Extraction and fractionation of alkylresorcinols from triticale bran by two-step supercritical carbon dioxide

Dissecting dietary alkylresorcinols: a compile of their distribution, biosynthesis, extraction and functional properties

Alkylresorcinols (ARs) are natural bioactive ingredients produced by: bacteria, fungi, sponges, and higher plants, possessing a lipophilic polyphenol structure with a myriad of biological properties. Focusing on the importance of ARs, several analogs can be extracted from different natural resources. Interestingly, the composition of ARs is usually reflective of their source, with structural differences to exist among ARs isolated from different natural sources. The identified compounds from marine are distinguished by sulfur atom and disulfide bond, while the alkyl chain of bacterial homologs are recognized for their saturated fatty acid chains. ARs occurrence in fungi is still poorly documented however most of the isolated fungal molecules are characterized by a sugar unit attached to their alkylated side chains. The biosynthetic pathway of ARs is postulated via a type III polyketide synthase in which the fatty-acyl chain is elongated and cyclized to generate ARs. The structure-activity relationship (SAR) has gained an increasing interest to mediate for ARs biological activities as discussed herein for the first time from their different resources. ARs extraction procedures showed much progress compared to classical methods compiling organic solvents with supercritical extraction appearing as a potential technique for producing highly purified food-grade of AR homologs. The current review also presents on the rapid qualitative and quantitative determination of ARs to increase accessibility for screening cereals as potential sources of these bioactives.

Comprehensive Study of Si-Based Compounds in Selected Plants (Pisum sativum L., Medicago sativa L., Triticum aestivum L.)

This review describes the role of silicon (Si) in plants. Methods of silicon determination and speciation are also reported. The mechanisms of Si uptake by plants, silicon fractions in the soil, and the participation of flora and fauna in the Si cycle in terrestrial ecosystems have been overviewed. Plants of Fabaceae (especially Pisum sativum L. and Medicago sativa L.) and Poaceae (particularly Triticum aestivum L.) families with different Si accumulation capabilities were taken into consideration to describe the role of Si in the alleviation of the negative effects of biotic and abiotic stresses. The article focuses on sample preparation, which includes extraction methods and analytical techniques. The methods of isolation and the characterization of the Si-based biologically active compounds from plants have been overviewed. The antimicrobial properties and cytotoxic effects of known bioactive compounds obtained from pea, alfalfa, and wheat were also described.

Sustainable solvents for β-diketone extraction from wheat straw wax and their molecular self-assembly into nano-structured tubules for hydrophobic coatings

Nonpolar, nonperoxide forming, sustainable and potentially bio-based solvents, namely 2,2,5,5-tetramethyloxolane (TMO) and 2,5-diethyl-2,5-dimethyloxolane (DEDMO), were utilized as an alternative to toxic petroleum-based hydrocarbon solvents for extraction of hentriacontane-14,16-dione from waste wheat straw waxes. This work is the first to report the application of DEDMO as a solvent for the extraction of natural products. The sustainable methodology developed in this research provided considerable advantages over previously reported systems in terms of high extraction yields, excellent selectivity towards the β-diketones and low amounts of waste generated. DEDMO provided the highest recovery yield for all the sustainable solvents investigated, recovering 23.7% of the wax (which is a 68.8% yield of the β-diketone). The extracted lipophilic hentriacontane-14,16-dione was utilised in combination with the sustainable solvents TMO or DEDMO to facilitate the creation of highly hydrophobic coatings. Moreover, the use of DEDMO was found to aid in the self-assembly of nano-structured tubule formation of both the unrefined wax and isolated β-diketone. Green metric evaluation using process mass intensity (PMI), E-factor, solvent intensity (SI), and water intensity (WI) demonstrated that the described extraction procedure for hentriacontane-14,16-dione was highly sustainable and safer than the previous methodology. This sustainable manufacturing process may create the potential to valorise agricultural wastes as part of a holistic biorefinery.

