Application of L-Cysteine Hydrochloride Delays the Ripening of Harvested Tomato Fruit.

Fruit ripening is controlled by internal factors such as hormones and genetic regulators, as well as external environmental factors. However, the impact of redox regulation on fruit ripening remains elusive. Here, we explored the effects of L-cysteine hydrochloride (LCH), an antioxidant, on tomato fruit ripening and elucidated the underlying mechanism. The application of LCH effectively delayed tomato fruit ripening, leading to the suppression of carotenoid and lycopene biosynthesis and chlorophyll degradation, and a delayed respiration peak. Moreover, LCH-treated fruit exhibited reduced hydrogen peroxide (H2O2) accumulation and increased activities of superoxide dismutase (SOD), catalase (CAT), and monodehydroascorbate reductase (MDHAR), compared with control fruit. Furthermore, transcriptome analysis revealed that a substantial number of genes related to ethylene biosynthesis (ACS2, ACS4, ACO1, ACO3), carotenoid biosynthesis (PSY, PDS, ZDS, CRTISO), cell wall degradation (PG1/2, PL, TBG4, XTH4), and ripening-related regulators (RIN, NOR, AP2a, DML2) were downregulated by LCH, resulting in delayed ripening. These findings suggest that the application of LCH delays the ripening of harvested tomato fruit by modulating the redox balance and suppressing the expression of ripening-related genes.

Spectrophotometric Determination of Cysteine Hydrochloride Content by Ferric Chloride-Potassium Ferricyanide.

In the acidic medium, hydrosulfuryl(-SH) in cysteine hydrochloride can reduce Fe3+ to Fe2+, then Fe2+ react with potassium ferricyanide to form KFe[Fe(CN)6](soluble Prussian blue). Prussian blue has a maximum absorption at 727 nm, Bill's law is observed between mass concentration of cysteine hydrochloride and absorbance of Prussian blue, the content of cysteine hydrochloride is indirectly determinated by measuring the absorbance of Prussian blue. An accurate, simple, fast spectrophotometric method for the determination of cysteine hydrochloride content by ferric chloride-potassium ferricyanide has been established. The optimal determination conditions of cysteine hydrochloride content are explored. The cysteine hydrochloride content is determinate by this method.

L-Cysteine hydrochloride inhibits Aspergillus flavus growth and AFB1 synthesis by disrupting cell structure and antioxidant system balance.

Aflatoxin B1 (AFB1) is the most potent known naturally occurring carcinogen and pose an immense threat to food safety and human health. L-Cysteine hydrochloride (L-CH) is a food additive often used as a fruit and vegetable preservative and also to approved bread consistency. In this study, we investigated the effects and mechanisms of L-CH as an antimicrobial on the growth of Aspergillus flavus (A. flavus) and AFB1 biosynthesis. L-CH significantly inhibited A. flavus mycelial growth, affected mycelial morphology and AFB1 synthesis. Furthermore, L-CH induced glutathione (GSH) synthesis which scavenged intracellular reactive oxygen species (ROS). RNA-Seq indicated that L-CH inhibited hyphal branching, and spore and sclerotia formation by controlling cell wall and spore development-related genes. Activation of the GSH metabolic pathway eliminated intracellular ROS, leading to hyphal dwarfing. L-CH treatment downregulated most of the Aflatoxin (AF) cluster genes and aflS, aflR, AFLA_091090 transcription factors. This study provides new insights into the molecular mechanism of L-CH control of A. flavus and AFB1 foundation. We believe that L-CH could be used as a food additive to control AFB1 in foods and also in the environment.

Green Synthesis of Crystalline Silica from Sugarcane Bagasse Ash: Physico-Chemical Properties.

Sugarcane bagasse South Africa is an agricultural waste that poses many environmental and human health problems. Sugarcane bagasse dumps attract many insects that harm the health of the population and cause many diseases. Sugarcane ash is a naturally renewable source of silica. This study presents for the first time the extraction of nanosilica from sugar cane bagasse ash using L-cysteine hydrochloride monohydrate acid and Tetrapropylammonium Hydroxide. The structural, morphological, and chemical properties of the extracted silica nanoparticles was cross examined using XRD, FTIR, SEM, and TGA. SEM analysis presents agglomerates of irregular sizes. It is possible to observe the structure of nanosilica formed by the presence of agglomerates of irregular shapes, as well as the presence of some spherical particles distributed in the structure. XRD analysis has revealed 2θ angles at 20, 26, 36, 39, 50, and 59 which shows that each peak on the xrd pattern is indicative of certain crystalline cubic phases of nanosilica, similar to results reported in the literature by Jagadesh et al. in 2015. The crystallite size estimated by the Scherrer equation based on the aforementioned peaks for ca-silica and L-cys-silica for the extracted particles had an average diameter of 26 nm and 29 nm, respectively. Furthermore, it showed a specific surface area of 21.6511 m2/g and 116.005 m2/g for ca-silica and L-cys silica, respectively. The Infrared (IR) spectra showed peaks at 461.231 cm-1, 787.381 cm-1 and 1045.99 cm-1 which corresponds to the Si~O~Si bending vibration, the Si~O~Si stretch vibration, and the Si~O~Si stretching vibration, respectively. This confirms the successful extraction of nanosilica from sugar cane bagasse ash. TGA analysis has revealed that the as received sugarcane bagasse has high loss on ignition (LOI) of 18%, corresponding to the presence of the unburnt or partial burnt particles, similar to results reported by Yadav et al. This study has shown that sugar cane bagasse ash is a natural resource of silica which should be harnessed for industrial purposes in south Africa.

