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Genipin-cross-linked collagen/chitosan biomimetic scaffolds for articular cartilage tissue engineering applications

Yan, Leping; Wang, Yingjun; Rei, Li; Wu, Gang; Caridade, S. G.; Fan, Jiabing; Wang, Lingyun; Ji, Peihong; Oliveira, Joaquim M.; Oliveira, João T.; Mano, J. F.; Reis, R. L.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em 20/07/2010 ENG
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This was the first study to use genipin to cross-link collagen and chitosan.; In this study, genipin-cross-linked collagen/chitosan biodegradable porous scaffolds were prepared for articular cartilage regeneration. The influence of chitosan amount and genipin concentration on the scaffolds physicochemical properties was evaluated. The morphologies of the scaffolds were characterized by scanning electron microscope (SEM) and cross-linking degree was investigated by ninhydrin assay. Additionally, the mechanical properties of the scaffolds were assessed under dynamic compression. To study the swelling ratio and the biostability of the collagen/chitosan scaffold, in vitro tests were also carried out by immersion of the scaffolds in PBS solution or digestion in collagenase, respectively. The results showed that the morphologies of the scaffolds underwent a fiber-like to a sheet-like structural transition by increasing chitosan amount. Genipin cross-linking remarkably changed the morphologies and pore sizes of the scaffolds when chitosan amount was less than 25%. Either by increasing the chitosan ratio or performing cross-linking treatment, the swelling ratio of the scaffolds can be tailored. The ninhydrin assay demonstrated that the addition of chitosan could obviously increase the cross-linking efficiency. The degradation studies indicated that genipin cross-linking can effectively enhance the biostability of the scaffolds. The biocompatibility of the scaffolds was evaluated by culturing rabbit chondrocytes in vitro. This study demonstrated that a good viability of the chondrocytes seeded on the scaffold was achieved. The SEM analysis has revealed that the chondrocytes adhered well to the surface of the scaffolds and contacted each other. These results suggest that the genipin-cross-linked collagen/chitosan matrix may be a promising formulation for articular cartilage scaffolding.; National Basic Research Program of China. Grant Number: 2005CB623902; State Key Program of National Natural Science of China. Grant Number: 50732003; Natural Science Foundation Team Project of Guangdong. Grant Number: 4205786; Key Projects in the National Science and Technology Pillar Program in the Eleventh Five-year Plan Period. Grant Number: 2006BA116B04; Guangdong Natural Science Foundation. Grant Number: 07300602

Genipin modified silk fibroin nanometric-nets

Silva, S. S.; Maniglio, D.; Motta, A.; Mano, J. F.; Reis, R. L.; Migliaresi, C.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em /08/2008 ENG
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Nanometric silk-fibroin nets were fabricated by electrospinning from regenerated Bombyx mori silk-fibroin (SF)/formic acid solutions with the addition of genipin (GE), 2, 15 and 24 h after the solution preparation. After spinning, the pure fibroin nanofibers were water soluble and needed a further stabilization process, whereas the reaction of fibroin with genipin resulted in water-insoluble fibroin nets due to conformational changes induced in the fibroin by the genipin. SFGE nanofibers presented diameters ranging from 140 to 590 nm and were generally thinner than pure SF nanofibers. The secondary structure of SF into SFGE nanofibers showed the presence of a β-sheet conformation together with β-turn intermediates (turns and bends). The approach described in this paper provides an alternative method of designing SF nanofibers that are already water insoluble, without any stability post-treatment needed.

