Phosphate Buffer Extracts Research Articles

1H NMR-based metabolomics of cacao pod husk: profile comparison of three drying treatments

Aim: The aim of this study is to apply untargeted proton nuclear magnetic resonance (1H NMR) and chemometric analysis to obtain the cacao pod husk (CPH) fingerprint and evaluate the effect of dehydration in the CPH metabolome. Methods: Phosphate buffer extracts (pH 6.5) were obtained and measured using a one-dimension (1D) 1H NMR spectrometry. The 1D 1H NMR spectra were recorded without spinning and using the presaturation (PRESAT) pulse sequence to suppress the residual H2O signal. The 3-(trimethylsilyl) propionic-2,2,3,3-d4 acid sodium salt (TSP) was used as an internal reference. Analysis of processed data, applying an orthogonal projection on latent structure-discriminant analysis (OPLS-DA) model was used to highlight significant differences between the three dehydration treatments. Signal assignment of CPH metabolites was carried out based on the coupling constant, software simulation prediction, published data comparison, and metabolomics databases. Results: A total of 25 compounds were detected by 1H NMR, methylxanthines, sugars, some amino acids, fatty acids, and organic acids were found among the identified compounds. The fingerprint spectra of the three dehydration methods were clustered separately discriminating the metabolome profile of each of the dehydration treatments, finding that metabolome remarkably differed in theanine, myristic acid, fumaric acid, and aspartic acid composition. Conclusions: An untargeted metabolomics to obtain the fingerprint of CPH was successfully established. A 1H NMR spectra with a detailed signal assignment aided to identify 25 metabolites present in CPH fresh and dried by different methods. The results complement the information about CPH composition and how it is affected by the temperature used during the dehydration process. The multivariate analysis points out that freeze drying (FD) preserves the metabolites better than microwave drying (MWD) or hot air drying (HAD). FD and MWD are similar in composition maintaining most of the compounds after drying.

Optimization of R-Phycoerythrin Extraction by Ultrasound-Assisted Enzymatic Hydrolysis: A Comprehensive Study on the Wet Seaweed Grateloupia turuturu

Enzyme-assisted extraction (EAE) and ultrasound-assisted extraction (UAE) are both recognized as sustainable processes, but little has been done on the combined process known as ultrasound-assisted enzymatic hydrolysis (UAEH), and even less on seaweed. The present study aimed to optimize the UAEH of the red seaweed Grateloupia turuturu for the extraction of R-phycoerythrin (R-PE) directly from the wet biomass by applying a response surface methodology based on a central composite design. Three parameters were studied: the power of ultrasound, the temperature and the flow rate in the experimental system. Data analysis demonstrated that only the temperature had a significant and negative effect on the R-PE extraction yield. Under the optimized conditions, the R-PE kinetic yield reached a plateau between 90 and 210 min, with a yield of 4.28 ± 0.09 mg·g-1 dry weight (dw) at 180 min, corresponding to a yield 2.3 times higher than with the conventional phosphate buffer extraction on freeze-dried G. turuturu. Furthermore, the increased release of R-PE, carbohydrates, carbon and nitrogen can be associated with the degradation of G. turuturu constitutive polysaccharides, as their average molecular weights had been divided by 2.2 in 210 min. Our results thus demonstrated that an optimized UAEH is an efficient method to extract R-PE from wet G. turuturu without the need for expensive pre-treatment steps found in the conventional extraction. UAEH represents a promising and sustainable approach that should be investigated on biomasses where the recovery of added-value compounds needs to be improved.

In Vitro Assessment Methods for Antidiabetic Peptides from Legumes: A Review.

