 decreased the excess peak of total triglycerides, total cholesterol, AST, ALT, ALP, LDL, BUN, and creatinine in the STZ-induced diabetic mice. Likewise, the histopathology of the kidneys, liver, and pancreas of the treated animals was also evaluated. Overall, the succinimde moiety, such as compound 3, can affect several targets simultaneously, and, finally, we were successful in synthesizing a multi-targeted preclinical therapy.

Organotin (IV) complexes with sulphonyl hydrazide moiety. Design, synthesis, characterization, docking studies, cytotoxic and anti-leishmanial activity

Due to a lack of therapeutic options for the pathological condition of leishmaniasis, which is characterized by polymorphic lesions and skin surface infections, Leishmania genus parasites damaged dermis and mucosa. There was a need to synthesize and characterize some new complexes. This study evaluated the biological activities preferably anti-Leishmanial activity of organotin (IV) containing sulphonyl hydrazide derivatives. A series of six new organotin (IV) complexes 1-6 labeled as R2SnL2; R = Methyl (1), Butyl (2), Phenyl (3) and R3SnL; R = Methyl (4), Butyl (5), Phenyl (6) has been synthesized as reflux method derived from N'- (2,4-dinitrophenyl)-4-methylphenylsulfonylhydrazide (L). All compounds were characterized through FT-IR, 1HNMR, 13CNMR, and elemental analysis. Structural analysis confirms the formation of six complexes (1-6). All derivatives have been screened for their pharmacological activities. Interestingly, compound 1 showed promising activity against leishmania promastigotes with low cytotoxicity. All results were further elaborated through docking studies performed on leishmania donovoni synthetase PDB: ID 3QW3 that acts as an essential building block for the viability of Leishmania promastigotes. This research effectively synthesized sulphonyl hydrazide ligand and its six new organotin (IV) derivatives, which were tested for biological properties such as antibacterial, anti-fungal, anti-oxidant, and ideally anti-leishmanial activity and cytotoxicity. Studies have confirmed that these compounds have the potency to be a good candidate against leishmaniasis. Computational studies were carried out to recognize the binding affinities for leishmania donovoni synthetase.Communicated by Ramaswamy H. Sarma.

In-Vitro, In-Vivo, Molecular Docking and ADMET Studies of 2-Substituted 3,7-Dihydroxy-4H-chromen-4-one for Oxidative Stress, Inflammation and Alzheimer's Disease

Plants' bioactives are well-known safe drugs for vital diseases. Flavones and Flavonoid-rich dietary supplements are known to exhibit neuroprotective potential. In this study, we isolated a flavone 2-(3,4-dimethoxyphenyl)-3,7-dihydroxy-4H-chromen-4-one from Notholirion thomsonianum and it was evaluated against various targets of the oxidative stress-related neurological disorders. The compound showed excellent acetyl and butyrylcholinesterase inhibitions in its profile, giving IC50 values of 1.37 and 0.95 μM, respectively. Similarly, in in-vitro MAO-B assay, our flavone exhibited an IC50 value of 0.14 μM in comparison to the standard safinamide (IC50 0.025 μM). In in-vitro anti-inflammatory assay, our isolated compound exhibited IC50 values of 7.09, 0.38 and 0.84 μM against COX-1, COX-2 and 5-LOX, respectively. The COX-2 selectivity (SI) of the compound was 18.70. The compound was found safe in animals and was very effective in carrageenan-induced inflammation. Due to the polar groups in the structure, a very excellent antioxidant profile was observed in both in-vitro and in-vivo models. The compound was docked into the target proteins of the respective activities and the binding energies confirmed the potency of our compound. Furthermore, absorption, distribution, metabolism, excretion, and toxicity (ADMET) results showed that the isolated flavone has a good GIT absorption ability and comes with no hepatic and cardiotoxicity. In addition, the skin sensitization test, in-vitro human cell line activation test (h-CLAT) and KeratinoSens have revealed that isolated flavone is not skin sensitive with a confidence score of 59.6% and 91.6%. Herein, we have isolated a natural flavone with an effective profile against Alzheimer's, inflammation and oxidative stress. The exploration of this natural flavone will provide a baseline for future research in the field of drug development.

Phytochemical Analysis, Total Phenolic, Flavonoid Contents, and Anticancer Evaluations of Solvent Extracts and Saponins of H. digitata

Cancer is one of the most challenging diseases in the modern era for the researchers and investigators. Extensive research worldwide is underway to find novel therapeutics for prevention and treatment of diseases. The extracted natural sources have shown to be one of the best and effective treatments for cell proliferation and angiogenesis. Different approaches including disc potato model, brine shrimp, and chorioallantoic membrane (CAM) assay were adopted to analyze the anticancer effects. Habenaria digitata was also evaluated for MTT activity against NIH/3T3 cell line. The dexamethasone, etoposide, and vincristine sulfate were used as a positive control in these assays. All of the extracts including crude extracts (Hd.Cr), saponin (Hd.Sp), n-hexane (Hd.Hx), chloroform (Hd.Chf), ethyl acetate (Hd.EA), and aqueous fraction (Hd.Aq) were shown excellent results by using various assays. For example, saponin and chloroform have displayed decent antitumor and angiogenic activity by using potato tumor assay. The saponin fraction and chloroform were shown to be the most efficient in potato tumor experiment, demonstrating 87.5 and 93.7% tumor suppression at concentration of 1000 μg/ml, respectively, with IC50 values of 25.5 and 18.3 μg/ml. Additionally, the two samples, chloroform and saponins, outperformed the rest of the test samples in terms of antiangiogenic activity, with IC50 28.63 μg/ml and 16.20 μg/ml, respectively. In characterizing all solvent fractions, the chloroform (Hd.Chf) and saponin (Hd.Sp) appeared to display good effectiveness against tumor and angiogenesis but very minimal activity against A. tumefaciens. The Hd.Chf and Hd.Sp have been prospective candidates in the isolation of natural products with antineoplastic properties.

Design, synthesis, in-vitro, in-vivo and ex-vivo pharmacology of thiazolidine-2,4-dione derivatives as selective and reversible monoamine oxidase-B inhibitors

Neurodegenerative ailments are a diverse set of syndromes distinguished by gradual deterioration of the structure as well as functions of the central nervous system or peripheral nervous system. Alzheimer's disease (AD) and Parkinson's disease (PD) have no cure, common, and are high prevalent neurodegenerative pathologies. In current research, rationally designed thiazolidine-2,4-dione based analogs were synthesized and tested for their inhibition potential against two isoforms of monoamine oxidase (MAO-A / MAO-B). Structure activity relationships were explored. Pyridinyl and thiazolyl hydrazone derivative 43 and 44 with IC₅₀ value of 0.013 µM and 0.008 µM (selectivity 228 / 226 times) exhibited higher potency than reference drug safinamide. Most active compounds showed BBB penetration in PAMPA in-vitro assay. Except nitro derivative 41, all compounds were non-neurotoxic in the studied concentration. Molecular docking studies supported the in-vitro experimental results and the selectivity by comparing the binding energy values against both MAO-A and MAO-B isoforms. All the results of current research suggest compounds 43 and 44 may serve as promising candidates for further research for treatment of neurodegenerative diseases.

