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Abstract Centrifugal partition chromatography (CPC) and countercurrent chromatography (CCC) are two preparative techniques mainly used for the isolation and purification of natural products. While CPC benefits from a larger sample capacity, CCC typically provides better peak resolutions and hereby higher purities. In this study, we aimed to combine both advantages by the direct linking of CPC and CCC which was achieved by installation of switching valves and connection tube. The hyphenated CPC-CCC setup was tested with major alkylresorcinols which were obtained from a transesterified and hydrogenated rye extract. Injections of 1- and 5-g samples into the individual CCC system confirmed the limited sample capacity because of immediate flooding with the 5-g sample (total loss of stationary phase). In comparison, the CPC system was stable with 5- and 10-g samples but the peak resolution with 1-g sample was poorer than with the CCC system. Injections of 5- and 10-g samples into the CPC-CCC system were successful. However, a sample load of 10 g resulted in lower purities of the alkylresorcinols (80% or less) due to peak tailing. By contrast, injection of 5-g sample provided high amounts of ~ 1.2 g alkylresorcinols with purities of > 95%.

A Web-based dietary assessment tool-RiksmatenFlex-was developed for the national dietary survey of adolescents in Sweden. This study aimed to describe the Web-based method RiksmatenFlex and to test the validity of the reported dietary intake by comparing dietary intake with 24-hour dietary recalls (recall interviews), estimated energy expenditure, and biomarkers. Adolescents aged 11-12, 14-15, and 17-18 years were recruited through schools. In total, 78 students had complete dietary information and were included in the study. Diet was reported a few weeks apart with either RiksmatenFlexDiet (the day before and a random later day) or recall interviews (face-to-face, a random day later by phone) in a cross-over, randomized design. At a school visit, weight and height were measured and blood samples were drawn for biomarker analyses. Students wore an accelerometer for 7 days for physical activity measurements. Dietary intake captured by both dietary methods was compared, and energy intake captured by both methods was compared with the accelerometer-estimated energy expenditure (EEest). Intake of whole grain wheat and rye and fruit and vegetables by both methods was compared with alkylresorcinol and carotenoid concentrations in plasma, respectively. The mean of the reported energy intake was 8.92 (SD 2.77) MJ by RiksmatenFlexDiet and 8.04 (SD 2.67) MJ by the recall interviews (P=.01). Intake of fruit and vegetables was 224 (169) g and 227 (150) g, and whole grain wheat and rye intake was 12.4 (SD 13.2) g and 12.0 (SD 13.1) g, respectively; the intakes of fruit and vegetables as well as whole grain wheat and rye did not differ between methods. Intraclass correlation coefficients ranged from 0.57 for protein and carbohydrates to 0.23 for vegetables. Energy intake by RiksmatenFlexDiet was overreported by 8% (P=.03) but not by the recall interviews (P=.53) compared with EEest. The Spearman correlation coefficient between reported energy intake and EEest was 0.34 (P=.008) for RiksmatenFlexDiet and 0.16 (P=.21) for the recall interviews. Spearman correlation coefficient between whole grain wheat and rye and plasma total alkylresorcinol homologs was 0.36 (P=.002) for RiksmatenFlexDiet and 0.29 (P=.02) for the recall interviews. Spearman correlations between intake of fruit and vegetables and plasma carotenoids were weak for both dietary tools. The strongest correlations were observed between fruit and vegetable intake and lutein/zeaxanthin for RiksmatenFlexDiet (0.46; P<.001) and for recall interviews (0.28; P=.02). RiksmatenFlexDiet provides information on energy, fruit, vegetables, and whole grain wheat and rye intake, which is comparable with intake obtained from recall interviews in Swedish adolescents. The results are promising for cost-effective dietary data collection in upcoming national dietary surveys and other studies in Sweden. Future research should focus on how, and if, new technological solutions could reduce dietary reporting biases.