Content of Phenolic Acids in the Grain of Selected Polish Triticale Cultivars and Its Products

The triticale grain has high nutritive value and good technological suitability. Triticale flour can be a valuable raw material for bread-making. The aim of this work was to determine the profile of phenolic acids in triticale grain of selected Polish cultivars and its products. Ultra-high-performance liquid chromatography (UPLC-PDA-MS/MS) was applied for separation and identification of these constituents. The grain of the examined triticale cultivars contained 13 phenolic acids, of which ferulic acid was determined in the largest amount and was constituted from 42–44% of the total content of phenolic acids in the grain. In addition, due to the large amounts of ferulic, di-ferulic, and sinapic acids, composition of the phenolic acids fraction in triticale grain of the tested cultivars varied in comparison with that of wheat and rye cultivars. In triticale flour, the number of phenolic acids was nearly 4 times lower than in the grain, as phenolic acids were removed along with bran, in which their proportion was almost 9 times higher than in the grain intended for grinding. The application of bran in the bread recipe resulted in a 3.5-fold increase in the fraction of phenolic acids compared to the bread produced from triticale flour without bran addition.

Inhibitors of α-amylase and α-glucosidase: Potential linkage for whole cereal foods on prevention of hyperglycemia

The strategy of reducing carbohydrate digestibility by controlling the activity of two hydrolyzing enzymes (α-amylase and α-glucosidase) to control postprandial hyperglycemia is considered as a viable prophylactic treatment of type 2 diabetes mellitus (T2DM). Thus, the consumption of foods rich in hydrolyzing enzyme inhibitors is recommended for diet therapy of diabetes. Whole cereal products have gained increasing interests for plasma glucose-reducing effects. However, the mechanisms for whole cereal benefits in relation to T2DM are not yet fully understood, but most likely involve bioactive components. Cereal-derived phenolic compounds, peptides, nonstarch polysaccharides, and lipids have been shown to inhibit α-amylase and α-glucosidase activities. These hydrolyzing enzyme inhibitors seem to make whole cereals become nutritional strategies in managing postmeal glucose for T2DM. This review presents an updated overview on the effects provided by cereal-derived ingredients on carbohydrate digestibility. It suggests that there is some evidence for whole cereal intake to be beneficial in amelioration of T2DM through inhibiting α-glucosidase and α-amylase activities.

Bioactive Compounds of a Wheat Bran Oily Extract Obtained with Supercritical Carbon Dioxide

A wheat bran oily extract obtained with supercritical carbon dioxide at 25.0 ± 0.1 MPa and 40 ± 2 °C has been analyzed in order to determine some valuable bioactive compounds as alkylresorcinols, α-linolenic acid, steryl ferulates, tocopherols and phenolic compounds, which levels were around 47, 37, 18, 7 and 0.025 mg/g oily extract, respectively. To our knowledge, this is the first time that the presence of steryl ferulates has been observed in a supercritical fluid extract of wheat bran and that γ-tocopherol has been described in wheat bran oily extracts. Other common quality parameters, directly correlated with oxidative degradation, were also evaluated. Acidity values around 15% oleic acid were detected, while low levels of hydroperoxides (around 2.4 meq O₂/kg) and very low levels of hexanal (0.21 ppb) were found. Composition of the wheat bran oily extract was stable during 155 days of storage at 21 °C and darkness, and only a slight decrease in alkylresorcinols and tocopherols contents (13% and 20%, respectively) was observed. These results indicated an attractive potential of the obtained oily extract for industrial applications as food ingredients, nutraceuticals, and others.

