Phytochemical profiling, antioxidant and anticancer activities of Gastrocotyle hispida growing in Saudi Arabia.

The present study aimed at isolation the phytocompounds from the aerial parts of Gastrocotyle hispida and to evaluate its antioxidant and anticancer potential using in vitro assay. Gastrocotyle hispida is belonging to the family Boraginaceae used as a refreshing drink like tea. The decoction of the leaves is diuretic and is used in the treatment of rheumatism. Phytochemical study of a methanol extract yielded five known compounds viz: ß-sitosterol (GH-1), ß-sitosterol 3-glucoside (GH-2), 1-O-ß-glucopyranosyl-1,4-dihydroxy-2-prenylbenzene (GH-3), 6-Hydroxy-2,2-dimethyl-3-chrom (GH-4) and rosmarinic acid (GH-5). Total phenolic and flavonoid contents were calculated for the extract and fractions, the methanolic extract contained the highest content of total flavonoids (178 mg/g, expressed as quercetin equivalents) and total polyphenol (98.4 mg/g, expressed as gallic acid equivalent). Compounds were isolated by using column chromatography. In vitro, antioxidant activity of the extract and isolated compounds was investigated by DPPH and ABTS radical scavenging assays. The four different cell lines HepG2 (Liver), HEK-293 (Kidney) MCF-7 (Breast) and MDA-MB 231 (Breast) were used against the compounds. The isolated compounds showed dose-dependent free radical scavenging property in all tested models with the IC50 values of 10.2 µg/mL rosmarinic acid (GH-5), 52.1 µg/mL ß-sitosterol (GH-1) and 85 µg/mL for ß-sitosterol 3-glucoside (GH-2). The ß-sitosterol (GH-1) showed significant activity against HepG2 and HEK 293 cell lines. Rosmarinic acid (GH-5) possesses potent anticancer activity against breast cancer cells (MCF7) with the IC50 value of 4.2 µg/mL. It can be concluded that Gastrocotyle hispida has potential antioxidant, anticancer activities and further used as an anticancer agent.

Inhibitory Effect of New Semisynthetic Usnic Acid Derivatives on Human Tyrosyl-DNA Phosphodiesterase 1.

Usnic acid, a lichen secondary metabolite produced by a whole number of lichens, has attracted the interest of researchers owing to its broad range of biological activity, including antiviral, antibiotic, anticancer properties, and it possessing a certain toxicity. The synthesis of new usnic acid derivatives and the investigation of their biological activity may lead to the discovery of compounds with better pharmacological and toxicity profiles. In this context, a series of new usnic acid derivatives comprising a terpenoid moiety were synthesized, and their ability to inhibit the catalytic activity of the human DNA repair enzyme tyrosyl-DNA phosphodiesterase 1 was investigated. The most potent compounds (15A, 15B, 15G: , and 16A, 16B, 16G: ) had IC50 values in the range of 0.33 - 2.7 µM. The inhibitory properties were mainly dependent on the flexibility and length of the terpenoid moiety, but not strongly dependent on the configuration of the asymmetric centers. The synthesized derivatives showed low cytotoxicity against human cell lines in an MTT assay. They could be used as a basis for the development of more effective anticancer therapies when combined with topoisomerase 1 inhibitors.

Zinc enhances the cellular energy supply to improve cell motility and restore impaired energetic metabolism in a toxic environment induced by OTA.

Exogenous nutrient elements modulate the energetic metabolism responses that are prerequisites for cellular homeostasis and metabolic physiology. Although zinc is important in oxidative stress and cytoprotection processes, its role in the regulation of energetic metabolism remains largely unknown. In this study, we found that zinc stimulated aspect in cell motility and was essential in restoring the Ochratoxin A (OTA)-induced energetic metabolism damage in HEK293 cells. Moreover, using zinc supplementation and zinc deficiency models, we observed that zinc is conducive to mitochondrial pyruvate transport, oxidative phosphorylation, carbohydrate metabolism, lipid metabolism and ultimate energy metabolism in both normal and toxic-induced oxidative stress conditions in vitro, and it plays an important role in restoring impaired energetic metabolism. This zinc-mediated energetic metabolism regulation could also be helpful for DNA maintenance, cytoprotection and hereditary cancer traceability. Therefore, zinc can widely adjust energetic metabolism and is essential in restoring the impaired energetic metabolism of cellular physiology.

Bufalin, a bufanolide steroid from the parotoid glands of the Chinese toad, suppresses hERG K+ currents expressed in HEK293 cells.