•Breakfast wheat alkylresorcinols (ARs) suppressed diet-induced obesity in mice.•Alkylresorcinols consumed at dinner did not suppress weight gain in mice.•Alkylresorcinol intake at breakfast increased fecal lipid excretion.•Alkylresorcinol intake at breakfast increased the homeostasis model assessment of insulin sensitivity.•Alkylresorcinol intake at breakfast suppressed diet-induced hyperleptinemia. The regular consumption of whole grains is linked to a lower likelihood of developing metabolic disorders. We previously found that chronic supplementation with wheat alkylresorcinols (ARs) prevents obesity and its associated metabolic symptoms induced by a high-fat high-sucrose diet (HFHSD) in mice. The aim of this study was to examine the time-of-day-dependence of these effects in mice. Eight-wk-old male C57 BL/6 J mice were individually housed under a 12-h light/dark cycle (Zeitgeber time; ZT0, lights on; ZT12, lights off) and given access to a HFHSD from ZT12–16 (activity onset) and ZT20–24 (activity offset) to respectively represent breakfast and dinner times for 3 wk. Thereafter, the HFHSD was replaced with the same diet containing 0.4% ARs at either ZT12–16 or ZT20–24 for 8 wk. Control mice received the HFHSD without ARs at both feeding times. Supplementation with ARs significantly suppressed feed efficiency when given at breakfast, but not at dinner. ARs consumed at breakfast increased fecal lipid content and decreased the expression of Fat/Cd36 in enterocytes that enhances lipid uptake, but did not affect hepatic and blood lipid levels. The consumption of ARs at breakfast also upregulated the expression of Irs1, a key gene for insulin signaling in white adipose tissue and attenuated elevated blood leptin levels induced by the diet. This led to high scores for the homeostasis model assessment of insulin sensitivity, and the adiponectin/leptin ratio, a negative index of adipose tissue dysfunction. These findings suggested that ARs ameliorate feed efficiency by decreasing dietary lipid absorption more effectively at the time of activity onset than offset. Further studies are needed to elucidate the molecular mechanism of the time-of-day-dependent effects of ARs on diet-induced metabolic disorders.

Background Alkylresorcinols (ARs) are compounds belonging to the class of phenolic lipids. A rich source of ARs are cereal grains such as rye, wheat, triticale or barley. ARs found in plants are characterized by a variety of biological properties such as antimicrobial, antifungal and cytotoxic activity. Moreover, they are proven to have a positive influence on human health. Here, we aimed to find and characterize the gene with ARs synthase activity in the species Secale cereale . Methods and results Using BAC library screening, two BAC clones containing the gene candidate were isolated and sequenced. Bioinformatic analyses of the resulting contigs were used to examine the structure and other features of the gene, including promoter, intron, 3’UTR and 5’UTR. Mapping using the FISH procedure located the gene on the 4R chromosome. Comparative analysis showed that the gene is highly similar to sequences coding for type III polyketide synthase. The level of gene expression in various parts of the plant was investigated, and the biochemical function of the gene was confirmed by heterologous expression in yeast. Conclusions The conducted analyses contributed to a better understanding of the processes related to ARs synthesis. Although the research concerned the rye model, the knowledge gained may help in understanding the genetic basis of ARs biosynthesis in other species of the Poaceae family as well.

Natural products are a valuable source of biologically active compounds with potential applications in medicine and agriculture. Unprecedented scaffold diversity of natural products and biocatalysts from their biosynthetic pathways are of fundamental importance. Heterologous expression and refactoring of natural product biosynthetic pathways are generally regarded as a promising approach to discover new secondary metabolites of microbial origin. Here, we present the identification of a new group of alkylresorcinols after transcriptional activation and heterologous expression of the type III polyketide synthase of Micromonospora endolithica. The most abundant compounds loseolamycins A1 and A2 have been purified and their structures were elucidated by NMR. Loseolamycins contain an unusual branched hydroxylated aliphatic chain which is provided by the host metabolism and is incorporated as a starter fatty acid unit. The isolated loseolamycins show activity against gram-positive bacteria and inhibit the growth of the monocot weed Agrostis stolonifera in a germination assay. The biosynthetic pathway leading to the production of loseolamycins is proposed in this paper.

Alkylresorcinols (∑ARs) are bioactive lipid compounds predominantly found in cereals. These amphiphilic compounds exist in a high structural diversity and can be divided into two main groups, i.e., 5-alkylresorcinols (ARs) and 2-methyl-5-alkylresorcinols (mARs). The pseudocereal quinoa has a very unique AR profile, consisting not only of straight-chain alkyl chains but also iso- and anteiso-branched isomers. Here, we describe a method for the isolation of such methyl-branched ARs and mARs from quinoa. The enrichment of the ∑AR fraction from the lipid extracts by centrifugal partition chromatography (CPC) was followed by ∑AR profiling using countercurrent chromatography (CCC) and GC/MS analysis of CCC fractions. A total of 112 ∑ARs could be detected, 63 of which had not been previously described in quinoa. Due to this high number of ∑ARs, the direct isolation of individual ARs was not possible using conventional CCC. Instead, the more powerful heart-cut mode was applied to enrich the target compounds. A final purification step—the separation of CCC-co-eluting mARs from ARs —was performed via silver ion chromatography. Altogether, ten rare branched-chain ∑ARs (five iso-branched mARs and five anteiso-branched ARs, including mAR19:0-i and AR20:0-a) were isolated with purities up to 98% in the double-digit mg range.