Properties of Chitosan-Genipin Films Grafted with Phenolic Compounds from Red Wine

Gonçalves, Fernando Jorge
Fonte: P.L. Soni Publicador: P.L. Soni
Tipo: Artigo de Revista Científica
Publicado em 20/02/2015 ENG
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Chitosan has been studied as a renewable biopolymer to form edible films and coatings to improve the shelf life of food products. Chemical modification of chitosan is a strategy to prepare chitosan films with enhanced properties to be used as food preservatives. Wine, particularly red wine, is a rich natural source of phenolic compounds, namely anthocyanins, proanthocyanidins, monomeric catechins, and phenolic acids. Phenolic compounds, in general, present strong antioxidant properties. The aim of this work was to develop chitosan-based films with higher antioxidant activity by grafting wine phenolic compounds. Fractions of red wine phenolic compounds, rich in phenolic acids, anthocyanins, and total phenolic compounds, were grafted to the glucosamine residues of chitosan by a radical mechanism using ammonium cerium (IV) nitrate. In order to increase the stability of the films in aqueous acidic medium, genipin, a natural compound with capacity of cross-linking chitosan, was also used in film preparation. The grafting of all phenolic compounds-rich fractions obtained from wine provided films with antioxidant activity more than 100% than those films prepared only with chitosan-genipin. Moreover, the use of genipin allowed obtaining stable films in a large range of pH. The chitosan-genipin film grafted with anthocyanins and total phenolic compounds lost less than 3% of their mass in acidic media after an exhaustive stirring during 7 days...

Interactions of chitosan/genipin hydrogels during drug delivery: a QSPR approach

Delgadillo-Armendariz,Nancy L.; Rangel-Vazquez,Norma A.; Marquez-Brazon,Edgar A.; Rojas-De Gascue,Blanca
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
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A hydrogel comprised of chitosan crosslinked using the low-toxicity crosslinker genipin was prepared, and the absorption of glibenclamide by the hydrogel was investigated. Optimized structures and their molecular electrostatic potentials were calculated using the AM1 method, and the results were used to evaluate the molecular interactions between the three compounds. The quantitative structure-property relationship model was also used to estimate the activity of the chemicals on the basis their molecular structures. In addition, theoretical Fourier transform infrared spectra were calculated to analyze the intermolecular interactions in the proposed system. Finally, the hydrophilicity of the hydrogel and its influence on the absorption process were also estimated.

Chitosan-Genipin Microspheres for the Controlled Release of Drugs: Clarithromycin, Tramadol and Heparin

Harris, Ruth; Lecumberri, Elena; Heras, Angeles
Fonte: Molecular Diversity Preservation International Publicador: Molecular Diversity Preservation International
Tipo: Artigo de Revista Científica
Publicado em 26/05/2010 EN
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The aim of this study was to first evaluate whether the chitosan hydrochloride-genipin crosslinking reaction is influenced by factors such as time, and polymer/genipin concentration, and second, to develop crosslinked drug loaded microspheres to improve the control over drug release. Once the crosslinking process was characterized as a function of the factors mentioned above, drug loaded hydrochloride chitosan microspheres with different degrees of crosslinking were obtained. Microspheres were characterized in terms of size, morphology, drug content, surface charge and capacity to control in vitro drug release. Clarithromycin, tramadol hydrochloride, and low molecular weight heparin (LMWH) were used as model drugs. The obtained particles were spherical, positively charged, with a diameter of 1–10 μm. X-Ray diffraction showed that there was an interaction of genipin and each drug with chitosan in the microspheres. In relation to the release profiles, a higher degree of crosslinking led to more control of drug release in the case of clarithromycin and tramadol. For these drugs, optimal release profiles were obtained for microspheres crosslinked with 1 mM genipin at 50 ºC for 5 h and with 5 mM genipin at 50 ºC for 5 h, respectively. In LMWH microspheres...

