Retention Of Bioactivity Research Articles

Total phenolics, anthocyanin profile and antioxidant activity of maqui, Aristotelia chilensis (Mol.) Stuntz, berries extract in freeze-dried polysaccharides microcapsules

The effect of different polysaccharides combinations on the stability of maqui extract was studied in order to design functional foods, dietary supplements or natural colorants. Encapsulation by freeze-drying using maltodextrin, gum Arabic and inulin at 10, 20 and 30% was performed and phenolics, anthocyanin, antioxidant capacity and color difference of the microcapsules were determined. The stability of the bioactives after 60 days storage at 25 °C was also evaluated, along with analysis of aw, adsorption isotherm, and microstructure to characterize the powders. 10% encapsulating polysaccharide produced best results, with maltodextrin leading to highest process efficiency, while the mixture of maltodextrin/inulin in equal proportion led to highest retention of polyphenols (91.1%) and anthocyanin (98.8%) during storage. The inulin microcapsules retained 94.1% of its antioxidant capacity compared to 25.3% for the freeze-dried maqui powder. Concentration level and polysaccharide matrix of encapsulating agent significantly affect retention of bioactives in the microcapsules.

Bioactivity of catalase loaded into vaterite CaCO3 crystals via adsorption and co-synthesis

Protein therapy gained a reputation of the most direct and safe approach for treating various diseases, yet biodegradation and loss of bioactivity of fragile therapeutic proteins limit their wide medical use. Recently, a new hard templating technology using decomposable mesoporous vaterite CaCO3 crystals became extremely popular strategy for formulation of protein nano(micro)-vectors. This study deciphers how protein bioactivity depends on protein loading/release for this technology utilizing catalase as a promising antioxidant therapeutic agent. Catalase has been loaded into CaCO3 using two approaches: i) passive - via adsorption (ADS) into pre-formed crystals and ii) active - via co-synthesis (COS) in the pH range 8–10. Crystal morphology, protein secondary structure and enzymatic bioactivity, and protein retention upon washing are assessed. The activity reduction (∼70% for COS and ∼20% for ADS) is caused by both protein exposure to an alkaline medium and protein aggregation induced by Ca2+. The aggregation significantly governs protein release kinetics. Catalase loading into the crystals is pH-independent and van der Waals interactions dominate over the electrostatics, while catalase activity strongly depends on pH. This study implicates the prime role of loading/release mechanism in the preservation of protein bioactivity and guide for the control over the retention of protein bioactivity.

Application of encapsulated natural bioactive compounds from red pepper waste in yogurt

Aim: The aim of this study was to encapsulate red pepper waste (RPW) bioactives and monitor their stability in yogurt.Methods: RPW extract was encapsulated in whey protein using spray and freeze-drying techniques. Physicochemical characteristics of encapsulates were evaluated, and better encapsulates were used to develop functional yogurt. Retention of bioactives was followed over 21 days of storage, and sensory analyses were assessed.Results: Freeze-dried encapsulates (FDE) showed better characteristics like water activity, moisture content, solubility, flowing and colour properties, and, therefore, incorporated in yogurt. Yogurt with FDE successfully retained carotenoids (71.43%) and caused increasing of polyphenol retention (up to 123.73%). This yogurt exhibited higher sensory and general acceptability scores compared to control sample. The fortification of yogurts had a positive influence on maintaining the initial number of lactic acid bacteria during storage.Conclusion: Freeze drying and utilisation of pepper waste are efficient for functional food development, with improved nutritional, colour and bioactive properties.

Hybrid-type strigolactone analogues derived from auxins.