In this study, we investigated the effect of bufalin on the human ether-à-go-go-related gene (hERG) K+ channels using the perforated patch recording technique. We measured a half-maximal inhibitory concentration (IC50 ) of 24.83 µM and maximal inhibitory effect of 39.45 ± 1.14% with bufalin. These findings suggest that bufalin is a potent hERG K+ channel blocker and may provide a new way for understanding Chan Su-induced arrhythmia.

Effects of ultra-high dilutions of sodium butyrate on viability and gene expression in HEK 293 cells.

BACKGROUND: Several recent studies reported the capability of high diluted homeopathic medicines to modulate gene expression in cell cultures. In line with these studies, we examined whether ultra-high dilutions (30C and 200C) of sodium butyrate (SB) can affect the expression levels of genes involved in acquisition of a senescence-associated secretory phenotype (SASP) in human embryonic kidney (HEK) 293 cells. METHODS: Cell viability was evaluated using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The expression levels of TNF-α, interleukin (IL)-2, IL-4, IL-6 and IL-10 genes were determined by real-time PCR assay. RESULTS: Exposure to both 30C and 200C during 48 h led to a significant decrease of the level of expression of TNF-α gene, while expression of IL-2 gene was increased when exposed to 30C, and expression of IL-10 gene was decreased when exposed to 200C. No changes in expression levels of all genes studied were observed in cells treated with both 30C and 200C remedies of SB during the 24 h. CONCLUSION: Observed changes in gene expression levels after exposure to 30C and 200C remedies of SB during 48 h suggest that extremely low concentrations of this agent can modulate the transcriptome of HEK 293 cells. These results are in line with findings from other studies confirming the ability of homeopathic remedies to modulate gene expression in cell cultures.

Synthesis and biological evaluation of novel flavanone derivatives as potential antipsychotic agents.

In this study, a series of novel flavanone derivatives were designed and synthesized, and the antipsychotic activities of the target compounds were evaluated in vitro and in vivo. The results showed that synthesized compounds 7a-7g decreased the activity of dopamine D2 receptors in HEK293 cells co-transfected with D2 receptor/G protein α16a, with IC50 values of 0.051-0.35 µm. Compounds 7a-7g inhibited the over-production of nitric oxide stimulated by lipopolysaccharide/interferon-γ in BV-2 microglial cells. In mice, intragastric administration of 7d, 7e, and 7g reversed the increase in locomotor activity induced by MK-801 (an antagonist of NMDA receptors) and decreased the hyperactivity of climbing behavior induced by apomorphine (a dopamine receptor agonist). These results suggest that some of the novel flavanone derivatives have potential antipsychotic effects and may be useful in the treatment of schizophrenia.

Unbiased screen identifies aripiprazole as a modulator of abundance of the polyglutamine disease protein, ataxin-3.

No disease-modifying treatment exists for the fatal neurodegenerative polyglutamine disease known both as Machado-Joseph disease and spinocerebellar ataxia type 3. As a potential route to therapy, we identified small molecules that reduce levels of the mutant disease protein, ATXN3. Screens of a small molecule collection, including 1250 Food and Drug Administration-approved drugs, in a novel cell-based assay, followed by secondary screens in brain slice cultures from transgenic mice expressing the human disease gene, identified the atypical antipsychotic aripiprazole as one of the hits. Aripiprazole increased longevity in a Drosophila model of Machado-Joseph disease and effectively reduced aggregated ATXN3 species in flies and in brains of transgenic mice treated for 10 days. The aripiprazole-mediated decrease in ATXN3 abundance may reflect a complex response culminating in the modulation of specific components of cellular protein homeostasis. Aripiprazole represents a potentially promising therapeutic drug for Machado-Joseph disease and possibly other neurological proteinopathies.

Antibacterial Diamines Targeting Bacterial Membranes.

Antibiotic resistance is a growing threat to human health exacerbated by a lack of new antibiotics. We now describe a series of substituted diamines that produce rapid bactericidal activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus and stationary-phase bacteria. These compounds reduce biofilm formation and promote biofilm dispersal in Pseudomonas aeruginosa. The most potent analogue, 3 (1,13-bis{[(2,2-diphenyl)-1-ethyl]thioureido}-4,10-diazatridecane), primarily acts by depolarization of the cytoplasmic membrane and permeabilization of the bacterial outer membrane. Transmission electron microscopy confirmed that 3 disrupts membrane integrity rapidly. Compound 3 is also synergistic with kanamycin, demonstrated by the checkerboard method and by time-kill kinetic experiments. In human cell toxicity assays, 3 showed limited adverse effects against the HEK293T human kidney embryonic cells and A549 human adenocarcinoma cells. In addition, 3 produced no adverse effects on Caenorhabditis elegans development, survival, and reproduction. Collectively, diamines related to 3 represent a new class of broad-spectrum antibacterials against drug-resistant pathogens.