Almost 65% of the human protein supply in the world originates from plants, with legumes being one of the highest contributors, comprising between 20 and 40% of the protein supply. Bioactive peptides from various food sources including legumes have been reported to show efficacy in modulating starch digestion and glucose absorption. This paper will provide a comprehensive review on recent in vitro studies that have been performed on leguminous antidiabetic peptides, focusing on the α-amylase inhibitor, α-glucosidase inhibitor, and dipeptidyl peptidase-IV (DPP-IV) inhibitor. Variations in legume cultivars and methods affect the release of peptides. Different methods have been used, such as in sample preparation, including fermentation (t, T), germination (t), and pre-cooking; in protein extraction, alkaline extraction, isoelectric precipitation, phosphate buffer extraction, and water extraction; in protein hydrolysis enzyme types and combination, enzyme substrate ratio, pH, and time; and in enzyme inhibitory assays, positive control type and concentration, inhibitor or peptide concentration, and the unit of inhibitory activity. The categorization of the relative scale of inhibitory activities among legume samples becomes difficult because of these method differences. Peptide sequences in samples were identified by means of HPLC/MS. Software and online tools were used in bioactivity prediction and computational modelling. The identification of the types and locations of chemical interactions between the inhibitor peptides and enzymes and the type of enzyme inhibition were achieved through computational modelling and enzyme kinetic studies.

Optimized Chemical Extraction Methods of Antimicrobial Peptides from Roots and Leaves of Extremophilic Plants: Anthyllis sericea and Astragalus armatus Collected from the Tunisian Desert.

Extraction methods depend mainly on the chemical nature of the extracted molecule. For these reasons, the selection of the extraction medium is a vital part of obtaining these molecules. The extraction of antimicrobial peptides (AMPs) from extremophile plants is important because of its potential pharmaceutical applications. This work focused on the evaluation of several solvents for the extraction of AMPs from the following two extremophile plants: Astragalus armatus and Anthyllis sericea from southern Tunisia. In order to identify the most efficient solvents and extraction solutions, we used sulfuric acid, dichloromethane, phosphate buffer, acetic acid and sodium acetate, and we tested them on leaves and roots of both the studied plants. The extracts obtained using sulfuric acid, dichloromethane and phosphate buffer extraction did not show any antimicrobial activity, whereas the acetic acid and sodium acetate extracts led to growth inhibition of some of the tested bacterial strains. The extracts of leaves and roots of An. sericea and As. armatus obtained by acetic acid and sodium acetate were proven to be active against Gram-positive bacteria and Gram-negative bacteria. Therefore, the most appropriate solvents to use for antimicrobial peptide extraction from both plants are acetic acid and sodium acetate.

Selenium speciation in soils using flow injection hydride generation atomic absorption spectrometry with on-line removal of organic matter interferences

A method based on flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) with an on-line pre-reduction of Se(VI) to Se(IV) was developed and optimized to determine phosphate-extractable Se (0.1 M phosphate buffer KH2PO4/K2HPO4 at pH 7). The extracted fraction involves water-soluble Se (i.e. the most mobile Se fraction) and exchangeable Se (i.e. sorbed onto soil component surface). Kinetic discrimination mechanisms allowed the complete removal of interferences caused by organic matter due to the formation of humic substances (HS)–Se(IV) complexes observed when batch pre-reduction processes were used. Se(IV) and Se(VI) recoveries ranged 95–105% at a fortification level of 150 μg kg−1. The pre-reduction was efficiently carried out in 20 s in a 6 M HCl medium at 100 °C. Results from phosphate-extractable fractions were comparable to those obtained by ICP-MS. Se bound to organic matter was released digesting the remaining material from the phosphate buffer extraction with 0.1 M K2S2O8. Detection and quantification limits were 15 μg kg−1 Se and 50 μg kg−1 Se, respectively, in each fraction. The methodology was applied to 10 agricultural soils from Argentina with total Se concentration levels between 130 μg kg−1 and 419 μg kg−1.

