Investigating the effect of ligand structure on the anticancer properties of several new Co(II) complexes of vitaminB3-based phosphoramides.

Nicotinamide, known as Vitamin-B3, has shown promising potential in improving various medical conditions. Carbacylamidophosphates (CAPh) are versatile phosphoramide ligands with a wide range of applications in both biochemistry and chemistry. Herein, to obtain compounds with enhanced anticancer activity and study the effect of the structure on this activity, four new Co(II) complexes of vitaminB3-based CAPh ligands with the formula of CoCl2[3-NC5H4CONHPO(NC5H10)2]2(C1), CoCl2[3-NC5H4CONHPO(NC5H9CH3)2]2(C2), CoCl2[3-NC5H4CONHPO(NC6H12)2]2(C3), and CoCl2[3-NC5H4CONHPO(NC4H10)2]2(C4) were designed and synthesized. FT-IR, UV-Vis, Atomic Absorption (AAS),1H, 13C, and 31PNMR, and Mass spectroscopies beside CHN and Molar conductivity methods were utilized to characterize the synthesized compounds. Using MTT-assay and Flow Cytometry, the anticancer effects of these complexes were studied on three distinct cell lines, including one normal cell line (MCF10A) and two cancer cell lines (MDA-MB-231, MCF-7). Results showed that our ligands could form complexes by coordinating with cobalt, which, not only have a very strong killing effect on cancer cells but also have a higher level of safety for normal cells and are more cost-efficient than Cisplatin. C3 was the most effective complex at inhibiting the growth of MCF-7 and MDA-MB-231 cells which exhibited a remarkable 97.5 % reduction in cancer cell growth and a Selectivity Index up to > 37. This is an impressive 93 and 54 times more selective and safer than commonly used drugs like Cisplatin and Doxorubicin, respectively.Flow Cytometry analysis shows complex-induced breast cancer cell apoptosis.The ligands' amine structure and ring size can directly impact the complexes' anticancer effect and safety for normal cells.

Synthesis, in vitro and cellular antioxidant activity evaluation of novel peptides derived from Saccharomyces cerevisiae protein hydrolysate: structure-function relationship : Antioxidant activity and synthetic peptides.

The relationship between structure and function of primary antioxidant peptide, YR-10 (YGKPVAVPAR) was considered by synthesizing three analogues including YHR-10 (YGKHVAVHAR), GA-8 (GKPVAVPA) and PAR-3 (PAR). Antioxidant activity was determined through in vitro and cellular assays. Substitution of Pro with His in the structure of YR-10 led to significant (P < 0.05) higher ABTS radical scavenging and ferric reducing activity. Following in silico simulated gastrointestinal digestion, Tyr and Arg were omitted, respectively, from N and C-terminal positions and resulted in decreasing DPPH, ABTS radical scavenging, and ferric reducing activities. PAR-3 showed the best inhibitory activity on linoleic acid oxidation. Pretreatment of Caco-2 cells with YR-10, YHR-10, and GA-8 (1000 µM) before exposure to H2O2 (160 µM) resulted in 34.10%, 39.66% and 29.159% reduction in malondialdehyde and 53.52%, 17.02% and 24.71% reduction in protein carbonyl levels. The peptide pretreatment reduced catalase level in cells and PAR-3 exhibited the most protective effects on the viability of cells exposed to oxidative stress.

In vitro and in silico studies of novel synthetic ACE-inhibitory peptides derived from Saccharomyces cerevisiae protein hydrolysate.