Genipin-Induced Inhibition of Uncoupling Protein-2 Sensitizes Drug-Resistant Cancer Cells to Cytotoxic Agents

Mailloux, Ryan J.; Adjeitey, Cyril Nii-Klu; Harper, Mary-Ellen
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 13/10/2010 EN
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Uncoupling protein-2 (UCP2) is known to suppress mitochondrial reactive oxygen species (ROS) production and is employed by drug-resistant cancer cells to mitigate oxidative stress. Using the drug-sensitive HL-60 cells and the drug-resistant MX2 subline as model systems, we show that genipin, a UCP2 inhibitor, sensitizes drug-resistant cells to cytotoxic agents. Increased MX2 cell death was observed upon co-treatment with genipin and different doses of menadione, doxorubicin, and epirubicin. DCFH-DA fluorimetry revealed that the increase in MX2 cell death was accompanied by enhanced cellular ROS levels. The drug-induced increase in ROS was linked to genipin-mediated inhibition of mitochondrial proton leak. State 4 and resting cellular respiratory rates were higher in the MX2 cells in comparison to the HL-60 cells, and the increased respiration was readily suppressed by genipin in the MX2 cells. UCP2 accounted for a remarkable 37% of the resting cellular oxygen consumption indicating that the MX2 cells are functionally reliant on this protein. Higher amounts of UCP2 protein were detected in the MX2 versus the HL-60 mitochondria. The observed effects of genipin were absent in the HL-60 cells pointing to the selectivity of this natural product for drug-resistant cells. The specificity of genipin for UCP2 was confirmed using CHO cells stably expressing UCP2 in which genipin induced an ∼22% decrease in state 4 respiration. These effects were absent in empty vector CHO cells expressing no UCP2. Thus...

Genipin Selectively Inhibits TNF-α-activated VCAM-1 But Not ICAM-1 Expression by Upregulation of PPAR-γ in Human Endothelial Cells

Hwa, Jung Seok; Mun, Lidiya; Kim, Hye Jung; Seo, Han Geuk; Lee, Jae Heun; Kwak, Jong Hwan; Lee, Dong-Ung; Chang, Ki Churl
Fonte: The Korean Physiological Society and The Korean Society of Pharmacology Publicador: The Korean Physiological Society and The Korean Society of Pharmacology
Tipo: Artigo de Revista Científica
EN
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Vascular inflammation process has been suggested to be an important risk factor in the development of atherosclerosis. Recently we reported that induction of peroxisome proliferator-activated receptor-γ (PPAR-γ) selectively inhibits vascular cell adhesion molecule-1 (VCAM-1) but not intercellular cell adhesion molecule-1 (ICAM-1) in tumor necrosis factor (TNF)-α-activated human umbilical vein endothelial cells (HUVEC). In this study, we investigated whether genipin inhibits expression of cellular adhesion molecules, which is relevant to inflammation. Pretreatment with genipin reduced reactive oxygen species (ROS) production and expression of VCAM-1, but not ICAM-1 in TNF-α-activated HUVEC. Genipin dose- and time-dependently increased PPAR-γ expression and inhibited TNF-α-induced phosphorylation of Akt and PKC with different degrees. Finally, genipin prevented TNF-α-induced adhesion of U937 monocytic cells to HUVEC. Taken together, these results indicate that upregualtion of PPAR-γ by genipin selectively inhibits TNF-α-induced expression of VCAM-1, in which regulation of Akt and/or PKC play a key role. We concluded that genipin can be used for the treatment of cardiovascular disorders such as atherosclerosis.

