Grain-protectant compounds from Duguetia lanceolata (Annonaceae) derivatives: Bioassay-guided searching and toxicity against the maize weevil

In order to obtain bioactive allelochemicals from Neotropical Annonaceae, bioguided chromatographic fractionations with derivatives prepared from Duguetia lanceolata St.-Hil. leaves were performed using the maize weevil, Sitophilus zeamais Mots. (Coleoptera: Curculionidae), as bioindicator, which is a primary insect pest of stored cereals in tropical conditions. For this end, four phases (hexane, dichloromethane, ethyl acetate and hydroalcohol) were obtained firstly by liquid-liquid partition and tested through a residual contact bioassay (at 1500 mg L⁻¹) in order to verify their bioactivity on adults of the maize weevil. Only the hexanic fraction caused significant mortality (74%) after the tenth day of insect exposure on treated samples of grains corn. Thus, thisfraction was separated into seven new subfractions by means of vacuum column chromatography and solvents of increasing polarities. Subfraction 2 promoted 90% of mortality whereas subfraction 6 promoted 30% of mortality of maize weevils. The aromatic compound 2,4,5-trimethoxystyrene and a mixture of steroids [campesterol (8.44%) + stigmasterol (12.37%) + sitosterol (79.19%)] were isolated from subfraction 2 and promoted promising grain protective activity, in a manner comparable to a diatomaceous-earth based formulation (our positive control). Furthermore, the results reported in the present study demonstrate the potential application of derivatives of D. lanceolata leaves in integrated pest management (IPM) of stored grains, mainly in the framework of maize weevil management.     

Antitumour properties of the leaf essential oil of Xylopia frutescens Aubl. (Annonaceae)

The aim of this study was to investigate the chemical composition and anticancer effect of the leaf essential oil of Xylopia frutescens in experimental models. The chemical composition of the essential oil was analysed by GC/FID and GC/MS. In vitro cytotoxic activity of the essential oil was determined on cultured tumour cells. In vivo antitumour activity was assessed in Sarcoma 180-bearing mice. The major compounds identified were (E)-caryophyllene (31.48%), bicyclogermacrene (15.13%), germacrene D (9.66%), δ-cadinene (5.44%), viridiflorene (5.09%) and α-copaene (4.35%). In vitro study of the essential oil displayed cytotoxicity on tumour cell lines and showed IC₅₀ values ranging from 24.6 to 40.0 μg/ml for the NCI-H358M and PC-3M cell lines, respectively. In the in vivo antitumour study, tumour growth inhibition rates were 31.0–37.5%. In summary, the essential oil was dominated by sesquiterpene constituents and has some interesting anticancer activity.     

Evaluation of the antioxidant and cytoprotective properties of the exotic fruit Annona cherimola Mill. (Annonaceae)

Cherimoya is a tropical and subtropical native exotic fruit which has become an important crop due to its tasty flavor, high pulp content, nutritional value and potential use in folk medicine.In this study the pulp of ripe fruits were extracted using three organic solvents (ethanol, methanol and dimethyl formammide) and analyzed for the total phenols, antioxidants power and cytoprotective activity on lymphocyte tert-butyl hydroperoxide treated. Also, potential antiperoxidative activity of each extract has been performed. Organic extracts from cherimoya pulp had powerful antioxidant and ferric reducing power activities and, among the extracts, the dimethyl formammide one showed the highest scavenging activity towards DPPH, ABTS⁺, O₂⁻ radical and FRAP assay, while the ethanol one showed the highest activity against lipid peroxidation induced by tert-butyl hydroperoxide. Extract protective activities were also evaluated in isolated human peripheral blood lymphocytes exposed to 250 ??M tert-butyl hydroperoxide. The results showed that all the extracts could significantly enhance cell survival and clearly decrease the release of lactate dehydrogenase, with data almost superimposable for all the tested samples. Moreover RP-HPLC-DAD-ITMS analysis reveals the presence of flavanols and procyanidins (dimers and trimers). These results highlight cherimoya extracts' strong antioxidant properties, remarkable decrease of lipid peroxidation and cytoprotective effects against strong oxidant, supporting their suitable employment as bioactive elements in cosmetic, pharmaceutical and food processing industries.     

