Preparation of a genipin blue from egg protein and genipin

Effect of different crosslinking agents on hybrid chitosan/collagen hydrogels for potential tissue engineering applications

Tissue engineering (TE) demands scaffolds that have the necessary resistance to withstand the mechanical stresses once implanted in our body, as well as excellent biocompatibility. Hydrogels are postulated as interesting materials for this purpose, especially those made from biopolymers. In this study, the microstructure and rheological performance, as well as functional and biological properties of chitosan and collagen hydrogels (CH/CG) crosslinked with different coupling agents, both natural such as d-Fructose (F), genipin (G) and transglutaminase (T) and synthetic, using a combination of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride with N-hydroxysuccinimide (EDC/NHS) will be assessed. FTIR tests were carried out to determine if the proposed crosslinking reactions for each crosslinking agent occurred as expected, obtaining positive results in this aspect. Regarding the characterization of the properties of each system, two main trends were observed, from which it could be established that crosslinking with G and EDC-NHS turned out to be more effective and beneficial than with the other two crosslinking agents, producing significant improvements with respect to the base CH/CG hydrogel. In addition, in vitro tests demonstrated the potential application in TE of these systems, especially for those crosslinked with G, T and EDC-NHS.

Genipa americana L.: A New Phytochemical for White Hair Coloring

This work describes a new hair dyeing methodology using a chemical reaction between geniposide, an iridoid glycoside extracted from the fruit of Genipa americana (geniposide extract, GE) and the amine group of hair keratin. The influence of reaction conditions (pH, temperature, and extract concentration) on the staining of hair fibers, color development, fiber morphology, and mechanical hair properties of black and white human hair samples, was evaluated before and after GE dyeing treatment. Eye contact safety of GE was also studied using HET-CAM. The treatment of white hair fibers using GE at 20 mg mL-1 , temperature of 80 °C and pH 5.5 presented the greatest color change (ΔE=54.0). The higher pH influence was observed at pH 10.0 on white hair tresses (ΔE=6.8), using an GE concentration of 20 mg mL-1 and room temperature (25 °C). Treated samples showed marked changes on mechanical and morphological properties. The HET-CAM did not show any change, thus demonstrating that using GE is safe. In conclusion, the temperature and concentration of the extract were the variables that mostly influenced the color and hair damage. A new approach for hair dyeing was established where iridoids may potentially be useful as a natural hair dyeing.

High efficiency biosynthesis of gardenia blue and red pigment by lactic acid bacteria: A great potential for natural color pigments

Current production methods of the food colorants, gardenia blue (GB) and red (GR) pigments have low efficiency. One potential approach involves using lactic acid bacteria (LAB), which produce a high level of β-glucosidase, produce the GB and GR using non-toxic and harmless process. The isolated strain Lactobacillus plantarum S3 and the reference strain Lb. plantarum KCTC3104 showed high β-glucosidase activity levels of 1.01 and 1.44 unit/mL, respectively. The 12-h bioconversion yield of geniposide to genipin using two strains were 93.4% and 100%, respectively, which are high conversion percentage. For GB, the maximal production yield obtained using Lb. plantarum S3 and Lb. plantarum KCTC3104 under optimal conditions were 2.17 and 2.18 mg/mL, respectively. For GR, glutamic acid (Glu) with Lb. plantarum S3 is the best combination. To the best of our knowledge, this is the first report of an effective alternative method for the production of natural food colorants using LAB.

Fabrication of a Gelatin-Based Microdevice for Vascular Cell Culture

This study presents a novel technique for fabricating microfluidic devices with microbial transglutaminase-gelatin gels instead of polydimethylsiloxane (PDMS), in which flow culture simulates blood flow and a capillary network is incorporated for assays of vascular permeability or angiogenesis. We developed a gelatin-based device with a coverslip as the bottom, which allows the use of high-magnification lenses with short working distances, and we observed the differences in cell dynamics on gelatin, glass, and PDMS surfaces. The tubes of the gelatin microfluidic channel are designed to be difficult to pull out of the inlet hole, making sample introduction easy, and the gelatin channel can be manipulated from the cell introduction to the flow culture steps in a manner comparable to that of a typical PDMS channel. Human umbilical vein endothelial cells (HUVECs) and normal human dermal fibroblasts (NHDFs) were successfully co-cultured, resulting in structures that mimicked blood vessels with inner diameters ranging from 10 µm to 500 µm. Immunostaining and scanning electron microscopy results showed that the affinity of fibronectin for gelatin was stronger than that for glass or PDMS, making gelatin a suitable substrate for cell adhesion. The ability for microscopic observation at high magnification and the ease of sample introduction make this device easier to use than conventional gelatin microfluidics, and the above-mentioned small modifications in the device structure are important points that improve its convenience as a cell assay device.