Taming Amphotericin B.

A strategy is introduced for enhancing the cellular selectivity of Amphotericin B (AmB) and other classes of membrane-disrupting agents. This strategy involves attaching the agent to a molecular umbrella to minimize the disruptive power of aggregated forms. Based on this approach, AmB has been coupled to a molecular umbrella derived from one spermidine and two cholic acid molecules and found to have antifungal activities approaching that of the native drug. However, in sharp contrast to AmB, the hemolytic activity and the cytotoxcity of this conjugate toward HEK293 T cells have been dramatically reduced.

Synthesis and Biological Evaluation of Manassantin Analogues for Hypoxia-Inducible Factor 1α Inhibition.

To cope with hypoxia, tumor cells have developed a number of adaptive mechanisms mediated by hypoxia-inducible factor 1 (HIF-1) to promote angiogenesis and cell survival. Due to significant roles of HIF-1 in the initiation, progression, metastasis, and resistance to treatment of most solid tumors, a considerable amount of effort has been made to identify HIF-1 inhibitors for treatment of cancer. Isolated from Saururus cernuus, manassantins A (1) and B (2) are potent inhibitors of HIF-1 activity. To define the structural requirements of manassantins for HIF-1 inhibition, we prepared and evaluated a series of manassantin analogues. Our SAR studies examined key regions of manassantin's structure in order to understand the impact of these regions on biological activity and to define modifications that can lead to improved performance and drug-like properties. Our efforts identified several manassantin analogues with reduced structural complexity as potential lead compounds for further development. Analogues MA04, MA07, and MA11 down-regulated hypoxia-induced expression of the HIF-1α protein and reduced the levels of HIF-1 target genes, including cyclin-dependent kinase 6 (Cdk6) and vascular endothelial growth factor (VEGF). These findings provide an important framework to design potent and selective HIF-1α inhibitors, which is necessary to aid translation of manassantin-derived natural products to the clinic as novel therapeutics for cancers.

Design and biological evaluation of novel quinolone-based metronidazole derivatives as potent Cu(2+) mediated DNA-targeting antibacterial agents.

A series of novel quinolone-based metronidazole derivatives as new type of antimicrobial agents were developed and characterized. Most of them gave good antibacterial activity towards the Gram-positive and negative bacteria. Noticeably, quinolone derivative 3i exhibited low MIC value of 0.25 µg/mL against Pseudomonas aeruginosa, which was even superior to reference drugs Norfloxacin, Ciprofloxacin and Clinafloxacin. The further research revealed that compound 3i could intercalate into P. aeruginosa DNA through copper ion bridge to form a steady 3i-Cu(2+)-DNA ternary complex which might further block DNA replication to exert the powerful bioactivities.

Protection of Gastrointestinal Mucosa from Acute Heavy Alcohol Consumption: The Effect of Berberine and Its Correlation with TLR2, 4/IL1ß-TNFα Signaling.

The purpose of the present study is to confirm the protective effect of berberine (BBR) on gastrointestinal injury caused by acute heavy alcohol exposure, an effect that has not been reported previously. Our research details how BBR protects against gastrointestinal injuries from acute alcohol exposure using both in vivo and in vitro experiments. Acute high alcohol concentrations lead to obvious damage to the gastrointestinal mucosa, resulting in necrosis of the intestinal mucosa. Oral administration of BBR was able to significantly reduce this alcohol-induced damage, inhibit increases of alcohol-induced TNFα and IL-1ß expression in gastrointestinal mucosa as well as their upstream signals TLR2 and TLR4, and regulate cytokines that modulate tight junctions. Alcohol consumption is a popular human social behavior worldwide, and the present study reports a comprehensive mechanism by which BBR protects against gastrointestinal injuries from alcohol stress, providing people with a novel application of BBR.

Lignans from the Fruits of Melia toosendan and Their Agonistic Activities on Melatonin Receptor MT1.