Design, synthesis, antiproliferative activity, estrogen receptors binding affinity of C-3 pregnenolone-dihydropyrimidine derivatives for the treatment of breast cancer

Breast cancer (BCa) is very common malignancy and globally, has become the second leading cause of cancer death among women. For the treatment of BCa, estrogen receptors-alpha (ERα) has proven to be a therapeutic target. In continuation of our previous reported dihydropyrimidine-based pregnenolone derivatives, we modified at C-3 hydroxyl group. Structural architecture of estrogen receptors (ER) with excellent ER binding affinity was used for modification. MTT assay was used to evaluate the synthesized steroidal analogs for their antiproliferative activities against ER-positive MCF-7, ER-negative MDA-MB-231 (ER^-) breast cancer cells and non-cancerous HEK-293 cells. Structure activity relationship (SAR) studies revealed that diethanolamine containing pregnenolone derivatives showed significant cytotoxicity against ER + MCF-7 and also showed good binding affinity with ERα and are relatively safe against HEK-293 cell model. Docking studies demonstrated that high binding affinity of diethanolamine analogs is due to their binding interaction with key amino acid residues present in the binding site of Erα.

Prospective Evaluation of an Amide-Based Zinc Scaffold as an Anti-Alzheimer Agent: In Vitro, In Vivo, and Computational Studies

Alzheimer's disease is the most common progressive neurodegenerative mental disorder associated with loss of memory, decline in cognitive function, and dysfunction of language. The prominent pathogenic causes of this disease involve deposition of amyloid-β plaques, acetylcholine neurotransmitter deficiency, and accumulation of neurofibrillary tangles. There are multiple pathways that have been targeted to treat this disease. The inhibition of the intracellular cyclic AMP regulator phosphodiesterase IV causes the increase in CAMP levels that play an important role in the memory formation process. Organometallic chemistry works in a different way in treating pharmacological disorders. In the field of medicinal chemistry and pharmaceuticals, zinc-based amide carboxylates have been shown to be a preferred pharmacophore. The purpose of this research work was to investigate the potential of zinc amide carboxylates in inhibition of phosphodiesterase IV for the Alzheimer's disease management. Swiss Albino mice under controlled conditions were divided into seven groups with 10 mice each. Group I was injected with carboxymethylcellulose (CMC) at 1 mL/100 g dose, group II was injected with Streptozotocin (STZ) at 3 mg/kg dose, group III was injected with Piracetam acting as a standard drug at 200 mg/kg dosage, while groups IV-VII were injected with a zinc scaffold at the dose regimen of 10, 20, 40, and 80 mg/kg through intraperitoneal injection. All groups except group I were injected with Streptozotocin on the first day and third day of treatment at the dose of 3 mg/kg through an intracerebroventricular route to induce Alzheimer's disease. Afterward, respective treatment was continued for all groups for 23 days. In between the treatment regimen, groups were analyzed for memory and learning improvement through various behavioral tests such as open field, elevated plus maze, Morris water maze, and passive avoidance tests. At the end of the study, different biochemical markers in the brain were estimated like neurotransmitters (dopamine, serotonin and adrenaline), oxidative stress markers (superoxide dismutase, glutathione, and catalase), acetylcholinesterase (AchE), tau proteins, and amyloid-β levels. A PCR study was also performed. Results showed that the LD₅₀ of the zinc scaffold is greater than 2000 mg/kg. Research indicated that the zinc scaffold has the potential to improve the memory impairment and learning behavior in Alzheimer's disease animal models in a dose-dependent manner. At the dose of 80 mg/kg, a maximum response was observed for the zinc scaffold. Maximum reduction in the acetylcholinesterase enzyme was observed at 80 mg/kg dose, which was further strengthened and verified by the PCR study. Oxidative stress was restored by the zinc scaffold due to the significant activation of the endogenous antioxidant enzymes. This research ended up with the conclusion that the zinc-based amide carboxylate scaffold has the potential to improve behavioral disturbances and vary the biochemical markers in the brain.

Phytochemical Profiling, Anti-Inflammatory, Anti-Oxidant and In-Silico Approach of Cornus macrophylla Bioss (Bark)

The objective of the current study was to evaluate the phytochemical and pharmacological potential of the Cornus macrophylla. C. macrophylla belongs to the family Cornaceae. It is locally known as khadang and is used for the treatment of different diseases such as analgesic, tonic, diuretic, malaria, inflammation, allergy, infections, cancer, diabetes, and lipid peroxidative. The crude extract and different fractions of C. macrophyll were evaluated by gas chromatography and mass spectroscopy (GC-MS), which identified the most potent bioactive phytochemicals. The antioxidant ability of C. macrophylla was studied by 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and 1,1 diphenyl-2-picryl-hydrazyl (DPPH) methods. The crude and subsequent fractions of the C. macrophylla were also tested against anti-inflammatory enzymes using COX-2 (Cyclooxygenase-2) and 5-LOX (5-lipoxygenase) assays. The molecular docking was carried out using molecular operating environment (MOE) software. The GC-MS study of C. macrophylla confirmed forty-eight compounds in ethyl acetate (Et.AC) fraction and revealed that the Et.AC fraction was the most active fraction. The antioxidant ability of the Et.AC fraction showed an IC₅₀ values of 09.54 μg/mL and 7.8 μg/mL against ABTS and DPPH assay respectively. Among all the fractions of C. macrophylla, Et.AC showed excellent activity against COX-2 and 5-LOX enzyme. The observed IC₅₀ values were 93.35 μg/mL against COX-2 and 75.64 μg/mL for 5-LOX respectively. Molecular docking studies supported these in vitro results and confirmed the anti-inflammatory potential of C. macrophylla. C. macrophylla has promising potential as a source for the development of new drugs against inflammation in the future.

Rational design, synthesis, antiproliferative activity against MCF-7, MDA-MB-231 cells, estrogen receptors binding affinity, and computational study of indenopyrimidine-2,5-dione analogs for the treatment of breast cancer

Based on the structural architecture of estrogen receptors (ER) agonists/antagonists, we rationally designed and synthesized indenopyrimidine-2,5-dione analogs as a starting point of current research targeting estrogen receptors. These analogs were evaluated for their antiproliferative activities against breast cancer MCF-7 (ER⁺), MDA-MB-231 (ER^-) and non-cancerous HEK-293 cells using MTT assay. Compounds with high antiproliferative activity against MCF-7 breast cancer cells were found devoid of cytotoxicity against HEK-293 cells. Competitive binding assay of estrogen receptors ERα and ERβ showed that diethanolamine derivative of 4-trifluoromethyl phenyl derivative 30 displayed 77.5-fold strong binding affinity towards ERα (IC₅₀ = 0.004 μM) as compared to ERβ (IC₅₀ = 0.31 μM). The calculated RBA value of compound 30 indicated that it has greater affinity with ER than estradiol. By docking studies, we demonstrated that high binding affinity with ERα is due to binding orientation and interaction of CF₃ with a number of key amino acid residues present in the active site of ERα.

