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The genetic basis of type 1 red-flesh color development in apple (Malus domestica) depends upon a particular allele of the MdMYB10 gene. Interestingly, type 1 red-flesh apples are fully red after fruit set, but anthocyanin pigmentation in apple fruit cortex may decrease during fruit growth and maturation, leading to variable red patterning and intensities in the mature cortical flesh. We developed a histogram-based color analysis method to quantitatively estimate pigmentation patterns. This methodology was applied to investigate the phenotypic diversity in four hybrid F1 families segregating for red-flesh color. Pigmentation patterns were found to be heritable allowing the identification of a new locus by QTL analysis. To further investigate the mechanisms involved in the spatial deposition of anthocyanin, metabolome, transcriptome and methylome comparisons between white and red flesh areas within the red-flesh genotype cv. 'R201' exhibiting flesh pigmentation patterns, was performed. Wide-targeted analysis showed that white-flesh areas accumulate more dihydrochalcones and hydroxycinnamic acids than red-flesh areas while red-flesh areas accumulate more flavonoids. Anthocyanin biosynthesis genes and anthocyanin positive regulators (MBW complex) were up-regulated in red-flesh areas, while a reduction in anthocyanin storage, transport and stability (increase of pH, down-regulation of MdGSTU22) and an increase in phenolic catabolism were concomitant with color fading process in white-flesh areas. Expression of MdGSTU22 was linked to a differentially methylated region (DMR) suggesting a potential environmental effect on the epigenetic control of gene expression involved in color fading. Altogether, these results provide the first characterization and functional identification of color fading in apple fruit flesh. [ABSTRACT FROM AUTHOR]

Chronic elevated blood pressure impinges on the functioning of multiple organs and therefore harms body homeostasis. Elucidating the protective mechanisms whereby the organism copes with sustained or repetitive blood pressure rises is therefore a topical challenge. Here we address this issue in the adrenal medulla, the master neuroendocrine tissue involved in the secretion of catecholamines, influential hormones in blood pressure regulation. Combining electrophysiological techniques with catecholamine secretion assays on acute adrenal slices from spontaneously hypertensive rats, we show that chromaffin cell stimulus-secretion coupling is remodeled, resulting in a less efficient secretory function primarily upon sustained cholinergic challenges. The remodeling is supported by revamped both cellular and tissular mechanisms. This first includes a decrease in chromaffin cell excitability in response to sustained electrical stimulation. This hallmark was observed both experimentally and in a computational chromaffin cell model, and occurs with concomitant changes in voltage-gated ion channel expression. The cholinergic transmission at the splanchnic nerve-chromaffin cell synapses and the gap junctional communication between chromaffin cells are also weakened. As such, by disabling its competence to release catecholamines in response sustained stimulations, the hypertensive medulla has elaborated an adaptive shielding mechanism against damaging effects of redundant elevated catecholamine secretion and associated blood pressure. [ABSTRACT FROM AUTHOR]

Gemmotherapy, a natural therapy based on bud macerates, has recently gained importance in the field of food supplements. However, two coexisting extraction methods employ a glycerin-based solvent, either in a binary or ternary solvent mixture. The absence of an official method for bud preparation leads to non-standardized bud macerates. Given this context, this study aimed to (i) assess the influence of solvent composition on the chemical profile of olive young shoot macerates obtained using glycerin-based solvents or using different solvent extractions and (ii) to compare the two coexisting traditional bud extraction methods described by Dr Pol Henry and by the European Pharmacopoeia. A comprehensive phytochemical analysis of all macerates was conducted using HPLC-DAD-ELSD-MS2, identifying 50 metabolites divided into 7 classes through dereplication. The extracts obtained with the solvent described by the European Pharmacopoeia (ethanol/glycerin) and by Dr Pol Henry (water/ethanol/glycerin) appeared to be the most diversified in terms of metabolite distribution and possessed higher rates of secondary metabolites. These observations reinforce the interest in a glycerin-based solvent mixture for bud extraction in gemmotherapy. In addition, the difference in composition between the two traditional solvents was highlighted. Indeed, iridoids were predominant in both macerates, representing about 50% of the chemical composition, but differences were observed from one macerate to another regarding the proportions of the other chemical classes. This emphasizes the necessity for standardized gemmotherapy macerates. [ABSTRACT FROM AUTHOR]