BACKGROUNDStrigolactones (SLs) have a vast number of ecological implications because of the broad spectrum of their biological activities. Unfortunately, the limited availability of SLs restricts their applicability for the benefit of humanity and renders synthesis the only option for their production. However, the structural complexity of SLs impedes their economical synthesis, which is unfeasible on a large scale. Synthesis of SL analogues and mimics with a simpler structure, but with retention of bioactivity, is the solution to this problem.RESULTSHere, we present eight new hybrid‐type SL analogues derived from auxin, synthesized via coupling of auxin ester [ethyl 2‐(1H‐indol‐3‐yl)acetate] and of ethyl 2‐phenylacetate with four D‐rings (mono‐, two di‐ and trimethylated). The new hybrid‐type SL analogues were bioassayed to assess the germination activity of seeds of the parasitic weeds Striga hermonthica, Orobanche minor and Phelipanche ramosa using the classical method of counting germinated seeds and a colorimetric method. The bioassays revealed that analogues with a natural monomethylated D‐ring had appreciable to good activity towards the three species and were the most active derivatives. By contrast, derivatives with the trimethylated D‐ring showed no activity. The dimethylated derivatives (2,4‐dimethyl and 3,4‐dimethyl) were slightly active, especially towards P. ramosa.CONCLUSIONSNew hybrid‐type analogues derived from auxins have been prepared. These analogues may be attractive as potential suicidal germination agents for parasitic weed control because of their ease of preparation and relevant bioactivity. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Cytotoxic Spliceostatin Analogs from Pseudomonas sp.

Two new spliceostatin analogs, designed as spliceostatins J and K (1 and 2), were isolated and identified from the culture of Pseudomonas sp., along with two known ones, FR901464 (3) and spliceostatin E (4). Their structures were elucidated by detailed interpretation of their spectroscopic data, especially 2D-NMR and HR-ESI-MS. Spliceostatin J (1) represented the first example of spliceostatins bearing an unusual hexahydrofuro[3,4-b]furan moiety. Biological assay showed all the isolated compounds except 1 displayed potent cytotoxic activities against two cancer cell lines (MDA-MB-231 and A-549). Structure-activity-relationship studies revealed that the tetrahydropyran ring in spliceostatin analogs was necessary for their bioactive retention.

Microencapsulation of cocoa liquor nanoemulsion with whey protein using spray drying to protection of volatile compounds and antioxidant capacity

The aim of this study was microencapsulated a nanoemulsion of cocoa liquor with whey protein by spray drying, and evaluate the effect of different inlet drying temperatures on the properties of microcapsules. The nanoemulsion showed a particle size of 202.13 nm, PdI of 0.424, and ζ-potential of −25.20 mV. The inlet drying temperature showed differences in physicochemical properties of microcapsules. Microcapsules presented good thermal stability and protection against the melting of cocoa liquor. Microcapsules obtained showed excellent yields of polyphenolic compounds (78–93%), and high retention of volatile compounds, especially of pyrazines. Greater microencapsulation yield of bioactive compounds and retention of volatile compounds was obtained at higher drying temperature (180 °C). Excellent stability of polyphenols content, antioxidant capacity, and volatile compounds of cocoa liquor were observed during storage of the microcapsules at different temperature conditions, indicating the feasibility of this powder for its incorporation into functional foods.

Comparative study on utilization of micro and nano sized starch particles for encapsulation of camel milk derived probiotics (Pediococcus acidolactici)

This study investigates the efficiency of starch nano-particles in comparison with native starch for encapsulation of probiotic bacterial cells (Pediococcus acidolactici). Bacterial cell-death after encapsulation, viability and bioactivity retention under simulated gastro-intestinal conditions (SGID) were studied. Encapsulation in native starch showed higher viable cells (2.65 log CFU/g) ascompared to those encapsulated in starch nano-particles (1.47 log CFU/g) (P < 0.05). The characteristic peak of free cells at 1248 cm−1 indicates the presence of Pediococcus acidolactici in capsules. The micrographs showed more coccus shaped cells at the surface of nano-starch capsules. The cells encapsulated in starch nano-particles showed no or less viability upon their transit through SGID conditions, whereas native starch released cells slowly with 5.03 log CFU/g reaching intestinal phase. Starch nano-particles could not offer thermal protection to cells at high temperature-high time treatment. Further, free cells did not retain their bioactivity under SGID conditions, however enhanced bioactivity was observed upon encapsulation. The results indicate that starch nano-particles may not be suitable for encapsulation of probiotics.

