Synthesis and evaluation of antioxidative properties of a series of organoselenium compounds

Dehydroxyselenocyanation of alcohols under grinding conditions

A novel strategy for dehydroxyselenocyanation of alcohols, utilizing a readily available electrophilic selenocyanating reagent N-selenocyanatophthalimide in combination with triphenylphosphine under grinding conditions within 2 min at room temperature was developed. This solvent-free methodology is time-efficient and features a broad substrate scope, enabling the late-stage functionalization of diverse pharmaceutical molecules and natural products.

Strong ion pair charge transfer interaction of 1,8-naphthalimide–bipyridinium conjugates with basic anions – towards the development of a new type of turn-on fluorescent anion sensors

Fluoride, acetate and benzoate anions reduce naphthalimide–viologen dyads into radicals, which is indicated by a strong fluorescence enhancement.

Therapeutic applications of selenium-derived compounds

Selenium is a biocompatible element and participates in several biochemical reactions occurring in the human body. Its biocompatibility and minimal toxicity has attracted researchers to develop selenium-based drugs. Hence, recent developments on biomedical applications of selenium-based compounds have been discussed. A structure activity relationship has also been interpreted.

Design and synthesis of novel thiobarbituric acid derivatives targeting both wild-type and BRAF-mutated melanoma cells

A series of novel thio- and seleno-barbituric acid derivatives were synthesized by varying the substituents at N1 and N3 (ethyl, methyl, allyl, and phenyl), and C5 tethered with dienyl and trienyl moieties attached to substituents such as phenyl, 2-furanyl, 2-thiophenyl, 1-naphthyl, and 3-pyridyl. The cytotoxic potential of these derivatives was evaluated by using MTT assay against melanoma cell lines expressing either wild-type (CHL-1) or mutant (UACC 903) BRAF gene. Among all, 2b and 8b were identified as the most potent compounds. Both 2b and 8b inhibited viability of various melanoma cells and induced cell death as evidenced by Live and Dead assay. Western blot analysis showed that they induce PARP cleavage and inhibit anti-apoptotic Bcl-2, Bcl-xL and Survivin in a dose-dependent manner within 24 h of the treatment. Novel thiobarbituric acid analogs also inhibited viability of various other solid tumor cell lines, such as pancreatic, breast, and colon. Overall, 2b, 2d, and 8b emerged as the most effective compounds and make good leads for the development of future therapeutic agents.

Stereochemical control of nucleosome targeting by platinum-intercalator antitumor agents

Platinum-based anticancer drugs act therapeutically by forming DNA adducts, but suffer from severe toxicity and resistance problems, which have not been overcome in spite of decades of research. And yet defined chromatin targets have generally not been considered in the drug development process. Here we designed novel platinum-intercalator species to target a highly deformed DNA site near the nucleosome center. Between two seemingly similar structural isomers, we find a striking difference in DNA site selectivity in vitro, which comes about from stereochemical constraints that limit the reactivity of the trans isomer to special DNA sequence elements while still allowing the cis isomer to efficiently form adducts at internal sites in the nucleosome core. This gives the potential for controlling nucleosome site targeting in vivo, which would engender sensitivity to epigenetic distinctions and in particular cell type/status-dependent differences in nucleosome positioning. Moreover, while both compounds yield very similar DNA-adduct structures and display antitumor cell activity rivalling that of cisplatin, the cis isomer, relative to the trans, has a much more rapid cytotoxic effect and distinct impact on cell function. The novel stereochemical principles for controlling DNA site selectivity we discovered could aid in the design of improved site discriminating agents.

Attenuation of cyclophosphamide-induced pulmonary toxicity in Swiss albino mice by naphthalimide-based organoselenium compound 2-(5-selenocyanatopentyl)-benzo[de]isoquinoline 1,3-dione

CONTEXT

The widely used antineoplastic drug cyclophosphamide causes pulmonary toxicity by inducing oxidative stress. Selenium, a dietary micronutrient, has been found to protect various organs from oxidative injuries.