Structure,physicochemical, and functional properties of protein isolates and major fractions from cumin (Cuminum cyminum) seeds

In this study, cumin protein isolates (CPI) and major protein fractions were extracted and separated from cumin seeds, their structure, physicochemical, and functional properties were investigated. Albumin (62.29%) and glutelin (25.16%) were the predominant protein fractions of cumin seeds. Glutamic acid (Glu) and aspartic acid (Asp) were the major amino acids of cumin proteins, whereas more hydrophobic and aromatic amino acids were predominantly found in chickpea protein isolates. Electrophoresis profiles indicated that CPI have more disulphide bonds than major protein fractions. The intrinsic fluorescence data revealed that glutelin displayed greater exposure of tyrosine (Tyr) and tryptophan (Trp) residues compared to albumin and CPI. Circular dichroism (CD) data showed CPI presented more α-helix (14.4%) and less β-strand (30.7%) than albumin and glutelin. The atomic force microscope (AFM) profile and hydrodynamic diameter (D_h) determination showed the presence of low particle size in albumin fractions. Differences in the hydrophobicity (H_o) and the zeta-potential (ζ) of CPI, albumin, and glutelin were also observed due to their difference in structure and amino acid composition. Compared with CPI and glutelin, albumin exhibited the highest emulsifying activity (103.67 m²/g) and stability (42.84 min) and the smallest emulsion particle size (4.29 μm). The CPI, albumin and glutelin presented typical U-shaped protein solubility–pH curves, with the lowest solubility at pH 4.0. Rheological investigation demonstrated that CPIs were efficient in forming a gel at 80.6°C, whereas glutelin could form the hardest gel at 92.6°C. The overall results suggested that the cumin proteins can be a promising protein source for the food industry.     

The Compound Characteristics Comparison (CCC) approach: a tool for improving confidence in natural compound identification

ABSTRACT

Compound identification is the main hurdle in LC-HRMS-based metabolomics, given the high number of ‘unknown’ metabolites. In recent years, numerous in silico fragmentation simulators have been developed to simplify and improve mass spectral interpretation and compound annotation. Nevertheless, expert mass spectrometry users and chemists are still needed to select the correct entry from the numerous candidates proposed by automatic tools, especially in the plant kingdom due to the huge structural diversity of natural compounds occurring in plants. In this work, we propose the use of a supervised machine learning approach to predict molecular substructures from isotopic patterns, training the model on a large database of grape metabolites. This approach, called ‘Compounds Characteristics Comparison’ (CCC) emulates the experience of a plant chemist who ‘gains experience’ from a (proof-of-principle) dataset of grape compounds. The results show that the CCC approach is able to predict with good accuracy most of the sub-structures proposed. In addition, after querying MS/MS spectra in Metfrag 2.2 and applying CCC predictions as scoring terms with real data, the CCC approach helped to give a better ranking to the correct candidates, improving users’ confidence in candidate selection. Our results demonstrated that the proposed approach can complement current identification strategies based on fragmentation simulators and formula calculators, assisting compound identification. The CCC algorithm is freely available as R package (https://github.com/lucanard/CCC) which includes a seamless integration with Metfrag. The CCC package also permits uploading additional training data, which can be used to extend the proposed approach to other systems biological matrices.

List of abbreviations: Acidic: acidic moiety; aliph: aliphatic chain; AUC: area under the ROC curve; bs: best glycosidic structure; CCC: Compounds’ Characteristics Comparison; Cees: Carbons estimation errors; CO: Carbon to Oxygen ratio; Het: Heterocyclic moiety; IMD: Isotopic Mass Defect (and Pattern); LC-HRMS: Liquid Chromatography – High Resolution Mass Spectrometry; md: mass defect; MM: Monoisotopic Mass; MS: Mass Spectrometry; MSE: Mean Squared Error; nC: number of Carbons; NN: Nitrogen; pC: percentage of Carbon mass on the total mass; Pho: Phosphate; PLSr: Partial Least Square regression; ppm: parts per million; QSRR: Quantitative structure-retention relationship; RMD: Relative Mass Defect; ROC: Receiver Operating Characteristics; rRMD: residual Relative Mass Defect; RT: retention time; Sul: Sulphur; UPLC-ESI-Q-TOF-MS: Ultra Performance Liquid Chromatography – ElectroSpray Ionization –Quadropole – Time of Flight – Mass Spectrometry; VAT: Vitis arizonica Texas     