The structure-function relation of YR-10 (YGKPVAVPAR) was investigated by synthesizing four structural analogs of that including YHR-10 (YGKHVAVHAR), GA-8 (GKPVAVPA), GHA-8 (GKHVAVHA), and PAR-3 (PAR). GA-8 (GKPVAVPA) was synthesized on the basis of simulated enzymatic gastrointestinal digestion performed by bioinformatics tools (expasy-peptide cutter). This study explains the molecular mechanisms for the interaction of synthetic peptides with ACE. The IC50 values of each were 139.554 ±â€¯2.3, 61.91 ±â€¯1.2, 463.230 ±â€¯3.56, 135.135 ±â€¯2.1, 514.024 ±â€¯5.86 µM, respectively. Results indicated that Pro replacement with His in YR-10 and GA-8 increased ACE inhibitory activity respectively, by 55.63% and 70.82%. Removal of Tyr and Arg from respectively N and C terminal positions of YR-10, following in silico simulated gastrointestinal digestion caused the 3.31 fold decrease in ACE inhibitory activity. YHR-10 showed the best docking poses, and GHA-8 exhibited interaction with Zn2+. Lineweaver-Burk plots of most active peptides suggest that they act as noncompetitive inhibitors against ACE.

Synergistic Cytotoxic Effect of Gold Nanoparticles and 5-Aminolevulinic Acid-Mediated Photodynamic Therapy against Skin Cancer Cells.

BACKGROUND: Photodynamic therapy (PDT) is a promising therapeutic modality for the treatment of cancer and other diseases. In this study, the epidermoid carcinoma cell line A431 and the normal fibroblasts were used to investigate whether gold nanoparticles (GNPs) can induce an increase in cell death during PDT using 5-aminolevulinic acid (5-ALA) as a photosensitizer. METHODS: Human fibroblast and A431 cells were grown in 96-well plates. The effect of GNPs on the efficacy of 5-ALA-mediated PDT (5-ALA-PDT) was evaluated by comparing the effect of 5-ALA with GNPs to the effect of 5-ALA alone. Cell viability was determined by the methyl- tetrazolium assay. RESULTS: Dark toxicity experiments showed that 5-ALA at concentrations 0.5, 1 and 2 mM had no significant effect on cell viability of both cell lines. However, treatment of cells with 5-ALA (0.5 to 2 mM) and light dose of 25 Jcm(-2) led to 5-10% and 31-42% decrease in cell viability of fibroblast and A431 cells respectively. The data also shows that GNPs in both the absence and the presence of light, results in a dose-dependent decrease in cell viability of both cell lines. However, the sensitivity of cancer cells to GNPs at concentrations more than 24 µg/ml was approximately 2.5- to 4-fold greater than healthy cells. Furthermore, data indicates that 5-ALA in combination with GNPs results in a synergistic reduction in viability of A431 cells. CONCLUSION: In summary, the findings of this study suggest that concomitant treatment with 5-ALA and GNPs may be useful in enhancing the effect of 5-ALA-PDT.

Photosensitive Chitosan-Based Injectable Hydrogel Chemically Cross-Linked by Perylene Bisimide Dopamine with Robust Antioxidant and Cytotoxicity Enhancer Properties for In Vitro Photodynamic Therapy of Breast Cancer.

Here, we report the fabrication of an antioxidant photosensitizing hydrogel system based on chitosan (CS-Cy/PBI-DOPA) covalently cross-linked with perylene bisimide dopamine (PBI-DOPA) as a photosensitizer. The severe insolubility and low tumor selectivity limitations of perylene were overcome by conjugation with dopamine and then to the chitosan hydrogel. The mechanical and rheological study of CS-Cy/PBI-DOPA photodynamic antioxidant hydrogels illustrated interconnected microporous morphologies with high elasticity, swelling ability, and suitable shear-thinning behavior. Bio-friendly properties, such as biodegradability and biocompatibility, excellent singlet oxygen production abilities, and antioxidant properties were also delivered. The antioxidant effects of the hydrogels control the physiological levels of reactive oxygen species (ROS) generated by photochemical reactions in photodynamic therapy (PDT), which are responsible for oxidative damage to tumor cells while protecting normal cells and tissues from ROS damage, including blood and endothelial cells. In vitro, PDT tests of hydrogels were conducted on two human breast cancer cell lines, MDA-MB-231 and MCF-7. These hydrogels offered more than 90% cell viability in the dark and good photocytotoxicity performance with 53 and 43% cell death for MCF-7 and MDA-MB-231 cells, which confirmed their promising potential for cancer therapeutic applications.

