Identification of phenolic compounds in Equisetum giganteum by LC–ESI-MS/MS and a new approach to total flavonoid quantification

AbstractEquisetum giganteum L., commonly called “giant horsetail”, is an endemic species of Latin America. Its aerial parts have been widely used in ethnomedicine as a diuretic and in herbal medicine and food supplements as a raw material. The phenolic composition of E. giganteum stems was studied by liquid chromatography coupled to diode array detection (LC–DAD) and liquid chromatography coupled to electrospray ionization-tandem mass spectrometry (LC–ESI-MS/MS), which identified caffeic acid derivatives, flavonoids and styrylpyrones. The most abundant glycosilated flavonoids in this sample were kaempferol derivatives. Other rare phenolic components, namely, quercetin-3-O-(caffeoyl)-glucoside and 3-hydroxyhispidin-3,4′-di-O-glucoside, were reported for first time in the Equisetum genus. An LC-UV method for the simultaneous quantification of flavonoid aglycones in E. giganteum obtained after hydrolysis was developed and validated. The method exhibited excellent linearity for all analytes, with regression coefficients above 0.998, LOD≥0.043μgmL−1, LOQ≥0.158μgmL−1 and recovery rates of 96.89–103.33% and 98.22–102.49% for quercetin and kaempferol, respectively. The relative standard deviation for the intra- and inter-day precision was≤3.75%. The hydrolysis process was optimized by central composite rotational design and response surface analysis. The second-order response models for the aglycones contents were as follows: quercetin (μgg−1)=24.8102+55.2823×HCl+0.776997×Time−7.23852×HCl2−7.46528E−04×Time2−0.229167×HCl×Time; kaempferol (μgg−1)=−9.66755+974.822×HCl+11.8059×Time−130.612×HCl2−0.0125694×Time2 −3.22917×HCl×Time, with estimated optimal conditions of 1.18M HCl and 205min of hydrolysis. The results obtained with these new methods were compared to those from a spectrophotometric assay used to determine the total flavonoids in the Equisetum arvense monograph (Horsetail, British Pharmacopoeia 2011). For all four species analyzed (E. giganteum, E. arvense, E. hyemale and E. bogotense), the calculated aglycone content was higher using the optimized hydrolysis conditions. Additionally, the LC method was more appropriate and specific for quantitative analysis

SPSB1-mediated inhibition of TGF-β receptor-II impairs myogenesis in inflammation

BACKGROUND: Sepsis-induced intensive care unit-acquired weakness (ICUAW) features profound muscle atrophy and attenuated muscle regeneration related to malfunctioning satellite cells. Transforming growth factor beta (TGF-β) is involved in both processes. We uncovered an increased expression of the TGF-β receptor II (TβRII)-inhibitor SPRY domain-containing and SOCS-box protein 1 (SPSB1) in skeletal muscle of septic mice. We hypothesized that SPSB1-mediated inhibition of TβRII signalling impairs myogenic differentiation in response to inflammation. METHODS: We performed gene expression analyses in skeletal muscle of cecal ligation and puncture- (CLP) and sham-operated mice, as well as vastus lateralis of critically ill and control patients. Pro-inflammatory cytokines and specific pathway inhibitors were used to quantitate Spsb1 expression in myocytes. Retroviral expression plasmids were used to investigate the effects of SPSB1 on TGF-β/TβRII signalling and myogenesis in primary and immortalized myoblasts and differentiated myotubes. For mechanistical analyses we used coimmunoprecipitation, ubiquitination, protein half-life, and protein synthesis assays. Differentiation and fusion indices were determined by immunocytochemistry, and differentiation factors were quantified by qRT-PCR and Western blot analyses. RESULTS: SPSB1 expression was increased in skeletal muscle of ICUAW patients and septic mice. Tumour necrosis factor (TNF), interleukin-1β (IL-1β), and IL-6 increased the Spsb1 expression in C2C12 myotubes. TNF- and IL-1β-induced Spsb1 expression was mediated by NF-κB, whereas IL-6 increased the Spsb1 expression via the glycoprotein 130/JAK2/STAT3 pathway. All cytokines reduced myogenic differentiation. SPSB1 avidly interacted with TβRII, resulting in TβRII ubiquitination and destabilization. SPSB1 impaired TβRII-Akt-Myogenin signalling and diminished protein synthesis in myocytes. Overexpression of SPSB1 decreased the expression of early (Myog, Mymk, Mymx) and late (Myh1, 3, 7) differentiation-markers. As a result, myoblast fusion and myogenic differentiation were impaired. These effects were mediated by the SPRY- and SOCS-box domains of SPSB1. Co-expression of SPSB1 with Akt or Myogenin reversed the inhibitory effects of SPSB1 on protein synthesis and myogenic differentiation. Downregulation of Spsb1 by AAV9-mediated shRNA attenuated muscle weight loss and atrophy gene expression in skeletal muscle of septic mice. CONCLUSIONS: Inflammatory cytokines via their respective signalling pathways cause an increase in SPSB1 expression in myocytes and attenuate myogenic differentiation. SPSB1-mediated inhibition of TβRII-Akt-Myogenin signalling and protein synthesis contributes to a disturbed myocyte homeostasis and myogenic differentiation that occurs during inflammation

The Role of Host Traits, Season and Group Size on Parasite Burdens in a Cooperative Mammal

The distribution of parasites among hosts is often characterised by a high degree of heterogeneity with a small number of hosts harbouring the majority of parasites. Such patterns of aggregation have been linked to variation in host exposure and susceptibility as well as parasite traits and environmental factors. Host exposure and susceptibility may differ with sexes, reproductive effort and group size. Furthermore, environmental factors may affect both the host and parasite directly and contribute to temporal heterogeneities in parasite loads. We investigated the contributions of host and parasite traits as well as season on parasite loads in highveld mole-rats (Cryptomys hottentotus pretoriae). This cooperative breeder exhibits a reproductive division of labour and animals live in colonies of varying sizes that procreate seasonally. Mole-rats were parasitised by lice, mites, cestodes and nematodes with mites (Androlaelaps sp.) and cestodes (Mathevotaenia sp.) being the dominant ecto- and endoparasites, respectively. Sex and reproductive status contributed little to the observed parasite prevalence and abundances possibly as a result of the shared burrow system. Clear seasonal patterns of parasite prevalence and abundance emerged with peaks in summer for mites and in winter for cestodes. Group size correlated negatively with mite abundance while it had no effect on cestode burdens and group membership affected infestation with both parasites. We propose that the mode of transmission as well as social factors constrain parasite propagation generating parasite patterns deviating from those commonly predicted

EAACI position paper on occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and non-European countries on Occupational Rhinitis (OR), a disease of emerging relevance which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored on that of occupational asthma, as well as a diagnostic algorithm based on steps allowing for different levels of diagnostic evidence are proposed. The needs for future research are pointed out. Key messages are issued for each item