Surface charge and conformational properties of phaseolin,the major globulin in red kidney bean (Phaseolus vulgaris L): effect of pH

The aim of this investigation was to explore the pH‐induced conformational changes of phaseolin using differential scanning calorimetry (DSC), fluorescence and circular dichroism (CD) spectra. The surface charges at the varying pH and ionic strength were also determined to probe the possible relationship between the surface charges of phaseolin and its conformation. The ζ‐potential of phaseolin decreased from 27.9 mV at pH 3.0 to –44 mV at pH 9.4, and the isoelectric point (iep) occurred at pH 4.21, which were comparable with the theoretical estimations derived from amino acid composition and pK values. The iep of phaseolin was independent of ionic strength, while the magnitude of ζ‐potential decreased as the ionic strength increased. The near‐UV CD, DSC and fluorescence spectra analyses indicated highly acidic and alkaline pH conditions induced the loss of tertiary conformation of phaseolin. The far‐UV CD spectra analysis confirmed pH‐shift led to the decreases in ordered secondary structure compositions. The present results suggested the loss of secondary and/or tertiary conformation of phaseolin as a result of the varying pattern in electrostatic interactions as pH shifted from 7.0 to acidic or alkalic pH.     

Antioxidant capacity,phenolic compound content and sensory properties of cookies produced from organic grape peel (Vitis labrusca) flour

The by-products of the food industry can be used as nutrient source to improve the nutritional characteristics of other food products. This study aimed to investigate the chemical composition, antioxidant activity and phenolic compound content of organic grape peel flour in cookies using response surface methodology. Composition analysis using different assays (DPPH, ABTS, FRAP, ORAC) revealed that this flour was low in calories (180.22 ± 0.25 kcal%), with low dietary fibre content (50.10 ± 0.01 g%) and high antioxidant capacity. The total phenolic compound analysis showed high values of phenolic compounds (1063.58 ± 8.09 mg%), consisting of resveratrol (54.27 ± 0.79 mg%), epicatechin (43.94 ± 0.90 mg%) and chlorogenic acid (35.70 ± 1.47 mg%). A 2³ factorial experimental design was formulated to optimise the ingredients for cookie production. The resulting cookies presented high acceptance and good sensory properties, confirming that organic grape flour did not interfere with product acceptability. Thus, cookies with an acceptable quality and improved nutrition can be prepared using organic grape peel flour.     

The composition of a gel formed when wheat flour is suspended in phenol-acetic acid-water (1:1:1, w/v/v)

A gel which formed when wheat flour was suspended in phenol-acetic acid-water (1:1:1, w/v/v/) was fractionated into a protein-rich soluble fraction and a carbohydrate-rich insoluble fraction. Gel electrophoresis showed that the soluble fraction contained several proteins and had an amino acid composition with a high content of proline and glutamyl residues and a low content of lysine. The soluble fraction also contained lipids which were mainly phospholipids, phospholipid derivatives and glycolipids and other compounds, which yielded galactose and glucose after acid hydrolysis. The insoluble fraction contained a polysaccharide with similar properties to starch, and lipids which were mainly neutral fats, sterols and sterol esters. Both fractions contained arabinoxylans and mannans. The gel did not contain any nucleic acids. The protein-rich soluble fractions of gels prepared from other wheat flours and air-classified flour fractions, from wheat gluten and from rye and barley flours, showed marked differences in amino acid composition. It is concluded that a heterogeneous class of proteins, rather than specific proteins in fixed proportions, is involved in gel formation.     