Investigation on the fruits of Melia toosendan afforded seven new lignans (1-7), along with seventeen known compounds (8-24). The structures of the new compounds, involving four neo-lignans (1-4), two sesquilignans (5-6), and a nor-lignan (7), were elucidated based on extensive spectroscopic analyses (high-resolution electrospray ionization mass spectra, ultraviolet, infrared, one-dimensional and two-dimensional nuclear magnetic resonance). Compound 24 exhibited activity on melatonin receptor type 1 with an agonistic rate of 57.77% at 1.02 mM according to the assay on HEK293 cell lines in vitro.

Design of highly potent urea-based, exosite-binding inhibitors selective for glutamate carboxypeptidase II.

We present here a structure-aided design of inhibitors targeting the active site as well as exosites of glutamate carboxypeptidase II (GCPII), a prostate cancer marker, preparing potent and selective inhibitors that are more than 1000-fold more active toward GCPII than its closest human homologue, glutamate carboxypeptidase III (GCPIII). Additionally, we demonstrate that the prepared inhibitor conjugate can be used for sensitive and selective imaging of GCPII in mammalian cells.

Identification of NF-κB inhibitors in Qishenyiqi dropping pills for myocardial infarction treatment based on bioactivity-integrated UPLC-Q/TOF MS.

Qishenyiqi dropping pills (QSYQ) are a type of standardized cardiovascular multiherb medicine for the treatment of myocardial infarction (MI). Knowledge concerning the systemic identification of nuclear factor-kappa B (NF-κB) inhibitors of QSYQ is generally lacking. Therefore, it is necessary to establish an effective method to screen the bioactive components of NF-κB inhibition. In the present study, a rat model of coronary artery ligation was used to assess the cardioprotective effects of QSYQ. The electrocardiograms, histopathology of heart tissues and serum biochemical indicators, such as brain natriuretic peptide, cardiac troponin I and inflammatory cytokines, were measured. Subsequently, ultra-performance liquid chromatography quadrupole/time-of-flight mass spectrometry (UPLC-Q/TOF MS) combined with the NF-κB luciferase reporter assay system was applied to screen the potential anti-inflammatory compounds in QSYQ. The results revealed that the administration of QSYQ could improve heart function, ameliorate neutrophil infiltration and diminish the levels of inflammatory cytokines in MI rats. Furthermore, 22 compounds were determined to be potential NF-κB inhibitors. In conclusion, NF-κB inactivation and cytokine suppression might be the main mechanisms of QSYQ for MI treatment. The method of UPLC-Q/TOF MS combined with a bioactive human cell functional evaluation system was proved to be a simple and effective strategy for screening bioactive compounds in traditional Chinese medicine prescriptions.

Affinity and kinetics study of anthranilic acids as HCA2 receptor agonists.

Structure-affinity relationship (SAR) and structure-kinetics relationship (SKR) studies were combined to investigate a series of biphenyl anthranilic acid agonists for the HCA2 receptor. In total, 27 compounds were synthesized and twelve of them showed higher affinity than nicotinic acid. Two compounds, 6g (IC50=75nM) and 6z (IC50=108nM) showed a longer residence time profile compared to nicotinic acid, exemplified by their kinetic rate index (KRI) values of 1.31 and 1.23, respectively. The SAR study resulted in the novel 2-F, 4-OH derivative (6x) with an IC50 value of 23nM as the highest affinity HCA2 agonist of the biphenyl series, although it showed a similar residence time as nicotinic acid. The SAR and SKR data suggest that an early compound selection based on binding kinetics is a promising addition to the lead optimization process.

Anti-mycobacterial triterpenes from the Canadian medicinal plant Alnus incana.

ETHNOPHARMACOLOGICAL RELEVANCE: Alnus incana, commonly known as the gray or speckled alder, is a medicinal plant used by some Canadian First Nations to treat symptoms associated with tuberculosis. The aim of this study was to assess the anti-mycobacterial activity of an Alnus incana bark extract and to identify the active constituents of the extract. MATERIALS AND METHODS: Methanolic extracts of the bark of A. incana were subjected to bioassay guided fractionation using Mycobacterium tuberculosis (H37Ra). The active constituents were identified by NMR and MS. RESULTS: Four pentacyclic lupane triterpenes were isolated and were identified as betulin, betulinic acid, betulone and lupenone. Betulin displayed a MIC of 12.5 µg/mL and an IC50 of 2.4 µg/mL against M. tuberculosis (H37Ra). Betulinic acid and betulone showed lower anti-mycobacterial activities with IC50 values of 84 and 57 µg/mL respectively. Lupenone was inactive against M. tuberculosis (H37Ra). CONCLUSIONS: Betulin, betulinic acid and betulone were identified as the major anti-mycobacterial constituents in the bark of A. incana and the functionality at carbons 3 and 28 of the lupane skeleton would seem to be important in determining the anti-mycobacterial activity of the triterpenes. This work supports the ethnopharmacological use of A. incana by Canadian First Nations communities as a treatment for tuberculosis.