Preparation and Characterization of Water-Insoluble Gardenia Blue Pigment

Based on molecular simulations, the synthetic route of water-insoluble gardenia blue pigment was prepared by the reaction of genipin and L-Phenylalanine methyl ester hydrochloride. A highly purified pigment was obtained after extraction by chloroform and purification by silica gel column chromatography, and the value of color is up to 288. A study on the structural characteristics of the pigment was implemented with a scanning electron microscope, ultraviolet-visible spectrophotometer, Fourier transform infrared spectrometer, X-ray photoelectron spectrometer, and quatropde-time of flight mass spectrometer. The results showed that the surface of the pigment was largely smooth and spherical; The λ_max was 607 nm, and the main functional groups include O-C=O, C=O, C-N, C=C, OH, and benzene ring; We detrained six different molecular weight and chemical structures of pigments and speculated the particular structures and formation mechanisms of three kinds of pigment, whose molecular weights are 690.1156, 720.1226, and 708.1246 Da, respectively. The pigment was only able to be dissolved in ethanol, methanol, acetone, ethyl acetate, and other strong polar organic solvents, but was not able to be dissolved in water, ethyl ether, petroleum ether, and other weak polar organic solvents. In terms of light and thermal stabilities, water-insoluble gardenia blue pigment is significantly better than water-soluble gardenia blue pigment (p < 0.05). When it is under direct light for 7 days or incubated at 80-120 °C for 24 h, the pigment residual rates were 74.90, 95.26, 88.27, and 87.72%, respectively.

Expression of heat-resistant β-glucosidase in Escherichia coli and its application in the production of gardenia blue

Gardenia blue is a natural blue pigment that is environmentally friendly, non-toxic, and stable. The hydrolysis of geniposide, catalyzed by β-glucosidase, is a critical step in the production process of gardenia blue. However, β-glucosidase is not resistant to high temperatures, limiting the production of gardenia blue. In this study, we investigated the effectiveness of a heat-resistant glucosidase obtained from Thermotoga maritima in the production of gardenia blue. The enzyme exhibited a maximum activity of 10.60 U/mL at 90 °C. Single-factor and orthogonal analyses showed that exogenously expressed heat-resistant glucosidase reacted with 470.3 μg/mL geniposide and 13.5 μg/mL glycine at 94.2 °C, producing a maximum yield of 26.2857 μg/mL of gardenia blue after 156.6 min. When applied to the dyeing of denim, gardenia blue produced by this method yielded excellent results; the best color-fastness was achieved when an iron ion mordant was used. This study revealed the feasibility and application potential of microbial production of gardenia blue.

Gardenia jasminoides Ellis: Ethnopharmacology, phytochemistry, and pharmacological and industrial applications of an important traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Gardenia jasminoides Ellis is a popular shrub in the Rubiaceae family. The desiccative ripe fruits of this plant (called Zhizi in China) are well known and frequently used not only as an excellent natural colourant, but also as an important traditional medicine for the treatment of different diseases, such as reducing fire except vexed, clearing away heat evil, and cooling blood and eliminating stasis to activate blood circulation. It has also been declared as the first batch of dual-purpose plants used for food and medical functions in China.

AIM OF THE STUDY

This review aims to provide a critical and systematic summary of the traditional uses, ethnopharmacology, phytochemistry, pharmacology, toxicity and industrial applications of Gardenia jasminoides Ellis and briefly proposes several suggestions for future application prospects.

MATERIALS AND METHODS

The related information on Gardenia jasminoides Ellis was obtained from internationally recognized scientific databases through the Internet (PubMed, CNKI, Google Scholar, Baidu Scholar, Web of Science, Medline Plus, ACS, Elsevier and Flora of China) and libraries.

RESULTS

Approximately 162 chemical compounds have been isolated and identified from this herb. Among them, iridoid glycosides and yellow pigment are generally considered the main bioactive and characteristic ingredients. Various pharmacological properties, such as a beneficial effect on the nervous, cardiovascular and digestive systems, hepatoprotective activity, antidepressant activity, and anti-inflammatory activity, were also validated in vitro and in vivo. Moreover, geniposide and genipin are the most important iridoid compounds isolated from Gardenia jasminoides Ellis, and genipin is the aglycone of geniposide. As the predominant active ingredient with a distinct pharmacological activity, genipin is also an outstanding biological crosslinking agent. Gardenia yellow pigment has also been widely used as an excellent natural dye-stuff. Hence, Gardenia jasminoides Ellis has been applied to many other fields, including the food industry, textile industry and chemical industry, in addition to its predominant medicinal uses.