Comparative in-vitro anti-inflammatory, anticholinesterase and antidiabetic evaluation: computational and kinetic assessment of succinimides cyano-acetate derivatives

This research was planned to synthesize cyano-acetate derivatives of succinimide and evaluate its comparative biological efficacy as anti-inflammatory, anti-cholinesterase and anti-diabetic, which was further validated by molecular docking studies. The three cyano-acetate derivatives of succinimide including compound 23 Methyl 2-cyano-2-(2,5-dioxopyrrolidin-3-yl)acetate, compound 31 Methyl 2-cyano-2-(1-methyl-2,5-dioxopyrrolidin-3-yl)acetate and compound 44 Methyl 2-cyano-2-(1-ethyl-2,5-dioxopyrrolidin-3-yl) acetate were synthesized. The mentioned compounds were checked for in vitro anti-inflammatory, anti-cholinesterase and anti-diabetic (α-amylase inhibition) activity. To validate the in vitro results, computational studies were carried out using molecular operating environment to analyse the BE, i.e. binding energies of all synthesized compounds against the respective enzymes. The Compounds 23, 31, 44 exhibited anti-inflammatory via inhibiting COX-2 (IC50 value of 204.08, 68.60 and 50.93 µM, respectively), COX-1 (IC50 value of 287, 185, and 143 µM, respectively) and 5-LOX (IC50 value of 138, 50.76 and 20, 87 µM respectively). They exhibited choline-mimetic potential, such as compound 23, 31 and 44 inhibited AChE enzyme (IC50 value of 240, 174, and 134 µM, respectively) and BChE enzyme (IC50 value of 203, 134 and 97 µM, respectively). The Compounds 23, 31, 44 exhibited anti-diabetic effect via inhibiting α-amylase enzyme (IC50 values of 250, 106 and 60 µM, respectively). Molecular docking studies revealed that the synthesized compounds have good binding affinity in the binding pockets of AChE, BChE, COX-2, 5-LOX and α-amylase enzyme and showed high binding energies. The synthesized succinimide derivatives, i.e. compound 23, 31, 44 showed marked inhibitory activities against cyclooxygenase, lipoxygenase, α-amylase and cholinesterase enzymes. Among these three, compound 44 and 31 showed strong anti-inflammatory and anti-diabetic activity while they displayed moderate anti-cholinesterase activity supported by molecular docking results.Communicated by Ramaswamy H. Sarma.

Diclofenac derivatives as concomitant inhibitors of cholinesterase, monoamine oxidase, cyclooxygenase-2 and 5-lipoxygenase for the treatment of Alzheimer's disease: synthesis, pharmacology, toxicity and docking studies

Targeting concomitantly cholinesterase (ChEs) and monoamine oxidases (MAO-A and MAO-B) is one of the key strategies to treat multifactorial Alzheimer's disease (AD).

Structural Modification, In Vitro, In Vivo, Ex Vivo, and In Silico Exploration of Pyrimidine and Pyrrolidine Cores for Targeting Enzymes Associated with Neuroinflammation and Cholinergic Deficit in Alzheimer's Disease

To obtain a multipotent framework that can target simultaneously COX-2, 5-LOX, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) to treat neuroinflammation, a series of derivatives containing pyrimidine and pyrrolidine cores were rationally synthesized and evaluated. Pyrazoline-pyrimidine hybrid (23g), (3-acetylcoumarin derivative of pyrrolidin-1-yl)benzenesulfonamide (27), and tacrine derivatives of (pyrrolidin-1-yl)benzenesulfonamide (31, 38) displayed excellent in vitro COX-2 inhibition having IC₅₀ value in the nanomolar range. Tacrine-pyrrolidine hybrids 36 and 38, and tacrine-pyrimidine hybrid (46) emerged as the most potent eeAChE inhibitors with IC₅₀ values of 23, 16, and 2 nM, respectively. However, compounds 27, 31, and 38 possessed excellent simultaneous and balanced inhibitory activity against all of the four tested targets and thus emerged as optimal multipotent hybrid compounds among all of the synthesized series of the compounds. In the ex vivo, transgenic animal models treated with compounds 36 and 46 displayed a significant decline in both AChE and BChE potentials in the hippocampus and cortical tissues. In anti-inflammatory activities, animals treated with compounds 36 and 46 displayed a significant % inhibition of edema induced by carrageenan and arachidonic acid. Biochemical analysis and histopathological examination of mice liver indicate that tacrine derivatives are devoid of hepatotoxicity and neurotoxicity against SH-SY5Y neuroblastoma cell lines. In vivo acute toxicity study showed the safety of synthesized compounds up to 1000 mg/kg dose. The inhibitory manner of interaction of these potent drugs on all of the studied in vitro targets was confirmed by molecular docking investigations.

Crude extract and isolated bioactive compounds from Notholirion thomsonianum (Royale) Stapf as multitargets antidiabetic agents: in-vitro and molecular docking approaches

Background

Diabetes mellitus is a common disease effecting the lifestyles of majority world population. In this research work, we have embarked the potential role of crude extracts and isolated compounds of Notholirion thomsonianum for the management diabetes mellitus.

Methods

The crude extracts of N. thomsonianum were initially evaluated for α-glucosidase, α-amylase and antioxidant activities. The compounds were isolated from the activity based potent solvent fraction. The structures of isolated compounds were confirmed with NMR and MS analyses. The isolated compounds were tested for α-glucosidase, α-amylase, protein tyrosine phosphatase 1B (PTP1B) and DPPH activities. The molecular docking studies were carried out to find the binding interactions of isolated compounds for α-glucosidase, α-amylase and PTP1B.

Results

Initially, we screened out crude extracts and subfractions of N. thomsonianum against different in-vitro targets. Among all, Nt.EtAc was observed a potent fraction among all giving IC₅₀ values of 67, 70, < 0.1, 89 and 16 μg/mL against α-glucosidase, α-amylase, DPPH, ABTS and H₂O₂ respectively. Three compounds (Nt01, Nt02 and Nt03) were isolated from Nt.EtAc of N. thomsonianum. The isolated compounds Nt01, Nt02 and Nt03 exhibited IC₅₀ values of 58.93, 114.93 and 19.54 μM against α-glucosidase, while 56.25, 96.54 and 24.39 μM against α-amylase respectively. Comparatively, the standard acarbose observed IC₅₀ values were 10.60 and 12.71 μM against α-glucosidase, α-amylase respectively. In PTP1B assay, the compounds Nt01, Nt02 and Nt03 demonstrated IC₅₀ values of 12.96, 36.22 and 3.57 μM in comparison to the standard ursolic acid (IC₅₀ of 3.63 μM). The isolated compounds also gave overwhelming results in DPPH assay. Molecular docking based binding interactions for α-glucosidase, α-amylase and PTP1B were also encouraging.

Conclusions

In the light of current results, it is obvious that N. thomsonianum is potential medicinal plant for the treatment of hyperglycemia. Overall, Nt.EtAc was dominant fraction in all in-vitro activities. Three compounds Nt01, Nt02 and Nt03 were isolated from ethyl acetate fraction. The Nt03 specifically was most potent in all in-vitro assays. The molecular docking studies supported our in-vitro results. It is concluded that N. thomsonianum is a rich source of bioactive antidiabetic compounds which can be further extended to in-vivo based experiments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03443-7.