GENIPIN-CROSSLINKED FIBRIN HYDROGELS AS A POTENTIAL ADHESIVE TO AUGMENT INTERVERTEBRAL DISC ANNULUS REPAIR

Schek, R.M.; Michalek, A.J.; Iatridis, J.C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 18/04/2011 EN
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Treatment of damaged intervertebral discs is a significant clinical problem and, despite advances in the repair and replacement of the nucleus pulposus, there are few effective strategies to restore defects in the annulus fibrosus. An annular repair material should meet three specifications: have a modulus similar to the native annulus tissue, support the growth of disc cells, and maintain adhesion to tissue under physiological strain levels. We hypothesized that a genipin crosslinked fibrin gel could meet these requirements. Our mechanical results showed that genipin crosslinked fibrin gels could be created with a modulus in the range of native annular tissue. We also demonstrated that this material is compatible with the in vitro growth of human disc cells, when genipin:fibrin ratios were 0.25:1 or less, although cell proliferation was slower and cell morphology more rounded than for fibrin alone. Finally, lap tests were performed to evaluate adhesion between fibrin gels and pieces of annular tissue. Specimens created without genipin had poor handling properties and readily delaminated, while genipin crosslinked fibrin gels remained adhered to the tissue pieces at strains exceeding physiological levels and failed at 15–30%. This study demonstrated that genipin crosslinked fibrin gels show promise as a gap-filling adhesive biomaterial with tunable material properties...

Genipin Attenuates Sepsis by Inhibiting Toll-Like Receptor Signaling

Kim, Tae-Hoon; Yoon, Seong-Jin; Lee, Sun-Mee
Fonte: ScholarOne Publicador: ScholarOne
Tipo: Artigo de Revista Científica
Publicado em 11/01/2012 EN
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The pathogenesis of sepsis is characterized by overwhelming inflammatory responses that lead to tissue damage and organ failure. Toll-like receptor (TLR) signaling is crucial for induction of hyperinflammatory responses and tissue injury during sepsis. Genipin, an aglycon of geniposide, has antiinflammatory and antimicrobial activities. The purpose of this study was to test the hypothesis that genipin reduces multiple organ dysfunction and mortality during sepsis through inhibition of TLR signaling. Male ICR were subjected to sepsis by cecal ligation and puncture (CLP) or endotoxemia by lipopolysaccharide (LPS). Various doses of genipin (1, 2.5 and 5 mg/kg) or a vehicle were administered intravenously immediately after CLP or intraperitoneally after LPS treatment. In another set of survival tests, mice were treated with 2.5 mg/kg of genipin 0 and 24 h after CLP. Genipin was found to improve survival and to attenuate multiple organ dysfunction. Genipin attenuated production of proinflammatory cytokines and release of high-mobility group box 1 (HMGB1). Genipin prevented TLR2 and TLR4, myeloid differentiation factor 88 and the Toll/interleukin-1 receptor domain-containing adaptor protein, inducing interferon-β overexpression. Phosphorylation of mitogen-activated protein kinases and interferon regulatory factor 3 and translocation of nuclear factor (NF)-κB were prevented by genipin. Moreover...

Genipin Inhibits Mitochondrial Uncoupling Protein 2 Expression and Ameliorates Podocyte Injury in Diabetic Mice

Qiu, Wenjing; Zhou, Yang; Jiang, Lei; Fang, Li; Chen, Lu; Su, Weifang; Tan, Ruoyun; Zhang, Chen-yu; Han, Xiao; Yang, Junwei
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/07/2012 EN
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Diabetic nephropathy (DN) is one of the most common causes of end stage renal disease (ESRD) in China, which requires renal replacement therapy. Recent investigations have suggested an essential role of podocyte injury in the initial stage of DN. This study investigated the potential therapeutic role of genipin, an active extract from a traditional Chinese medicine, on progression of DN in diabetic mice induced by intraperitoneally injection of streptozocin (STZ). In diabetic mice, orally administration of genipin postponed the progression of DN, as demonstrated by ameliorating body weight loss and urine albumin leakage, attenuating glomerular basement membrane thickness, restoring the podocyte expression of podocin and WT1 in diabetic mice. The protective role of genipin on DN is probably through suppressing the up-regulation of mitochondrial uncoupling protein 2 (UCP2) in diabetic kidneys. Meanwhile, through inhibiting the up-regulation of UCP2, genipin restores podocin and WT1 expression in cultured podocytes and attenuates glucose-induced albumin leakage through podocytes monolayer. Therefore, these results revealed that genipin inhibited UCP2 expression and ameliorated podocyte injury in DN mice.

