(−)-Menthylamine derivatives as potent and selective antagonists of transient receptor potential melastatin type-8 (TRPM8) channels

A series of twenty-two (?)-menthylamine derivatives was synthesized and tested on TRPM8, TRPV1, and TRPA1 channels. Five of the novel compounds, that is, 1d, 1f, 2b, 2c, and 2e behaved as potent TRPM8 antagonists with IC₅₀ values versus icilin and (?)-menthol between 20 nM and 0.7 μM, and were between 4- and ～150-fold selective versus TRPV1 and TRPA1 activation. Compound 1d also induced caspase 3/7 release in TRPM8-expressing LNCaP prostate carcinoma cells, but not in non-TRPM8 expressing DU-145 cells. Five other derivatives, that is, 1a, 1g, 1h, 2f, and 2h were slightly less potent than previous compounds but still relatively selective versus TRPV1 and TRPA1.     

Evaluation of 2-indolcarbohydrazones as potent α-glucosidase inhibitors,in silico studies and DFT based stereochemical predictions

2-Indolcarbohydrazones 1–28 were synthesized and evaluated for their α-glucosidase inhibitory potential. A varying degree of inhibitory potential with IC₅₀ values in the range of 2.3 ± 0.11–226.4 ± 6.8 μM was observed while comparing these outcomes with the standard acarbose (IC₅₀ = 906.0 ± 6.3 μM). The stereochemistry of ten (10) randomly selected compounds (1, 3, 6, 8, 12, 18, 19, 23, 25 and 28) was predicted by Density Functional Theory (DFT). The stability of E isomer was deduced by comparing the calculated and experimental vibration modes of ν_CO, ν_NC and ν_CH (CH in NCH-R). It was observed that except compound 18, all other compounds were deduced to have E configuration while molecular modeling studies revealed the key interactions between enzyme and synthesized compounds.     

Calibration of nitric oxide flux generation from diazeniumdiolate NO donors

The 1-(secondary amino) diazen-1-ium-1,2-diolates (NONOates) are the most commonly utilized nitric oxide (NO, nitrogen monoxide) donor because of the ability of different NONOates to spontaneously break down liberating NO at different rates, which can be utilized to control NO fluxes. However, the parameters that determine these fluxes of NO generation, half-lives and stoichiometry of NO per donor, can vary significantly with specific experimental conditions in addition to the donor chosen. Here we report straightforward methods that can be used to determine these parameters. For donors of intermediate half-life (10–80 min) a real-time oxymyoglobin (oxyMb) assay can be analyzed to simultaneously determine both the half-life and the total amount of NO liberated, from which the NO flux can be obtained for any given donor concentration. The half-lives obtained by oxyMb assay are very similar to those obtained by following NONOate decomposition kinetics spectrophotometrically, and a survey of several NONOates from different commercial sources show consistent results. These data provide validation for the methodologies employed. In addition, procedures are described for calibration of donors with shorter (<10 min) and longer (>80 min) half-lives. These procedures can be used to reproducibly and routinely calibrate NO fluxes for a variety of donors under any specific condition.     

Free radical scavenging activity from different extracts of leaves of Bauhinia vahlii Wight & Arn.

The objectives of this study were to determine phenolic content and antioxidant activities of chloroform, acetone, methanol and hot water extracts of Bauhinia vahlii leaves. The hot water extract afforded the highest yield (6.3%) while the lowest yield was obtained from the chloroform extract (2.1%). The methanol extract contains higher levels of total phenolics (48.7 ± 0.7 g GAE/100 g extract), tannins (21.7 ± 0.7 g GAE/100 g extract) and flavonoids (10.3 ± 0.2 RE/100 g extract). The extracts were subjected to assess their antioxidant potential using various in vitro systems such as DPPH, ABTS⁺, FRAP, OH, β-carotene linoleic acid bleaching system, phosphomolybdenum reduction and Fe²⁺ chelation. It is concluded that the methanolic extract of B. vahlii leaves have strong antioxidant potential. Further study is necessary for isolation and characterization of the active antioxidants, which may serve as a potential source of natural antioxidants.     

