Interaction,cytotoxicity and sustained release assessment of a novel anti-tumor agent using bovine serum albumin nanocarrier

Abstract

The interaction ability of bovine serum albumin (BSA) with 2,6-divanillylidenecyclohexanone (DVH) as a stable curcumin derivative was investigated using fluorescence and circular dichroism (CD) spectroscopy techniques under simulative physiological conditions (pH = 7.2). Following the obtained results of binding studies, bovine serum albumin nanoparticles (BSANPs) were synthesized and characterized using Fourier transform infrared spectroscopy (FT-IR), filed emission scanning electron microscopy (FE-SEM), atomic force microscope (AFM) and dynamic light scattering (DLS). The stable BSANPs showed a spherical shape with a diameter of 149.14?±?46.69?nm and the formulation of BSA had no change during the fabrication process. DVH was loaded on BSANPs (DVH@BSANPs) and the release studies showed sustained release of DVH from BSANPs. The validation of DVH@BSANPs system confirmed that the Fickian release mechanism of DVH followed on Korsmeyer–Pepas model. The in vitro studies on HFFF2 and MDA-MB-231 were investigated using MTT assay, DAPI and annexinV/PI staining that showed biocompatible BSANPs reduced the cytotoxicity of DVH in normal cell lines significantly, and antitumor activity of DVH was increased when it was loaded onto BSANPs without necrosis. These results suggest that DVH@BSANPs are a novel biocompatible sustained release system for effective therapeutic approach.

Communicated by Ramaswamy H. Sarma     

Nanocapsules: A Novel Lipid Formulation Platform for Platinum-based Anti-cancer Drugs

Platinum-based anti-cancer agents have been used for many years to treat many different types of cancer. However, the efficacy of these drugs is limited by serious side effects. One of the strategies to reduce the side effects is encapsulation of the drug in a lipid formulation. Recently, we discovered a novel method for the efficient encapsulation of cisplatin in a lipid formulation. The method is unique in that it does not generate conventional liposomes but nanocapsules: small aggregates of solid cisplatin covered by a lipid bilayer. Also carboplatin, a cisplatin-derived anti-cancer drug with different chemical properties, can be efficiently encapsulated by a similar method. The encapsulation in nanocapsules dramatically improves the in vitro cytotoxicity of the platinum drugs. Our results hold the promise that the nanocapsule technology could prove successful in the efficient encapsulation of many other (platinum-based) drugs, and thereby improve their therapeutic index and profile in vivo.     

Formulation and transport properties of tenofovir loaded liposomes through Caco-2 cell model

Abstract

The aim was to investigate the potential of proliposomes to improve the permeability of tenofovir, anti-HIV, for oral delivery. Tenofovir was incorporated into phosphatidylcholine proliposomes and their absorption was determined in Caco-2 cell cultures grown on Transwell inserts using aqueous drug solutions as reference. Five batches of proliposomes were prepared with different stearylamine levels and characterized in terms of vesicular morphology, drug encapsulation efficiency (EEF), drug leakage, vesicular sizing and surface charges. Cytotoxicity of the reconstituted liposomes was evaluated by the MTT assay. The obtained results showed that increasing the incorporated percentage of stearylamine led to an increase in drug encapsulation, a slower drug leakage and larger liposomes formed. Compared to the drug solutions at corresponding concentrations, the proposed formulations showed a positive relationship (R^2?=?0.9756) for the influence of increasing the stearylamine percentage on reduction of mitochondrial activity. Regarding the drug permeability, enhancements of apparent permeability by 16.5- and 5.2-folds were observed for proliposomes formulations with 5% and 15% stearylamine, respectively. A good correlation was observed between the Caco-2 and dialysis models that might indicate passive diffusion as well as paracellular transport as suggested mechanisms for drug absorption. Cationic proliposomes offered a potential formulation to improve the permeation of tenofovir.     

Mitochondria-targeted liposomes improve the apoptotic and cytotoxic action of sclareol

Current efforts toward improving the effectiveness of drug therapy are increasingly relying on drug-targeting strategies to effectively deliver bioactive molecules to their molecular targets. Pharmaceutical nanocarriers represent a major tool toward this aim, and our efforts have been directed toward achieving nanocarrier-mediated subcellular delivery of drug molecules with mitochondria as the primary subcellular target. Meeting the need for specific subcellular delivery is essential to realizing the full potential of many poorly soluble anticancer drugs. In this article, we report that mitochondria-targeted liposomes significantly improve the apoptotic and cytotoxic action of sclareol, a poorly soluble potential anticancer drug. The results support the broad applicability of our nanocarrier-mediated subcellular targeting approach as a means to improve the effectiveness of certain anticancer therapeutics.     

Evaluation of (ɳ6-p-cymene) ruthenium diclofenac complex as anticancer chemotherapeutic agent: interaction with biomolecules,cytotoxicity assays

abstract

The designing of metal-based anticancer therapeutic agents can be optimized in a better and rapid way if the ligands utilized have standalone properties. Therefore, even when the organometallic/coordination complex (i.e., metallodrug) gets dissociated in extreme conditions, the ligand can endorse its biological properties. Herein, we have synthesized and characterized ?⁶-p-cymene ruthenium diclofenac complex. Furthermore, the ruthenium complex interactions with human serum albumin (HSA) and ct-DNA have been studied using various spectroscopic studies viz., UV, fluorescence, and circular dichroism and exhibited a significant binding propensity. Furthermore, in vitro cytotoxicity assays were carried out against human breast cancer “MCF-7” cell line. The ?⁶-p-cymene ruthenium diclofenac complex registered significant cytotoxicity with an IC₅₀ value of ～25.0?µM which is comparable to the standard drugs. The ?⁶-p-cymene ruthenium diclofenac complex was able to decrease the MCF-7 cell proliferation and induced significant levels of apoptosis with relatively low toxicity.     