Metabolism of Genipin in Rat and Identification of Metabolites by Using Ultraperformance Liquid Chromatography/Quadrupole Time-of-Flight Tandem Mass Spectrometry

Ding, Yue; Hou, Jian-Wei; Zhang, Yong; Zhang, Li-Ying; Zhang, Tong; Chen, Yi; Cai, Zhen-Zhen; Yang, Li
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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The in vivo and in vitro metabolism of genipin was systematically investigated in the present study. Urine, plasma, feces, and bile were collected from rats after oral administration of genipin at a dose of 50 mg/kg body weight. A rapid and sensitive method using ultraperformance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF MS) was developed for analysis of metabolic profile of genipin in rat biological samples (urine, plasma, feces, and bile). A total of ten metabolites were detected and identified by comparing their fragmentation patterns with that of genipin using MetaboLynx software tools. On the basis of the chromatographic peak area, the sulfated and glucuronidated conjugates of genipin were identified as major metabolites. And the existence of major metabolites G1 and G2 was confirmed by the in vitro enzymatic study further. Then, metabolite G1 was isolated from rat bile by semipreparative HPLC. Its structure was unambiguously identified as genipin-1-o-glucuronic acid by comparison of its UV, IR, ESI-MS, 1H-NMR, and 13C-NMR spectra with conference. In general, genipin was a very active compound that would transform immediately, and the parent form of genipin could not be observed in rats biological samples. The biotransformation pathways of genipin involved demethylated...

DIFFERENTIAL CROSS-LINKING AND RADIO-PROTECTIVE EFFECTS OF GENIPIN ON MATURE BOVINE AND HUMAN PATELLA TENDONS

Ng, Kenneth W.; Wanivenhaus, Florian; Chen, Tony; Abrams, Valarian D.; Torzilli, Peter A.; Warren, Russell F.; Maher, Suzanne A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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Gamma irradiation is a proven sterilization method, but is not widely used on allografts for anterior cruciate ligament (ACL) reconstruction (e.g., patella tendon) due to radiation-induced decreases in mechanical strength. Addressing this drawback would improve the safety and supply of allografts to meet current and future demand. It was hypothesized that genipin-induced collagen cross-linking would increase the tensile modulus of patella tendon tissue such that 5 MRad gamma irradiation would not reduce the tissue mechanical strength below the original untreated values. Optimized genipin treatment increased the tensile modulus of bovine tendons by ~2.4-fold. After irradiation, genipin treated tissue did not significantly differ from native tissue, proving the hypothesis. Optimized genipin treatment of human tendons increased the tensile modulus by ~1.3-fold. After irradiation, both control and genipin-treated tissues possessed ~50–60% of their native tendon modulus, disproving the hypothesis. These results highlight possible age- and species-dependent effects of genipin cross-linking on tendon tissue. Cross-linking of human allografts may be beneficial only in younger donor tissues. Future research is warranted to better understand the mechanisms and applications of collagen cross-linking for clinical use.

Genipin Inhibits TNF-α-Induced Vascular Smooth Muscle Cell Proliferation and Migration via Induction of HO-1

Jiang, Fengrong; Jiang, Rilei; Zhu, Xiaojia; Zhang, Xu; Zhan, Zhan
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 27/08/2013 EN
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Vascular smooth muscle cell (VSMC) proliferation and migration triggered by inflammatory stimuli contributes importantly to the pathogenesis of atherosclerosis and restenosis. On the other hand, genipin, an aglycon of geniposide, exhibits diverse pharmacological functions such as antitumor and anti-inflammatory effects. The protective effects of genipin on the cardiovascular system have also been reported. However, the molecular mechanism involved remains unknown. This study aimed to elucidate the precise function of genipin in VSMCs, focusing particularly on the role of heme oxygenase-1 (HO-1), a potent anti-inflammatory enzyme. We found that pretreatment of genipin induced HO-1 mRNA and protein levels, as well as its activity in VSMCs. Genipin inhibited TNF-α-induced VSMC proliferation and migration in a dose-dependent manner. At the molecular level, genipin prevented ERK/MAPK and Akt phosphorylation while left p38 MAPK and JNK unchanged. Genipin also blocked the increase of ROS generation induced by TNF-α. More importantly, the specific HO-1 siRNA partially abolished the beneficial effects of genipin on VSMCs. These results suggest that genipin may serve as a novel drug in the treatment of these pathologies by inducing HO-1 expression/activity and subsequently decreasing VSMC proliferation and migration.