CONCLUSIONS

According to this review, Gardenia jasminoides Ellis is outstanding traditional medical plant used in medicine and food. Pharmacological investigations support the traditional use of this herb and may validate the folk medicinal use of Gardenia jasminoides Ellis to treat different diseases. Iridoid glycosides are potential medicines. Gardenia yellow pigment has been the most important source of a natural colourant for food, cloth and paint for thousands of years. This herb has made great contributions to human survival and development. Moreover, it has also achieved outstanding progress in human life and even in art. Although Gardenia jasminoides Ellis has extremely high and comprehensive utilization values, it is still far from being completely explored. Therefore, the comprehensive development of Gardenia jasminoides Ellis deserves further analysis.

Expression of a highly active β-glucosidase from Aspergillus niger AS3.4523 in Escherichia coli and its application in gardenia blue preparation

Purpose

Gardenia blue is one of the natural food additives used in East Asia for many years. Its biosynthesis relies on a key rate-limiting cellulase: β-glucosidase (BGL), which mainly exists in Aspergillus niger (A. niger) cells. The purpose of this study was to obtain active β-glucosidase by cell engineering method and applied to gardenia blue synthesis, which would help to promote the application and reduce the cost of β-glucosidase and gardenia blue.

Methods

A. niger was identified based on 18S rRNA gene sequencing. β-Glucosidase gene was cloned and expressed based on PCR and prokaryotic expression. The enzyme activity of β-glucosidase was measured based on p-nitrophenyl-β-D-glucopyranoside method.

Results

An A. niger isolate (AS3.4523) was identified from soil. The β-glucosidase gene of AS3.4523 was cloned and sequenced, which encoded a new type of β-glucosidase mutant containing two specific amino acid substitutions (Asp154Gly and Ser163Pro). Prokaryotic expression of wild-type β-glucosidase in Escherichia coli BL21 showed low cellulase activity (0.29 ± 0.13 U/mL). However, after removing its signal peptide, the β-glucosidase of A. niger AS3.4523 exhibited extremely higher activity (25.88 ± 0.45 U/mL) compared with wild type β-glucosidase (12.59 ± 1.07 U/mL) or other A. niger strains M85 (3.61 ± 0.24 U/mL) and CICC2041 (4.36 ± 0.76 U/mL). Furthermore, recombinant β-glucosidase was applied to geniposide hydrolysis, and gardenia blue pigment was successfully synthesized with the reaction of genipin and Lys.

Conclusions

This work has discovered a new type of highly active β-glucosidase and provided a theoretical basis for large-scale producing β-glucosidase, which lays a brand-new foundation for gardenia blue preparation with high efficiency and low cost.

Jagua blue derived from Genipa americana L. fruit: A natural alternative to commonly used blue food colorants?

Due to consumers' increasing health awareness, food industry aims at replacing synthetic dyes by natural counterparts. The substitution of blue synthetic dyes is particularly challenging since current natural alternatives such as phycocyanin (Spirulina) suffer from poor stability. Jagua blue (produced from Genipa americana L. fruit) might represent a potential novel blue pigment source. However, only little is known about its color properties, and application in food systems. Therefore, the blue color and the stability of Jagua blue were assessed for the first time and compared to commonly used colorants, namely, Spirulina, brilliant blue FCF (Blue no. 1), and indigo carmine (Blue no. 2). The reaction rate of Jagua blue was independent of its concentration, confirming thermal degradation to follow first-order kinetics. Between pH 3.6 and 5.0, the color hue of Jagua blue solutions was similar to that of Blue no. 2. However, Jagua blue revealed markedly higher storage stabilities (t_1/2=86-105days) than Blue no. 2 (t_1/2≤9days) and was less susceptible to acidic pH of 3.6 (t_1/2=86days) than Spirulina (t_1/2=70days). High negative b* values (blueness) of colored gelatin gels were only obtained for Jagua blue and Spirulina, and the former exhibited higher light stabilities (t_1/2=15days) than Spirulina gels (t_1/2=4days). Our findings indicate Jagua blue to be a most promising alternative to synthetic dyes, providing relevant information regarding potential food applications.