OBJECTIVE

This study was designed to investigate the protective efficacy of an organoselenium compound 2-(5-selenocyanato-pentyl)-benzo[de]isoquinoline 1,3-dione against cyclophosphamide-induced pulmonary toxicity in Swiss albino mice.

MATERIALS AND METHODS

Cyclophosphamide (25 mg/kg b.w.) was administered intraperitoneally for 10 d and the organoselenium compound (3 mg/kg b.w.) was given by oral gavage in concomitant and pretreatment schedules. Various biochemical parameters related to oxidative stress and antioxidant enzymes along with histology of lungs were evaluated to assess the effect of the test compound.

RESULTS

The oral LD50 of the test compound was more than 1000 mg/kg b.w. in Swiss albino mice. The test compound substantially ameliorated cyclophosphamide-induced pulmonary injury by reducing the levels of reactive oxygen species, reactive nitrogen species, and lipid peroxidation, respectively, by 14.88, 18.54, and 21.10% in concomitant treatment schedule and by 23.89, 35.73, and 30.76% in the pretreatment schedule as well as by restoring the level of reduced glutathione and activities of glutathione-S-transferase, superoxide dismutase, catalase, and glutathione peroxidase, respectively, by 36.88, 42.43, 38.0, 35.0, and 34.06% in the concomitant treatment schedule and by 66.02, 59.29, 57.23, 71.59, and 57.22% in the pretreatment schedule. The test compound also attenuated cyclophosphamide-induced histological alterations of lung tissue.

DISCUSSION AND CONCLUSION

The test compound emerged as an efficient antioxidant protecting lungs tissue from cyclophosphamide-induced injury.

Sensitization of cisplatin therapy by a naphthalimide based organoselenium compound through modulation of antioxidant enzymes and p53 mediated apoptosis

The widely used anti-cancer drug cisplatin imparts various toxic manifestations in the host, with nephrotoxicity being the most severe one. The trace element selenium shows antioxidant activity in both human and animals. The present study was designed to assess the chemoprotecting and chemoenhancing efficacy of a naphthalimide based organoselenium compound 2-(5-selenocyanato-pentyl)-benzo[de]isoquinoline 1,3-dione during cisplatin chemotherapy in mice bearing Ehrlich ascites carcinoma cells. Cisplatin (5 mg/kg b.w.) was administered intraperitoneally and the organoselenium compound (3 mg/kg b.w.) was given by oral gavage in concomitant and pretreatment schedule. The effects of the test compound was evaluated by assaying biochemical, hematological, histological, genotoxicity parameters and by investigating induction of apoptosis in tumor cells, and calculating tumor growth response in the host. The organoselenium compound significantly prevented cisplatin induced generation of reactive oxygen species (ROS), reactive nitrogen species, and onset of lipid peroxidation in the kidney tissue of the experimental mice. In addition, the test compound was also substantially restored cisplatin induced depleted activities of the renal antioxidant enzymes and reduced glutathione level; prevented the serum blood urea nitrogen level, creatinine level, chromosomal aberration, DNA damage, histological alterations of kidney, and normalized the hematological profile of the tumor bearing mice. Furthermore, the organoselenium compound alone or during combination therapy induced apoptosis in tumor cells through mitochondria mediated and DNA damage mediated pathway and ultimately increased the life span of the tumor bearing host. Hence, the results showed that the test compound not only reduced the toxicity of cisplatin but also enhanced its anti-tumor efficacy.

Enhancement in intramolecular interactions and in vitro biological activity of a tripodal tetradentate system upon complexation

Naphthalimide appended metal complexes uniquely exhibited intramolecular interactions, affinity for DNA/proteins and apoptosis mediated anticancer activity.

Synthesis and cytotoxicity evaluation of naphthalimide derived N-mustards

A series of N-mustards, which was conjugated to mono- or bis-naphthalimides with a flexible amine link, were synthesized and evaluated for cytotoxicity against five cancer cell lines (HCT-116, PC-3, U87 MG, Hep G2 and SK-OV-3). Several compounds displayed better activities than the control compound amonafide. Further evaluations by fluorescence spectroscopy studies and DNA-interstrand cross-linking assays revealed that the derivatives showed both alkylating and intercalating properties. Among the derivatives, the bis-naphthalimide N-mustard derivative 11b was found to exhibit the highest cytotoxic activity and DNA cross-linking ability. Both 11b and 7b induce HCT-116 cell apoptosis by S phase arrest.

