Synthesis of flaxseed gum/melanin-based scaffold: A novel approach for nano-encapsulation of doxorubicin with enhanced anticancer activity.

Doxorubicin is a powerful chemotherapy medicine that is frequently used to treat cancer, but because of its extremely destructive side effects on other healthy cells, its applications have been severely constrained. With the aim of using lower therapeutic doses of doxorubicin while maintaining the same anti-cancerous activity as those of higher doses, the present study designs nano-encapsulation of doxorubicin by acrylamide grafted melanin as core and acrylic acid grafted flax seed gum as shell (DOX@AAM-g-ML/AA-g-FSG-NPs) for studies in-vivo and in-vitro anticancer activity. For biological studies, the cytotoxicity of DOX@AAM-g-ML/AA-g-FSG-NPs was examined on a cancerous human cell line (HCT-15) and it was observed that DOX@AAM-g-ML/AA-g-FSG-NPs exhibited very high toxicity towards HCT-15. In-vivo investigation in colon cancer-inflicted rat model also showed that DOX@AAM-g-ML/AA-g-FSG-NPs showed better anticancer activity against cancerous cells as compared to free doxorubicin. The drug release behavior of DOX@GML-GFS-NPs was studied at several pH and maximum drug release (95 %) was recorded at pH -7.2, and kinetic data of drug release was follows the Higuchi (R2 = 0.9706) kinetic model. Our study is focussed on reducing the side effects of doxorubicin by its nano-encapsulation in acrylamide grafted melanin as core and acrylic acid grafted flax seed gum that will also enhance its efficiency.

Exploring the Charge Transport of a Natural Eumelanin for Sustainable Technologies.

Eumelanin, the main quinone-based biomaterial of the melanin family of compounds, is emerging as a model for medical and sustainable electronic interfaces due to its biocompatibility, biodegradability, and transducing abilities. The study utilizes current-voltage measurements and impedance/dielectric spectroscopy under a controlled hydration atmosphere to investigate the charge transport of eumelanin produced from the S. parvus BSB49 strain. We show no differences in the electrical response in highly hydrated conditions compared to the standard synthetic eumelanin. Hence, our findings provide the groundwork to assess the potential use of this natural eumelanin in sustainable organic (bio)electronic applications.

Extraction of Functional Compounds from Tarragon (Artemisia dracunculus L.) by Deep Eutectic Solvents at Different Properties.

In this study, it was aimed to examine the capacity of deep eutectic solvents (DESs) with different contents to extract bioactive compounds from tarragon (Artemisia dracunculus L.) plant. For this reason, the total phenolic-flavonoid content, total proanthocyanidin content and antioxidant/antimicrobial activities of the prepared DES extracts were investigated, as well as the individual phenolic and individual amino acid profiles. According to the results, DES10 had the highest efficiency in terms of its capacity to extract individual phenolics (approximately 59 mg/100 g) and individual amino acids (approximately 2500 mg/kg), and also gave a higher yield compared to ethanol (approximately 44 mg/100 g for individual phenolics and about 19810 mg/kg for individual amino acids) and methanol (approximately 58 mg/100 g for individual phenolics and approximately 21430 mg/kg for individual amino acids). However, the total phenolic content, total flavonoid content and antioxidant activity values of DES extracts were determined between 59.09-77.50 mg GAE/100 g, 28.68-45.55 mg GAE/100 g and 42.96-146.86 mg TE/100 g, respectively. Therefore, it can be recommended to use these green solvents, which are known as environmentally friendly, as an alternative to organic solvents in the process of preparing extracts of this important medicinal plant in different areas.

Determination of toxicity and radioprotective properties of bacterial and fungal eumelanin pigments.

PURPOSE: Determination of the protective property of melanin, an organic polymer class consisting of phenolic and/or indolic compounds isolated from bacteria and fungi, against fast neutron radiation. To show that these melanin samples, which also have antioxidant and metal chelating properties, can be used as an active ingredient for a drug to be developed against neutrons used in nuclear research and medicine. MATERIALS AND METHODS: Bacterial and fungal media were prepared, and melanin pigments were produced and isolated. For molecular characterization of pigments, bacterial genomic DNA extraction, 16S rDNA gene amplification processes, and fungal genomic DNA extraction, ITS1, and ITS4 Gene Regions amplification were performed. The DEL assay was implemented to determine the genotoxicity properties of bacterial and fungal melanin pigments. Samples were prepared in a pad measuring 10 ml volume (60 × 15 mm) at a concentration of 0.2-1 microgram in 1% agarose gel for radiation-absorbed dose measurements. Absorption measurements were made using 241Am-Be fast neutron source and Canberra brand NP series BF3 gaseous detector to determine the neutron radiation absorption capacity of all samples. The results obtained to determine the absorption degrees of melanin samples were compared with paraffin and normal concrete, which are widely used in neutron radiation shielding studies. RESULTS: Melanin pigments were obtained using different bacteria and fungi strains. Afterwards, the fast neutron radiation absorption capacity of these purified pigments were determined. Compared to reference samples, these pigments were found to have slightly lower radiation absorbing ability. In addition to these experiments, cytotoxicity tests were carried out using the Yeast DEL assay technique to evaluate the potential for use of these organic pigments in fields such as medicine and pharmacology. According to the results obtained from the tests, it was determined that these melanin samples did not have any toxic effects. CONCLUSION: It was determined that these melanin samples have the potential to be used as a radioprotective drug active substance to protect the tissues and cells of people exposed to neutron radiation after a nuclear accident or nuclear war.Giving a drug that will be developed by using these active ingredients before or after people are exposed to a radiation environment can provide great benefits.