Neuroprotective potentials of selected natural edible oils using enzyme inhibitory, kinetic and simulation approaches

BACKGROUND

Edible oils have proven health benefits in the prevention and treatment of various disorders since the establishment of human era. This study was aimed to appraise neuropharmacological studies on the commonly used edible oils including Cinnamomum verum (CV), Zingiber officinale (ZO) and Cuminum cyminum (CC).

METHODS

The oils were analyzed via GC-MS for identifications of bioactive compounds. Anti-radicals capacity of the oils were evaluated via 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals scavenging assays. The samples were also tested against two important acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) which are among the important drug targets in Alzheimer's disease. Lineweaver-Burk plots were constructed for enzyme inhibition studies which correspond to velocity of enzymes (Vmax) against the reciprocal of substrate concentration (Km) in the presence of test samples and control drugs following Michaelis-Menten kinetics. Docking studies on AChE target were also carried out using Molecular Operating Environment (MOE 2016.0802) software.

RESULTS

(Gas chromatography-mass spectrometry GC-MS) analysis revealed the presence of thirty-four compounds in Cinnamon oil (Cv.Eo), fourteen in ginger oil (Zo.Eo) and fifty-six in cumin oil (Cc.Eo). In the antioxidant assays, Cv.Eo, Zo.Eo and Cc.Eo exhibited IC50 values of 85, 121, 280 μg/ml sequentially against DPPH radicals. Whereas, in ABTS assay, Cv.Eo, Zo.Eo and Cc.Eo showed considerable anti-radicals potentials with IC50 values of 93, 77 and 271 μg/ml respectively. Furthermore, Cv.Eo was highly active against AChE enzyme with IC50 of 21 μg/ml. Zo.Eo and Cc.Eo exhibited considerable inhibitory activities against AChE with IC50 values of 88 and 198 μg/ml respectively. In BChE assay, Cv.Eo, Zo.Eo and Cc.Eo exhibited IC50 values of 106, 101 and 37 μg/ml respectively. Our results revealed that these oils possess considerable antioxidant and cholinesterase inhibitory potentials. As functional foods these oils can be effective remedy for the prevention and management of neurological disorders including AD. Synergistic effect of all the identified compounds was determined via binding energy values computed through docking simulations. Binding orientations showed that all the compounds interact with amino acid residues present in the peripheral anionic site (PAS) and catalytic anionic site (CAS) amino acid residues, oxyanion hole and acyl pocket via π-π stacking interactions and hydrogen bond interactions.

Mechanistic evaluation of a novel cyclohexenone derivative's functionality against nociception and inflammation: An in-vitro, in-vivo and in-silico approach

The synthesis of a novel cyclohexanone derivative (CHD; Ethyl 6-(4-metohxyphenyl)-2-oxo-4-phenylcyclohexe-3-enecarboxylate) was described and the subsequent aim was to perform an in vitro, in vivo and in silico pharmacological evaluation as a putative anti-nociceptive and anti-inflammatory agent in mice. Initial in vitro studies revealed that CHD inhibited both cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) enzymes and it also reduced mRNA expression of COX-2 and the pro-inflammatory cytokines TNF-α and IL-1β. It was then shown that CHD dose dependently inhibited chemically induced tonic nociception in the abdominal constriction assay and also phasic thermal nociception (i.e. anti-nociception) in the hot plate and tail immersion tests in comparison with aspirin and tramadol respectively. The thermal test outcomes indicated a possible moderate centrally mediated anti-nociception which, in the case of the hot plate test, was pentylenetetrazole (PTZ) and naloxone reversible, implicating GABAergic and opioidergic mechanisms. CHD was also effective against both the neurogenic and inflammatory mediator phases induced in the formalin test and it also disclosed anti-inflammatory activity against the phlogistic agents, carrageenan, serotonin, histamine and xylene compared with standard drugs in edema volume tests. In silico studies indicated that CHD possessed preferential affinity for GABAA, opioid and COX-2 target sites and this was supported by molecular dynamic simulations where computation of free energy of binding also favored the formation of stable complexes with these sites. These findings suggest that CHD has prospective anti-nociceptive and anti-inflammatory properties, probably mediated through GABAergic and opioidergic interactions supplemented by COX-2 and 5-LOX enzyme inhibition in addition to reducing pro-inflammatory cytokine expression. CHD may therefore possess potentially beneficial therapeutic effectiveness in the management of inflammation and pain.

Prospective Application of Two New Pyridine-Based Zinc (II) Amide Carboxylate in Management of Alzheimer's Disease: Synthesis, Characterization, Computational and in vitro Approaches

Background

Alzheimer’s disease (AD) is a neurodegenerative illness described predominantly by dementia. Even though Alzheimer’s disease has been known for over a century, its origin remains a mystery, and researchers are exploring many therapy options, including the cholinesterase technique. A decreased acetylcholine ACh neurotransmitter level is believed to be among the important factors in the progression of Alzheimer’s disease.

Methods

In continuation of synthesizing potential anti-Alzheimer agents and known appreciative pharmacological potential of amide-containing compounds, this study presents the synthesis of two novel amide-based transition metal zinc (II) complexes, AAZ7 and AAZ8, attached with a heterocyclic pyridine ring, which was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis, ¹H_NMR, and ¹³C_NMR. FT-IR spectroscopic records showed the development of bidentate ligand as Δν value was decreased in both complexes when compared with the free ligand. Both of the synthesized complexes were analyzed for acetylcholinesterase and butyrylcholinesterase inhibitory potential along with the antioxidizing activity.

Results

Importantly, the complex of AAZ8 exhibited more potent activity giving IC₅₀ values of 14 µg/mL and 18µg/mL as AChE and BChE cholinesterase inhibitors, respectively, when compared with standard positive control galantamine. Interestingly, AAZ8 also displayed promising antioxidant potential by showing IC₅₀ values of 35 µg/mL for DPPH and 29 µg/mL for ABTS in comparison with positive control ascorbic acid.

Conclusion

Herein, we report two new amide carboxylate zinc (II) complexes which were potentially analyzed for various biological applications like acetylcholinesterase (AChE), butyrylcholinesterase (BChE) inhibitory potentials, and antioxidant assays. Computational docking studies also simulated results to understand the interactions. Additionally, thermodynamic parameters utilizing molecular dynamic simulation were performed to determine the ligand protein stability and flexibility that supported the results. Studies have shown that these compounds have the potential to be good anti-Alzheimer candidates for future studies due to inhibition of cholinesterase enzymes and display of free radical scavenging potential against DPPH as well as ABTS free radicals.

Phytochemical profiling of bioactive compounds, anti-inflammatory and analgesic potentials of Habenaria digitata Lindl.: Molecular docking based synergistic effect of the identified compounds

ETHNOPHARMACOLOGICAL RELEVANCE

Members of Orchidaceae family has a long history in herbal and Chinese medicines. Members of this family are most commonly famous in the management of inflammation and analgesia in folk medicine. Habenaria digitata, an unexplored specie of Orchidaceae is found in North areas of Pakistan and is used by the local population for the management of analgesia and inflammation.