Adsorption characteristics of sulfur powder by bamboo charcoal to restrain sulfur allergies

Exposures to particulate matter with a diameter of 2.5 μm or less (PM2.5) may influence the risk of birth defects and make you allergic, which causes serious harm to human health. Bamboo charcoal can adsorb harmful substances,that was of benefitto people’s health. In order to figure out the optimal adsorbtion condition and the intrinsic change of bamboo charcoal, five chemicals were adsorbed by bamboo charcoal and were analyzed by FT-IR. The optimal blast time was 80 min of Na₂SO₃, 100 min of Na₂S₂O₈, 20 min of Na₂SO₄, 120 min of Fe₂(SO₄)₃ and 60 min or 100 min of S. FT-IR spectra showed that bamboo charcoal had five characteristic peaks of SS stretch, H₂O stretch, OH stretch, CO stretch or CC stretch, and NO₂ stretch at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹, respectively. For Na₂SO₃, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 20 min. For Na₂S₂O₈, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. For Na₂SO₄, the peaks at 3850 cm⁻¹, 3740 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. For Fe₂(SO₄)₃, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 120 min. For S, the peaks at 3850 cm⁻¹ and 3740 cm⁻¹ achieved the maximum at 40 min, the peaks at 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. It proved that bamboo charcoal could remove sulfur powder from air to restrain sulfur allergies.     

Synthesis of new mer,trans-rhodium(III) hydrido-bis(acetylide) complexes: Structure of mer,trans-[(PMe3)3Rh(CC–C6H4-4-NMe2)2H]

Terminal alkynes (R–CC–H, R = 1-naphthyl, 9-anthryl, 4-Me₂N–C₆H₄–, or the longer analogue, 4-(4-Me₂N–C₆H₄–CC–)–C₆H₄–) react with [Rh(PMe₃)₄Me] at ambient temperature, with loss of methane and one PMe₃ ligand, to form the corresponding mer,trans-[(PMe₃)₃Rh(CCR)₂H] compounds in excellent yield. In this preliminary study, the synthesis and spectroscopic characterization of the four new compounds are reported, along with the single-crystal structure of the R = 4-Me₂N–C₆H₄ derivative.     

Synthesis,antioxidant, and antimicrobial evaluation of some 2-arylbenzimidazole derivatives

A series of 2-arylbenzimidazole derivatives (3a–3p and 4a–4i) were synthesized and evaluated as potential antioxidant and antimicrobial agents. Their antioxidant properties were evaluated by various in vitro assays including hydroxyl radical (HO) scavenging, superoxide radical anion (O₂^?) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, and ferric reducing antioxidant power. Results demonstrated that compounds with hydroxyl group at the 5-position of benzimidazole ring had a comparable or better antioxidant activity in comparison to standard antioxidant tert-butylhydroquinone (TBHQ). Markedly, compound 4h that showed the highest HO scavenging activity (EC₅₀ = 46 μM) in vitro had a significant reduction of 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced intracellular oxidative stress and H₂O₂-induced cell death. In addition, these compounds showed moderate to good inhibitory activity against Staphylococcus aureus selectively at noncytotoxic concentrations.     

Mechanisms and kinetic profiles of superoxide-stimulated nitrosative processes in cells using a diaminofluorescein probe