Partial Purification of Phytocystatin from Moringa oleifera lam

Background: Phytocystatins are plants cysteine protease inhibitors (CPIs) that are known for their numerous uses in medicine and biotechnology. Methods: Different extraction media which include, Sodium Hydroxide, Hydrochloric acid, Sodium Chloride, Sodium phosphate buffer and distilled Water were used to evaluate flower, leave, root, latex, and stem bark of Moringa oleifera for inhibitory activity against cysteine protease (Papain enzyme). The phosphate buffer extract with higher protease inhibitory activity was concentrated by cold acetone precipitation and further subjected to partial purification using ammonium sulphate fractionation and Hydrophobic chromatography on Phenyl Sepharose column. The molecular weight of partially purified protein was estimated by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis. Results: The extracts of Sodium phosphate buffer from the seeds of Moringa oleifera showed higher CPI activity of 11.23 units/mg protein. Cold acetone precipitated extract gave high yield of 94.6% protein with 60% inhibition of protease. The partially purified protein showed a fifty percent inhibitory concentration (IC50) of 1.22±0.3 mg/ml protein against the enzyme with 63% inhibition. An estimated molecular weight of 13.5kDa was obtained from electrophoretic analysis of partially purified protein. Conclusion: Moringa oleifera seeds could be a good source of low molecular weight protein Inhibitor of Cysteine protease and might be useful in biotechnology of traditional medicinal plants, in transgenic crops to arrest the negative pathogenic over expressions of cysteine proteases

Quantitative extraction of chromium VI and III from tanned leather: a comparative study of pretreatment methods

In this study, seven pretreatment methods for chromium speciation in tanned leather were evaluated: acidic mineralization, ethylenediaminetetraacetic acid (EDTA) extraction, diethylenetriaminepentaacetic acid (DTPA) extraction, alkaline extraction (NH4OH), ammonium nitrate extraction (NH4NO3), water extraction, and phosphate buffer extraction. Acidic mineralization permitted the decomposition of the organic matter and ensured the complete digestion of leathers, giving access to the total content of chromium in each sample using inductively coupled plasma-atomic emission spectrometry (ICP-AES). From all the extractant media tested, EDTA proved to be the most efficient, allowing the extraction of Cr(VI) and Cr(III) as a Cr(III)-EDTA complex, quantitatively. Method validation is presented for EDTA extraction and direct mineralization. For the EDTA extraction, method detection limit (MDL) and method quantification limit (MQL) for total Cr in leather were 3.4 ppb and 11.2 ppb (µg of total Cr per L of extraction solution), respectively. Due to the lack of leather certified reference materials (CRMs) for Cr(VI), accuracy was evaluated by spiking leather samples with a Cr(VI) solution. The spike recovery of EDTA microwave assisted extraction ranged from 91.0 to 108.6%. Interday precision was also evaluated and all variation coefficients were below 5%, for both mineralization and EDTA extraction. This article provides an efficient procedure to extract quantitatively chromium from leather, while maintaining the speciation, which can be further followed by ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS).

Antifungal Activity and Mechanism of Action of Different Parts of Myrtus communis Growing in Saudi Arabia against Candida Spp.

Discovering new antifungal drugs from natural products is a key target for the treatment of infections, such as candidiasis and other Candida-related infections. As current therapeutic drugs for the treatment of infections, such as candidiasis and other Candida-related infections, have adverse effects on human health, discovering new antifungal drugs from natural products is urgently needed. The objective of this study was to evaluate the antifungal activity of the methanolic and sodium phosphate buffer extracts derived from various parts of Myrtus communis, a plant that is traditionally used in Saudi Arabia, against Candida albicans (ATCC 10213), Candida glabrata (ATCC 2001), Candida kefyr (ATCC 66028), Candida parapsilosis (ATCC 22019), and Candida tropicalis (ATCC 750). A well diffusion assay was performed to assess the antifungal activity through the measurement of the zone of inhibition. Of the extracts, those extracted with methanol from the roots and leaves displayed strong inhibitory activity against Candida glabrata ( 23.5 ± 0.12 and 20.7 ± 0.22 , respectively), at 50 mg/ml, with 5 mg/ml fluconazole administered as the standard control. The minimal inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values were 12.5 mg/ml and 25 mg/ml for the M. communis root extract and 25 mg/ml and 50 mg/ml for the M. communis leaf extract against Candida glabrata. The results were confirmed by scanning electron microscopy (SEM) imaging of the control and treated strains of Candida glabrata. Based on SEM, these extracts could alter the morphology and cause loss of cell integrity. The effect of M. communis root and leaf extracts on Candida cells was also determined by measuring the absorbance at 260 nm after treatment for 1 h at 37°C. Interestingly, the 260 nm absorbing material was higher in Candida glabrata than in the resistant strain, Candida parapsilosis (ATCC 22019). Based on our findings, the crude methanolic extract of M. communis roots and leaves exhibited good antifungal activity against the Candida glabrata strain. SEM results and estimation of the 260 nm absorbance material proved that the extract might act on the cell wall and cell membrane of Candida cells, further leading to cell death.

