S-nitrosothiol-modified dendrimers as nitric oxide delivery vehicles.

The synthesis and characterization of two generation-4 polyamidoamine (PAMAM) dendrimers with S-nitrosothiol exteriors are reported. The hyperbranched macromolecules were modified with either N-acetyl-D, L-penicillamine (NAP) or N-acetyl-L-cysteine (NACys) and analyzed via 1H and 13C NMR, UV absorption spectroscopy, MALDI-TOF mass spectrometry, and size exclusion chromatography. Treatment of the dendritic thiols with nitrite solutions yielded the corresponding S-nitrosothiol nitric oxide (NO) donors (G4-SNAP, G4-NACysNO). Chemiluminescent NO detection demonstrated that the dendrimers were capable of storing approximately 2 micromol NO x mg (-1) when exposed to triggers of S-nitrosothiol decomposition (e.g., light and copper). The kinetics of NO release were found to be highly dependent on the structure of the nitrosothiol (i.e., tertiary vs primary) and exhibited similar NO release characteristics to classical small molecule nitrosothiols reported in the literature. As a demonstration of utility, the ability of G4-SNAP to inhibit thrombin-mediated platelet aggregation was assayed. At equivalent nitrosothiol concentrations (25 microM), the G4-SNAP dendrimer resulted in a 62% inhibition of platelet aggregation, compared to only 17% for the small molecule NO donor. The multivalent NO storage, the dendritic effects exerted on nitrosothiol stability and reactivity, and the utility of dendrimers as drug delivery vehicles highlight the potential of these constructs as clinically useful S-nitrosothiol-based therapeutics.

Synthesis of succinimidyl-(S)-naproxen ester and its application for indirect enantioresolution of penicillamine by reversed-phase high-performance liquid chromatography.

Synthesis of N-succinimidyl-(S)-2-(6-methoxynaphth-2-yl) propionate was carried out by the reaction of (S)-naproxen with N-hydroxysuccinimide in the presence of dicyclohexyl carbodiimide. It was characterized and was used as a chiral derivatizing reagent, under mild conditions, to form diastereomers of dl-penicillamine which were resolved by reversed-phase high-performance liquid chromatography using triethyl ammonium phosphate buffer (pH 4.0, 5mM)-acetonitrile (linear gradient (30min) of acetonitrile from 30 to 70%). Excellent separation was achieved with gradient mobile phase. The detection limit was at pmol level.

Pentaethylenehexamine and d-penicillamine co-functionalized graphene quantum dots for fluorescent detection of mercury(II) and glutathione and bioimaging.

Pentaethylenehexamine and d-penicillamine co-functionalized graphene quantum dots (PEHA-GQD-DPA) was made via one two-step thermal pyrolysis. The resulting PEHA-GQD-DPA is composed of the graphene sheets with an average size of 3.16 nm and the rich of functional groups. It gives an ultra strong fluorescence emission with the fluorescent quantum yield of 90.91% and sensitive and selective optical response towards Hg2+. The fluorescence intensity linearly decreases with the increase of Hg2+ in the range of 1.0 × 10-10-2 × 10-4 M with the detection limit of 4.6 × 10-11 M (S/N = 3). No species tested interfere with detection of Hg2+. The fluorescence quenched by Hg2+ can be well recovered by glutathione. The fluorescence intensity linearly increases with the increase of glutathione in the range of 5 × 10-8-2.5 × 10-6 M with the detection limit of 1.7 × 10-8 M (S/N = 3). The PEHA-GQD-DPA as a fluorescence probe has been successfully applied in determination of Hg2+ in natural water and glutathione in human serum and SW480 cell imaging.

Diagnosis of penicillin allergy: a MOFs-based composite hydrogel for detecting ß-lactamase in serum.

An as-synthesized MOFs-based hydrogel exhibits high sensitivity for ß-lactamase through an "ON-OFF-OFF-ON" luminescence trigger. It allows achieving an unprecedented strategy for the judgement of penicillin allergy via luminescence detection of ß-lactamase in serum.

New chemical and biological aspects of S-nitrosothiols.

Nitric oxide (NO) possesses many physiological effects and S-nitrosothiols have been identified in a variety of tissues exhibiting many NO-like activities. This review focuses on the latest discoveries pertaining to the biological functions of S-nitrosothiols and the recent research progress in the chemical properties and biomedical applications of RSNOs.

N-Terminal dipeptides of D(-)-penicillamine as sequestration agents for acetaldehyde.