Exopolysaccharide activities from probiotic bifidobacterium: Immunomodulatory effects (on J774A.1 macrophages) and antimicrobial properties

Exopolysaccharides (EPSs) are a metabolite of probiotics which have gained wide interest recently, but little is known about their function. EPS was isolated from Bifidobacterium longum BCRC 14634 and sterilized by 0.22 μm filter. The proliferation of J77A.1 macrophages and their secretion of the anti-inflammatory cytokine interleukin-10 (IL-10) was elevated after treatment with heat-killed B. longum or 5 μg/mL EPS. The endotoxin, lipopolysaccharides (LPS), a potent inducer of pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), significantly suppressed the growth of J77A.1 cells, and induced the secretion of TNF-α from J774A.1 cells. Furthermore, 24 h pretreatment with 5 μg/ml EPS suppressed 100 ng/ml LPS-induced cell growth inhibition and release of TNF-α from J774A.1 cells. Additional experiments showed that 80 μg/mL EPS had antimicrobial activity against 7 species of food-spoilage and infection bacteria. Our results suggest that EPS from B. longum might be useful as a mild immune modulator for macrophages, contributing to the capacity of B. longum to fight against gastrointestinal infections, and even some food-spoilage microbe.     

The antioxidant properties of alcoholic extracts from Sambucus nigra L. (antioxidant properties of extracts)

The antioxidant properties of alcoholic extracts from the leaves, berries and flowers of Sambucus nigra L. are estimated by means of DPPH and β-carotene/linoleic acid methods, and considered in relation to the extraction temperature (in the range 20-200 °C) and to the level of flavonoids most representative for this plant. The extracts of S. nigra act as antioxidants neutralizing the activities of free radicals and inhibiting the co-oxidation reactions of linoleic acid and β-carotene. There is no direct correlation between the level of flavonoids in the extracts and their antioxidant activity. The data presented show that the extraction temperature strongly influences the antioxidant properties of the extracts, especially in the case of leaves.     

Crystal structure of a major seed storage protein, 11S proglobulin, from Amaranthus hypochondriacus: insight into its physico-chemical properties

Amaranth is a crop known for its high quality proteins. 11S Globulin is one of the most abundant and important storage proteins of the amaranth grain. Here, we report the crystal structure of amaranth 11S proglobulin at a final resolution of 2.28 Å. It belonged to the space group P6₃ with cell dimensions a = b = 96.6, c = 75.0 Å. It contains one asymmetric unit consisting of 372 residues and 100 water molecules. Disordered regions in the model approximately correspond to the variable regions of the 11S globulins. The structure has an extended α-helix and β-barrel domains at both N-terminal and C-terminal regions, which are characteristic of the 11S and 7S globulins. The three dimensional structure suggests that its high thermal stability is due to the cumulative effects of many factors and its good emulsifying property depended on the balance between its surface hydrophobicity and hydrophilicity.     

The use of spray drying to microencapsulate 2-acetyl-1-pyrroline, a major flavour component of aromatic rice

Summary Different ratios of gum acacia and maltodextrins were used to investigate the appropriate wall materials for encapsulation, by spray drying, of 2‐acetyl‐1‐pyrroline (ACPY). This compound, which is the major flavour component of aromatic rice, was extracted from pandan (Pandanus amaryllifolius) leaves by steam distillation. The amounts of ACPY before and after spray drying encapsulation were not significantly different (P < 0.05). Better retention of ACPY was obtained by encapsulation. In its liquid form ACPY degraded quickly as 63% reduction occurred in a basic solution after 7 days; however, only 30% reduction was found in acidic solution after 35 days of storage. After 72 days of storage, the amount of ACPY in encapsulated powders made with differing amounts of gum acacia and maltodextrin decayed as follows: ratios of gum acacia:maltodextrin of 70:30, 60:40, 50:50, 40:60, 30:70 and 0:100 gave the following amounts of degradation of 27.7, 33.4, 43.2, 35.7, 30.6 and 32.6% respectively. Encapsulation in 70:30 gum acacia:maltodextrin gave the best retention of ACPY.     