In this study, we examined the mechanisms and kinetic profiles of intracellular nitrosative processes using diaminofluorescein (DAF-2) as a target in RAW 264.7 cells. The intracellular formation of the fluorescent, nitrosated product diaminofluorescein triazol (DAFT) from both endogenous and exogenous nitric oxide (NO) was prevented by deoxygenation and by cell membrane-permeable superoxide (O₂⁻) scavengers but not by extracellular bovine Cu,Zn-SOD. In addition, the DAFT formation rate decreased in the presence of cell membrane-permeable Mn porphyrins that are known to scavenge peroxynitrite (ONOO⁻) but was enhanced by HCO₃⁻/CO₂. Together, these results indicate that nitrosative processes in RAW 264.7 cells depend on endogenous intracellular O₂⁻ and are stimulated by ONOO⁻/CO₂-derived radical oxidants. The N₂O₃ scavenger sodium azide (NaN₃) only partially attenuated the DAFT formation rate and only with high NO (>120 nM), suggesting that DAFT formation occurs by nitrosation (azide-susceptible DAFT formation) and predominantly by oxidative nitrosylation (azide-resistant DAFT formation). Interestingly, the DAFT formation rate increased linearly with NO concentrations of up to 120–140 nM but thereafter underwent a sharp transition and became insensitive to NO. This behavior indicates the sudden exhaustion of an endogenous cell substrate that reacts rapidly with NO and induces nitrosative processes, consistent with the involvement of intracellular O₂⁻. On the other hand, intracellular DAFT formation stimulated by a fixed flux of xanthine oxidase-derived extracellular O₂⁻ that also occurs by nitrosation and oxidative nitrosylation increased, peaked, and then decreased with increasing NO, as previously observed. Thus, our findings complementarily show that intra- and extracellular O₂⁻-dependent nitrosative processes occurring by the same chemical mechanisms do not necessarily depend on NO concentration and exhibit different unusual kinetic profiles with NO dynamics, depending on the biological compartment in which NO and O₂⁻ interact.     

Protection against cardiac injury by small Ca2 +-sensitive K+ channels identified in guinea pig cardiac inner mitochondrial membrane

We tested if small conductance, Ca^2 +‐sensitive K⁺ channels (SK_Ca) precondition hearts against ischemia reperfusion (IR) injury by improving mitochondrial (m) bioenergetics, if O₂‐derived free radicals are required to initiate protection via SK_Ca channels, and, importantly, if SK_Ca channels are present in cardiac cell inner mitochondrial membrane (IMM). NADH and FAD, superoxide (O₂^?), and m[Ca^2 +] were measured in guinea pig isolated hearts by fluorescence spectrophotometry. SK_Ca and IK_Ca channel opener DCEBIO (DCEB) was given for 10 min and ended 20 min before IR. Either TBAP, a dismutator of O₂^?, NS8593, an antagonist of SK_Ca isoforms, or other K_Ca and K_ATP channel antagonists, were given before DCEB and before ischemia. DCEB treatment resulted in a 2-fold increase in LV pressure on reperfusion and a 2.5 fold decrease in infarct size vs. non-treated hearts associated with reduced O₂^? and m[Ca^2 +], and more normalized NADH and FAD during IR. Only NS8593 and TBAP antagonized protection by DCEB. Localization of SK_Ca channels to mitochondria and IMM was evidenced by a) identification of purified mSK_Ca protein by Western blotting, immuno-histochemical staining, confocal microscopy, and immuno-gold electron microscopy, b) 2-D gel electrophoresis and mass spectroscopy of IMM protein, c) [Ca^2 +]‐dependence of mSK_Ca channels in planar lipid bilayers, and d) matrix K⁺ influx induced by DCEB and blocked by SK_Ca antagonist UCL1684. This study shows that 1) SK_Ca channels are located and functional in IMM, 2) mSK_Ca channel opening by DCEB leads to protection that is O₂^? dependent, and 3) protection by DCEB is evident beginning during ischemia.     

Scavenging and antioxidant activities of immunomodulating polysaccharides isolated from Salvia officinalis L.

Crude polysaccharides, isolated from the aerial parts of sage (Salvia officinalis L.) by sequential extraction with water (A), hot ammonium oxalate (B), dimethyl sulfoxide (C), 1 M (D) and 4 M (E) potassium hydroxide solutions, and six ion-exchange fractions of A were examined for their ability to inhibit peroxidation of liposome lipid by hydroxyl radicals and to reduced DPPH radical content. The highest inhibition of liposome lipid peroxidation was found with crude polysaccharides A, B and D, antioxidant activities reached ～37%. The purified fractions A1 and A2 inhibited the liposome peroxidation to ～35%. However, the radical scavenging abilities of the most active crude polysaccharides A, B and C on DPPH radicals were found in the range 80–90%, while the most active purified fractions A₃–A₆ in three or fourfold doses achieved 75–92%. The least effective tested polysaccharides succeeded 20% inhibition using both methods.     