Combination of monoammonium glycyrrhizinate and cysteine hydrochloride protects mice against acetaminophen-induced liver injury via Keap1/Nrf2/ARE pathway.

OBJECTIVES: Acetaminophen (APAP) overdose has been the primary cause of drug-induced liver injury (DILI) in western countries. Monoammonium glycyrrhizinate (MG) is a primary active ingredient from glycyrrhiza. Cysteine hydrochloride (CH) is a component of glutathione (GSH). The study aimed to explore the therapeutical effect of MG-CH against DILI incurred by intragastric APAP. METHODS: Mice were randomized into eight groups: control, APAP, three groups accepted APAP and the combination of MG and CH (15, 30, 60 mg/kg), two groups accepted APAP and MG (40 mg/kg) or CH (20 mg/kg), moreover, one group received MG-CH (60 mg/kg) without APAP. After pretreatment with MG-CH or MG and CH alone for 3 days, mice were administered APAP by oral gavage. The serum and tissue were collected to detect the activities of liver enzymes and evaluate the change of histomorphology and explore the possible mechanism of MG-CH in protecting against DILI. KEY FINDINGS: MG-CH pretreatment remarkably alleviated hepatic injury and decreased the activities of ALT, AST, ALP and LDH. The hepatic ROS and MDA contents were decreased, and the level of GSH and GSH-PX activities was increased in the serum. Furthermore, MG-CH improved the expression of Nrf2, HO-1, GCLM and NQO1 to increase antioxidant ability and induce detoxification. The expression of IL-10 suppressing excessive inflammatory responses was enhanced. CONCLUSION: The study demonstrated that MG-CH had protective effects against DILI induced by APAP and the potential mechanisms were based on inhibiting oxidative stress and activating the Keap1/Nrf2/ARE pathway.

Effects of fructans and probiotics on the inhibition of Klebsiella oxytoca and the production of short-chain fatty acids assessed by NMR spectroscopy.

Generally, the selection of fructans prebiotics and probiotics for the formulation of a symbiotic has been based on arbitrary considerations and in vitro tests that fail to take into account competitiveness and other interactions with autochthonous members of the intestinal microbiota. However, such analyzes may be a valuable step in the development of the symbiotic. The present study, therefore, aims to investigate the effect of lactobacilli strains and fructans (prebiotic compounds) on the growth of the intestinal competitor Klebsiella oxytoca, and to assess the correlation with short-chain fatty acids production. The short-chain fatty acids formed in the fermentation of the probiotic/prebiotic combination were investigated using NMR spectroscopy, and the inhibitory activities were assessed by agar diffusion and co-culture methods. The results showed that Lactobacillus strains can inhibit K. oxytoca, and that this antagonism is influenced by the fructans source and probably associated with organic acid production.

Far-infrared terahertz properties of L-cysteine and its hydrochloride monohydrate.

As the building blocks of proteins, amino acids serve vital metabolic functions in addition to protein synthesis and thus attract enormous interest. Here we reported the far-infrared optical properties of L-cysteine (Lcys) and its hydrochloride monohydrate (LCHM) characterized by terahertz time-domain spectroscopy. The Lcys and LCHM exhibit quite distinct characteristics in the terahertz region due to diverse collective vibrations of the molecules, which is further confirmed by the solid-state density functional theory (DFT) calculations. The presented studies indicate that the intermolecular hydrogen bonds play a critical role in the far-infrared terahertz response of Lcys and LCHM.

Smartphone-based Ellman's colourimetric methods for the analysis of d-penicillamine formulation and thiolated polymer.

