Investigation on Key Molecules of Huanglongbing (HLB)-Induced Orange Juice Off-flavor.

Orange fruits from huanglongbing (HLB)-infected trees do not fully mature and show a severe off-flavor described as bitter-harsh, metallic, and less juicy and fruity. The investigation of juice from HLB-infected (HLBOJ) and healthy control oranges (COJ) by gas chromatography-mass spectrometry showed higher concentrations of fruity esters, such as ethyl butyrate and ethyl 2-methylbutyrate, and soapy-waxy alkanals, such as octanal and decanal, in the COJ, whereas the HLBOJ showed higher concentrations of green aldehydes such as hexanal and degradation compounds of limonene and linalool such as α-terpineol. Application of aroma extract dilution analysis on terpeneless peel oil led to the identification of long-chained aldehydes such as ( E, E)-2,4-decadienal, ( Z)-8-tetradecenal, trans-4,5-epoxy-( E)-2-decenal, ( Z)-4-decenal, and octanal with the highest flavor dilution factors among 25 odor-active volatiles in the peel oil of healthy oranges. Taste-guided fractionation and identification of the HLBOJ secondary metabolites followed by sensory validation revealed that flavanoids such as hesperidin may modulate the flavor to evoke the unacceptable harsh/metallic taste impression. Quantitation of the bitter components showed good correlation between the limonoid and flavanoid concentrations with the off-flavor and quality of the oranges obtained throughout the season.

Protein Corona Formation on Colloidal Polymeric Nanoparticles and Polymeric Nanogels: Impact on Cellular Uptake, Toxicity, Immunogenicity, and Drug Release Properties.

The adsorption of biomolecules to the surface of nanoparticles (NPs) following administration into biological environments is widely recognized. In particular, the "protein corona" is well understood in terms of formation kinetics and impact upon the biological interactions of NPs. Its presence is an essential consideration in the design of therapeutic NPs. In the present study, the protein coronas of six polymeric nanoparticles of prospective therapeutic use were investigated. These included three colloidal NPs-soft core-multishell (CMS) NPs, plus solid cationic Eudragit RS (EGRS), and anionic ethyl cellulose (EC) nanoparticles-and three nanogels (NGs)-thermoresponsive dendritic-polyglycerol (dPG) nanogels (NGs) and two amino-functionalized dPG-NGs. Following incubation with human plasma, protein coronas were characterized and their biological interactions compared with pristine NPs. All NPs demonstrated protein adsorption and increased hydrodynamic diameters, although the solid EGRS and EC NPs bound notably more protein than the other tested particles. Shifts toward moderately negative surface charges were also observed for all corona bearing NPs, despite varied zeta potentials in their pristine states. While the uptake and cellular adhesion of the colloidal NPs in primary human keratinocytes and human umbilical vein endothelial cells were significantly decreased when bearing the protein corona, no obvious impact was seen in the NGs. By contrast, corona bearing NGs induced marked increases in cytokine release from primary human macrophages not seen with corona bearing colloidal NPs. Despite this, no apparent enhancement to in vitro toxicity was noted. Finally, drug release from EGRS and EC NPs was assessed, where a decrease was seen in the EGRS NPs alone. Together these results provide a direct comparison of the physical and biological impact the protein corona has on NPs of widely varied character and in particular highlights a distinction between the corona's effects on NGs and colloidal NPs.

Sensory active piperine analogues from Macropiper excelsum and their effects on intestinal nutrient uptake in Caco-2 cells.

The phytochemical profile of Macropiper excelsum (G.Forst.) Miq. subsp. excelsum (Piperaceae), a shrub which is widespread in New Zealand, was investigated by LC-MS-guided isolation and characterization via HR-ESI-TOF-MS and NMR spectroscopy. The isolated compounds were sensorily evaluated to identify their contribution to the overall taste of the crude extract with sweet, bitter, herbal and trigeminal impressions. Besides the known non-volatile Macropiper compounds, the lignans (+)-diayangambin and (+)-excelsin, four further excelsin isomers, (+)-diasesartemin, (+)-sesartemin, (+)-episesartemin A and B were newly characterized. Moreover, piperine and a number of piperine analogues as well as trans-pellitorine and two homologues, kalecide and (2E,4E)-tetradecadienoic acid N-isobutyl amide were identified in M. excelsum, some of them for the first time. Methyl(2E,4E)-7-(1,3-benzodioxol-5-yl)hepta-2,4-dienoate was identified and characterized for the first time in nature. Sensory analysis of the pure amides indicated that they contributed to the known chemesthetic effects of Macropiper leaves and fruits. Since the pungent piperine has been shown to affect glucose and fatty acid metabolism in vivo in previous studies, piperine itself and four of the isolated compounds, piperdardine, chingchengenamide A, dihydropiperlonguminine, and methyl(2E,4E)-7-(1,3-benzodioxol-5-yl)hepta-2,4-dienoate, were investigated regarding their effects on glucose and fatty acid uptake by enterocyte-like Caco-2 cells, in concentrations ranging from 0.1 to 100 µM. Piperdardine showed the most pronounced effect, with glucose uptake increased by 83 ± 18% at 100 µM compared to non-treated control cells. An amide group seems to be advantageous for glucose uptake stimulation, but not necessarily for fatty acid uptake-stimulating effects of piperine-related compounds.