Protective Capacity of Fusarium oxysporum Extract Against Gamma Radiation. Study for Some Biochemical Parameters in Albino Male Rats

The present work search the protective capacity of Fusarium oxysporum phosphate buffer extract (FO) against gamma radiation (ɣ-IR) based on evaluating the changes in some blood components in rat model. The variations in haematological and pairs of biochemical parameters were determined for 40 albino male rats which divided into five groups : negative control , positive control, i.e. irradiated only , and three treated groups administrated increasing dose of (FO) after single four Gray (Gy) gamma irradiation dose. Three doses of FO extract (0.15, 0.3 and 0.6 mg/g body mass) were chosen, as protective doses, for subsequent evaluating of its antioxidant activity and ameliorating capacity toward radiation-induced oxidative stress. The changes in the chosen parameters, due to 4 Gy irradiation and then administrating the FO, were computed after 1, 2, 3 and 7 days. Total serum protein, albumin, total globulin, besides some parameters of complete blood count (CPC) were determined and the data reached were analysed to evaluate the capacity of FO to compensate the gamma irradiation injures. The present work is assuming that: biocomponents extracted from FO fungi have a protective role against gamma radiation which can establish protocols for medical management of radiation injuries based on natural medication.

In-vivo anti-plasmodial activity of phosphate buffer extract of Calotropis procera latex in mice infected with Plasmodium berghei

Ethnopharmacological relevanceMalaria is a global health problem with the greatest burden in sub-Saharan Africa (sSA). The resistance to available antimalarial agents necessitate for the development of new and safe drugs for which medicinal plants provides credible alternative sources for discovering new and cheap therapeutic agents. Calotropis procera is used in several folk or traditional medicines for the treatment of various diseases across different regions of the world. In Nigeria traditional medicine, C. procera latex is used either alone or in combination with other herbs to cure common diseases including malaria. In Malaka district (Indonesia), Calotropis gigantea (a member of Apocyanceae), is one of the most used herbs to treat malaria patient via the massage method.Aim of the study: This study aimed to evaluate the anti-plasmodial activity of phosphate buffer extract of Calotropis procera latex in mice infected with Plasmodium berghei. Materials and methodsThe plant's anti-plasmodial agent was extracted using 0.2 M-phosphate buffer (pH 7.0), followed by precipitation using acetone. 90 (ninety) mice were divided into three main groups of 30 (thirty) mice each, used for the curative, suppressive and prophylactic tests, respectively. The 30 (thirty) mice in each of the main groups were sub-divided into five groups of 6 (six) mice. The mice in the group 1, 2 and 3 (test groups) were made to receive graded doses of 25 mg/kg, 50 mg/kg and 75 mg/kg of the extract of C. procera latex intraperitoneally; group 4 (negative control group) received 0.2 ml of normal saline; while group 5 (positive control group) were administered with 5 mg/kg chloroquine. The phytochemical constituents of the plant and its intraperitoneal median lethal dose (LD50) were also undertaken. ResultsThe freeze-dried acetone extract exhibited acute toxicity with median lethal dose (LD50) of 745 mg/kg body weight in mice. The highest percentage parasite suppression (61.85%), percentage parasite cure (50.26%), and percentage parasite prophylaxis (65.47%), were obtained for the groups treated with 75 mg/kg bodyweight/day of the extract. The least percentage parasite suppression (44.74%), percentage parasite cure (35.21%), and percentage parasite prophylaxis (45.21%), were obtained for the groups treated with 25 mg/kg body weight of the extract. Also, a dose-dependent percentage parasite suppression (53.03%), percentage parasite cure (39.70%), and percentage parasite prophylaxis (49.82%) were obtained for the groups treated with 50 mg/kg body weight. This is comparable to the groups treated with standard chloroquine. The extract also produced a significant elevation in body weight of the animals for suppressive and curative tests. However, there were observable significant decreases in body weight of the animals in the case of prophylactic test. ConclusionThis study showed that the phosphate buffer extract of C. procera latex possess anti-plasmodial activity. The results of this study can be used as a basis for further phytochemical investigations in the search for new and locally affordable antimalarial agents.