Drying of Maltodextrin solution in a vacuum spray dryer

New drying strategies that use low temperatures can have a significant impact on the improvement of food quality, in particular regarding the retention of flavor compounds, bioactives and other thermosensitive components. The vacuum spray dryer (VSD) is a spray dryer that operates with a low-pressure drying chamber, which consequently reduces the increases the thermodynamic driving force for water removal and allows drying at significantly reduced temperatures. In order to understand the process behavior and define operational strategies, a mathematical model that encompasses mass and energy balances was validated with experimental measurements of pressure and temperature during drying of large chained maltodextrin (dextrose equivalent = 10). Results from experiments carried out in a pilot VSD present a good fit with the proposed model and confirmed its underlying assumptions. In addition, comparative analyses were performed regarding physical aspects of particles produced by VSD and by conventional spray dryer (SD) in the same equipment, but without vacuum. Under the tested conditions, VSD particles presented a higher moisture content (8%) and smaller time of wettability than SD particles. The morphological changes were caused by the vacuum and can be interesting for technological applications.

Structure of gellan gum-hydrolyzed collagen particles: Effect of starch addition and coating layer.

In this work, we developed biopolymeric structures, based on electrostatic attraction, through dripping gellan gum into hydrolyzed collagen (HC), to deliver hydrophilic compounds. Moreover, we evaluated the influence of starch addition on the polymeric network as well as the coating effects promoted by an outer gellan layer. The lowest tested gellan gum concentration in the core (0.5% w/w) was the best one to build spherical beads, with high retention of bioactives (>84% for anthocyanin and >68% for HC). Moreover, the minimum HC concentration (2.5% w/w) in the gelling bath allowed the saturation of active sites of gellan gum presented in the core, as regardless of the HC concentration in the peptide bath, particles presented the same amount of adsorbed peptide. Starch disturbed the interactions between HC and gellan, increasing porosity and pore size, but it presented an important role in retaining anthocyanin in the particle's core. Finally, we demonstrated that addition of a gellan coating layer affected the structure of beads: Peptide molecules (positively charged), already adsorbed onto the beads, diffused out of the core, attracted by the negatively charged gellan coating layer. Consequently, it decreased particle size and increased pore size in the outer part of the particles, which was associated with a reduction in the retention of bioactives. These findings bring important contributions to particle engineering: A new process for particle production was proposed, in which hydrogels were produced by dripping the polysaccharide into the protein bath to be externally gelled, without previous crosslinking with salts.

Manipulating the release of growth factors from biodegradable microspheres for potentially different therapeutic effects by using two different electrospray techniques for microsphere fabrication

Appropriate administration of growth factors is of great importance for directing cell behavior in regenerative medicine, which usually needs suitable carriers to protect the growth factors and to control their releases in specific spatiotemporal manners. Electrospray techniques, particularly emulsion electrospray and coaxial electrospray, have been proven effective to generate capsular/core-shell structured microspheres for growth factor delivery with superior convenience and high bioactivity retention. However, the difference in the release behavior of growth factors from emulsion electrosprayed microspheres and coaxial electrosprayed microspheres remains ambiguous, which causes the difficulty in selecting appropriate approach for certain growth factor-based therapy. In our investigation, vascular endothelial growth factor (VEGF) was used as a model molecule to be encapsulated in the microspheres prepared respectively by emulsion electrospray and coaxial electrospray using the same biodegradable poly(lactic-co-glycolic acid) (PLGA) polymer, for which size distribution, structure, morphology and in vitro degradation properties were studied and found to be tunable by different electrospray techniques. PLGA microspheres fabricated by emulsion electrospray presented nanoporous surface morphology and interior multi-compartment cores, resulting in sustained VEGF release. In comparison, the microspherical vehicles made by coaxial electrospray showing golf-ball-like textured surface morphology and interior monolithic cores led to initial fast release of VEGF. Vascular endothelial cells responded differently under the stimuli of locally released VEGF from different types of electrosprayed PLGA microspheres. The underlying mechanisms for different release behaviors of the encapsulated growth factors that were affected by microspherical vehicles formed by different electrospray techniques were presented, which would offer the design rationale for growth factor delivery vehicles with specific release kinetics, suiting for different therapeutic purposes.

