Structurally different mixed linkage ß-glucan supplements differentially increase secondary bile acid excretion in hypercholesterolaemic rat faeces.

Mixed linkage (1→3),(1→4)-ß-d-glucan (BG) is a soluble fibre available from oat and barley grains that has been gaining interest due to its health-promoting role in cardiovascular diseases and its ability to modulate the glycaemic index which is beneficial for people with diabetes. This study investigates the effect of three purified barley BGs, with different molecular weight and block structure, on faecal bile acid excretion in hypercholesterolaemic rats. Wistar rats (48 male) were divided in four groups: Control group fed with the cellulose-rich diet (CON); Glucagel group fed with the commercial BG (GLU, 100 kDa), and rats fed with low molecular weight BG (LBG, 150 kDa) and medium molecular weight BG (MBG, 530 kDa). The bile acid profiles of rat faecal samples were measured using gas chromatography-mass spectrometry (GC-MS). A metabolite profiling approach led to the identification of 7 bile acids and 45 other compounds such as sterols, fatty acids and fatty alcohols. Subsequent application of ANOVA-simultaneous component analysis and Principal Component Analysis revealed that all three BG diets increased bile acid faecal excretion compared to the control group. The bile acid excretion was found to be different in all three BG diets and the MBG group showed a significantly higher level of faecal secondary bile acids, including deoxycholic acid, hyodeoxycholic acid, and lithocholic acid. We hypothesise that the hydrophobic surface of the secondary bile acids, which are known to cause colon cancer, has high affinity to the hydrophobic surfaces of cellulosic blocks of the BG. This in vivo study demonstrates that the molecular weight and/or block structures of BG modulate the excretion of secondary bile acids. This finding suggests that developing diets with designed BGs with an optimal molecular structure to trap carcinogenic bile acids can have a significant impact on counteracting cancer and other lifestyle associated diseases.

Novel stilbenoids, including cannabispiradienone glycosides, from Tragopogon tommasinii (Asteraceae, Cichorieae) and their potential anti-inflammatory activity.

A phytochemical investigation of Tragopogon tommasinii Sch.Bip. (Asteraceae, Cichorieae) yielded a total of 21 natural products, two simple phenolic acids (4-hydroxybenzoic acid and p-coumaric acid), four caffeic acid derivatives (chlorogenic acid, 3-O-caffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, and 4,5-O-dicaffeoylquinic acid), six flavonoids (luteolin, luteolin 7-O-glucoside, vitexin, orientin, quercetin 3-O-glucoside, and isorhamnetin 3-O-glucoside), three simple bibenzyls [2-carboxyl-5-hydroxy-3-methoxy-4'-ß-glucopyranosyl-oxybibenzyl, 3-caffeoyl-(9→5)-ß-apiosyl-(1→6)-ß-glucopyranosyloxy-5,4'-dihydroxy-3'-methoxybibenzyl, 3-caffeoyl-(9→5)-ß-apiosyl-(1→6)-ß-glucopyranosyloxy-4'-dihydroxy-5,3'-dimethoxybibenzyl], three phtalides [3-(4-ß-glucopyranosyloxybenzyl)-7-hydroxy-5-methoxyphtalide, 7-ß-glucopyranosyloxy-(S)-3-(4-hydroxybenzyl)-5-methoxyphtalide, and 7-(1→6)-α-rhamnosyl-ß-glucopyranosyloxy-(S)-3-(4-hydroxybenzyl)-5-methoxyphtalide], two cannabispiradienone derivatives [3-O-ß-glucopyranosyldemethoxycannabispiradienone and 3-caffeoyl-(9→5)-ß-apiosyl-(1→6)-ß-glucopyranosyloxydemethoxycannabispiradienone], and tetra-N-coumaroyl spermine. The three bibenzyls, the latter two benzylphthalides, and both cannabispiradienone derivatives represent new natural compounds and all compounds, except the caffeic acid derivatives and the flavonoids were new for T. tommasinii. The structures were established by HR mass spectrometry, extensive 1D and 2D NMR spectroscopy, and CD spectroscopy. Moreover, the potential anti-inflammatory activities of the new compounds were assayed using human neutrophils and their production of IL-1b, IL-8, TNF-α and MMP-9 as well as the expression of TLR-4, respectively.

Application of "magnetic tongue" to the sensory evaluation of extra virgin olive oil.

The perception of odour and flavour of foods is a complicated physiological and psychological process that cannot be explained by simple models. Unfortunately, taste is not objective, but partially subjective and it depends also on the mood of the taster. Generally, sensory analysis is used to describe sensory features. The availability of a number of instrumental techniques has opened up the possibility to calibrate the sensory perception. Here we have tested the potentiality of nuclear magnetic resonance spectroscopy as "magnetic tongue" to measure sensory descriptors in extra-virgin olive oil. We were able to correlate the NMR metabolomic fingerprints of extra-virgin olive oil to the sensory descriptors: tomato, bitter, pungent, rosemary, artichoke, sweet, grassy and leaf.

A more detailed picture of the interactions between virtual screening-derived hits and the DNA G-quadruplex: NMR, molecular modelling and ITC studies.

The growing amount of literature about G-quadruplex DNA clearly demonstrates that such a structure is no longer viewed as just a biophysical strangeness but it is instead being considered as an important target for the treatment of various human disorders such as cancers or venous thrombosis. In this scenario, with the aim of finding brand new molecular scaffolds able to interact with the groove of the DNA quadruplex [d(TGGGGT)](4), we recently performed a successful structure-based virtual screening (VS) campaign. As a result, six molecules were found to be somehow groove binders. Herein, we report the results of novel NMR titration experiments of these VS-derived ligands with modified quadruplexes, namely [d(TGG(Br)GGT)](4) and [d(TGGGG(Br)T)](4). The novel NMR spectroscopy experiments combined with molecular modelling studies, allow for a more detailed picture of the interaction between each binder and the quadruplex DNA. Noteworthy, isothermal titration calorimetry (ITC) measurements on the above-mentioned compounds revealed that 2, 4, and 6 besides their relatively small dimensions bind the DNA quadruplex [d(TGGGGT)](4) with higher affinity than distamycin A, to the best of our knowledge, the most potent groove binder identified thus far.

NMR solution structure of a parallel LNA quadruplex.

The solution structure of a locked nucleic acid (LNA) quadruplex, formed by the oligomer d(TGGGT), containing only conformationally restricted LNA residues is reported. NMR and CD spectroscopy, as well as molecular dynamics and mechanic calculations, has been used to characterize the complex. The molecule adopts a parallel stranded conformation with a 4-fold rotational symmetry, showing a right-handed helicity and the guanine residues in an almost planar conformation with three well-defined G-tetrads. The thermal stability of Q-LNA has been found to be comparable with that of [r(UGGGU)]4, while a T(m) increment of 20 degrees C with respect to the corresponding DNA quadruplex structure [d(TGGGT)]4 has been observed. The structural features of the LNA quadruplex reported here may open new perspectives for the biological application of LNAs as novel versatile tools to design aptamer or catalyst oligonucleotides.