Design, synthesis and evaluation of seleno-dihydropyrimidinones as potential multi-targeted therapeutics for Alzheimer's disease

We report the design, synthesis and evaluation of a series of seleno-dihydropyrimidinones as potential multi-targeted therapeutics for Alzheimer's disease.

One-Pot Synthesis of 5-Arylamino-1,3,4-Selenadiazol-2(3H)-Ones from Arylisoselenocyanates

A one-pot reaction of arylisoselenocyanates, hydrazine and bis(trichloromethyl) carbonate, in the presence of a base provides an efficient route for the synthesis of 5-arylamino-1,3,4-selenadiazol-2(3H)-ones in good to excellent yields. A plausible mechanism is proposed for the reaction.

In vitro radioprotection studies of organoselenium compounds: differences between mono- and diselenides

Organoselenium compounds belonging to the class of monoselenides, such as selenomethionine (SeM) and methylselenocysteine (MSeCys) and diselenides including selenocystine (SeCys) and selenopropionic acid (SePA), were examined for their comparative radioprotective effects using in vitro models. Effects of these compounds on the inhibition of gamma-radiation induced lipid peroxidation in liposomes, protein carbonylation in bovine serum albumin (BSA) and strand breaks in pBR322 plasmid DNA, assessed, respectively, by the formation of thiobarbituric acid reactive substances, formation of 2,2'-dinitrophenyl hydrazine (DNPH) carbonyl complex and horizontal gel electrophoresis, were used to compare their radioprotective ability. The IC 50 values for SeCys, SePA, SeM and MSeCys for lipid peroxidation were 27 +/- 1, 33 +/- 2, 200 +/- 8 and 163 +/- 4 microM, respectively, and the values for inhibition of protein carbonylation were >200, 300 +/- 6, 464 +/- 8 and 436 +/- 3 microM, respectively. Inhibition of DNA strand break formation was tested at 200 microM for all the compounds and SePA and SeCys exhibited a protective effect on DNA, while SeM and MSeCys did not lead to any protection. The in vitro cytotoxicity studies in normal and tumor cells revealed that MSeCys and SeM were not cytotoxic to lymphocytes and EL4 tumor cells at the concentrations employed. In contrast, SeCys was toxic, with a higher effect on tumor cells than lymphocytes. Our studies suggest that the non-toxic diselenides like SePA should be explored as protective agents against gamma-irradiation induced damage.

Prevention of cadmium induced lipid peroxidation, depletion of some antioxidative enzymes and glutathione by a series of novel organoselenocyanates

A series of organoselenocyanate compounds 4a-d were synthesized utilizing 1,8-naphthalic anhydride as the building unit. To evaluate the preventive potential of the Se compounds against Cd induced hepatic lipid peroxidation and oxidative stress, female Swiss Albino mice were exposed to Cd (as CdCl(2)) during 20 days at a dose of 1 or 2mg/kg bw given ip and the selenium compounds were given at the dose of 3mg/kg bw orally in a pretreatment and concomitant treatment schedule. Hepatic lipid peroxidation level was increased significantly by Cd, whereas the glutathione-S-transferase (GST), superoxide dismutase(SOD), reduced glutathione(GSH) and catalase(CAT) levels were decreased. The selenium compounds effectively decreased the hepatic lipid peroxidation level of the animals treated with Cd. The compounds were also effective in restoring the GST, SOD, and GSH as well as CAT level towards normal. Cadmium induced enhanced Serum alanine aminotransferase (ALT) and aspertate aminotransferase (AST) level were also decreased by the selenium compounds. The study evidences the preventive effects of organoselenocyanates 4a-d (Scheme 1) against Cd induced lipid peroxidation and oxidative stress, 4d showing the highest activity.