Iron deprivation-induced reactive oxygen species generation leads to non-autolytic PCD in Brassica napus leaves

Using iron-deprived (–Fe) chlorotic as well as green iron-deficient (5 μM Fe) and iron-sufficient supplied (50 μM Fe) leaves of young hydroponically reared Brassica napus plants, we explored iron deficiency effects on triggering programmed cell death (PCD) phenomena. Iron deficiency increased superoxide anion but decreased hydroxyl radical (OH) formation (TBARS levels). Impaired photosystem II efficiency led to hydrogen peroxide accumulation in chloroplasts; NADPH oxidase activity, however, remained on the same level in all treatments. Non-autolytic PCD was observed especially in the chlorotic leaf of iron-deprived plants, to a lesser extent in iron-deficient plants. It correlated with higher DNAse-, alkaline protease- and caspase-3-like activities, DNA fragmentation and chromatin condensation, hydrogen peroxide accumulation and higher superoxide dismutase activity. A significant decrease in catalase activity together with rising levels of dehydroascorbic acid indicated a strong disturbance of the redox homeostasis, which, however, was not caused by OH formation in concordance with the fact that iron is required to catalyse the Fenton reaction leading to OH generation. This study documents the chain of events that contributes to the development of non-autolytic PCD in advanced stages of iron deficiency in B. napus leaves.     

Examination of the superoxide/hydrogen peroxide forming and quenching potential of mouse liver mitochondria

Pyruvate dehydrogenase (PDHC) and α-ketoglutarate dehydrogenase complex (KGDHC) are important sources of reactive oxygen species (ROS). In addition, it has been found that mitochondria can also serve as sinks for cellular hydrogen peroxide (H₂O₂). However, the ROS forming and quenching capacity of liver mitochondria has never been thoroughly examined. Here, we show that mouse liver mitochondria use catalase, glutathione (GSH), and peroxiredoxin (PRX) systems to quench ROS. Incubation of mitochondria with catalase inhibitor 3-amino-1,2,4-triazole (triazole) induced a significant increase in pyruvate or α-ketoglutarate driven O₂⁻/H₂O₂ formation. 1-Choro-2,4-dinitrobenzene (CDNB), which depletes glutathione (GSH), elicited a similar effect. Auranofin (AF), a thioredoxin reductase-2 (TR2) inhibitor which disables the PRX system, did not significantly change O₂⁻/H₂O₂ formation. By contrast catalase, GSH, and PRX were all required to scavenging extramitochondrial H₂O₂. In this study, the ROS forming potential of PDHC, KGDHC, Complex I, and Complex III was also profiled. Titration of mitochondria with 3-methyl-2-oxovaleric acid (KMV), a specific inhibitor for O₂⁻/H₂O₂ production by KGDHC, induced a ~ 86% and ~ 84% decrease in ROS production during α-ketoglutarate and pyruvate oxidation. Titration of myxothiazol, a Complex III inhibitor, decreased O₂⁻/H₂O₂ formation by ~ 45%. Rotenone also lowered ROS production in mitochondria metabolizing pyruvate or α-ketoglutarate indicating that Complex I does not contribute to ROS production during forward electron transfer from NADH. Taken together, our results indicate that KGDHC and Complex III are high capacity sites for O₂⁻/H₂O₂ production in mouse liver mitochondria. We also confirm that catalase plays a role in quenching either exogenous or intramitochondrial H₂O₂.     