Background/objectivesStudies on the health effects of whole grains typically use self-reported intakes which are prone to large measurement errors. Dietary biomarkers that can provide an objective measure of intake are needed. New alkylresorcinol (AR) metabolites (3,5-dihydroxycinnamic acid (DHCA), 2-(3,5-dihydroxybenzamido)acetic acid (DHBA-glycine) and 5-(3,5-dihydroxyphenyl) pentanoic acid (DHPPTA)) in 24 h urine samples have been suggested as biomarkers for whole grain (WG) wheat and rye intake but remain to be evaluated in spot urine samples.Subjects/methodsThe reproducibility of the new AR metabolites (DHCA, DHBA-glycine and DHPPTA) was investigated in 4 repeated samples over a period of 2 wk in spot urine from 40 Swedish men and women enroled in the SCAPIS-study, after adjustment of creatinine. Metabolite concentrations were correlated with total whole grain intake estimated during the same period.ResultsThe medium-term reproducibility determined for DHCA, DHPPTA and DHBA-glycine varied from moderate to excellent (intra-class correlation coefficient = 0.35–0.67). Moreover, DHCA and DHBA-glycine were independently associated with self-reported total WG intake (β = 0.18, P = 0.08 and β = 0.18, P = 0.02, respectively) and all metabolites except for DHPPA were higher among women.ConclusionsThis study supports the idea of using AR metabolites in one or several spot urine samples as biomarkers of whole grain intake. These findings need to be confirmed in different populations.

The present review details in a first part the structures of secondary metabolites discovered in Proteaceae up to now. In a second part, biological activities of bis-5-alkylresorcinols, a typical group of metabolites from Proteaceae, and their cyclized analogues are summarized. The scientific data required to make the inventory were exclusively compiled from books and journals. Using the list of plant genus, the bibliographic references were collected from (i) The Dictionary of Natural Products (DNP) and (ii) SciFinder Chemical abstract services. More than 130 references were carefully analyzed to found about 327 secondary metabolites. The most important classes of metabolites in Proteaceae were found as phenol glycosides (31%), derivatives of 5-alkylresorcinols (30%) and tropane alkaloids (11%).

Wheat and rye, the most consumed whole grains (WG) in the Nordic countries, contain alkylresorcinols (AR) in their bran. AR concentrations in human adipose tissue might reflect long-term WG rye and wheat intake. We aimed to evaluate AR concentrations in adipose tissue biopsies as a long-term biomarker of WG wheat and rye intake in free-living Swedish men and women. Cross-sectional study. AR concentrations in adipose tissue biopsies were analysed and compared with long-term WG intake assessed by three FFQ (repeated over a period of 14 years in men, 17 years in women) and with plasma AR concentrations. The Cohort of Swedish Men between 1997 and 2010 and the Swedish Mammography Cohort between 1987 and 2003, Sweden. Men (n 149) and women (n 109). Long-term WG rye intake estimated with repeated FFQ correlated (r=0·31-0·41, P<0·01) with adipose-tissue AR concentrations, while WG wheat intake correlated only weakly (r=0·17-0·33, P<0·05). Total AR concentration in adipose tissue was 61 % lower in women than in men at similar energy-adjusted WG wheat and rye intakes, but plasma concentrations were similar. AR concentrations in adipose tissue correlated well with plasma concentrations (r=0·49-0·81, P<0·001). AR in adipose tissue reflected long-term WG rye but not WG wheat intake, probably due to poor precision in estimating WG wheat intake by FFQ. AR in adipose tissue appears promising as a biomarker of long-term WG rye intake but should be adjusted for sex.

Imbalanced nutrition, such as a high-fat/high-carbohydrate diet, is associated with negative effects on human health. The composition and metabolic activity of the human gut microbiota are closely related to the type of diet and have been shown to change significantly in response to changes in food content and food supplement administration. Alkylresorcinols (ARs) are lipophilic molecules that have been found to improve lipid metabolism and glycemic control and decrease systemic inflammation. Furthermore, alkylresorcinol intake is associated with changes in intestinal microbiota metabolic activity. However, the exact mechanism through which alkylresorcinols modulate microbiota activity and host metabolism has not been determined. In this study, alterations in the small intestinal microbiota (SIM) and the large intestinal microbiota (LIM) were investigated in mice fed a high-fat diet with or without pentadecylresorcinol (C15) supplementation. High-throughput sequencing was applied for jejunal and colonic microbiota analysis. The results revealed that C15 supplementation in combination with a high-fat diet could decrease blood glucose levels. High-throughput sequencing analysis indicated that C15 intake significantly increased (p < 0.0001) the abundance of the probiotic bacteria Akkermansia muciniphila and Bifidobacterium pseudolongum in both the small and large intestines and increased the alpha diversity of LIM (p < 0.05), but not SIM. The preliminary results suggested that one of the mechanisms of the protective effects of alkylresorcinol on a high-fat diet is the modulation of the content of SIM and LIM and metabolic activity to increase the probiotic bacteria that alleviate unhealthy metabolic changes in the host.