Three New Triterpene Glycosides from the Roots of x "Strawberry Fields" (Hydrangeaceae).

Three new triterpene glycosides were isolated from x "Strawberry Fields" cultivar via aqueous-ethanolic extraction of the roots, including one derivative of sumaresinolic acid and two of echinocystic acid: 3--β-D-glucuronopyranosylsumaresinolic acid 28--β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl ester, 3--β-D-glucuronopyranosylechinocystic acid 28--β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl ester, and 3--α-L-arabinopyranosyl-(1→3)-β-D-glucuronopyranosylechinocystic acid 28-O-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl ester. As none of the isolated saponins were previously documented in the literature, their structural elucidation required extensive 1D and homo- and heteronuclear 2D NMR spectroscopy, as well as mass spectrometry analysis. All three glycosides were tested for their stimulatory activity of the sweet taste receptor TAS1R2/TAS1R3.

Optimized vector for functional expression of the human bitter taste receptor TAS2R14 in HEK293 cells.

Bitter is one of the five basic taste qualities, along with salty, sour, sweet and umami, used by mammals to access the quality of their food and orient their eating behaviour. Bitter taste detection prevents the ingestion of food potentially contaminated by bitter-tasting toxins. Bitter taste perception is mediated by a family of G protein-coupled receptors (GPCRs) called TAS2Rs.

Ligand discrimination in hOR1A1 based on the capacitive response.

Odorant discrimination mechanisms are based on the differential interactions between odorant molecules and olfactory receptors (ORs). Biohybrid sensors based on ORs described to date show selectivity towards specific versus non-specific binding of odorants, being unable to distinguish between specific ligands of different affinity. Here we disclose a method that enables odorant discrimination based on the modulation of the capacitive response of the receptor, which allows the differentiation of three high-affinity hOR1A1 agonists.

A receptor-based assay to study the sweet and bitter tastes of sweeteners and binary sweet blends: the SWEET project.

Sweeteners are used in the food industry to provide sweetness similar to sugar and to decrease the caloric intake and risks associated with obesity. However, some sweeteners are characterized by bitter, metallic and other off-tastes. Sensory and cellular studies have demonstrated synergies between sweetener blends, which are responsible for enhancing sweetness.

A status report on human odorant receptors and their allocated agonists.

Olfactory perception begins when odorous substances interact with specialized receptors located on the surface of dedicated sensory neurons. The recognition of smells depends on a complex mechanism involving a combination of interactions between an odorant and a set of odorant receptors (ORs), where molecules are recognized according to a combinatorial activation code of ORs. Although these interactions have been studied for decades, the rules governing this ligand recognition remain poorly understood, and the complete combinatorial code is only known for a handful of odorants.

Millettia dubia De Wild. (Fabaceae): Structural analysis of the oleanane-type glycosides and stimulation of the sweet taste receptors TAS1R2/TAS1R3.

From the root barks of a Central African tree Millettia dubia De Wild. (Fabaceae), ten previously undescribed oleanane-type glycosides were isolated by various chromatographic protocols. Their structures were elucidated by spectroscopic methods, mainly 2D NMR experiments and mass spectrometry, as mono- and bidesmosidic glycosides of mesembryanthemoidigenic acid, hederagenin and oleanolic acid.

Modulation of bitter taste receptors by yeast extracts.

Yeast extracts (YEs) are used in foods because of their flavour properties and ability to reduce bitterness. The adenosine 5'-monophosphate (AMP) found in YEs is known to decrease the bitterness of some compounds. This study aimed to investigate the ability of YEs to inhibit bitter taste receptors (TAS2Rs) using in vitro cell-based assays.

Tas1R3 Dependent and Independent Recognition of Sugars in the Urethra and the Role of Tuft Cells in this Process.

Increased sugar concentrations on mucosal surfaces display risk factors for infections. This study aims to clarify sugar monitoring in the urethra. Urethral tuft cells (UTC) are known sentinels monitoring the urethral lumen for potentially harmful substances and initiating protective mechanisms.

Correction: The odorant metabolizing enzyme UGT2A1: Immunolocalization and impact of the modulation of its activity on the olfactory response.

[This corrects the article DOI: 10.1371/journal.pone.

M2OR: a database of olfactory receptor-odorant pairs for understanding the molecular mechanisms of olfaction.

Mammalian sense of smell is triggered by interaction between odorant molecules and a class of proteins, called olfactory receptors (ORs). These receptors, expressed at the surface of olfactory sensory neurons, encode myriad of distinct odors via a sophisticated activation pattern. However, determining the molecular recognition spectrum of ORs remains a major challenge.

Faba Bean ( L. ) Bitterness: An Untargeted Metabolomic Approach to Highlight the Impact of the Non-Volatile Fraction.