Identification of an anti-inflammatory potential of Eriodictyon angustifolium compounds in human gingival fibroblasts.

Polyphenol-rich plant extracts have been shown to possess anti-inflammatory activity against oral pathogen-induced cytokine release in model systems of inflammation. Here, it was hypothesized that a flavanone-rich extract of E. angustifolium exhibits an anti-inflammatory potential against endotoxin-induced inflammatory response in human gingival fibroblasts (HGF-1). HGF-1 cells were stimulated with lipopolysaccharide from Porphyromonas gingivalis (pg-LPS) to release pro-inflammatory cytokines. Concentrations of interleukins IL-6 and IL-8 and macrophage chemoattractant protein-1 in the incubation media upon stimulation were determined by means of magnetic bead analysis. A crude ethanol/water extract of E. angustifolium (EE) was fractionated via gel permeation chromatography into a flavanone-rich fraction (FF) and an erionic acid-rich fraction (EF). Individual flavanones and erionic acids as well as EE, EF and FF were tested in the pg-LPS-stimulated HGF-1 cells for their anti-inflammatory potential. The E. angustifolium extract possessed anti-inflammatory potential in this model system, attenuating the pg-LPS-induced release of IL-6 by up to 52.0 ± 15.5%. Of the individual flavanones, eriodictyol and naringenin had the most pronounced effect. However, a mixture of the flavanones did not possess the same effect as the entire flavanoid fraction, indicating that other compounds may contribute to the anti-inflammatory potential of E. angustifolium. For the first time, an anti-inflammatory potential of E. angustifolium and containing erionic acids has been determined.

Rubemamine and Rubescenamine, Two Naturally Occurring N-Cinnamoyl Phenethylamines with Umami-Taste-Modulating Properties.

Sensory screening of a series of naturally occurring N-cinnamoyl derivatives of substituted phenethylamines revealed that rubemamine (9, from Chenopodium album) and rubescenamine (10, from Zanthoxylum rubsecens) elicit strong intrinsic umami taste in water at 50 and 10 ppm, respectively. Sensory tests in glutamate- and nucleotide-containing bases showed that the compounds influence the whole flavor profile of savory formulations. Both rubemamine (9) and rubescenamine (10) at 10-100 ppm dose-dependently positively modulated the umami taste of MSG (0.17-0.22%) up to threefold. Among the investigated amides, only rubemamine (9) and rubescenamine (10) are able to directly activate the TAS1R1-TAS1R3 umami taste receptor. Moreover, both compounds also synergistically modulated the activation of TAS1R1-TAS1R3 by MSG. Most remarkably, rubemamine (9) was able to further positively modulate the IMP-enhanced TAS1R1-TAS1R3 response to MSG ∼ 1.8-fold. Finally, armatamide (11), zanthosinamide (13), and dioxamine (14), which lack intrinsic umami taste in vivo and direct receptor response in vitro, also positively modulated receptor activation by MSG about twofold and the IMP-enhanced MSG-induced TAS1R1-TAS1R3 responses approximately by 50%. In sensory experiments, dioxamine (14) at 25 ppm in combination with 0.17% MSG exhibited a sensory equivalent to 0.37% MSG.

Feasibility study for intraepidermal delivery of proteins using a solid microneedle array.

Solid microneedles (MN) are a promising tool for dermal drug delivery. Particular focus lies on the field of vaccination due to pain-free, safe, hygienic and patient compliant antigen deposition. Diverse coating techniques and formulations have been developed to preserve vaccine activity and to enable targeted drug deposition in the skin. Process and long-term storage stability of coated MN, however, have not yet been studied in detail. Hence, a feasibility study was conducted determining the appropriate needle length (300 µm) for local intraepidermal protein delivery. Moreover, a protein-stabilizing coating formulation was developed. Coating of the MN resulted in protein concentrations between 10 and 23 µg, 90% of the bioactivity of the model protein asparaginase was maintained for 3 months. Skin experiments verified the intraepidermal deposition of 68.0 ± 11.7% of the coated model protein after single application. Slightly increased interleukin 8 levels right after MN insertion indicated minor skin irritation due to the mechanical piercing stress. Thus, specifically highlighting protein stabilization during storage, we demonstrated that selective intraepidermal deposition of proteins or peptides' using solid MN is a feasible approach.

Thermosensitive dendritic polyglycerol-based nanogels for cutaneous delivery of biomacromolecules.