Antinociceptive activity of extracts and secondary metabolites from wild growing and micropropagated plants of Renealmia alpinia.

ETHNOPHARMACOLOGICAL RELEVANCE: Renealmia alpinia is native to the American continent and can be found from Mexico to Brazil, and in the Caribbean islands. It is known as "matandrea" in Colombia, and it has been commonly used in traditional medicine to treat painful diseases and ailments. Based on its traditional uses, it is of interest to evaluate the pharmacologic effects of this plant and its secondary metabolites. MATERIALS AND METHODS: Methanol and aqueous extracts of wild and micropropagated R. alpinia (leaves) were obtained and chemically compared by High Performance Thin Layer Chromatography (HPTLC). The antinociceptive activity of these extracts was examined using an in vivo assay (Siegmund test). Additionally, the dichloromethane extract of R. alpinia was fractionated and pure compounds were isolated by chromatographic methods. The structure elucidation of isolated compounds was performed by NMR experiments and spectroscopic techniques and comparison with the literature data. Purified compounds were evaluated for their in vitro binding affinity for opioids and cannabinoids receptors. RESULTS: The dichloromethane extract of the plant's aerial part afforded sinostrobin (1), naringenin 7,4'-dimethyl ether (2), 2',6'-dihydroxy-4'-methoxychalcone (3), 4-methoxy-6-(2-phenylethenyl)-2H-pyran-2-one (4), naringenin 7-methyl ether (5) and 3,5-heptanediol, 1,7-diphenyl (6), which were isolated using chromatographic methods. Their chemical structures were established by physical and spectroscopic techniques. The antinociceptive effects observed in mice by extracts of wild and micropropagated plants were similar. The compounds isolated from R. alpinia do not show affinity to opioid or cannabinoid receptors. CONCLUSION: Aqueous and methanol extracts of R. alpinia provide antinociceptive and analgesic effects in an in vivo model. These results contribute additional insight as to why this plant is traditionally used for pain management. Also, this is the first comprehensive report of a phytochemical study of R. alpinia.

Fluoro-substituted phenylazocarboxamides: Dopaminergic behavior and N-arylating properties for irreversible binding.

Phenylazocarboxamides can serve as bioisosteres for cinnamides, which are widely occurring substructures in medicinal chemistry. Starting from our lead compound 2, the introduction of additional fluoro substituents and the exchange of the methoxyphenylpiperazine head group by an aminoindane moiety was investigated resulting in dopamine D3 receptor antagonists and agonists with Ki values in the sub- and low-nanomolar range. As a potentially irreversible ligand, the 3,4,5-trifluoro-substituted phenylazocarboxamide 7 was investigated for its N-arylating properties by incubation with the protected lysine analog 18 and with the L89K mutant of the dopamine D3 receptor. Whereas covalent bond formation with the lysine unit in TM2 of D3 could not be detected, substantial N-arylation of the side chain of the model compound 18 has been observed.

Synthesis and pharmacological evaluation of N-benzyl substituted 4-bromo-2,5-dimethoxyphenethylamines as 5-HT2A/2C partial agonists.

N-Benzyl substitution of phenethylamine 5-HT2A receptor agonists has dramatic effects on binding affinity, receptor selectivity and agonist activity. In this paper we examine how affinity for the 5-HT2A/2C receptors are influenced by N-benzyl substitution of 4-bromo-2,5-dimethoxyphenethylamine derivatives. Special attention is given to the 2' and 3'-position of the N-benzyl as such compounds are known to be very potent. We found that substitutions in these positions are generally well tolerated. The 2'-position was further examined using a range of substituents to probe the hydrogen bonding requirements for optimal affinity and selectivity, and it was found that small changes in the ligands in this area had a profound effect on their affinities. Furthermore, two ligands that lack a 2'-benzyl substituent were also found to have high affinity contradicting previous held notions. Several high-affinity ligands were identified and assayed for functional activity at the 5-HT2A and 5-HT2C receptor, and they were generally found to be less efficacious agonists than previously reported N-benzyl phenethylamines.