In-Vitro α-amylase, α-glucosidase Inhibitory Activities and In-Vivo Anti-Hyperglycemic Potential of Different Dosage Forms of Guduchi (Tinospora Cordifolia [Willd.] Miers) Prepared With Ayurvedic Bhavana Process.

Guduchi (Tinospora cordifolia [Willd.] Miers) is a flagship rejuvenating herb of Ayurveda with reported anti-diabetic potential. In the present study, different dosage forms of Guduchi stem (growing on neem tree) were developed by adopting Ayurvedic pharmaceutical process of Bhavana (levigation). Guduchi Churna (GC) was subjected to 07 times Bhavana separately with its own extracted juice, decoction and potable water, and dosage forms namely Svarasa Bhavita Guduchi Churna (SBGC), Kwatha Bhavita Guduchi Churna (KBGC), and Jala Bhavita Guduchi Churna (JBGC) were prepared. The present study was aimed to evaluate the role of Bhavana on the potentiation of therapeutic properties of Guduchi. Sequential solvent extracts (5, 10, 15 and 25%) of GC, SBGC, KBGC and JBGC were prepared in different solvents [phosphate buffer, hexane, dichloromethane (DCM), chloroform] and screened for the α-amylase and α-glucosidase inhibitory activity. The results revealed that phosphate buffer and DCM extracts of SBGC exhibited strong α-amylase inhibitory potential (>80% inhibition at 25% concentration) followed by KBGC, JBGC and GC with reference to the standard acarbose. In α-glucosidase inhibitory activity, maximum inhibition was observed in DCM and chloroform extracts of SBGC (>85% inhibition at 25% concentration), followed by KBGC (>80% inhibition at 25% concentration), JBGC and GC. In vivo anti-hyperglycemic studies were carried out by oral glucose tolerance test in Swiss albino mice. Test drugs (JBGC, KBGC, SBGC) treated groups showed marginal decrease of blood glucose levels in normo glycemic mice. However, the blood glucose level in test drug JBGC, KBGC and SBGC treated groups was still within normal range in overnight fasted mice. In oral glucose tolerance test, among all dosage forms SBGC (51.08%) produced pronounced anti-hyperglycemic effect followed by KBGC (42.57%) at a dose of 520 mg/kg. The GC, JBGC, KBGC and SBGC samples were also standardized using berberine (a well established anti-diabetic compound) as a marker compound by HPTLC fingerprint analysis. Findings of the present study indicate that SBGC and KBGC can be used in the treatment of diabetes mellitus and gives supporting evidence to Ayurvedic claims that the Bhavana process has pharmaceutico-therapeutic significance in Ayurvedic drug development.

γ-Non-Symmetrically Dimasked TriPPPro Prodrugs as Potential Antiviral Agents against HIV.