Organogold(I) complexes of a C2-symmetric diacetylide ligand derived from 1,1′-bi-2-naphthol

Alkynylgold(I) complexes incorporating a chiral binaphthyl group have been prepared. Bis(alkyne) reagents [rac-1,1′-C₂₀H₁₂-2,2′-(OCH₂CCH)₂] (1) and [rac-1,1′-C₂₀H₁₂-2,2′-(OC(O)CH₂CCH)₂] (2), react with [AuCl(SMe₂)] and base to give insoluble oligomeric alkynylgold(I) complexes [rac-1,1′-C₂₀H₁₂-2,2′-(OCH₂CCAu)₂]_n (3) and [rac-1,1′-C₂₀H₁₂-2,2′-(OC(O)CH₂CCAu)₂]_n (4), which react with phosphine or diphosphine ligands to give soluble complexes [rac-1,1′-C₂₀H₁₂-2,2′-(OCH₂CCAuPR₃)₂] (5), R = Ph or Cy, [rac-1,1′-C₂₀H₁₂-2,2′-(OCH₂CCAu)₂(Ph₂P(CH₂)_nPPh₂)] (6), or [rac-1,1′-C₂₀H₁₂-2,2′-(OC(O)CH₂CCAu)₂(Ph₂P(CH₂)_nPPh₂)] (7), with n = 3–5. Several of the complexes 6 and 7 are shown to exist as mixtures of isomeric forms in solution.     

An experimental and theoretical study of the electronic spectra of tetraethylammonium [bis(1,3-dithiole-2-thione-4,5-dithiolato)zincate(II)], [NEt4]2[Zn(dmit)2], and tetraethylammonium [bis(1,3-dithiole-2-one-4,5-dithiolato)zincate(II)], [NEt4]2[Zn(dmio)2]

Metal-dmit complexes and related compounds have been the object of intense study in the last decade. Despite such efforts on the study of its structural properties, very few attempts have been made to the spectroscopic study of these metal complexes. Experimental reports of its infrared, Raman and UV–Vis spectra present the main spectroscopic features, however, many details of the electronic structure have still to be fully investigated and inconsistent assignments are found in the literature. This work presents a detailed analysis of the UV–Vis spectra of the zinc-dmit, [Zn(dmit)₂]⁻², and the zinc-dmio complex, [Zn(dmio)₂]⁻². The experimental spectrum was deconvoluted and analysed with several theoretical methodologies including ab initio CI calculations, ab initio TD and zindo semi-empirical methods. The results confirm the multi-configuration nature of several excited states and the calculated results were concordant for several transitions. The results lead to a new assignment of the 457 nm band in the [Zn(dmit)₂]⁻² as π(pS_m) → π*CS band. In the metal-dmio, the sulfur substitution by oxygen results in a larger HOMO–LUMO gap and a change in the nature of the frontier orbitals. As the first transition we found, for the dmit compound, a high-intensity π → π*CS while for the zinc-dmio, a low-intensity π → σ*C–S transition.     

N-1 and C-3 substituted indole Schiff bases as selective COX-2 inhibitors: synthesis and biological evaluation

A group of N-1 and C-3 disubstituted-indole Schiff bases bearing an indole N-1 (R′ = H, CH₂Ph, COPh) substituent in conjunction with a C-3 –CHN–C₆H₄–4-X (X = F, Me, CF₃, Cl) substituent were synthesized and evaluated as inhibitors of cyclooxygenase (COX) isozymes (COX-1/COX-2). Within this group of Schiff bases, compounds 15 (R¹ = CH₂Ph, X = F), 17 (R¹ = CH₂Ph, X = CF₃), 18 (R¹ = COPh, X = F) and 20 (R¹ = COPh, X = CF₃) were identified as effective and selective COX-2 inhibitors (COX-2 IC₅₀’s = 0.32–0.84 μM range; COX-2 selectivity index (SI) = 113 to >312 range). 1-Benzoyl-3-[(4-trifluoromethylphenylimino)methyl]indole (20) emerged as the most potent (COX-1 IC₅₀ >100 μM; COX-2 IC₅₀ = 0.32 μM) and selective (SI >312) COX-2 inhibitor. Furthermore, compound 20 is a selective COX-2 inhibitor in contrast to the reference drug indomethacin that is a potent and selective COX-1 inhibitor (COX-1 IC₅₀ = 0.13 μM; COX-2 IC₅₀ = 6.9 μM, COX-2 SI = 0.02). Molecular modeling studies employing compound 20 showed that the phenyl CF₃ substituent attached to the CN spacer is positioned near the secondary pocket of the COX-2 active site, the CN nitrogen atom is hydrogen bonded (N?NH = 2.85 Å) to the H90 residue, and the indole N-1 benzoyl is positioned in a hydrophobic pocket of the COX-2 active site near W387.     