Since acetaldehyde (AcH), a toxic oxidation product of ethanol, may play an etiologic role in the initiation of alcoholic liver disease, we had earlier pioneered the development of beta, beta-disubstituted-beta-mercapto-alpha-amino acids as AcH-sequestering agents. We now report the synthesis of a series of N-terminal dipeptides of D(-)-penicillamine, prepared from the synthon 3-formyl-2,2,5,5-tetramethylthiazolidine-4S-carboxylic acid (3), a cyclized N-protected derivative of D(-)-penicillamine. These dipeptides were equally or more effective than penicillamine in trapping AcH in a cell-free system. In experiments using a hepatocyte culture system, two of the dipeptides, D-penicillamylglycine (6a) and D-penicillamyl-beta-alanine (6d), at 1/20 the molar concentration of ethanol, lowered the concentration of ethanol-derived AcH by 79% and 84%, respectively, at 2 h. The presence of cyanamide (an inhibitor of aldehyde dehydrogenase) in the incubation medium resulted in a 45-fold increase in ethanol-derived AcH; nevertheless, dipeptides 6a and 6c (D-penicillamyl-alpha-aminoisobutyric acid) were able to reduce this AcH level by approximately one-third.

Synthesis and pharmacological properties of [1-L-penicillamine,4-L-leucine]oxytocin.

For the synthesis of [1-L-penicillamine,4-L-leucine]oxytocin (2), Z-Tyr(Bzl)-Ile-Leu-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 was treated with anhydrous HBr, and the resulting partially deprotected octapeptide was coupled with Z-penicillamine(Bzl) in a condensation reaction mediated by dicyclohexylcarbodiimide and 1-hydroxybenzotriazole. The protected nonapeptide Z-penicillamine(Bzl)-Tyr-Ile-Leu-Asn-Cys(Bzl)-Pro-Leu-Gly-NH2 was treated with Na in NH3 and the resulting disulfhydryl compound was subjected to oxidative cyclization in H2O-CH3OH with ICH2CH2I, Purification of 2 was effected by partition chromatography and gel filtration. The analog possesses antioxytocic and antiavian vasodepressor pA2 values of 6.77 and 7.21, respectively, and has no antipressor or anti-ADH activity. Its biological activity spectrum is qualitatively identical with that of [1-penicillamine]oxytocin. In contrast to the marked natriuretic-diuretic and anti-antidiuretic activity of [Leu4]oxytocin, 2 exhibits none of these effects on the rat kidney.

Immunopharmacological studies of new 3-benzoyl-4-mercaptobutyric acid derivatives. II. Immunosuppressive effects.

A number of D-penicillamine (PA) derivatives (3-benzoyl-4-mercaptobutyric acids) with an acetylthio group on the gamma-position of the carboxylic acid were synthesized. Their immunological effects were examined and compared with PA and other immunosuppressors. PA derivatives suppressed adjuvant-induced arthritis in SD and Lewis rats, suppressed delayed-type hypersensitivity and IgE antibody response in mice, and prolonged the survival time of NZBXNZW F1 hybrid (BWF1) mice, as did immunosuppressors. In vitro, PA derivatives suppressed lymphocyte transformation and the proliferation of KB cells. 4-Acetylthio-3-[-4-(4-chlorophenyl)benzoyl]butyric acid was the most effective of the PA derivatives. Thus, these PA derivatives with an acetylthio group on the gamma-position of the carboxylic acid showed immunosuppressive effects and, furthermore, substitution of the halogen atom on the phenyl group increased immunosuppressive activities.

Labeling of penicillamine di sulfide with technetium-99m.

Complex forming conditions of Penicillamine di sulfide with 99mTc have been specified. Labeling of penicillamine di sulfide with 99mTc by direct reduction with SnCl2 did not give favorable good results while the 99mTc complex of penicillamine can be easily obtained. Ligand exchange reaction with 99mTc-gluconate was attempted and a 95% labeling efficiency was obtained. Radiopharmaceutical potential of 99mTc-PADS (99mTc-Penicillamine di sulfide) has been investigated with a gamma camera in rabbits and the complex was found to be uptaken mostly by the liver and kidneys.

Synthesis and possible applications of biotin-linked copper clusters.