Nucleoside analogue reverse transcriptase inhibitors (NRTI) and nucleoside analogue monophosphate prodrugs are used in combination antiretroviral therapy (cART). The design of antivirally active nucleoside triphosphate prodrugs is a recent and an important advancement in the field of nucleoside analogue drug development. Here, we report on TriPPPro‐derivatives of nucleoside analogue triphosphates (NTPs) that comprised two different acyloxybenzyl‐masks at the γ‐phosphate of the NTP aiming to achieve the metabolic bypass. Thus, γ‐non‐symmetrically dimasked TriPPPro‐compounds (γ‐(AB,ab)‐d4TTPs) were synthesized and they proved to be active against HIV‐1 and HIV‐2 in cultures of infected wild‐type human CD4+ T‐lymphocyte (CEM/0) cells and more importantly also in thymidine kinase‐deficient CD4+ T‐cells (CEM/TK‐). From hydrolysis studies both in phosphate buffer (PB, pH 7.3) and CEM cell extracts, there was surprisingly no differentiation in the cleavage of the two acyloxybenzyl prodrug‐masks. However, if within one of the two acyloxybenzyl groups a short PEG‐type methoxytriglycol group was introduced, the “standard” acyloxybenzyl‐mask was cleaved with high preference.

Formation and Immobilization of Cr(VI) Species in Long-Term Tannery Waste Contaminated Soils

Chromium speciation in naturally contaminated soils appears more complex than spiked studies have shown. This study characterized Cr speciation (oxidation states; availability; molecular geometry) intended to highlight the genesis of immobile Cr(VI) species in long-term tannery waste-contaminated soils. In a series of samples obtained from Shuitou in China, chemical extraction methods showed that Cr(III) was dominant(>96.7% of total Cr), with Cr(VI) concentration up to 144 mg kg-1. Of the total Cr(VI) present, immobile Cr(VI) represents >90%. Synchrotron-based X-ray near-edge structure spectroscopy (XANES) showed the occurrence of Cr(VI), which was not removed by phosphate buffer extraction, confirming a significant amount of immobile Cr(VI) fractions in soils. X-ray fluorescence maps exhibited the heterogeneous distribution of Cr in soils associated with both Mn and Fe. Such a distribution suggests Cr(III) oxidation to Cr(VI) by Mn oxides and a possible immobilization of both Cr(III) and Cr(VI) onto Fe (hydr)oxides. Linear combination fitting of XANES spectra revealed that fractional weights (%) in samples were CrFeO3 (49.3-53.6), CrOOH (22.3-30.8), and CaCrO4 (13.2-25.3). Our results demonstrate that (i) Cr(VI) is immobilized in soils and (ii) mechanisms of Cr(VI) immobilization are CaCrO4 precipitation and recrystallization with Fe (hydr)oxides.

Is downstream ultrafiltration enough for production of food-grade phycocyanin from Arthrospira platensis?

Phycocyanin (PC), a natural blue pigment found in the cyanobacterium Arthrospira platensis, has anticancer, anti-inflammatory, and antioxidant properties. The purity of PC is the key factor for its application in the food, pharmaceutical and medical industries; however, the purification processes needed to achieve high purity can impact its bioactivity. This study evaluates whether microfiltration (MF) or ultrafiltration (UF) can be used to produce PC with food-grade purity. MF and UF following freeze-thaw extraction of PC from A. platensis biomass resulted in a low product purity, with other cellular constituents forming a cake on the membrane surface during the filtration process and preventing the concentration of PC. Phosphate buffer extraction resulted in more PC (65.5 mg g−1) with purity of 0.53. When the UF was followed by one step of diafiltration, purity was further enhanced to 0.76. However, the purification resulted in a 30% loss of antioxidant activity. This study demonstrates that phosphate buffer extraction followed by UF and one step of DF is suitable to produce food-grade PC from A. platensis, with the advantage of only requiring a single piece of equipment to perform the purification.