AIM OF THE STUDY

Based on the effective outcomes of the natural products as alternative therapies, we have evaluated Habenaria digitata for the management of analgesia and inflammation. The aim of the designed project is to provide a scientific basis of using this plant for the management of analgesia and inflammation.

MATERIALS AND METHODS

The H. digitata crude extract (Hd.Cr) and subfractions, i.e. n-hexane (Hd.Hex), chloroform (Hd.Chf), ethyl acetate (Hd.EtAc), n-butanol (Hd.Bt) and aqueous (Hd.Aq) were used. The GC-MS analysis was used for the identification of phytochemicals. The plants samples were subjected to cyclooxygenase (COX 2) and lipoxygenase (5-LOX) enzymes assays. The hot plate model, acetic acid induced writhing and formalin induced paw licking models were used for in-vivo analgesic studies. The in-vivo anti-inflammatory potential was determined with carrageenan induced paw edema test. Molecular docking studies of the identified compounds were carried out by using Molecular Operating Environment (MOE, 2016.08).

RESULTS

The GC-MS analysis confirmed sixty-five compounds in Hd.Cr. Among the fractions, Hd.Chf and Hd.EtAc displayed highest activities. The observed IC₅₀ values were 21.30 and 32.39 μg/ml against COX 2 while 14.42and 16.40 μg/ml for 5-LOX respectively. The in-vivo inflammatory and analgesic studies were pre-requisited with acute toxicity tests. In carrageenan induced inflammation, Hd.Chf excelled the standard drug aspirin by giving 62.92% inhibition of paw edema at 4^th h. Similarly, at highest concentration (75 mg/kg) of acetic acid induced analgesia, Hd.Chf was more potent than the standard drug. In formalin method, Hd.Chf exhibited 85.81% inhibition at phase-I and 74.15% at Phase-II. In hot plate model, Hd.Chf exhibited average reaction time of 10.90 at 15, 30, 45 and 60 min intervals. Docking studies supported our results and confirm the synergistic effects of phytochemicals.

CONCLUSIONS

Our experimental results concluded that H. digitata contains several bioactive compounds. These bioactive compounds synergistically have therapeutic efficacy for the management of inflammation and analgesia. We have confirmed both of these potentials from the in-vitro and in-vivo experiments. Moreover, it is also obvious that the chloroform and ethyl acetate fractions are rich in these bioactive compounds. Specifically, the Hd.Chf is observed to be more practical in all the tested models of analgesia and inflammation. Computed binding energies of the compounds revealed that all the compounds have synergistic effect to prevent analgesia and inflammation.

Comparative Cholinesterase, α-Glucosidase Inhibitory, Antioxidant, Molecular Docking, and Kinetic Studies on Potent Succinimide Derivatives

Introduction

The current study was designed to synthesize derivatives of succinimide and compare their biological potency in anticholinesterase, alpha-glucosidase inhibition, and antioxidant assays.

Methods

In this research, two succinimide derivatives including (S)-1-(2,5-dioxo-1-phenylpyrrolidin-3-yl) cyclohexanecarbaldehyde (Compound 1) and (R)-2-((S)-2,5-dioxo-1-phenylpyrrolidin-3-yl)-2-phenylpropanal (Compound 2) were synthesized using Michael addition. Both the compounds, ie, 1 and 2 were evaluated for in-vitro acetylcholinesterase (AChE), butyrylctcholinesterase (BChE), antioxidant, and α-glucosidase inhibitory potentials. Furthermore, molecular docking was performed using Molecular Operating Environment (MOE) to explore the binding mode of both the compounds against different enzymes. Lineweaver-Burk plots of enzyme inhibitions representing the reciprocal of initial enzyme velocity versus the reciprocal of substrate concentration in the presence of synthesized compounds and standard drugs were constructed using Michaelis-Menten kinetics.

Results

In AChE inhibitory assay, compounds 1 and 2 exhibited IC₅₀ of 343.45 and 422.98 µM, respectively, against AChE enzyme. Similarly, both the compounds showed IC₅₀ of 276.86 and 357.91 µM, respectively, against BChE enzyme. Compounds 1 and 2 displayed IC₅₀ of 157.71 and 471.79 µM against α-glucosidase enzyme, respectively. In a similar pattern, compound 1 exhibited to be more potent as compared to compound 2 in all the three antioxidant assays. Compound 1 exhibited IC₅₀ values of 297.98, 332.94, and 825.92 µM against DPPH, ABTS, and H₂O₂ free radicals, respectively. Molecular docking showed a triple fold in the AChE and BChE activity for compound 1 compared with compound 2. The compound 1 revealed good interaction against both the AChE and BChE enzymes which revealed the high potency of this compound compared to compound 2.

Conclusion

Both succinimide derivatives exhibited considerable inhibitory activities against cholinesterases and α-glucosidase enzymes. Of these two, compound 1 revealed to be more potent against all the in-vitro targets which was supported by molecular docking with the lowest binding energies. Moreover, compound 1 also proved to have antiradical properties.

Pharmacological Evaluation of Aldehydic-Pyrrolidinedione Against HCT-116, MDA-MB231, NIH/3T3, MCF-7 Cancer Cell Lines, Antioxidant and Enzyme Inhibition Studies

Purpose

The current work was designed to synthesize a bioactive derivative of succinimide and evaluate it for anti-Alzheimer, anticancer and anti-diabetic potentials.

Methods

The compound was synthesized by Michael addition of butyraldehyde with N-phenylmaleimide. The synthesized compound was screened for biological potentials including anti-cholinesterase, in-vitro anti-diabetic, antioxidant and anthelmintic potentials. The anti-cholinesterase potential was evaluated against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), anti-diabetic potential against α-glucosidase, antioxidant potential against ABTS, DPPH and H₂O₂ and anthelmintic potential against Perethima posthuma and Ascaridia galli respectively.

Results

The compound demonstrated significant AChE and BChE inhibition i.e., 71.34±1.92 and 73.42 ±1.92 at the concentration of 1000 µg/mL respectively. Other dilutions exhibited concentration-dependent inhibitory activity against both enzymes. In the MTT assay, the newly synthesized compound was found active against all of the cell lines viz, HCT-116, MDA-MB231, NIH/3T3 and MCF-7 and the highest cytotoxicity potential was observed against the colon cancer cell line (HCT-116) with an IC₅₀ value of 78 µg/mL exhibiting its highest potential. Moreover, the compound exhibited prominent α-glucosidase inhibitory potentials (79.86±2.54% at 1000 µg/mL) with IC₅₀ value of 156.23 µg/mL. Further, our test compound exhibited considerable scavenging activity against DPPH, ABTS and H₂O₂ free radicals with percent inhibitions of 75.84±1.58, 72.85±1.17 and 54.82±1.82 and IC₅₀ values of 84.36, 139.74 and 752.21 µg/mL respectively. Our test sample exhibited significant anthelmintic potentials. It demonstrated significant paralysis and death of the test worms in an unbelievably short time in comparison with albendazole.