In the context of climate change, faba beans are an interesting alternative to animal proteins but are characterised by off-notes and bitterness that decrease consumer acceptability. However, research on pulse bitterness is often limited to soybeans and peas. This study aimed to highlight potential bitter non-volatile compounds in faba beans.

Activation of bitter taste receptors by saponins and alkaloids identified in faba beans (Vicia faba L. minor).

Despite their interests, faba beans are characterised by bitterness but little is known about its compounds that activate the 25 human bitter receptors (TAS2Rs). This study aimed to determine the bitter molecules in faba beans, especially saponins and alkaloids. These molecules were quantified by UHPLC-HRMS in flour, starch and protein fractions of 3 faba bean cultivars.

Oleanolic Acid Glycosides from and : Structural Analysis and Cytotoxicity.

In the field of research on medicinal plants from the Armenian flora, the phytochemical study of two L. species, M. Bieb.

Non-Volatile Compounds Involved in Bitterness and Astringency of Pulses: A Review.

Despite the many advantages of pulses, they are characterised by off-flavours that limit their consumption. Off-notes, bitterness and astringency contribute to negative perceptions of pulses. Several hypotheses have assumed that non-volatile compounds, including saponins, phenolic compounds, and alkaloids, are responsible for pulse bitterness and astringency.

Origins of volatile compounds and identification of odour-active compounds in air-classified fractions of faba bean (Vicia faba L. minor).

Faba bean (Vicia faba L. minor) has many interests but is characterised by off-notes (negative odours/aromas) due to volatile compounds that are promoted during seed processing. Little is known about the volatile compounds of faba bean and their contribution to its odour.

Activation of a Sweet Taste Receptor by Oleanane-Type Glycosides from .

The phytochemical study of (Sims) DC. (Fabaceae), commonly known as the Chinese Wisteria, led to the isolation of seven oleanane-type glycosides from an aqueous-ethanolic extract of the roots. Among the seven isolated saponins, two have never been reported before: 3--α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-β-D-glucuronopyranosyl-22--acetylolean-12-ene-3β,16β,22β,30-tetrol, and 3--β-D-xylopyranosyl-(1→2)-β-D-glucuronopyranosylwistariasapogenol A.

Proteomic Characterization of Proboscis.

flies use their proboscis to taste and distinguish edible compounds from toxic compounds. With their proboscis, flies can detect sex pheromones at a close distance or by contact. Most of the known proteins associated with probosci's detection belong to gustatory receptor families.

Detection of Bitterness in Vitamins Is Mediated by the Activation of Bitter Taste Receptors.

Vitamins are known to generate bitterness, which may contribute to an off-taste or aftertaste for some nutritional supplements. This negative sensation can lead to a reduction in their consumption. Little is known about the bitter taste threshold and taste sensing system for the bitter taste detection of vitamins.

Heat Treatment, Cultivar and Formulation Modify the Sensory Properties and Consumer Acceptability of Gels Containing Faba Bean ( L. ) Protein Concentrates.

Faba bean ( L. ) is an emerging plant-based ingredient due to its environmental, nutritional and functional benefits. However, like other pulses, it exhibits many off-flavours that limit its consumption.

Determination of the nanoscale electrical properties of olfactory receptor hOR1A1 and their dependence on ligand binding: Towards the development of capacitance-operated odorant biosensors.

The transduction of odorant binding into cellular signaling by olfactory receptors (ORs) is not understood and knowing its mechanism would enable developing new pharmacology and biohybrid electronic detectors of volatile organic compounds bearing high sensitivity and selectivity. The electrical characterization of ORs in bulk experiments is subject to microscopic models and assumptions. We have directly determined the nanoscale electrical properties of ORs immobilized in a fixed orientation, and their change upon odorant binding, using electrochemical scanning tunneling microscopy (EC-STM) in near-physiological conditions.

Functional Characterization of the Venus Flytrap Domain of the Human TAS1R2 Sweet Taste Receptor.

The human sweet taste receptor is a heterodimeric receptor composed of two distinct G-protein-coupled receptors (GPCRs), TAS1R2 and TAS1R3. The TAS1R2 and TAS1R3 subunits are members of a small family of class C GPCRs whose members share the same architecture, comprising a Venus Flytrap (VFT) module linked to the seven transmembrane domains (TMDs) by a short cysteine-rich region (CRR). The VFT module of TAS1R2 contains the primary binding site for most of the sweet-tasting compounds, including natural sugars and artificial and natural sweeteners.

Extracellular loop 2 of G protein-coupled olfactory receptors is critical for odorant recognition.

G protein-coupled olfactory receptors (ORs) enable us to detect innumerous odorants. They are also ectopically expressed in nonolfactory tissues and emerging as attractive drug targets. ORs can be promiscuous or highly specific, which is part of a larger mechanism for odor discrimination.