Genetic skin diseases caused by mutations resulting in diminished protein synthesis could benefit from local substitution of the missing protein. Proteins, however, are excluded from topical applications due to their physicochemical properties. We prepared protein-loaded thermoresponsive poly(N-isopropylacrylamide)-polyglycerol-based nanogels exhibiting a thermal trigger point at 35°C, which is favorable for cutaneous applications due to the native thermal gradient of human skin. At≥35°C, the particle size (~200nm) was instantly reduced by 20% and 93% of the protein was released; no alterations of protein structure or activity were detected. Skin penetration experiments demonstrated efficient intraepidermal protein delivery particularly in barrier deficient skin, penetration of the nanogels themselves was not detected. The proof of concept was provided by transglutaminase 1-loaded nanogels which efficiently delivered the protein into transglutaminase 1-deficient skin models resulting in a restoration of skin barrier function. In conclusion, thermoresponsive nanogels are promising topical delivery systems for biomacromolecules. FROM THE CLINICAL EDITOR: Many skin disorders are characterized by an absence of a specific protein due to underlying gene mutation. In this article, the authors described the use of a thermoresponsive PNIPAM-dPG nanogel for cutaneous protein delivery in a gene knock-down model of human skin. The results may have implication for nano-based local delivery of therapeutic agents in skin.

Recent advances in topical delivery of proteins and peptides mediated by soft matter nanocarriers.

Proteins and peptides are increasingly important therapeutics for the treatment of severe and complex diseases like cancer or autoimmune diseases due to their high specificity and potency. Their unique structure and labile physicochemical properties, however, require special attention in the production and formulation process as well as during administration. Aside from conventional systemic injections, the topical application of proteins and peptides is an appealing alternative due to its non-invasive nature and thus high acceptance by patients. For this approach, soft matter nanocarriers are interesting delivery systems which offer beneficial properties such as high biocompatibility, easiness of modifications, as well as targeted drug delivery and release. This review aims to highlight and discuss technological developments in the field of soft matter nanocarriers for the delivery of proteins and peptides via the skin, the eye, the nose, and the lung, and to provide insights in advantages, limitations, and practicability of recent advances.

Astringency is a trigeminal sensation that involves the activation of G protein-coupled signaling by phenolic compounds.

Astringency is an everyday sensory experience best described as a dry mouthfeel typically elicited by phenol-rich alimentary products like tea and wine. The neural correlates and cellular mechanisms of astringency perception are still not well understood. We explored taste and astringency perception in human subjects to study the contribution of the taste as well as of the trigeminal sensory system to astringency perception. Subjects with either a lesion or lidocaine anesthesia of the Chorda tympani taste nerve showed no impairment of astringency perception. Only anesthesia of both the lingual taste and trigeminal innervation by inferior alveolar nerve block led to a loss of astringency perception. In an in vitro model of trigeminal ganglion neurons of mice, we studied the cellular mechanisms of astringency perception. Primary mouse trigeminal ganglion neurons showed robust responses to 8 out of 19 monomeric phenolic astringent compounds and 8 polymeric red wine polyphenols in Ca(2+) imaging experiments. The activating substances shared one or several galloyl moieties, whereas substances lacking the moiety did not or only weakly stimulate responses. The responses depended on Ca(2+) influx and voltage-gated Ca(2+) channels, but not on transient receptor potential channels. Responses to the phenolic compound epigallocatechin gallate as well as to a polymeric red wine polyphenol were inhibited by the Gαs inactivator suramin, the adenylate cyclase inhibitor SQ, and the cyclic nucleotide-gated channel inhibitor l-cis-diltiazem and displayed sensitivity to blockers of Ca(2+)-activated Cl(-) channels.

Evaluation of unsaturated alkanoic acid amides as maskers of epigallocatechin gallate astringency.

Some foods, beverages, and food ingredients show characteristic long-lasting aftertastes. The sweet, lingering taste of high intensity sweeteners or the astringency of tea catechins are typical examples. Epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea, causes a long-lasting astringency and bitterness. These sensations are mostly perceived as aversive and are only accepted in a few foods (e.g., tea and red wine). For the evaluation of the aftertaste of such constituents over a certain period of time, Intensity Variation Descriptive Methodology (IVDM) was used. The approach allows the measurement of different descriptors in parallel in one panel session. IVDM was evaluated concerning the inter- and intraindividual differences of panelists for bitterness and astringency of EGCG. Subsequently, the test method was used as a screening tool for the identification of potential modality-selective masking compounds. In particular, the intensity of the astringency of EGCG (750 mg kg(-1)) could be significantly lowered by 18-33% during the time course by adding the trigeminal-active compound trans-pellitorine (2E,4E-decadienoic acid N-isobutyl amide 1, 5 mg kg(-1)) without significantly affecting bitterness perception. Further, structurally related compounds were evaluated on EGCG to gain evidence for possible structure-activity relationships. A more polar derivative of 1, (2S)-2-[[(2E,4E)-deca-2,4-dienoyl]amino]propanoic acid 9, was also able to reduce the astringency of EGCG similar to trans-pellitorine but without showing the strong tingling effect.