Kinetic of α-amylase inhibition by Gracilaria corticata and Sargassum angustifolium extracts and zinc oxide nanoparticles

Abstract In this research, Gracilaria corticata red algae and Sargassum angustifolium brown algae were collected from tidal zones of the coastal areas of Bushehr (Persian Gulf coastline), and were extracted with methanol, ethanol, and sodium phosphate buffer. Zinc oxide nanoparticles were synthesized by chemical deposition. α-Amylase inhibition was evaluated using a colorimetric method based on the reduction of maltose released from a starch solution. The results showed that with increased sample concentration, the α-amylase was increasingly inhibited. The phosphate buffer extract of Gracilaria corticata showed the highest α-amylase inhibition, with an IC50 of 0.44 mg/mL and with inhibition following a competitive mechanism. The phosphate buffer extract of Sargassum angustifolium showed the lowest α-amylase inhibition with an IC50 of 1.85 mg/mL. Zinc oxide nanoparticles inhibited with an IC50 of 0.34 mg/mL with inhibition following a competitive mechanism. The two species of algae studied in this research, which both exhibited anti-diabetic activity, have potential for lowering intestinal glucose uptake in diabetic patients.

Inhibitory effect of tartary buckwheat seedling extracts and associated flavonoid compounds on the polyphenol oxidase activity in potatoes (Solanum tuberosum L.)

To improve the processing quality of potatoes, phosphate buffer extract (PBE), 50% ethanol (E50), and aqueous extract (AE) of tartary buckwheat seedlings were evaluated for their ability to inhibit the enzymatic browning of potatoes. The results suggest that all extracts of tartary buckwheat seedlings exert significant inhibitory effects on the polyphenol oxidase (PPO) activity in potatoes. The relative concentrations required for a 50% reduction in the PPO activity (IC50) were 0.21, 0.28 and 0.41 mg mL−1, for PBE, E50 and AE, respectively. The strongest inhibitory activity was observed for PBE, followed by E50 and AE. Four flavone compounds in the PBE of tartary buckwheat seedlings (i.e., rutin, kaempferol-3-O-rutinoside, quercetin, and kaempferol) were identified by high-performance liquid chromatography. These compounds were subsequently evaluated for their roles in the inhibition of PPO from potatoes using a model system. The results indicated that rutin exhibited the highest inhibition rate on the PPO of potato. A synergistic inhibitory effect was observed by mixing rutin, kaempferol-3-O-rutinoside, quercetin, and proteins. The inhibitory patterns of rutin, kaempferol-3-O-rutinoside, and quercetin on the enzyme were noncompetitive and reversible, with inhibitory constants of 0.12, 0.31, and 0.40 mg mL−1, respectively. Flavonoids from tartary buckwheat seedlings may exhibit a common mechanism with phenolic compounds, involving the blockage of the reaction of oxygen with PPO leading to the inhibition of the enzymes involved in browning. Based on these results, extracts of tartary buckwheat seedlings can be used as potent natural inhibitors.

Purification and characterization of an antimicrobial protein from <i>Gastrodia elata</i> Blume tubers

Purpose: To purify and characterize a novel antimicrobial protein from the Gastrodia elata Blume (Bl.) plant, which has long been used in herbal medicine. Methods: The procedure for isolation and purification of Gastrodia elata protein (GEP) involved phosphate buffer extraction, ammonium sulfate precipitation, ion-exchange chromatography, and gelfiltration chromatography. Sodium dodecyl sulfate - polyacrylamide gel electrophoresis was employed to detect the apparent molecular mass and determine homogeneity, while paper disc diffusion was used to measure the antibacterial activity of GEP. A hemolytic assay was performed on rabbit red blood cells. The effect of pH, salt concentration, and temperature on the antibacterial activity of GEP was evaluated by minimum inhibitory concentration assay. Results: GEP was a 14-kDa monomer and displayed antimicrobial activity against Staphylococcus aureus and Candida albicans , with 8.0-mm and 9.4-mm zones of inhibition, respectively, but no antibacterial activity was observed against Escherichia coli . GEP had little hemolytic activity on red blood cells even at a concentrations of up to 200 mg/ml. GEP was thermally stable at temperatures below 70 °C for 30 min, and displayed higher antibacterial activity in the pH range 5.0 to 7.0. Conclusion: GEP protein is relatively thermostable and possesses antimicrobial activity. The results suggest that GEP protein has potential agricultural and industrial applications, such as in transgenic plants. Keywords: Antimicrobial protein, Gastrodia elata , Protein characterization