Targeted Metabolite Profiling-Based Identification of Antifungal 5-n-Alkylresorcinols Occurring in Different Cereals against Fusarium oxysporum

A rapid and convenient biochemometrics-based analysis of several cereal-derived extracts was used to identify n-alkyl(enyl)resorcinols (AR) as antifungals against Fusarium oxysporum. Total AR content and liquid chromatography/mass spectrometry (LC-MS)-based profiles were recorded for each extract, in addition to their antifungal activity, to help integrate these chemical and biological datasets by orthogonal partial least squares regression. In this study, we developed and used a micro-scale amended medium (MSAM) assay to evaluate the in vitro mycelial growth inhibition at low amounts of extracts. Triticale husk-derived extracts had the highest AR content (662.1 µg olivetol equivalent/g dry extract), exhibiting >79% inhibition at the highest doses (10.0–1.0 µg/µL). Correlation of the chemical and antifungal datasets using supervised metabolite profiling revealed that 5-n-nonadecanylresorcinol, 5-n-heneicosylresorcinol, and 5-n-tricosyl-resorcinol were the most active ARs occurring in cereal products from Colombia. Hence, we propose the biochemometrics-based approach as a useful tool for identifying AR-like antifungals against F. oxysporum.

Comprehensive study of valuable lipophilic phytochemicals in wheat bran

Wheat bran, the major side-stream generated in the milling of wheat grains in the production of white flour, contains significant quantities of carbohydrate and proteins. While not interfering with flour utilization, the bran could be considered as an important feedstock within a biorefinery concept. Wheat bran also contains some amounts of lipids that can be used as a source of valuable phytochemicals. Gas chromatography and mass spectrometry analysis of the lipid composition of destarched wheat bran demonstrated that the predominant lipids found in wheat bran were free fatty acids (ca. 40% of total lipids), followed by acylglycerols (40%). Additionally, important amounts of alkylresorcinols (13% of total lipids) and steroid compounds (hydrocarbons, ketones, free sterols, sterol glycosides, sterol esters, and sterol ferulates) (7% of total lipids) were also present among the lipids of wheat bran. The use of wheat bran as a valuable source of phytochemicals of interest in the context of a wheat bran biorefinery is discussed.

Supercritical fluid extraction in natural products analyses

Supercritical fluids (SCFs) are increasingly replacing the organic solvents, e.g., n-hexane, chloroform, dichloromethane, or methanol, that are conventionally used in industrial extraction, purification, and recrystallization operations because of regulatory and environmental pressures on hydrocarbon and ozone-depleting emissions. In natural products extraction and isolation, supercritical fluid extraction (SFE), especially employing supercritical CO(2), has become a popular choice. Sophisticated modern technologies allow precise regulation of changes in temperature and pressure, and thus manipulation of solvating property of the SCF, which helps the extraction of natural products of a wide range of polarities. This chapter deals mainly with the application of the SFE technology in the natural products extraction and isolation, and outlines various methodologies with specific examples.

Antioxidant activity of alkylresorcinols from rye bran and their protective effects on cell viability of PC-12 AC cells

Alkylresorcinols (ARs) are phenolic lipids that are present in high amounts in the bran layer of different cereals. Rye samples, cultivar Hazlet, and a white rye genotype, RT202, were analyzed for their antioxidant properties and AR content and composition, based on six fractions of the bran, where 1 was the outermost fraction and 6 was the bran fraction closest to the endosperm. Gas chromatography-mass spectrometry (GC-MS) analysis demonstrated that the most commonly found AR homologue in Hazlet rye is C19:0 and that the total amount of ARs decreases from the outermost to innermost fractions. The antioxidant activity using oxygen radical absorbance capacity (ORAC) for both white rye genotype RT202 and Hazlet brans was determined to decrease from the outermost fraction (136.05 μmol TE/g for Hazlet fraction 1 and 186.57 μmol TE/g for white rye genotype RT202 fraction 1) to the innermost fraction (9.84 μmol TE/g for Hazlet fraction 6 and 78.75 μmol TE/g for white rye genotype RT202 fraction 2). A positive relationship was seen with GC-MS results. Treatment of PC-12 AC cells with Hazlet fraction 1 increased mitochondrial biogenesis as determined using mitochondrial fluorescent dyes. In the presence of a prooxidant (AAPH), PC-12 AC cells were better protected from free radical attack when treated with Hazlet fraction 1 than with all other bran fractions. The results suggest that higher AR content in bran fractions confers antioxidant protection against free radical damage.