Conclusion

Going into the detail of all observations, it may be deduced that the newly synthesized succinimide derivative could be an important drug candidate against neurodegenerative disorders like Alzheimer's disease, cancer, diabetes mellitus and worms. Further detailed studies in animal models are required for in-vivo analysis of the compound.

Design, synthesis, in-vitro, in-vivo and in-silico studies of pyrrolidine-2,5-dione derivatives as multitarget anti-inflammatory agents

In recent years, drug discovery paradigm has been shifted from conventional single target inhibition toward multitarget design concept. In current research, we have reported synthesis, in-vitro, in-vivo and acute toxicity determination of N-substituted pyrrolidine-2,5-dione derivatives as multitarget anti-inflammatory agents. We synthesized cycloalkyl, alkyl and aryl carbonyl derivatives by the Michael addition of ketones to N-substituted maleimides using self-assembled three component system as an organocatalyst. Anti-inflammatory potential of the compounds was determined by using different in-vitro assays, like cyclooxygenase-1, cyclooxygenase-2 and 5-lipoxygenase, albumin denaturation and anti-protease assays. Amongst the synthesized compounds, 13a-e series of compounds showed inhibition in low micromolar to submicromolar ranges. These compounds also demonstrated COX-2 selectivity. Compound 13e with IC₅₀ value 0.98 μM and SI of 31.5 emerged as the most potent inhibitor of COX-2. Based on in-vitro results, in-vivo anti-inflammatory investigations were performed on compounds 3b and 13evia carrageenan induced paw edema test. The possible mode of action of compounds 3b and 13e were ascertained with various mediators like histamine, bradykinin, prostaglandin and leukotriene. In-vivo acute toxicity study showed the safety of synthesized compounds up to 1000 mg/kg dose. The selectivity of the compounds against cyclooxygenase isoforms was supported by docking simulations. Selective COX-2 inhibitors showed significant interactions with the amino acid residues present in additional secondary COX-2 enzyme pocket. Furthermore, in-silico pharmacokinetic predictions confer the drug-like characteristics.

Design, synthesis and bioevaluation of tricyclic fused ring system as dual binding site acetylcholinesterase inhibitors

Due to recently discovered non-classical acetylcholinesterase (AChE) function, dual binding-site AChE inhibitors have acquired a paramount attention of drug designing researchers. The unique structural arrangements of AChE peripheral anionic site (PAS) and catalytic site (CAS) joined by a narrow gorge, prompted us to design the inhibitors that can interact with dual binding sites of AChE. Eighteen homo- and heterodimers of desloratadine and carbazole (already available tricyclic building blocks) were synthesized and tested for their inhibition potential against electric eel acetylcholinesterase (eeAChE) and equine serum butyrylcholinesterase (eqBChE). We identified a six-carbon tether heterodimer of desloratadine and indanedione based tricyclic dihydropyrimidine (4c) as potent and selective inhibitor of eeAChE with IC₅₀ value of 0.09 ± 0.003 μM and 1.04 ± 0.08 μM (for eqBChE) with selectivity index of 11.1. Binding pose analysis of potent inhibitors suggest that tricyclic ring is well accommodated into the AChE active site through hydrophobic interactions with Trp84 and Trp279. The indanone ring of most active heterodimer 4b is stabilized into the bottom of the gorge and forms hydrogen bonding interactions with the important catalytic triad residue Ser200.

Design, synthesis, in-vitro thymidine phosphorylase inhibition, in-vivo antiangiogenic and in-silico studies of C-6 substituted dihydropyrimidines

Thymidine phosphorylase (TP) is an angiogenic enzyme. It plays an important role in angiogenesis, tumour growth, invasion and metastasis. In current research work, we study the effect of structural modification of dihydropyrimidine-2-ones (DHPM-2-ones) on TP inhibition. A series of eighteen new derivatives of 3,4-dihydropyrimidone-2-one were designed and synthesized through the structural modification at C-6 position. All these new derivatives were then assessed for in-vitro inhibition of thymidine phosphorylase (TP) from E. coli. Oxadiazole derivatives 4a-e exhibited excellent TP-inhibition at low micromolar concentration levels better than standard drug 7-deazaxanthine (7-DX). Among all these compounds, 4b was found to be the most potent with IC₅₀ = 1.09 ± 0.004 μM. Anti-angiogenesis potential of representative compounds were also studied in a chorioallantoic membrane (CAM) assay. Here again, compound 4b was found to be the potent anti-angiogenesis compound in a CAM assay. Docking studies were also performed with Molecular Operating Environment (MOE) to further analyse the mode of inhibition of these compounds. Binding mode analysis of the most active inhibitors showed that these are well accommodated into the binding site of enzyme though stable hydrogen bonding and hydrophobic interactions.

HPLC-DAD finger printing, antioxidant, cholinesterase, and α-glucosidase inhibitory potentials of a novel plant Olax nana

BACKGROUND

The medicinal importance of a novel plant Olax nana Wall. ex Benth. (family: Olacaceae) was revealed for the first time via HPLC-DAD finger printing, qualitative phytochemical analysis, antioxidant, cholinesterase, and α-glucosidase inhibitory assays.

METHODS

The crude methanolic extract of O. nana (ON-Cr) was subjected to qualitative phytochemical analysis and HPLC-DAD finger printing. The antioxidant potential of ON-Cr was assessed via 1,1-diphenyl,2-picrylhydrazyl (DPPH), 2,2-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) and hydrogen peroxide (H2O2) free radical scavenging assays. Furthermore, acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities were performed using Ellman's assay, while α- glucosidase inhibitory assay was carried out using a standard protocol.

RESULTS

The qualitative phytochemical analysis of ON-Cr revealed the presence of secondary metabolites like alkaloids, flavonoids, tannins, sterols, saponins and terpenoids. The HPLC-DAD finger printing revealed the presence of 40 potential compounds in ON-Cr. Considerable anti-radical activities was revealed by ON-Cr in the DPPH, ABTS and H2O2 free radical scavenging assays with IC50 values of 71.46, 72.55 and 92.33 μg/mL, respectively. Furthermore, ON-Cr showed potent AChE and BChE inhibitory potentials as indicated by their IC50 values of 33.2 and 55.36 μg/mL, respectively. In the α-glucosidase inhibition assay, ON-Cr exhibited moderate inhibitory propensity with an IC50 value of 639.89 μg/mL.

CONCLUSIONS

This study investigated Olax nana for the first time for detailed qualitative phytochemical tests, HPLC-DAD finger printing analysis, antioxidant, anticholinesterase and α-glucosidase inhibition assays. The antioxidant and cholinesterase inhibitory results were considerable and can provide scientific basis for further studies on the neuroprotective and anti-Alzheimer's potentials of this plant. ON-Cr may further be subjected to fractionation and polarity guided fractionation to narrow down the search for isolation of bioactive compounds.

Anticholinesterase and antioxidant potentials of Nonea micrantha Bioss. & Reut along with GC-MS analysis

BACKGROUND

Nonea micrantha Boiss. & Reut . being an unexplored member of Boraginaceae was investigated for GC/MS analysis, acetylcholinesterase (AChE), butyrylcholinesterase (BChE) inhibitory and antioxidant activities in an attempt to find its effectiveness in neurological disorders.