Fumigant toxicity of Apiaceae essential oils and their constituents against Sitophilus oryzae and their acetylcholinesterase inhibitory activity

We evaluated the insecticidal and acetylcholinesterase (AChE) inhibition activities of the essential oils and their constituents of 10 Apiaceae on the adult rice weevil, Sitophilus oryzae. Of the 10 species tested, dill (Anethum graveolens), caraway (Carum carvi), and cumin (Cuminum cyminum) essential oils showed strong fumigant toxicity against adult S. oryzae. LC₅₀ values of caraway, dill, and cumin essential oils were 2.45, 3.29, and 4.75 mg/L air, respectively. Among the test compounds, (+)-carvone, (?)-carvone, cuminaldehyde, dihydrocarvone, linalool oxide, carveol, trans-anethole, and neral demonstrated strong fumigant toxicity against adult S. oryzae with LC₅₀ values of 0.61, 0.84, 1.12, 2.92, 3.76, 4.29, 5.02, and 6.60 mg/L air, respectively. α-Pinene showed the strongest AChE inhibition activity followed by β-pinene and limonene. The measured toxicity of the artificial blends of the constituents identified in dill and cumin oils indicated that (+)-carvone and cuminaldehyde were major contributors to the fumigant toxicity of the artificial blend.     

Mitochondria generated nitric oxide protects against permeability transition via formation of membrane protein S-nitrosothiols

Mitochondria generated nitric oxide (NO) regulates several cell functions including energy metabolism, cell cycling, and cell death. Here we report that the NO synthase inhibitors (L-NAME, L-NNA and L-NMMA) administered either in vitro or in vivo induce Ca²⁺-dependent mitochondrial permeability transition (MPT) in rat liver mitochondria via a mechanism independent on changes in the energy state of the organelle. MPT was determined by the occurrence of cyclosporin A sensitive mitochondrial membrane potential disruption followed by mitochondrial swelling and Ca²⁺ release. In in vitro experiments, the effect of NOS inhibitors was dose-dependent (1 to 50 µM). In addition to cyclosporin A, L-NAME-induced MPT was sensitive to Mg²⁺ plus ATP, EGTA, and to a lower degree, to catalase and dithiothreitol. In contrast to L-NAME, its isomer D-NAME did not induce MPT. L-NAME-induced MPT was associated with a significant decrease in both the rate of NO generation and the content of mitochondrial S-nitrosothiol. Acute and chronic in vivo treatment with L-NAME also promoted MPT and decreased the content of mitochondrial S-nitrosothiol. SNAP (a NO donor) prevented L-NAME mediated MPT and reversed the decrease in the rate of NO generation and in the content of S-nitrosothiol. We propose that S-nitrosylation of critical membrane protein thiols by NO protects against MPT.     

Stereoselective synthesis of novel antiproliferative steroidal (E,E) dienamides through a cascade aldol/cyclization process

The stereoselective and metal-free protocol involving a cascade aldol/cyclization process for the synthesis of steroidal (E, E) dienamides from steroidal α, α-dicyanoalkene was reported. This protocol efficiently achieved the construction of CC bond and selective conversion of cyano group into carboxamide in one-pot procedure under mild condition. Further biological evaluation showed that some of these compounds had moderate to excellent cytotoxic activities against all the tested cancer cell lines and were more potent than well-known drug 5-fluorouracil. Particularly, compound 3c represented excellent inhibitory effect against MCF-7 (IC₅₀ = 0.76 μM), which was about 10-fold more potent than 5-fluorouracil.