Green Synthesis, Characterization, Antioxidant, Antibacterial and Enzyme Inhibition Effects of Chestnut (Castanea sativa) Honey-Mediated Silver Nanoparticles.

In this study, chestnut honey-based silver nanoparticles (CH-AgNPs) were synthesized at different temperatures (30, 60 and 90 °C) and these nanoparticles were characterized by different techniques such as UV-vis spectrophotometer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The DPPH free radical scavenging assay was used to determine the antioxidant activity of the obtained nanoparticles. The inhibition effects of these nanoparticles for some clinically important enzymes such as myeloperoxidase and collagenase were investigated. In addition, the disk diffusion method (DDM), agar well diffusion (AWD), and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) techniques were used to determine the antibacterial activity of CH-AgNPs. In honey-based silver nanoparticle production processes using green synthesis, it was determined that the nanoparticle sizes decreased from 55 to 27 nm with an increase in temperature. In addition, it was determined that the rate of inhibition of myeloperoxidase (36.4% to 34.0%) and collagenase enzymes (74.2% to 68.7%) increased with a decrease in particle size. As a result of the antibacterial activity tests, it was observed that CH-AgNPs have antibacterial activity against all target pathogens including Gram-positive and Gram-negative bacteria. The obtained results show that CH-AgNPs produced using chestnut honey have the potential to be used in fields such as medicine, pharmacy and cosmetic technology.

Optimization of Ultrasonic Extraction of Nutraceutical and Pharmaceutical Compounds from Bee Pollen with Deep Eutectic Solvents Using Response Surface Methodology.

In recent years, there has been increasing interest in green extraction methods and green solvents due to their many advantages. In this study, the effects of an ultrasonic extraction method and deep eutectic solvents (DESs) on the extraction of different bioactive substances from bee pollen were investigated. In this regard, the effects of process variables such as the molar ratio of the DES (1, 1.5, and 2), sonication time (15, 30, and 45 min), and ultrasonic power (90, 135 and 180 W) on total individual amino acids, total individual organic acids, and total individual phenolic compounds were investigated by response surface methodology (RSM). The optimal conditions were found to be a molar ratio of 2, sonication time of 45 min, and ultrasonic power of 180 W (R2 = 0.84). Extracts obtained via the maceration method using ethanol as a solvent were evaluated as the control group. Compared with the control group, the total individual amino acid and total individual organic acid values were higher using DESs. In addition, compounds such as myricetin, kaempferol, and quercetin were extracted at higher concentrations using DESs compared to controls. The results obtained in antimicrobial activity tests showed that the DES groups had broad-spectrum antibacterial effects against all bacterial samples, without exception. However, in yeast-like fungus samples, this inhibition effect was negligibly low. This study is the first to evaluate the impact of DESs on the extraction of bioactive substances from bee pollen. The obtained results show that this innovative and green extraction technique/solvent (ultrasonic extraction/DES) can be used successfully to obtain important bioactive compounds from bee pollen.

Eumelanin protects the liver against diethylnitrosamine-induced liver injury.

This study aims to evaluate in vivo protective effects of eumelanin (EU) on diethylnitrosamine (DEN)-induced liver injury. Wistar albino male rats were divided into 6 groups (n = 6), Control, DMSO, DEN, DEN + EU10, DEN + EU15, and DEN + EU20. Animals in the DEN group were injected i.p a single dose of 200 mg/kg DEN, DEN + EU10 group was given 10 mg/kg EU, DEN + EU15 group was given 15 mg/kg, DEN + EU20 group was given 20 mg/kg EU for a week. The results showed that there was no significant difference in vessel volume density between the groups. Inflammatory cell infiltration, hydropic degeneration, and necrotic cells were observed in the DEN group, and these histopathological changes were significantly reduced in all treatment groups. Although there was a low intensity of PAS-positive staining in the DEN groups, moderate staining was observed in the treatment groups. While Caspase-3, PCNA, TNF-α, and IL-6 expressions increased in the DEN group, their expressions decreased in the EU-treated groups. DEN increased AST, ALT, and MDA levels and decreased CAT levels. In particular, the EU10 dose significantly improved these parameters. The present study revealed that eumelanin has protective effects against DEN-induced liver injury.

A comparative characterization study between fungal and bacterial eumelanin pigments.