METHODS

The AChE and BChE inhibitory activities of crude methanolic extract (Nm.Cr), subsequent fractions; n-hexane (Nm.Hex), chloroform (Nm.Cf), ethyl acetate (Nm.EtAc), aqueous (Nm.Aq) and crude saponins (Nm.Sp) from N. micrantha were conducted using Ellman's assay. The antioxidant activity of the plant samples using DPPH and ABTS free radical scavenging potential following quantitative spectrophotometric and qualitative TLC method were also studied. Moreover the total reducing power (TRP) of all the samples was also figured out.

RESULTS

The GC/Ms analysis confirmed that the plant is rich in bioactive molecules. Among different fractions, Nm.Hex, Nm.EtAc and Nm.Cf exhibited highest AChE inhibitory activities causing 75.51 ± 0.73, 68.54 ± 0.59 and 63.48 ± 0.59% enzyme inhibition respectively and IC₅₀ of 44, 100 and 144 μg/mL respectively. In BChE inhibiton assay, Nm.Aq, Nm.Sp and Nm.Cr showed highest activity causing 83.49 ± 0.27, 81.49 ± 0.89 and 75.31 ± 0.56% enzyme inhibition with IC₅₀ of 90, 110 and 44 μg/mL respectively. In DPPH assay, Nm.Aq, Nm.Cf, Nm.Hex and Nm.Cr were most potent exhibiting IC₅₀ values of 3, 5, 93 and 120 μg/ml respectively. In ABTS assay Nm.EtAc, Nm.Aq, Nm.Sp and Nm.Cr showed IC₅₀ values of 60, 95, 100 and 150 μg/mL respectively. Likewise ABTS inhibition was most prominent for Nm.Sp, Nm.EtAc and Nm.Aq causing 78.26 ± 0.49, 67.67 ± 0.73 and 63.58 ± 0.45% inhibition respectively at 1 mg/mL. These results were further confirmed by qualitative screening using DPPH and ABTS staining.

CONCLUSIONS

Our anticholinesterase and antioxidant results signify the N. micrantha as a potential source of natural bioactive compounds. Moreover isolation of natural bioactive compounds from this plant may lead to novel drug candidates against neurodegenerative disorders.

Synthesis, anticholinesterase and antioxidant potentials of ketoesters derivatives of succinimides: a possible role in the management of Alzheimer's

Background

Based on the pharmacological potency and structural features of succinimides, this study was designed to synthesize new ketoesters derivatives of succinimides. Furthermore, the synthesized compounds were evaluated for their possible anticholinesterase and antioxidant potentials. The compounds were synthesized by organocatalytic Michael additions of α-ketoesters to N-aryl maleimides. Acetyl and butyrylcholinesterase inhibitory activities were determined using Ellman’s spectrophotometric assay. The antioxidant activity was performed with DPPH and ABTS free radicals scavenging assay.

Results

The Michael additions of α-ketoesters to maleimides was promoted by 8-hydroxyquinoline. The organocatalyst (8-hydroxyquinoline, 20 mol %) produced the compounds in relatively shorter time (20–24 h) and with excellent isolated yields (84-98 %). The synthesized compounds (1–4) showed outstanding acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potentials, i.e., 98.75 and 90.00 % respectively for compound 2, with IC₅₀ < 0.1 μg/mL. Additionally, compounds 1–4 revealed moderate antioxidant activity at different concentrations. In DPPH free radical scavenging assay, compound 1 showed dominant result with 72.41 ± 0.45, 52.49 ± 0.78 and 35.60 ± 0.75 % inhibition at concentrations of 1000, 500 and 250 μg/mL respectively, IC₅₀ value of 440 μg/mL. However, the free radical scavenging was better when used ABTS free radicals. In ABTS free radicals scavenging assay compound 1 exhibited 88.51 ± 0.62 % inhibition at highest tested concentration i.e., 1000 μg/mL.

Conclusions

Herein, we have synthesized four ketoesters derivatives of succinimides in a single step reaction and high yields. As a highlight, we have showed a first report on the anticholinesterase and antioxidant potentials of succinimides. All the compounds showed overwhelming enzyme inhibitions and moderate antioxidant potentials.

Graphical Abstract

In vivo staphylococcal enterotoxin B (SEB)-primed murine splenocytes secrete mediators which suppress CD25(hi) expression and cell cycle progression of naive splenocytes in response to SEB in vitro

Administration of bacterial superantigen results in clonal activation of T cells followed by a state of hyporesponsiveness to subsequent antigen stimulation. Using a coculture system, we showed that the splenocytes from staphylococcal enterotoxin B (SEB)-injected BALB/c mice suppressed the proliferative response of naive splenocytes to SEB stimulation. The suppressive effect also occurred in Fas-deficient MRL-lpr/lpr mice. When naive responder cells were separated by a semipermeable membrane from SEB-primed effector cells, the suppressive effect remained apparent. The hyporesponsiveness of responder cells did not result from excessive induction of apoptosis, but rather from prevention of entering the S and G2/M phases of the cell cycle. The IL-2 levels in culture supernatants were low with the presence of SEB-primed effector cells. However, addition of IL-2 to the cocultures only partially reversed the inhibitory effect. Further studies revealed a reduced level of the CD25(hi) subpopulation in responder cells when cultured in the transwell with the presence of SEB-primed effector cells compared to that with saline-primed controls. This inhibitory effect was not observed for SEB-induced activation of CD25(int) and CD69 expression. Taken together, using a transwell culture system, we show in this study an inhibition of CD25(hi) expression and cell cycle arrest in target cells, which may serve at least in part the mechanisms of SEB-induced hyporesponsiveness.

alpha-Difluoromethylornithine blocks thymocyte apoptosis via a reduction in tyrosine phosphorylation

The effect of alpha-difluoromethylornithine on cell apoptosis was investigated. Freshly isolated mouse thymocytes were cultured in the medium alone or with dexamethasone, and apoptotic cell death was monitored after 6 h. A correlation was seen between cell apoptosis and a reduction in the polyamine levels of thymocytes. Addition of exogenous polyamines decreased the levels of apoptosis induced spontaneously in the culture medium or by dexamethasone. However, addition of alpha-difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase, to the cultures did not enhance apoptosis but rather caused inhibition of thymocyte apoptosis. Analysis of the mechanism of alpha-difluoromethylornithine-mediated inhibition of apoptosis indicated that alpha-difluoromethylornithine treatment blocked protein tyrosine phosphorylation, which was elevated drastically during the first hour of thymocyte cultivation. Treatment with the phosphotyrosine phosphatase inhibitor phenylarsine oxide reversed this inhibitory effect of alpha-difluoromethylornithine on apoptotic cell death. Our results provide an alternative mechanism for alpha-difluoromethylornithine showing the inhibition of apoptosis via reduction of protein tyrosine phosphorylation.