Porous PolyHIPE microspheres for protein delivery from an injectable bone graft

Delivery of osteoinductive factors such as bone morphogenetic protein 2 (BMP-2) has emerged as a prominent strategy to improve regeneration in bone grafting procedures. However, it remains challenging to identify a carrier that provides the requisite loading efficiency and release kinetics without compromising the mechanical properties of the bone graft. Previously, we reported on porous, polymerized high internal phase emulsion (polyHIPE) microspheres fabricated using controlled fluidics. Uniquely, this solvent-free method provides advantages over current microsphere fabrication strategies including in-line loading of growth factors to improve loading efficiency. In the current study, we utilized this platform to fabricate protein-loaded microspheres and investigated the effect of particle size (∼400 vs ∼800 μm) and pore size (∼15 vs 30 μm) on release profiles. Although there was no significant effect of these variables on the substantial burst release profile of the microspheres, the incorporation of the protein-loaded microspheres within the injectable polyHIPE resulted in a sustained release of protein from the bulk scaffold over a two-week period with minimal burst release. Bioactivity retention of encapsulated BMP-2 was confirmed first using a genetically-modified osteoblast reporter cell line. A functional assay with human mesenchymal stem cells established that the BMP-2 release from microspheres induced osteogenic differentiation. Finally, microsphere incorporation had minimal effect on the cure and compressive properties of an injectable polyHIPE bone graft. Overall, this work demonstrates that these microsphere-polyHIPE composites have strong potential to enhance bone regeneration through controlled release of BMP-2 and other growth factors. Statement of significanceThis manuscript describes a method for solvent-free fabrication of porous microspheres from high internal phase emulsions using a controlled fluids setup. The principles of emulsion templating and fluid dynamics provide exceptional control of particle size and pore architecture. In addition to the advantage of solvent-free fabrication, this method provides in-line loading of protein directly into the pores of the microspheres with high loading efficiencies. The incorporation of the protein-loaded microspheres within an injectable polyHIPE scaffold resulted in a sustained release of protein over a two-week period with minimal burst release. Retention of BMP-2 bioactivity and incorporation of microspheres with minimal effect on scaffold compressive properties highlights the potential of these new bone grafts.

Review of thin layer chromatography in pesticide analysis: 2016-2018

Publications reporting techniques and applications of thin layer chromatography (planar chromatography) for the separation, detection, qualitative and quantitative determination, and preparative isolation of pesticides and their metabolites are reviewed for the period from November 1, 2016 to November 1, 2018. Analyses are described for a variety of samples types and pesticide classes. In addition to references on residue analysis, studies such as pesticide chromatographic retention, identification and characterization of natural pesticides (biopesticides), metabolism, bioactivity, degradation, soil mobility, and lipophilicity are covered. A summary and thoughts on future prospects are provided.

A Novel Venom-Derived Peptide for Brachytherapy of Glioblastoma: Preclinical Studies in Mice.

We developed a bacterial expression system to produce a recombinant disintegrin, vicrostatin (VCN), whose structure is based on a natural disintegrin isolated from southern copperhead snake venom. Our goal is to develop VCN for potential clinical translation as an anti-cancer agent. VCN is a peptide of 69 amino acids with a single tyrosine residue. We have employed VCN as integrin-targeted radionuclide therapy (brachytherapy) for treatment of glioblastoma (GBM, glioma). GBM is a deadly brain cancer that doesn’t discriminate between sexes and knows no age limit. We established that the tyrosine residue in VCN can be radioiodinated with full retention of bioactivity. 131I-VCN was utilized for integrin-targeted radionuclide therapy using mouse models of glioma. The combination of radioiodinated VCN plus temozolomide (a DNA alkylating agent) significantly prolonged survival of glioma-bearing mice. We also obtained similar results using an immunocompetent mouse model and a murine glioma cell line. In summary, as demonstrated in studies reported here we have shown that VCN as targeted radionuclide therapy for GBM has significant translational potential for therapy of this deadly disease.