A new, smartphone-based colourimetric method for the assay of d-penicillamine formulations relying on the Ellman's reaction was developed by performing the colourimetric reaction in a microplate. Subsequently, the plate was positioned on a white illuminating screen of an iPad placed in a dark box in order to capture a top-view image using an iPhone 5s back camera. The intensity of yellow colour was converted to Red-Green-Blue pixels using a free mobile application. Under the optimal conditions for the reaction and photography, the intensity of blue colour, which was logarithmically transformed, showed an excellent linearity over the drug concentration range of 5-40 µg/mL. The assay was validated and successfully applied to the assay of drug content and the determination of drug amount released in the dissolution test in the capsule dosage forms. Apart from that, a smartphone was employed for the colour measurement as an alternative to a spectrophotometer in the currently used method for the quantitation of free sulfhydryl groups in polymers. Using cysteine-conjugated chitosan as a sample and l-cysteine as a standard, the smartphone method gave the results in agreement with those obtained from the absorbance measurement on a microplate reader. In conclusion, smartphone-based colourimetry has been proved to be a reliable, fast, simple and affordable alternative means for the analysis of d-penicillamine and cysteine-conjugated polymer and can be potentially applied to other thiol-containing drugs and excipients.

Enhanced transmucosal delivery of itraconazole by thiolated d-ɑ-tocopheryl poly(ethylene glycol) 1000 succinate micelles for the treatment of Candida albicans.

This study aimed to investigate the transmucosal delivery of itraconazole (ITZ) by thiolated d-ɑ-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS-Cys) micelles. TPGS-Cys polymer was successfully synthesized by the simple coupling between carboxyl-activated TPGS and Cys as confirmed by NMR and FTIR techniques. Afterwards, the TPGS/TPGS-Cys micelles were prepared using the blend of TPGS and TPGS-Cys at 10:0, 7:3, 5:5, 3:7 and 0:10mass ratios. All micelles had the size ranged from 8 to 10nm with narrow size distribution and showed spherical in shape. The surface of the 10:0 TPGS micelles exhibited negatively charge while, the TPGS-Cys micelles demonstrated the slightly positive surface charge. The critical micelle concentration, loading capacity and release profiles of TPGS/TPGS-Cys micelles were comparable to the TPGS micelles. The release of ITZ from all micelles was biphasic and sustained in simulated saliva fluid over 48h. The 3:7 and 0:10 TPGS/TPGS-Cys micelles had a good mucoadhesive property. Meanwhile, only 0:10 TPGS/TPGS-Cys micelles enhanced the permeability through buccal mucosa and potentiated the antifungal activity of ITZ against Candida albicans by at least 1.35 folds as compared to ITZ alone. Therefore, this formulation can be further developed for the transmucosal delivery of ITZ for the treatment of C. albicans.

In vitro evaluation of glycol chitosan based formulations as oral delivery systems for efflux pump inhibition.

Recently, we have reported that glycol chitosan (GCS) was able to reverse the P- glycoprotein (P-gp) efflux pump. The objective of the present study was to evaluate the potential of two GCS-based dosage forms (aqueous solution or nanoparticle suspension) for oral administration of the P-gp substrate Rho-123. A further aim of the present study was to assess the effect of the glycol chitosan-4-thiobutylamidine thiomer (GCS-TBA) on P-gp activity considering that the corresponding thiomer of chitosan series is a well-known P-gp inhibitor. Pre-treatment of Caco-2 cell monolayer with a GCS solution or GCS-based nanoparticles increased the absorptive transport of Rho-123 across the monolayer of 1.43-fold. The modification of GCS with 2-iminothiolane led to GCS-TBA conjugate which did not show any P-gp inhibitory activity. Therefore, GCS polymer and corresponding dosage forms may contribute to increase the oral bioavailability of Pgp-substrate drugs, while GCS-TBA cannot be used for the same purpose.

A novel injectable formulation of 6-fluoro-l-DOPA imaging agent for diagnosis of neuroendocrine tumors and Parkinson's disease.

Two [19F]F-l-DOPA (F-DOPA) new ß-cyclodextrin (CD)-based dosage forms (FA and FB, respectively) have been studied and their physico-chemical and pharmacological features determined to overcome the administration site reactions showed by the currently used [18F]F-l-DOPA formulation (IASOdopa®) to perform PET-CT diagnosis in oncology (neuroendocrine tumors) and neurological (Parkinson's disease) field. Chemical stability of FA and FB was found to be longer than IASOdopa® by adding the thiol-antioxidant agent, L-Cysteine. 1H and 19F NMR investigations suggest the formation of an inclusion complex of F-DOPA with ß-CD. In vitro experiments on the effects of FA and FB on mouse skeletal muscle fibers and on the human neuroblastoma SH-SY5Y and embryonal kidney tsA201 cell lines viability showed that FA was the most performant formulation compared to F-DOPA solutions. In vivo tolerability tests of FA on adult male rat showed no significant effects on body weight and no change in their dried organs weight. In addition, their metabolic and physiological parameters were not affected. In conclusion, [18F]F-l-DOPA, formulated as FA, constitutes a promising dosage form for PET-CT diagnosis of both neuroendocrine tumors and Parkinson's disease.