Bad overexpression sensitizes NIH/3T3 cells to undergo apoptosis which involves caspase activation and ERK inactivation

The effect of Bad overexpression on apoptosis was demonstrated by a mouse Bad transgene stably expressed in NIH/3T3 cells. The cells overexpressing Bad treated with either serum starvation or ceramide showed apoptotic characteristics evident at 18 and 8 h, respectively. Whether serum deprivation and ceramide utilize a common death pathway requires further investigation. The time for the first apoptosis detection was shortened to 2 h and was prominent at 4 h, while above that time cells were maintained under serum-depleted conditions in the presence of ceramide (40 microM). Further investigation revealed that the activity of caspase-3 (CPP32) was elevated after ceramide treatment in Bad-transfected cells compared to that of the cells without Bad transfection, indicating the involvement of caspase cascade. Furthermore, the Bad-transfected cells showed reduced phosphorylation of extracellular signal-regulated kinase (ERK). Taken together, we hypothesize that Bad-overexpressing NIH/3T3 cells in the presence of ceramide undergo apoptosis by activating caspase cascade. Simultaneously, the cell survival pathway was blocked possibly by inactivation of the MAPK pathway such as the down-regulation of ERK.

Is green fluorescent protein toxic to the living cells?

Green fluorescent protein (GFP) has become more popular to be used as a living marker for positively transfected clones in many studies. To establish stable cell lines constitutively expressing GFP, three GFPs expressed from plasmid pBIEGFP, pSG5GFP, and pRSGFP were introduced into NIH/3T3, BHK-21, Huh-7, and HepG2 cells. All the GFPs we used are the mutant forms of a common wild phenotype. The pBIEGFP expressed enhanced GFP (EGFP). The pRSGFP and pSG5GFP expressed red shift GFP (RSGFP). The RSGFP gene in pSG5GFP was driven by a strong SV40 promoter and showed at least 20-fold higher RSGFP expression by western blot analysis. Despite of the variation in the levels of GFP expression, many GFP expressing cells contracted, rounded-up, and died, which was confirmed by decreasing luciferase activity. CPP32 activity and flow cytometric analyses further demonstrate that cells expressing GFP underwent apoptosis. Our observation is contradictory to other reports that GFP is nontoxic to the cells. Most importantly, this paper shows for the first time the link between expression of GFP and induction of apoptosis. This finding should promote studies of GFP cytotoxicity and attempts to isolate new non-toxic mutants of GFP.

Selective activation of Ha-ras(val12) oncogene increases susceptibilityof NIH/3T3 cells to TNF-alpha

This is the first report demonstrating that NIH/3T3 fibroblasts utilize the Raf-1/MAPK pathway to sensitize themselves to tumor necrosis factor-alpha (TNF-alpha) cytotoxicity under Ha-rasVal12 oncogene-overexpressed conditions. This paper clearly shows that the sensitivity of NIH/3T3 cells to TNF-alpha cytotoxicity positively correlated with the expression level of activated Ha-ras transgene, which was manipulated either positively by isopropyl-beta-d-thiogalactoside (IPTG) induction or negatively by a ribozyme or a dominant negative Ras suppression. Further analysis revealed that after TNF-alpha treatment, Ha-ras-overexpressed transformants underwent apoptosis. Overexpression of dominant negative Raf-1, Rac1, or RhoA in the Ha-ras transformants clarified that among these factors, only dominant negative Raf-1 could reverse the cell sensitivity to TNF-alpha, indicating that Raf-1, as a proapoptotic factor, indeed participates in TNF-alpha cytotoxicity. The anti-apoptotic roles of Bcl-2 and PI(3) kinase are also demonstrated by the Ha-ras transformants which became more resistant to TNF-alpha while overexpressing Bcl-2 or the activated p110 catalytic subunit. The analyses of the cell cycle and nuclear transcription factor activities revealed that TNF-alpha treatment caused the Ha-ras overexpressed transformants to shift from S to G0/G1 phase and increased the responses of AP-1, c-fos, and c-myc. Taken together, we suggest that the possible action of Ha-ras overexpression to sensitize TNF-alpha-treated fibroblasts is predominantly through the Ras/Raf-1/MAPK pathway to increase the responses of AP-1, c-fos, and c-myc, which are possibly involved in the aberration of cell cycle machinery, and subsequently to turn on the death program.

Requirement of I-E molecule for thymocyte apoptosis induced by staphylococcal enterotoxin B in vivo

In vivo administration of bacterial superantigen staphylococcal enterotoxin B (SEB) to BALB/c mice led to thymus atrophy resulting from thymocyte apoptosis. In this study, we demonstrated that SEB induced a substantial reduction in thymocyte numbers in BALB/c, B10. D2 (H-2(d) haplotype), B10.BR, C3H/HeJ, C3H/HeN (H-2(k)), and (BALB/c x B6)F1 (H-2(dxb)), but caused little or no effect in I-E- strains such as B6, B10, A.BY (H-2(b)), and A.SW (H-2(s)) mice. Elimination of CD4(+)CD8(+) cells predominantly accounted for the thymocyte loss, although the numbers of other subpopulations may also be reduced. Thymocyte apoptosis was shown by an increase in the level of DNA fragmentation in BALB/c but not in B6 mice after SEB administration. Treatment with anti-I-Ed monoclonal antibody to BALB/c mice blocked SEB-induced thymocyte apoptosis when anti-I-Ad exerted less effect. In contrast to SEB, staphylococcal enterotoxin A led to comparable levels of thymus atrophy in BALB/c and B6 mice. Studies on the surface marker expression indicated that CD25 expression was upregulated on BALB/c mouse thymocytes but with only a moderate increase in B6 mice. The CD4(+)CD8(+) cells were the major (>90%) population that expressed elevated levels of CD25 in BALB/c mice. An increase in the expression of TCRalphabeta, CD3, and CD69 surface markers was also observed on thymocytes from BALB/c mice, but not from I-E- strains. The differential response of I-E+ and I-E- mice to SEB may be exploited as a model for the study of apoptosis in the thymus.

Ha-rasVal12 oncogene increases susceptibility of NIH/3T3 cells to lovastatin

This study demonstrates that Ha-rasVal12 oncogene overexpression sensitizes NIH/3T3 fibroblasts to lovastatin (LOV) cytotoxicity. This sensitization is through apoptosis, which was characterized by increasing CPP32 (caspase-3) activity and DNA fragmentation. Bcl-2 overexpression increased the resistance of the Ha-ras transformants to LOV and rescued the cells from apoptosis, further confirming that the LOV-sensitive cells died of apoptosis. Further analysis showed that Ha-ras activity inversely correlated with WAF1 activity. LOV treatment suppressed Ha-ras activity but induced WAF1 activity and disrupted the cell population in G0/G1 and S phases. The Ha-ras transformants expressing either dominant negative RasAsn17 or Raf-1CB4 showed reverted susceptibility to LOV. These data confirm the involvement of Ras and demonstrate that Raf-1 signalling is required for LOV-induced cell death. Taken together, the possible action of LOV-induced apoptosis is through suppressing Ha-ras activity and increasing WAF1 activity, which alters cell cycle progression and finally activates suppressed apoptotic pathway in a Fas/Fas-L- and p53-independent fashion.