Melanins are the most common and the most enigmatic natural pigments in the nature that found in many different taxa group such as bacteria, yeasts, fungi, insects, plants, reptiles, birds and mammals. These biological macromolecules are highly complex cross-linked, heterogeneous biopolymers and composed of polymerized phenolic and/or indolic compounds. Recently, interest in these ubiquitous biopolymers has been increasing considerably in many different areas such as medicine, pharmacology, cosmetics, organic electronic and optoelectronics because of their versatile properties. In this study, four different extracellular eumelanin pigments (two bacterial eumelanins and two fungal eumelanins) were characterized by different spectrometric techniques such as FT-IR, XRD, NMR and UV-vis. In XRD analyzes, purified fungal and bacterial eumelanin pigments were characterized by giving a wide peak at about 22o with an angle of 2θ. Furthermore, in the 1 H NMR spectra of these biopolymers, it was observed that all pigments have signals in both aromatic and aliphatic regions. In addition to these analyzes, nanostructures of these biopolymers were characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Finally, eumelanin pigment producer microorganisms were molecularly characterized. 16 S rDNA and 18 S rDNA sequence analysis results of these microorganisms (Streptomyces fulvissimus MPPS4, Streptomyces xiamenensis MPPS6, Aspergillus niger MPPF16 and Aspergillus terreus MPPF25) were deposited in NCBI GenBank® database with accession number MT825594, MT973972, MW652652 and MW652653 respectively. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-022-01012-1.

Production, purification, and characterization of Streptomyces sp. strain MPPS2 extracellular pyomelanin pigment.

Melanins are natural pigments widely distributed in nature from bacteria to humans. These complex, negatively charged, amorphous, high molecular mass natural biopolymers have many different bioactive properties such as antimicrobial, antiviral, antioxidant, liver protective effects, etc. In this study, some chemical and physical properties of the purified extracellular pyomelanin pigment were investigated via XRD (X-ray diffraction), FT-IR (Fourier transform infrared), and 1H NMR (Nuclear magnetic resonance). Additionally, the melanin pigment producer Streptomyces sp. strain MPPS2 was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and 16S rDNA sequence analysis. 16S rDNA nucleotide sequence analysis result was deposited in NCBI GenBank® under accession number MT825616.

Screening of Plant Pollen Sources, Polyphenolic Compounds, Fatty Acids and Antioxidant/Antimicrobial Activity from Bee Pollen.

In this study, the botanical origin, total flavonoid and phenolic content, antioxidant activity, phenolic profile and fatty acid composition of mixed bee pollen loads collected in Bayburt, Turkey, were determined. In addition to these assays, antibacterial activity of bee-collected pollen extract (BCPE) against a variety of food-borne pathogenic bacteria was determined in vitro. Pollen loads were classified into five botanical families based on their color: Asteraceae, Fabaceae, Campanulaceae, Cistaceae and Rosaceae. Total flavonoid, total phenolic, CUPRAC and CERAC concentrations were 173.52 mg GAE/g, 79.21 mg QE/g, 85.59 mg Trolox/g and 118.13 mg Trolox/g, respectively. Twenty-three phenolic compounds were scanned in bee pollen extract by LC-MS/MS, with rutin being the most abundant. Cis-4,7,10,13,16,19 docosahexaenoic acid was the predominant fatty acid, followed by cis-11-eicosenoic acid, palmitic acid, and alfa linolenic acid. In addition, the agar well diffusion (AWD) and micro-broth dilution methods were used to determine of the antibacterial activity of the BCPE sample. MIC values were observed to vary between 2.5-5 mg/mL for Gram-positive bacteria and 5-10 mg/mL for Gram-negative bacteria. These findings indicate that bee pollen could be a potential source of antioxidants and antimicrobials.

Bioproduction, structure elucidation and in vitro antiproliferative effect of eumelanin pigment from Streptomyces parvus BSB49.

In this study, the structure of the purified extracellular eumelanin pigment isolated from Streptomyces spp. was elucidated by detailed analysis via two different spectroscopic techniques (FT-IR and NMR). In vitro antiproliferative effects of eumelanin were evaluated on HeLa cell line. These experiments were carried out with the evaluation of the parameters including cell viability, cell index, and mitotic index. With the cell viability and cell index, IC50 concentration of eumelanin was determined as 10 µM. This result showed that the IC50 concentration of eumelanin decreased the values of cell viability, cell index and mitotic index. These changes are statistically significant (p < 0.01). The ability of the dissolved eumelanin (250 µg mL-1) to scavenge free radicals was determined via DPPH and ABTS and was shown to be about 87.73% and 75.2%, respectively, compared with standard antioxidants. It was observed that dry weights of eumelanin yield among the selected strains ranged from 160 to 240 mg L-1. The strain with the highest production potential was selected for 16S rDNA sequence analysis and, accordingly, the selected strain BSB49 was identified as Streptomyces parvus and the sequence analysis results were deposited in NCBI under accession number MK894155.