Physicochemical, nutritional, and antimicrobial properties of wine grape (cv. Merlot) pomace extract-based films

Abstract: Wine grape pomace (WGP) (cv. Merlot) extract‐based films were studied in terms of their physicochemical, mechanical, water barrier, nutritional, and antibacterial properties. Pomace extract (PE) was obtained by hot water extraction and had a total soluble solid of 3.6% and pH 3.65. Plant‐based polysaccharides, low methoxyl pectin (LMP, 0.75% w/w), sodium alginate (SA, 0.3% w/w), or Ticafilm^® (TF, 2% w/w), was added into PE for film formation, respectively. Elongation at break and tensile strength were 23% and 4.04 MPa for TF‐PE film, 25% and 1.12 MPa for SA‐PE film, and 9.89% and 1.56 MPa for LMP‐PE film. Water vapor permeability of LMP‐PE and SA‐PE films was 63 and 60 g mm m^?2 d^?1 kPa, respectively, lower than that of TF‐PE film (70 g mm m^?2 d^?1 kPa) (P < 0.05). LMP‐PE film had higher water solubility, indicated by the haze percentage of water after 24 h of film immersion (52.8%) than that of TF‐PE (25.7%) and SA‐PE (15.9%) films, and also had higher amount of released phenolics (96.6%) than that of TF‐PE (93.8%) and SA‐PE (80.5%) films. PE films showed antibacterial activity against both Escherichia coli and Listeria innocua, in which approximate 5‐log reductions in E. coli and 1.7‐ to 3.0‐log reductions in L. innocua were observed at the end of 24 h incubation test compared with control. This study demonstrated the possibility of utilizing WGP extracts as natural, antimicrobial, and antioxidant promoting film‐forming material for various food applications. Practical Application: WGP extract‐based edible films with the addition of a small amount of commercial polysaccharides showed attractive color and comparable mechanical and water barrier properties to other edible films. The films also demonstrated their potential antioxidant and antimicrobial functions. Hence, they may be used as colorful wraps or coatings for food, pharmaceutical, or other similar applications.     

Polyphenol oxidase properties,anti-urease,and anti-acetylcholinesterase activity of Diospyros lotus L. (Plum Persimmon)

Diospyros lotus fruit polyphenol oxidase was purified using affinity chromatography, resulting in a 15-fold enrichment in specific activity. The purified enzyme, having 16.5 kDa molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, exhibited the highest activity toward 4-methylcatechol. Maximum diphenolase activity was reached at pH 7.0 and 60°C in the presence of 4-methylcatechol. K_m and V_max values were calculated as 3.8 mM and 1250 U/mg protein, respectively. Ascorbic acid was a promising inhibitor with an IC₅₀ value of 0.121 µM. The activity of the purified enzyme was stimulated by Fe²⁺, Sr²⁺, Zn²⁺, and K⁺ and deeply inhibited by Hg²⁺, at 1 mM final concentration. Aqueous extract of Diospyros lotus L. fruit showed strong substantial urease and acetylcholinesterase inhibition, with IC₅₀ values of 1.55 ± 0.05 and 16.75 ± 0.11 mg/mL, respectively.     

Characterisation of 2-Cys peroxiredoxin isozyme (Prx1) from Taiwanofungus camphorata (Niu-chang-chih): Expression and enzyme properties

Peroxiredoxins (Prxs) are a family of antioxidant peroxidases. The functions of Prxs comprises of cell protection against oxidative stress and regulation of cell proliferation. A putative 2-Cys Prx isozyme (Prx1) cDNA was cloned from Taiwanofungus camphorata (commonly known as Niu-chang-chih in Taiwan). The deduced amino acid sequence is conserved amongst the reported Prxs. A 3-D homology structure was created for this Prx1. To characterise the T. camphorata Prx1, the coding region was subcloned into a pAVD10 and transformed into Escherichia coli. The recombinant 6His-tagged Prx1 was expressed and purified by Ni²⁺-nitrilotriacetic acid sepharose. The purified enzyme showed two forms using a 15% SDS–PAGE. The enzyme retained 60% activity at 60 °C for 2.5 min. The enzyme was stable under a broad pH range from 5 to 11. The enzyme showed 57% activity after 40 min of incubation at 37 °C with trypsin. The ability of the enzyme to protect intact supercoiled plasmid DNA from ^·OH induced nicking was demonstrated.