Improving biomass and carbohydrate production of microalgae in the rotating cultivation system on natural carriers.

Biofilm-based algal technologies have gained popularity due to higher biomass productivity, efficient harvesting, and water-saving over suspended growth systems. A rotating attached system was designed to assess the biofilm-forming capacity of different isolated microalgal strains from the Persian Gulf. Four microalgal strains, including two Chlorella sp., one Picochlorum sp. and one filamentous cyanobacterium Desmonostoc sp. were cultivated on four carriers: jute, cotton, yarn and nylon. The carriers' physicochemical surface characteristics and attachment effects, like contact angle, were investigated. The incorporated biomass and exopolysaccharides (EPS) content in the suspended and biofilm system was calculated and compared. The results showed that the cyanobacterium strain had the biofilm formation capability on both jute and cotton in the attached cultivation system. Under the same culture conditions, the biomass productivity on jute and cotton carriers was significantly higher (4.76 and 3.61 g m- 2 respectively) than the growth in aqueous suspension (1.19 g m- 2 d- 1). The greatest incorporated exopolysaccharides amount was observed on jute (43.62 ± 4.47%) and the lowest amount was obtained from the growth on positive charge yarn (18.62 ± 1.88%). This study showed that in comparison with planktonic growth, the colonization of cyanobacterial cells and subsequent production of extracellular matrix and biofilm formation can lead to increased biomass production.

Characterization, antioxidant and anticoagulant properties of exopolysaccharide from marine microalgae.

The sulfated exopolysaccharide extracted from marine microalgae attracted considerable attention from both the nutraceutical and pharmaceutical industries. In the present study biomass of five marine microalgae were screened to find strains with high capacity for the production of sulfated exopolysaccharides. The anticoagulant and antioxidant activities of extracted sulfated polysaccharides were evaluated using activated partial thromboplastin time (aPTT), prothrombin time (PT), DPPH and ABTS assays, respectively. The sulfated polysaccharides extracted from Picochlorum sp. showed a strong DPPH scavenging effect with 85% antioxidant activity. The sulfated polysaccharides of Chlorella sorokiniana, Chlorella sp. (L2) and Chlorella sp. (D1) scavenged more than 90% of the ABTS radicals. However, the sulfated polysaccharide extracted from Chlorella sorokiniana, and Chlorella sp. (N4) showed anticoagulant properties. The dual anticoagulant-antioxidant activities in Chlorella sorokiniana could be explained by the combination of various factors including sulfate content and their binding site, monosaccharide residue and glycoside bond which are involved in the polysaccharide's bioactivity.

Dual effect of Sapogenins extracted from Spirulina platensis on telomerase activity in two different cell lines.

Spirulina platensis is a photosynthetic filamentous, edible cyanobacterium that is known as a superfood. In this study, sapogenins were extracted from the spirulina and the effects of these compounds on telomerase activity were evaluated in MCF7 and HDF cell lines using Telomeric Repeat Amplification Protocol and ELIZA assay. The highest increase in telomerase activity was observed at 0.004 mg/ml of sapogenin by 26% ±20.5 in MCF7 cells, while in HDF cells in the same concentration telomerase activity decreased down to 47%±0.48 and the highest inhibition of telomerase activity was observed at 0.070 mg/ml of sapogenins from Spirulina by 68%±0.43. In conclusion, a compound could play a role as a telomerase activator in one cell line while it could play another role as a telomerase inhibitor in another cell line so introducing compounds as a telomerase inhibitor (anticancer) or as a telomerase activator (anti-aging) should be done with discreet.

Dual antioxidant-photosensitizing hydrogel system: Cross-linking of chitosan with tannic acid for enhanced photodynamic efficacy.