The trifunctional aziridine XAMA-7 (CAS 57116-45-7) has been used to form crosslinks between a deep red-violet copper cluster of the type Cu(I)8Cu(II)6pen12Cl5- (pen=penicillamine) and molecules with biological activity such as d-biotin and proteins. A complex containing biotin, bovine serum albumin and the copper cluster displayed activity toward affinity columns of avidin on Agarose, and the red-violet pigment was immobilized on the gel. This interaction was completely blocked in gels which had been pretreated with d-biotin carboxylic acid. The free and biologically active versions of the cluster have some potential for biomedical applications. For example, the short-lived positron emitter 64Cu (suitable for positron tomography) may be carried in the cluster's structure. The cluster is paramagnetic, but it is a relatively weak effector of water proton spin-lattice relaxation. Other members of this structural group of inorganic compounds may have better magnetic properties, and the crosslinking reaction with aziridines appears to be generally applicable to the group.

Facile preparation of chiral penicillamine protected gold nanoclusters and their applications in cell imaging.

A facile synthesis of chiral penicillamine protected Au nanoclusters with different optical properties has been reported. We have for the first time observed the reversal of CD signals after the scaffolds adsorbed onto the surface of Au NCs. Such Au NCs are utilized for bioimaging due to their low cytotoxicity and stable fluorescence emission.

99mTc-d-penicillamine-glucuronide: synthesis, radiolabeling, in vitro and in vivo evaluation.

The current study was aimed at synthesizing a glucuronide derivative of D-penicillamine (D-PA) to be used for imaging purposes. First of all, D-PA-glucuronide (D-PA-Glu) was synthesized by experimental treatments starting with uridine 5'-diphospho-glucuronosyltransferase enzyme rich microsome preparate. Then, the synthesized compound was labeled with technetium ((99m)Tc) by using a reduction method with stannous chloride. Quality controls were performed by using high-performance liquid chromatography and thin-layer radio chromatography (TLRC). Radiolabeling yield of (99m)Tc-D-PA-Glu was more than 98% according to TLRC results. In vitro evaluations of radiolabeled complexes were investigated on PC-3 human prostate cancer cells. (99m)Tc-D-PA-Glu exhibited more accumulation on PC-3 cells versus (99m)Tc-D-PA at 240 minutes. In order to determine its radiopharmaceutical potential, biodistribution studies were carried out in male Albino Wistar rats. The biodistribution results of (99m)Tc-D-PA-Glu, showed the highest uptake in prostate at 120 minutes postinjection with the main excretion route being through kidneys and bladder. (99m)Tc-D-PA-Glu and (99m)Tc-D-PA have exhibited different biodistribution results.

Biological and conformational evaluation of bifunctional compounds for opioid receptor agonists and neurokinin 1 receptor antagonists possessing two penicillamines.

Neuropathic pain states and tolerance to opioids can result from system changes in the CNS, such as up-regulation of the NK1 receptor and substance P, lead to antiopioid effects in ascending or descending pain-signaling pathways. Bifunctional compounds, possessing both the NK1 antagonist pharmacophore and the opioid agonist pharmacophore with delta-selectivity, could counteract these system changes to have significant analgesic efficacy without undesirable side effects. As a result of the introduction of cyclic and topological constraints with penicillamines, 2 (Tyr-cyclo[d-Pen-Gly-Phe-Pen]-Pro-Leu-Trp-NH-[3',5'-(CF(3))(2)-Bzl]) was found as the best bifunctional compound with effective NK1 antagonist and potent opioid agonist activities, and 1400-fold delta-selectivity over the mu-receptor. The NMR structural analysis of 2 revealed that the relative positioning of the two connected pharmacophores as well as its cyclic and topological constraints might be responsible for its excellent bifunctional activities as well as its significant delta-opioid selectivity. Together with the observed high metabolic stability, 2 could be considered as a valuable research tool and possibly a promising candidate for a novel analgesic drug.

A novel water-soluble gossypol derivative increases chemotherapeutic sensitivity and promotes growth inhibition in colon cancer.

Compound 1 ((-)-gossypol) has been long known as a chemical anticancer agent. With its low water solubility and toxicity, it is not widely used as a commercial drug. To overcome these disadvantages, several novel derivatives of gossypol were designed, synthesized, and analyzed. One of the derivatives, compound 7 (6-aminopenicillanic acid sodium-gossypolone), was identified with great water solubility and anticancer property, suggested by inducing a dramatically decrease in Bcl-2 and Bcl-xL protein expression level found in vitro and growth inhibition of murine colon tumor in vivo. Furthermore, it was also recognized with less toxicity than compound 1 in vivo and significantly increased chemotherapeutic sensitivity against colon cancer in combination with traditional chemotherapeutic agent 5-fluorouracil. Therefore, it is concluded that compound 7 is superior to parent compound 1, and further preclinical studies of compound 7 is necessary for colon cancer therapy.