Optimizing Extraction Conditions of Actinidin from Kiwifruit (Actinidia deliciosa)

Kiwifruit (Actinidia deliciosa) is one many fruits that is rich of enzymes like Actinidin. Actinidin is a member of cysteine protease. In this study, different parameters and conditions were tested for optimal Actinidin extraction from kiwifruit. The tested parameters are optimum buffers, pH, Molarity, time, and amounts (gm) of kiwifruit to volume (ml) of buffer ratio. The best buffer for Actinidin extraction from kiwifruit was Sodium phosphate because it gave high activity, with casein as a substrate. The next experiments used sodium phosphate as an optimal buffer for Actinidin extraction and casein as a substrate, detected the optimal Actinidin extraction conditions were carried out at pH 7.0, 0.1 M of sodium phosphate, 2.5 min of extraction time, 1:0.5 (gm of kiwifruit fruit/ v of sodium phosphate buffer) extraction percentage, and 30 min of incubation time. Also this study showed that the maximum enzyme activity for Actinidin extracted from kiwifruit was at pH 7and at 30 min of incubation with casein as substrate.

Elemental sulfur amendment decreases bio-available Cr-VI in soils impacted by leather tanneries

This study investigated the potential use of elemental S (S0) to convert Cr-VI to Cr-III which should decrease the bio-availability hence, toxicity of Cr-VI in soils. The bio-available fraction of Cr in soil was measured by phosphate buffer extraction (PBE) and the results showed that the fraction is about 10% of the total Cr-VI and varied from 12.8 to 42.5 mg kg−1. The addition of 4.0 mg g−1 S0 decreased PBE Cr-VI to <0.4 mg kg−1 limit established for Cr-VI toxicity in soils. Synchrotron-based X-ray absorption near-edge structure (XANES), X-ray fluorescence (XRF) and micro-XRD revealed that Cr-III was the dominant species (99% of total Cr) and Cr was retained by hematite and goethite in soil. Fe-containing minerals may have provided sufficient protection to render the dominant Cr-III species biochemically inert to redox processes in soils. It is concluded that S0amendment is a promising approach to remediate Cr-VI contaminated soils.

Hidden Fumonisins: Simple and Innovative Extractions for Their Determination in Maize and Derived Products

Fumonisins B (FBs) can occur in maize as free forms and as hidden FBs (interaction between FBs and matrix macro-constituents). The analytical methods to detect free FBs in maize and derived products usually involve extraction with aqueous methanol and/or acetonitrile; for hidden FBs, alkaline hydrolysis (2 M KOH) and following CH3CN extraction is used. Recently, we proposed a simple phosphate buffer (PB) extraction to detect free FBs in masa and maize samples. This study aimed at evaluating if this method is suitable to detect also hidden FBs; then, a comparison between the most common solvents, PB, and alkaline hydrolysis was carried out. For maize samples, the results showed that 0.4 M PB can extract both free and most hidden FBs; however, this method was not suitable for some categories of maize-based processed food products, in particular cornflakes, chips, and crispbreads. To solve this drawback, a modified PB extraction, which entails the addition of Carrez solutions in order to precipitate proteins, was tested and satisfactory results were obtained. Finally, the alkaline hydrolysis of maize-based food extracts showed that bound FBs can be co-extracted together with free forms by 0.4 M PB and quantified as hydrolyzed FBs.