Herein, a new antioxidant-photosensitizing hydrogel based on chitosan has been developed to control photodynamic therapy (PDT) activity in cancer treatment. In PDT, photosensitizers generate reactive oxygen species (ROS) during photochemical reactions, leading oxidative damage to cancer cells. However, high ROS levels are lethal to non-target healthy cells and tissues such as endothelial cells and blood cells. To mediate these drawbacks, we improved PDT with a natural polyphenolic antioxidant, Tannic acid (TA), to control the ROS level and minimize side effects through singlet oxygen (1O2) scavenging. In this work, chitosan-based hydrogels were designed using tannic acid as an antioxidant cross-linker and loaded with water-soluble N, N'-di-(l-alanine)-3,4,9,10-perylene tetracarboxylic diimide (PDI-Ala) as a photosensitizer. Our results showed that the hydrogel formed a three-dimensional (3D) microstructure with good mechanical strength and significant singlet oxygen production and antioxidant activity. In addition, the behavior of human melanoma cell line A375 and dental pulp stem cells (as normal cells) was compared and studied during an in vitro photodynamic treatment. Normal cells had a higher viability than cancer cells, indicating that the PDT is more effective on cancer cells than on normal cells. The new hydrogels could be applied as an effective new drug to control PDT performance.

Functional and structural alterations induced by copper in xanthine oxidase.

Xanthine oxidase (XO), a key enzyme in purine metabolism, produces reactive oxygen species causing vascular injuries and chronic heart failure. Here, copper's ability to alter XO activity and structure was investigated in vitro after pre-incubation of the enzyme with increasing Cu(2+) concentrations for various periods of time. The enzymatic activity was measured by following XO-catalyzed xanthine oxidation to uric acid under steady-state kinetics conditions. Structural alterations were assessed by electronic absorption, fluorescence, and circular dichroism spectroscopy. Results showed that Cu(2+) either stimulated or inhibited XO activity, depending on metal concentration and pre-incubation length, the latter also determining the inhibition type. Cu(2+)-XO complex formation was characterized by modifications in XO electronic absorption bands, intrinsic fluorescence, and alpha-helical and beta-sheet content. Apparent dissociation constant values implied high- and low-affinity Cu(2+) binding sites in the vicinity of the enzyme's reactive centers. Data indicated that Cu(2+) binding to high-affinity sites caused alterations around XO molybdenum and flavin adenine dinucleotide centers, changes in secondary structure, and moderate activity inhibition; binding to low affinity sites caused alterations around all XO reactive centers including FeS, changes in tertiary structure as reflected by alterations in spectral properties, and drastic activity inhibition. Stimulation was attributed to transient stabilization of XO optimal conformation. Results also emphasized the potential role of copper in the regulation of XO activity stemming from its binding properties.

Cell-specific and pH-sensitive nanostructure hydrogel based on chitosan as a photosensitizer carrier for selective photodynamic therapy.

The major problems of porphyrins as promising materials for photodynamic therapy (PDT) are their low solubility, subsequently aggregation in biological environments, and a lack of tumor selectivity. With this in mind, a chitosan-based hydrogel conjugated with tetrakis(4-aminophenyl)porphyrin (NH2-TPP) and 2,4,6-tris(p-formylphenoxy)-1,3,5-triazine (TRIPOD) via Schiff base linkage, functionalized with folate was designed and synthesized as a pH-sensitive, self-healable and injectable targeted PS delivery system. This new hydrogel was characterized by FT-IR, 1H NMR, SEM, UV-vis, fluorescence spectroscopy and zeta potential. Formation of imine bonds with the aldehyde group of TRIPOD and amine group of NH2-TPP and chitosan, as a dynamic connection, was approved by rheological analysis. Spectroscopic characterizations revealed that aggregation of porphyrin in aqueous media was eliminated due to diminished π stacking interaction of porphyrin in 3D cross-linked hydrogel structure. Hydrogel 3D microporous structure efficiently transfers the excitation energy to the porphyrin unit, yielding improvement singlet oxygen releases. Cytotoxicity and phototoxicity analysis of the CS/NH2-TPP/FA hydrogels indicating an excellent capability to kill cancer cells selectively and prevent damage to normal cells. This work presents a new and efficient model for the preparation of highly efficient and targeting photosensitizer delivery system.