Molecular mechanisms and in vitro antioxidant effects of Lactobacillus plantarum MA2.

Lactobacillus plantarum MA2 was isolated from Chinese traditional Tibetan kefir grains. The antioxidant activities in vitro of this strain were evaluated extensively. The results showed that L. plantarum MA2 can tolerate hydrogen peroxide up to 2.0mM, and its fermentate (fermented supernatant, intact cell and cell-free extract) had strong reducing capacities, lipid peroxidation inhibition capacities, Fe2+-chelating abilities, as well as various free radical scavenging capacities. Additionally, both the fermented supernatant and cell homogenate exhibited glutathione peroxidase activity and superoxide dismutase activity. In order to investigate the antioxidant mechanism of L. plantarum MA2 at the molecular level, eight antioxidant-related genes were identified, and further analyzed. Three groups of genes cat, gshR and npx, were found up-regulated under H2O2 challenge.

Chemical characterization and prebiotic activity of fructo-oligosaccharides from Stevia rebaudiana (Bertoni) roots and in vitro adventitious root cultures.

Stevia rebaudiana (Bertoni) is widely studied because of its foliar steviol glycosides. Fructan-type polysaccharides were recently isolated from its roots. Fructans are reserve carbohydrates that have important positive health effects and technological applications in the food industry. The objective of the present study was to isolate and characterize fructo-oligosaccharides (FOSs) from S. rebaudiana roots and in vitro adventitious root cultures and evaluate the potential prebiotic effect of these molecules. The in vitro adventitious root cultures were obtained using a roller bottle system. Chemical analyses (gas chromatography-mass spectrometry, (1)H nuclear magnetic resonance, and off-line electrospray ionization-mass spectrometry) revealed similar chemical properties of FOSs that were obtained from the different sources. The potential prebiotic effects of FOSs that were isolated from S. rebaudiana roots enhanced the growth of both bifidobacteria and lactobacilli, with strains specificity in their fermentation ability.

Thiolated nanocarriers for oral delivery of hydrophilic macromolecular drugs.

It was the aim of this study to investigate the effect of unmodified as well as thiolated anionic poly(acrylic acid) (PAA) and cationic chitosan (CS) utilized in free-soluble form and as nanoparticulate system on the absorption of the hydrophilic compound FD4 across intestinal epithelial cell layer with and without a mucus layer. Modifications of these polymers were achieved by conjugation with cysteine to PAA (PAA-Cys) and thioglycolic acid to CS (CS-TGA). Particles were prepared via ionic gelation and characterized based on their amount of thiol groups, particle size and zeta potential. Effects on the cell layer concerning absorption enhancement, transepithelial electrical resistance (TEER) and cytotoxicity were investigated. Permeation enhancement was evaluated with respect to in vitro transport of FD4 across Caco-2 cells, while mucoadhesion was indirectly examined in terms of adsorption behaviour when cells were covered with a mucus layer. Lyophilized particles displayed around 1000 µmol/g of free thiol groups, particle sizes of less than 300 nm and a zeta potential of 18 mV (CS-TGA) and -14 mV (PAA-Cys). Cytotoxicity studies confirmed that all polymer samples were used at nontoxic concentrations (0.5% m/v). Permeation studies revealed that all thiolated formulations had pronounced effects on the paracellular permeability of mucus-free Caco-2 layers and enhanced the permeation of FD4 3.0- to 5.3-fold. Moreover, polymers administered as particles showed a higher permeation enhancement than their corresponding solutions. However, the absorption-enhancing effect of each thiolated formulation was significantly (p<0.05) reduced when cells were covered with mucus layer. In addition, all formulations were able to decrease the TEER of the cell layer significantly (p<0.05). Therefore, both thiolated polymers as nanoparticulate delivery systems represent a promising tool for the oral administration of hydrophilic macromolecules.

Assessment of serum L-fucose in brain tumor cases.

BACKGROUND: Glycosylation of altered tumor cell in relation to cellular heterogeneity in human intracranial tumors remains relatively unexposed. Serum protein-bound carbohydrate, L-Fucose is reported to be overexpressed during tumor progression by many investigators. Therefore, there is a need to determine the diagnostic, prognostic, functional significance of glycoprotein elevations in various cases of tumors. OBJECTIVE: The objective of the present study was to evaluate the clinical utility of serum L-fucose in patients with brain tumor. MATERIALS AND METHODS: Serum glyco-conjugate levels were estimated in 99 patients with brain tumors. Estimation of L-fucose was carried out colorimetrically by the method of Winzler using cysteine hydrochloride. RESULTS: There was a significant increase in L-fucose level in most of the patients. In the posttreatment cases, the L-fucose levels were apparently low compared to preoperative values. CONCLUSION: Our results showed that the rise in serum L-fucose may be used as a general marker for brain tumors in addition to other markers.