Probing the interaction of silver nanoparticles with tau protein and neuroblastoma cell line as nervous system models

Interestingly pharmaceutical sciences are using nanoparticles (NPs) to design and develop nanomaterials-based drugs. However, up to recently, it has not been well realized that NPs themselves may impose risks to the biological systems. In this study, the interaction of silver nanoparticles (AgNPs) with tau protein and SH-SY5Y neuroblastoma cell line, as potential nervous system models, was examined with a range of techniques including intrinsic fluorescence spectroscopy, circular dichroism (CD) spectroscopy, 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and acridine orange/ethidium bromide (AO/EB) dual staining method. Fluorescence study showed that AgNPs with a diameter of around 10–20 nm spontaneously form a static complex with tau protein via hydrogen bonds and van der Waals interactions. CD experiment revealed that AgNPs did not change the random coil structure of tau protein. Moreover, AgNPs showed to induce SH-SY5Y neuroblastoma cell mortality through fragmentation of DNA which is a key feature of apoptosis. In conclusion, AgNPs may induce slight changes on the tau protein structure. Also, the concentration of AgNPs is the main factor which influences their cytotoxicity. Since, all adverse effects of NPs are not well detected, so probably additional more specific testing would be needed.     

Leucine Dehydrogenase from Corynebacterium pseudodiphtheriticum: Purification and Characterization

Leucine dehydrogenase [EC 1.4.1.9] was purified to homogeneity from Corynebacterium pseudodiphtheriticum ICR 2210. The enzyme consisted of a single polypeptide with a molecular weight of about 34,000. Stepwise Edman degradation provided the N-terminal sequence of the first 24 amino acids, and carboxypeptidase Y digestion provided the C-terminal sequence of the last 2 amino acids. Although the enzyme catalyzed the reversible deamination of various branched-chain l-amino acids, l-valine was the best substrate for oxidative deamination at pH 10.9 and the saturated concentration. The enzyme, however, had higher reactivity for l-leucine, and the k_cat/Km value for l-leucine was higher than that for l-valine. The enzyme required NAD⁺ as a natural coenzyme. The NAD⁺ analogs 3-acetylpyridine-NAD⁺ and deamino-NAD⁺ were much better coenzymes than NAD ⁺. The enzyme activity was significantly reduced by sulfhydryl reagents and pyridoxal 5′-phosphate. d-Enantiomers of the substrate amino acids competitively inhibited the oxidation of l-valine.     

Structure of Bovine κ-Casein: Spectrophotometric Titration and Molecular Size Changes in Alkaline Solution

The ionization of tyrosyl groups in bovine κ-casein and S-carboxyamidomethyl-κ-casein (CAM-κ) was studied by spectrophotometric titration at 295 mµ. In the denaturing solvent 8 m urea, the titration curves are reversible and the pK_app values of eight tyrosyl groups both in κ-casein and in CMA-κ-casein are 10.7. In 0.2 m KCl solution, κ-casein has six tyrosyl groups with normal pK_app value of 10.5 and two groups with higher pK_app value of 11.4. CAM-κ-casein has eight tyrosyl groups with pK_app value of 10.6 in 0.2 m KCl solution. These observations suggest that -S-S- bondings in κ-casein are concerned with the ‘masking’ of the tyrosyl groups. The evidence of the rupture of intermolecular -S-S- bondings of κ-casein in alkaline solution was shown by the study of gel Chromatograph y on Sephadex G–150. One of the possible explanation is that the ionization of tyrosyl groups with higher pK_app value is associated with the destruction of hydrophobic regions, and this destruction is due to the rupture of intermolecular -S-S- bondings under alkaline conditions.     

A New Enzymatic Microdetermination Procedure for Ethanol with Particulate Alcohol Dehydrogenase from Acetic Acid Bacteria

A new enzymatic method for microdetermination of ethanol has been established with particulate alcohol dehydrogenase from acetic acid bacteria and applied to the practical purposes. The enzyme had an optimum pH for ethanol oxidation at a fairly acidic region. Trace amounts of ethanol could be assayed by measuring the initial reaction rate as successful as by reading the end point of the reaction. Some advantages in using this enzyme for ethanol determination were pointed out comparing with NAD-linked alcohol dehydrogenase from yeast or horse liver. Impurity in the enzyme preparations, stability of reagents and coexistence of other substances in the assay mixture were not as critical as in NAD-linked enzyme. Acidic samples could also be directly determined for ethanol without preadjustment of sample pH.     

Production and Properties of Lipase from a Newly Isolated Chromobacterium

Out of some 750 strains of microorganisms, a potent bacterium for lipase production was isolated from soil and was identified as Chromobacterium viscosum.

The bacterium accumulates lipase in culture fluid when grown aerobically at 26°C for 3 days in a medium composed of soluble starch, soy bean meal, lard and inorganic salts.

Chromobacterium lipase had an optimum pH of 7.0 for activity at 37°C, and an optimal temperature of 65°C at pH 7.0. The enzyme retained 80% of the activity when heated for 10 min at 70°C. This lipase was capable of hydrolyzing a variety of natural fats and oils, and it was more active on lard and butter than on olive oil. The activity was stimulated by Ca²⁺, Mg²⁺, Mn²⁺ and inhibited by Cu²⁺, Hg²⁺ and Sn²⁺. It was not diminished but rather stimulated by a high concentration of bile-salts.