Antioxidant enzymes during hypoxia-anoxia signaling events in Crocus sativus L. corm.

The activity of reactive oxygen species (ROS)-scavenging enzymes, catalase, superoxide dismutase (SOD), glutathione peroxidase, o-dianisidine and ascorbate peroxidases, was investigated in Crocus sativus L. corms cultivated in normoxic and hypoxic-anoxic conditions. The activity of the ROS-scavenging enzymes studied varied during cultivation. However, the pattern of ROS-scavenging enzymes production was different in corms cultivated in normoxic and hypoxic-anoxic conditions. In normoxic conditions, only the activities of peroxidases and SOD were stimulated. In dormant corms placed under hypoxia-anoxia, the activities of catalase, SOD, and glutathione peroxidase were stimulated, with the highest stimulation observed for catalase, followed by SOD, and then glutathione peroxidase. In corms that had been rooted for 3 days before being placed in hypoxia-anoxia, the activities of all ROS-scavenging enzymes studied were stimulated with the highest stimulation still observed for catalase, followed by the peroxidases, and finally SOD. Thus catalase was the prevailing enzyme produced under hypoxia-anoxia.

The efficacy of Radachlorin-mediated photodynamic therapy in human hepatocellular carcinoma cells.

BACKGROUND: Photodynamic therapy (PDT) is a relatively novel modality for the treatment of cancer and some non-malignant lesions. PDT uses a photosensitive drug and light to destroy malignant cells. The aim of this study was to determine in vitro efficacy of Radachlorin-based PDT (Radachlorin-PDT) on human hepatocellular carcinoma (HCC). METHODS: The study used human liver cancer cells (HepG2) and normal liver cells (HFLF-PI4) to evaluate cell viability using the standard 2-(4, 5-dimethyl-2-thiazolyl)-3,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The mechanism of cell death following Radachlorin-PDT was determined by DNA agarose gel electrophoresis and flow cytometry. RESULTS: Radachlorin without light irradiation had no toxic effect on HepG2 and HFLF-PI4 cells. Cell survival of HepG2 and HFLF-PI4 cells were decreased following PDT in a concentration-dependent manner. However, HepG2 cells were much more sensitive to Radachlorin-PDT than HFLF-PI4 cells. Radachlorin LD50 on HepG2 cells was 30µg/ml and 20µg/ml, 24h after exposure to doses of 5J/cm(2) and 15, or 25J/cm(2), respectively. Optimal Radachlorin and light dose to kill HepG2 cells with minimal effects on normal HFLF-PI4 cells were 100µg/ml and 15J/cm(2), respectively. Our results also showed that apoptosis is induced in HepG2 cells following Radachlorin-PDT. CONCLUSION: Our in vitro data suggest that the use of PDT with Radachlorin can be effective in the treatment of HCC.

Effect of gold nanoparticles on photodynamic efficiency of 5-aminolevolenic acid photosensitiser in epidermal carcinoma cell line: an in vitro study.

In the recent years, enhanced functionality of treatment systems based on nanostructures has attracted a lot of interest. Photodynamic therapy (PDT) is one such treatment method. Here, the authors report the results of the investigations on synthesis and characterisation of gold nanoparticles (GNPs) and their application in PDT along with 5-aminolevolenic acid (5-ALA) (as photosensitiser) with no conjugation. Three sizes of GNPs were synthesised and their cytotoxicity was investigated by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on epidermal carcinoma cell line. The results showed that the PDT efficiency of ALA increased in presence of GNPs. This effect was more considerable for 4 nm particles.