One-step solid-oil-water emulsion for sustained bioactive ranibizumab release

ABSTRACTBackground: The advent of therapeutic proteins highlights the need for delivery systems that protect and extend the duration of its action. Ranibizumab-VEGF is one such drug used for treating wet AMD. This paper describes a facile method to sustain bioactive ranibizumab release from PLGA-based particles.Methods: Two emulsion techniques were explored namely: water-in-oil-in-water (WOW) and solid-in-oil-in-water (SOW) emulsion. The bioactivity of ranibizumab was evaluated by comparing its binding capability to VEGF, measured with ELISA to total protein measured by microBCA.Results: During the emulsion process, contact of ranibizumab with the water-oil interface is the main destabilizing factor and this can be prevented with the use of amphiphilic PVA and solid-state protein in WOW and SOW emulsion respectively. In vitro release of the ranibizumab-loaded particles indicated that a 15-day release could be achieved with SOW particles while the WOW particles generally suffered from a burst release. Released ranibizumab was capable of inhibiting endothelial cell growth indicating its retention of bioactivity. The suppression of burst release from the SOW particles was attributed to the relatively smooth surface morphology of the SOW microparticles.Conclusions: The use of SOW encapsulation in modulating ranibizumab release while maintaining their bioactivity has been highlighted.

Modern frontiers and applications of spray‐freeze‐drying in design of food and biological supplements

AbstractSpray‐freeze‐drying (SFD) is a unique tandem technique combining spray drying (SD) and freeze drying (FD), and exploiting the advantages of both. SFD is particularly suitable for volatiles, biologicals, and food supplements that are sensitive to process extremities of temperature (SD) and time and cost (FD). Although SFD has been an area of interest to scientists for some time, there have been few very interesting investigations in food science in the recent past, which highlight the versatility and utility of this method, and been discussed in this review. The sources for SFD range from flavor ingredients to vegetables, lipids, enzymes, vitamins, and proteins. The extensive research findings in this domain have been collated in this focused review with the objective of providing the readers an essence of the forays made in this technology and the future possibilities it promises.Practical applicationsSpray‐freeze‐drying is suitable for volatiles, biologicals, and food supplements that are sensitive to process extremities of temperature (spray drying) and time and cost (freeze drying). Applications of SFD range from flavor ingredients to vegetables, lipids, enzymes, vitamins, and proteins. It offers reduced drying time, higher retention of bioactives postdrying, and improved rehydration, which makes it a method of choice. Considering the possibilities that this technique offers, further research on more types of feed is warranted, that would benefit industry and academia both.

New hybrid type strigolactone mimics derived from plant growth regulator auxin

Strigolactones (SLs) constitute a new class of plant hormones of increasing importance in plant science. The structure of natural SLs is too complex for ready access by synthesis. Therefore, much attention is being given to design of SL analogues and mimics with a simpler structure but with retention of bioactivity. Here new hybrid type SL mimics have been designed derived from auxins, the common plant growth regulators. Auxins were simply coupled with the butenolide D-ring using bromo (or chloro) butenolide. D-rings having an extra methyl group at the vicinal C-3′ carbon atom, or at the C-2′ carbon atom, or at both have also been studied. The new hybrid type SL mimics were bioassayed for germination activity of seeds of the parasitic weeds S. hermonthica, O. minor and P. ramosa using the classical method of counting germinated seeds and a colorimetric method. For comparison SL mimics derived from phenyl acetic acid were also investigated. The bioassays revealed that mimics with a normal D-ring had appreciable to good activity, those with an extra methyl group at C-2′ were also appreciably active, whereas those with a methyl group in the vicinal C-3′ position were inactive (S. hermonthica) or only slightly active. The new hybrid type mimics may be attractive as potential suicidal germination agents in agronomic applications.

Nano-encapsulation of catechin in starch nanoparticles: Characterization, release behavior and bioactivity retention during simulated in-vitro digestion

Novel starch-based nanoparticles from three sources: horse chestnut (HSC), water chestnut (WSC) and lotus stem (LSC) were prepared for nano-encapsulation of catechin. Average particle size of HSC, WSC and LSC based nano-particles were 322.7, 559.2 and 615.6 nm with encapsulation efficiency of 59.09, 48.30, and 55.00% and negative zeta potential of −18.05, −21.5 and −18.05 mv, respectively. Structural, physical and thermal properties were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). SEM revealed capsule formation with entrapped catechin, while broad characteristic peaks at 3475, 1650, 1383, 1148, 1083 and 790 cm−1 depicts encapsulation of catechin in starch nanoparticles without any evident interaction. XRD showed loss of crystallinity after encapsulation. Higher content of catechin in intestinal juice ensured controlled release in intestine. Bioactive properties were retained at higher level in encapsulated catechin compared to free catechin upon in-vitro digestion.