Protective Effects of Geniposide and Genipin against Hepatic Ischemia/Reperfusion Injury in Mice

Kim, Joonki; Kim, Hyo-Yeon; Lee, Sun-Mee
Fonte: The Korean Society of Applied Pharmacology Publicador: The Korean Society of Applied Pharmacology
Tipo: Artigo de Revista Científica
Publicado em /03/2013 EN
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Geniposide is an active product extracted from the gardenia fruit, and is one of the most widely used herbal preparations for liver disorders. This study examined the cytoprotective properties of geniposide and its metabolite, genipin, against hepatic ischemia/reperfusion (I/R) injury. C57BL/6 mice were subjected to 60 min of ischemia followed by 6 h of reperfusion. Geniposide (100 mg/kg) and genipin (50 mg/kg) were administered orally 30 min before ischemia. In the I/R mice, the levels of serum alanine aminotransferase and hepatic lipid peroxidation were elevated, whereas hepatic glutathione/glutathione disulfide ratio was decreased. These changes were attenuated by geniposide and genipin administration. On the other hand, increased hepatic heme oxygenase-1 protein expression was potentiated by geniposide and genipin administration. The increased levels of tBid, cytochrome c protein expression and caspase-3 activity were attenuated by geniposide and genipin. Increased apoptotic cells in the I/R mice were also significantly reduced by geniposide and genipin treatment. Our results suggest that geniposide and genipin offer significant hepatoprotection against I/R injury by reducing oxidative stress and apoptosis.

Preliminary Characterization of Genipin-Cross-Linked Silk Sericin/Poly(vinyl alcohol) Films as Two-Dimensional Wound Dressings for the Healing of Superficial Wounds

Siritientong, Tippawan; Ratanavaraporn, Juthamas; Srichana, Teerapol; Aramwit, Pornanong
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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The genipin-cross-linked silk sericin/poly(vinyl alcohol) (PVA) films were developed aiming to be applied as two-dimensional wound dressings for the treatment of superficial wounds. The effects of genipin cross-linking concentration on the physical and biological properties of the films were investigated. The genipin-cross-linked silk sericin/PVA films showed the increased surface density, tensile strength, and percentage of elongation, but decreased percentage of light transmission, water vapor transmission rate, and water swelling, compared to the non-cross-linked films. This explained that the cross-linking bonds between genipin and silk sericin would reduce the mobility of molecular chains within the films, resulting in the more rigid molecular structure. Silk sericin was released from the genipin-cross-linked films in a sustained manner. In addition, either L929 mouse fibroblast or HaCat keratinocyte cells showed high percentage of viability when cultured on the silk sericin/PVA films cross-linked with 0.075 and 0.1% w/v genipin. The in vivo safety test performed according to ISO 10993-6 confirmed that the genipin-cross-linked silk sericin/PVA films were safe for the medical usages. The efficacy of the films for the treatment of superficial skin wounds will be further investigated in vivo and clinically. The genipin-cross-linked silk sericin/PVA films would be promising choices of two-dimensional wound dressings for the treatment of superficial wounds.