Introduction: Propolis is a resinous natural substance collected by honeybees from buds and exudates of various trees and plants; it is widely accepted that the composition of propolis depends on the phytogeographic characteristics of the site of collection. Objectives: The aim of this study was to determine the phytochemical composition of ethanolic extracts from eight propolis batches collected in different regions of Benin (north, center, and south) and Congo, Africa. Material and methods: Characterization of propolis samples was performed by using different hyphenated chromatographic methods combined with carbon‐13 nuclear magnetic resonance (13C NMR) dereplication with MixONat software. Their antioxidant or anti‐advanced glycation end‐product (anti‐AGE) activity was then evaluated by using diphenylpicrylhydrazyl and bovine serum albumin assays, respectively. Results: Chromatographic analyses combined with 13C NMR dereplication showed that two samples from the center of Benin exhibited, in addition to a huge amount of pentacyclic triterpenes, methoxylated stilbenoids or phenanthrenoids, responsible for the antioxidant activity of the extract for the first one. Among them, combretastatins might be cytotoxic. For the second one, the prenylated flavanones known in Macaranga‐type propolis were responsible for its significant anti‐AGE activity. The sample from Congo was composed of many triterpene derivatives belonging to Mangifera indica species. Conclusion: Therefore, propolis from the center of Benin seems to be of particular interest, due to its antioxidant and anti‐AGE properties. Nevertheless, as standardization of propolis is difficult in tropical zones due to its great chemodiversity, a systematic phytochemical analysis is required before promoting the use of propolis in food and health products in Africa. The composition of propolis depends on the phytogeographic characteristics of the collection site, including the plant species in the area. Propolis samples were analyzed using chromatographic methods combined with 13C NMR dereplication and MixONat software. Two Beninese ethanolic extracts showed common pentacyclic triterpenes and methoxylated stilbenoids or phenanthrenoids responsible for the antioxidant activity, and prenylated flavanones with significant anti‐AGE activity. The sample from Congo contained triterpene derivatives belonging to Mangifera indica species. [ABSTRACT FROM AUTHOR]

The isoquinoline alkaloids (IAs) represent a large and diverse subfamily of phytochemicals in terms of structures and pharmacological activities, including ion channel inhibition. Several IAs, such as liriodenine (an oxoaporphine) and curine (a bisbenzylisoquinoline (BBIQ), inhibit the L-type voltage-gated Ca2+ channels (LTCC). In this study, we aimed to search for new blockers of LTCC, which are therapeutic targets in neurological and cardiovascular diseases. We set up a screening assay using the rat pituitary GH3b6 cell line, which expresses two LTCC isoforms, CaV1.2 and CaV1.3. Both LTCC subtypes can be indirectly activated by KCl concentration elevation or directly by the dihydropyridine (DHP), BAY K8644, leading to an increase in the intracellular Ca2+ concentration ([Ca2+]i). These Ca2+ responses were completely blocked by the selective LTCC DHP inhibitor, nifedipine. Thereby, 16 selected IAs were tested for their ability to inhibit KCl and BAY K8644-induced Ca2+ responses. We then identified three new potent LTCC blockers, namely, oxostephanine, thaliphyline, and thalmiculine. They inhibited LTCC with IC50 values in the micromolar range through interaction to a binding site different to that of dihydropyridines. The two subfamilies of IAs, oxoaporphine with oxostephanine, and BBIQs with both thalyphilline and thalmiculine, constitute interesting pharmacophores for the development of future therapeutic leads for neurological and cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Voltage-gated Na+ (NaV) channels are significant therapeutic targets for the treatment of cardiac and neurological disorders, thus promoting the search for novel NaV channel ligands. With the objective of discovering new blockers of NaV channel ligands, we screened an In-House vegetal alkaloid library using fluorescence cell-based assays. We screened 62 isoquinoline alkaloids (IA) for their ability to decrease the FRET signal of voltage sensor probes (VSP), which were induced by the activation of NaV channels with batrachotoxin (BTX) in GH3b6 cells. This led to the selection of five IA: liriodenine, oxostephanine, thalmiculine, protopine, and bebeerine, inhibiting the BTX-induced VSP signal with micromolar IC50. These five alkaloids were then assayed using the Na+ fluorescent probe ANG-2 and the patch-clamp technique. Only oxostephanine and liriodenine were able to inhibit the BTX-induced ANG-2 signal in HEK293-hNaV1.3 cells. Indeed, liriodenine and oxostephanine decreased the effects of BTX on Na+ currents elicited by the hNaV1.3 channel, suggesting that conformation change induced by BTX binding could induce a bias in fluorescent assays. However, among the five IA selected in the VSP assay, only bebeerine exhibited strong inhibitory effects against Na+ currents elicited by the hNav1.2 and hNav1.6 channels, with IC50 values below 10 µM. So far, bebeerine is the first BBIQ to have been reported to block NaV channels, with promising therapeutical applications. [ABSTRACT FROM AUTHOR]