2 research outputs found
Inhibition of Glucose Transport by Tomatoside A, a Tomato Seed Steroidal Saponin, through the Suppression of GLUT2 Expression in Caco‑2 Cells
We
investigated whether tomatoside A (5α-furostane-3β,22,26-triol-3-[<i>O</i>-β-d-glucopyranosyl (1→2)-β-d-glucopyranosyl (1→4)-β-d-galactopyranoside]
26-<i>O</i>-β-d-glucopyranoside), a tomato
seed saponin, may play a role in the regulation of intestinal glucose
transport in human intestinal Caco-2 cells. Tomatoside A could not
penetrate through Caco-2 cell monolayers, as observed in the transport
experiments using liquid chromatography–mass spectrometry.
The treatment of cells with 10 μM tomatoside A for 3 h resulted
in a 46.0% reduction in glucose transport as compared to untreated
cells. Western blotting analyses revealed that tomatoside A significantly
(<i>p</i> < 0.05) suppressed the expression of glucose
transporter 2 (GLUT2) in Caco-2 cells, while no change in the expression
of sodium-dependent glucose transporter 1 was observed. In glucose
transport experiments, the reduced glucose transport by tomatoside
A was ameliorated by a protein kinase C (PKC) inhibitor and a multidrug
resistance-associated protein 2 (MRP2) inhibitor. The tomatoside A-induced
reduction in glucose transport was restored in cells treated with
apical sodium-dependent bile acid transporter (ASBT) siRNA or an ASBT
antagonist. These findings demonstrated for the first time that the
nontransportable tomato seed steroidal saponin, tomatoside A, suppressed
GLUT2 expression via PKC signaling pathway during the ASBT-influx/MRP2-efflux
process in Caco-2 cells
Metabolic Profiling Approach To Explore Compounds Related to the Umami Intensity of Soy Sauce
A metabolic
profiling approach was employed to explore the compounds
that affect the intensity of umami taste in soy sauce. Twenty-five
kinds of soy sauces were analyzed using GC-MS and LC-MS, wherein measurement
data for 427 compounds were obtained. The umami taste intensity of
each soy sauce sample was also quantitated by sensory evaluation and
a projection to latent structure (PLS) regression analysis was conducted
using the compounds’ measurements and umami taste intensity
data. Variable importance for the projection (VIP) value obtained
via PLS was used for the estimation of the relevance for umami taste
intensity. <i>N</i>-(1-Deoxyfructos-1-yl)Âglutamic acid (Fru-Glu)
had the highest VIP value, and addition of Fru-Glu to soy sauce increased
umami taste intensity better than glutamic acid at the same concentration
as confirmed by sensory evaluation. This study showed that the combination
of metabolic profiling approach and sensory evaluation can be used
effectively to determine compounds related to taste