Temperature-Responsive Gelation of Type I Collagen Solutions Involving Fibril Formation and Genipin Crosslinking as a Potential Injectable Hydrogel

Yunoki, Shunji; Ohyabu, Yoshimi; Hatayama, Hirosuke
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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We investigated the temperature-responsive gelation of collagen/genipin solutions using pepsin-solubilized collagen (PSC) and acid-solubilized collagen (ASC) as substrates. Gelation occurred in the PSC/genipin solutions at genipin concentrations 0–2 mM under moderate change in temperature from 25 to 37°C. The PSC/genipin solutions exhibited fluidity at room temperature for at least 30 min, whereas the ASC/genipin solutions rapidly reached gel points. In specific cases PSC would be preferred over ASC as an injectable gel system. The temperature-responsive gelation of PSC/genipin solutions was due to temperature responses to genipin crosslinking and collagen fibril formation. The elastic modulus of the 0.5% PSC/genipin gel system could be adjusted in a range of 2.5 to 50 kPa by the PSC and genipin concentrations, suggesting that a PSC/genipin solution is a potential injectable gel system for drug and cell carriers, with mechanical properties matching those of living tissues.

Preparation and characterization of genipin-cross-linked silk fibroin/chitosan sustained-release microspheres

Zeng, Shuguang; Ye, Manwen; Qiu, Junqi; Fang, Wei; Rong, Mingdeng; Guo, Zehong; Gao, Wenfen
Fonte: Dove Medical Press Publicador: Dove Medical Press
Tipo: Artigo de Revista Científica
Publicado em 04/05/2015 EN
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We report the effects of distinct concentrations of genipin and silk fibroin (SF):chitosan (CS) ratios on the formation of SF–CS composite microspheres. We selected microspheres featuring an SF:CS ratio of 1:1, encapsulated various concentrations of bovine serum albumin (BSA), and then compared their encapsulation efficiency and sustained-release rate with those of pure CS microspheres. We determined that the following five groups of microspheres were highly spherical and featured particle sizes ranging from 70 μm to 147 μm: mass ratio of CS:SF =1:0.5, 0.1 g or 0.5 g genipin; CS:SF =1:1, 0.05 g or 1 g genipin; and CS:SF =1:2, 0.5 g genipin. The microspheres prepared using 1:1 CS:SF ratio and 0.05 g genipin in the presence of 10 mg, 20 mg, and 50 mg of BSA exhibited encapsulation efficiencies of 50.16%±4.32%, 56.58%±3.58%, and 42.19%±7.47%, respectively. Fourier-transform infrared spectroscopy (FTIR) results showed that SF and CS were cross-linked and that the α-helices and random coils of SF were converted into β-sheets. BSA did not chemically react with CS or SF. Moreover, thermal gravimetric analysis (TGA) results showed that the melting point of BSA did not change, which confirmed the FTIR results, and X-ray diffraction results showed that BSA was entrapped in microspheres in a noncrystalline form...

Extracción, caracterización y valoración de genipina a partir del fruto de la Genipa Americana

Álvarez Ochoa, Giselle
Fonte: Universidad Icesi; Facultad de Ciencias Naturales; Química Farmacéutica; Ciencias Químicas Publicador: Universidad Icesi; Facultad de Ciencias Naturales; Química Farmacéutica; Ciencias Químicas
Tipo: bachelorThesis; Trabajo de grado Formato: pdf; 54 p.; Electrónico
SPA
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Este trabajo explora la extracción eficiente de genipina de alta pureza a partir del fruto verde del árbol Genipa americana empleando un método de extracción sencillo y económico y la caracterización de la genipina obtenida mediante técnicas instrumentales. El árbol Genipa americana, es nativo de América Central y América del sur tropical, por lo que presenta un gran potencial de aprovechamiento en la industrialización de los frutos como alternativa para la extracción de la genipina. Los frutos verdes de Genipa americana se recolectaron en la ciudad de Buga, Valle del Cauca, Colombia. Se seleccionó como método de extracción la extracción líquido-líquido asistida por ultrasonido, empleando como solvente acetato de etilo, la separación se realiza mediante cromatografía flash, la valoración de la genipina obtenida se realizó por Cromatografía Líquida de Ultra alta eficiencia (UPLC) con detector de matriz de fotodiodos (PDA) y su caracterización por las siguientes técnicas instrumentales: Espectrometría de Masas con Ionización por Electrospray (ESI-MS), Espectroscopía Infrarroja con Transformada de Fourier (FTIR), UPLC y Espectroscopía de Resonancia Magnética Nuclear (RMN) unidimensional y bidimensional. A partir de los resultados obtenidos se encontró que empleando el método descrito se logró la extracción de genipina de alta pureza a partir del fruto de la Genipa americana con un porcentaje de rendimiento del 45%...