Potency of a Scalable Nanoparticulate Subunit Vaccine.

Nanoparticulate vaccines can potentiate immune responses by site-specific drainage to lymph nodes (LNs). This approach may benefit from a nanoparticle engineering method with fine control over size and codelivery of antigen and adjuvant. Here, we applied the flash nanocomplexation (FNC) method to prepare nanovaccines via polyelectrolyte complexation of chitosan and heparin to coencapsulate the VP1 protein antigen from enterovirus 71, which causes hand-foot-mouth disease (HFMD), with tumor necrosis factor α (TNF) or CpG as adjuvants. FNC allows for reduction of the nanovaccine size to range from 90 to 130 nm with relatively narrower size distribution and a high payload capacity. These nanovaccines reached both proximal and distal LNs via subcutaneous injection and subsequently exhibited prolonged retention in the LNs. The codelivery induced strong immune activation toward a Th1 response in addition to a potent Th2 response, and conferred effective protection against lethal virus challenge comparable to that of an approved inactivated viral vaccine in mouse models of both passive and active immunization setting. In addition, these nanovaccines also elicited strong IgA titers, which may offer unique advantages for mucosal protection. This study addresses the issues of size control, antigen bioactivity retention, and biomanufacturing to demonstrate the translational potential of a subunit nanovaccine design.

Effective Bioactivity Retention of Low-Concentration Antibodies on HFBI-Modified Fluorescence ICTS for Sensitive and Rapid Detection of PSA.

Nowadays, increasing analytical sensitivity is still a big challenge in constructing membrane-based fluorescence immunochromatography test strips (FICTS). However, the bioactivity of antibody (Ab) immobilized on the test line (T line) of porous nitrocellulose membrane (PNM), which directly influences the analytical sensitivity, is less studied. In this work, a novel amphiphilic hydrophobin (HFBI) protein was introduced to modify the T line to effectively retain the Abs' bioactivity. The results indicated that HFBI could self-assemble on the PNM and immobilize the Abs in the "stand-up" orientation. Compared with the conventional FICTS, the HFBI-modified FICTS with only 0.2 mg/mL of monoclonal Abs on T line enable more accurate quantitative detection and better sensitivity (0.06 ng/mL for prostate specific antigen), which is more than 2 orders of magnitude lower than that of the conventional FICTS with the same concentration of monoclonal Abs on T line. Furthermore, the accuracy of this HFBI-modified FICTS was investigated by testing 150 clinical serum samples and the detection results were coincident with those by electrochemiluminescence immunoassay. Our results provide a novel and promising strategy of Ab immobilization on FICTS for near-patient and point-of-care application.

Strigolactones: new plant hormones in the spotlight.

The development and growth of plants are regulated by interplay of a plethora of complex chemical reactions in which plant hormones play a pivotal role. In recent years, a group of new plant hormones, namely strigolactones (SLs), was discovered and identified. The first SL, strigol, was isolated in 1966, but it took almost 20 years before the details of its structure were fully elucidated. At present, two families of SLs are known, one having the stereochemistry of (+)-strigol and the other that of (-)-orobanchol, the most abundant naturally occurring SL. The most well-known bioproperty of SLs is the germination of seeds of the parasitic weeds Striga and Orobanche. It is evident that SLs are going to play a prominent role in modern molecular botany. In this review, relevant molecular and bioproperties of SLs are discussed. Items of importance are the effect of stereochemistry, structure-activity relationships, design and synthesis of analogues with a simple structure, but with retention of bioactivity, introduction of fluorescent labels into SLs, biosynthetic origin of SLs, mode of action in plants, application in agriculture for the control of parasitic weeds, stimulation of the branching of arbuscular mycorrhizal (AM) fungi, and the control of plant architecture. The future potential of SLs in molecular botany is highlighted.