Effect of genipin crosslinking on the optical spectral properties and structures of collagen hydrogels

Hwang, Yu-Jer; Larsen, Jillian; Krasieva, Tatiana B.; Lyubovitsky, Julia G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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Genipin, a natural cross-linking reagent extracted from the fruits of Gardenia jasminoides, can be effectively employed in tissue engineering applications due to its low cytotoxicity and high biocompatibility. The cross-linking of collagen hydrogels with genipin was followed with one-photon fluorescence spectroscopy, second harmonic generation, fluorescence and transmission electron microscopy. The incubation with genipin induced strong auto-fluorescence within the collagen hydrogels. The fluorescence emission maximum of the fluorescent adducts formed by genipin exhibit a strong dependence on the excitation wavelength. The emission maximum is at 630 nm when we excite the cross-linked samples with 590 nm light and shifts to 462 nm when we use 400 nm light instead. The fluorescence imaging studies show that genipin induces formation of long aggregated fluorescent strands throughout the depth of samples. The second harmonic generation (SHG) imaging studies suggest that genipin partially disaggregates 10 μm ‘fiber-like’ collagen structures due to the formation of these fluorescent cross-links. Transmission electron microscopy (TEM) studies reveal that genipin largely eliminates collagen's characteristic native fibrillar striations. Our study is the first one to non-destructively follow and identify the structure within collagen hydrogels in situ and to sample structures formed on both micro- and nano-scales. Our findings suggest that genipin cross-linking of collagen follows a complex mechanism and this compound modifies the structure within the collagen hydrogels in both micro- and nano-scale.

Genipin inhibits NLRP3 and NLRC4 inflammasome activation via autophagy suppression

Yu, Shui-Xing; Du, Chong-Tao; Chen, Wei; Lei, Qian-Qian; Li, Ning; Qi, Shuai; Zhang, Xiao-Jing; Hu, Gui-Qiu; Deng, Xu-Ming; Han, Wen-Yu; Yang, Yong-Jun
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Text
Publicado em 11/12/2015 EN
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Inflammasomes are cytoplasmic, multiprotein complexes that trigger caspase-1 activation and IL-1β maturation in response to diverse stimuli. Although inflammasomes play important roles in host defense against microbial infection, overactive inflammasomes are deleterious and lead to various autoinflammatory diseases. In the current study, we demonstrated that genipin inhibits the induction of IL-1β production and caspase-1 activation by NLRP3 and NLRC4 inflammasomes. Furthermore, genipin specifically prevented NLRP3-mediated, but not NLRC4-mediated, ASC oligomerization. Notably, genipin inhibited autophagy, leading to NLRP3 and NLRC4 inflammasome inhibition. UCP2-ROS signaling may be involved in inflammasome suppression by genipin. In vivo, we showed that genipin inhibited NLRP3-dependent IL-1β production and neutrophil flux in LPS- and alum-induced murine peritonitis. Additionally, genipin provided protection against flagellin-induced lung inflammation by reducing IL-1β production and neutrophil recruitment. Collectively, our results revealed a novel role in inhibition of inflammatory diseases for genipin that has been used as therapeutics for centuries in herb medicine.