Recent scientific evidences show that polyphenols derived from the olive tree leaf (Olea europaea) may have applications in obesity-related pathologies through AMPK activation. We aimed to explore ...the effect of olive leaf extract (OLE) on lipid accumulation, oxidative stress and mitochondrial potential in adipocyte model.
In the present work, we used a glucotoxicity-induced insulin-resistant hypertrophic 3T3-L1-adipocytes model. Intracellular ROS generation and mitochondrial function was measured by ROS-sensitive fluorescent probes.
Our results indicate that OLE showed the capacity to reduce triglyceride accumulation in hypertrophic adipocytes. In addition, the extract exhibited a dose-dependent decrease of intracellular ROS generations as well as restored the mitochondrial membrane potential in adipocytes. Therefore, olive leaf polyphenols may become for the dietary intervention focused on the management of obesity-associated disturbances.
The enrichment of cancer stem cell (CSC)-like cellular states has not previously been considered to be a causative mechanism in the generalized progression of EGFR-mutant non-small cell lung ...carcinomas (NSCLC) after an initial response to the EGFR tyrosine kinase inhibitor erlotinib. To explore this possibility, we utilized a pre-clinical model of acquired erlotinib resistance established by growing NSCLC cells containing a TKI-sensitizing EGFR exon 19 deletion (ΔE746-A750) in the continuous presence of high doses of erlotinib. Genome-wide analyses using Agilent 44K Whole Human Genome Arrays were evaluated via bioinformatics analyses through GSEA-based screening of the KEGG pathway database to identify the molecular circuitries that were over-represented in the transcriptomic signatures of erlotinib-refractory cells. The genomic spaces related to erlotinib resistance included a preponderance of cell cycle genes (E2F1, -2, CDC2, -6) and DNA replication-related genes (MCM4, -5, -6, -7), most of which are associated with early lung development and poor prognosis. In addition, metabolic genes such as ALDH1A3 (a candidate marker for lung cancer cells with CSC-like properties) were identified. Thus, we measured the proportion of erlotinib-resistant cells expressing very high levels of aldehyde dehydrogenase (ALDH) activity attributed to ALDH1/3 isoforms. Using flow cytometry and the ALDEFLUOR
®
reagent, we confirmed that erlotinib-refractory cell populations contained drastically higher percentages (>4500%) of ALDH
bright
cells than the parental erlotinib-responsive cells. Notably, strong decreases in the percentages of ALDH
bright
cells were observed following incubation with silibinin, a bioactive flavonolignan that can circumvent erlotinib resistance in vivo. The number of lung cancer spheres was drastically suppressed by silibinin in a dose-dependent manner, thus confirming the ability of this agent to inhibit the self-renewal of erlotinib-refractory CSC-like cells. This report is the first to show that: (1) loss of responsiveness to erlotinib in EGFR-mutant NSCLC can be explained in terms of erlotinib-refractory ALDH
bright
cells, which have been shown to exhibit stem cell-like properties; and (2) erlotinib-refractory ALDH
bright
cells are sensitive to the natural agent silibinin. Our findings highlight the benefit of administration of silibinin in combination with EGFR TKIs to target CSCs and minimize the ability of tumor cells to escape cell death in EGFR-mutant NSCLC patients.
The aqueous extracts of
Hibiscus sabdariffa
have been commonly used in folk medicine. Nevertheless, the compounds or metabolites responsible for its healthy effects have not yet been identified. The ...major metabolites present in rat plasma after acute ingestion of a polyphenol‐enriched
H
ibiscus sabdariffa
extract were characterized and quantified in order to study their bioavailability. The antioxidant status of the plasma samples was also measured through several complementary antioxidant techniques. High‐performance liquid chromatography coupled to time‐of‐flight mass spectrometry (
HPLC
‐
ESI
‐
TOF
‐
MS
) was used for the bioavailability study. The antioxidant status was measured by ferric reducing ability of plasma method, thiobarbituric acid reactive substances assay, and superoxide dismutase activity assay. Seventeen polyphenols and metabolites have been detected and quantified. Eleven of these compounds were metabolites. Although phenolic acids were found in plasma without any modification in their structures, most flavonols were found as quercetin or kaempferol glucuronide conjugates. Flavonol glucuronide conjugates, which show longer half‐life elimination values, are proposed to contribute to the observed lipid peroxidation inhibitory activity in the cellular membranes. By contrast, phenolic acids appear to exert their antioxidant activity through ferric ion reduction and superoxide scavenging at shorter times. We propose that flavonol‐conjugated forms (quercetin and kaempferol) may be the compounds responsible for the observed antioxidant effects and contribute to the healthy effects of
H
. sabdariffa
polyphenolic extract.
•Drying kinetics were well described considering a compositional diffusion model.•Effective diffusivity for pits fraction was higher than in pulps and peels one.•Drying at high temperatures led to an ...improved antioxidant potential.•Long drying times at high temperatures increased antioxidant potential.•An efficient extraction can be achieved in only 5h.
This work aims to evaluate the influence of olive pomace drying (a solid by-product of the olive oil industry) on both antioxidant potential and drying kinetics. The two main fractions of olive pomace (pits, PI and pulps+peels, P+P) were characterized by image analysis and density measurement. The drying process was analyzed in experiments carried out at different temperatures (from 50 to 150°C) and mathematically described from the diffusion and Weibull models. The antioxidant potential of the extracts (ethanol–water 80:20 v/v, 22±1°C, 170rpm for 24h) obtained from the dry product was analyzed by measuring the total phenolic content and antioxidant capacity and the main polyphenols were quantified by HPLC–DAD/MS–MS.
The drying behavior of olive pomace was well described by considering the diffusion in the PI and P+P fractions separately and the influence of temperature on effective moisture diffusivities was quantified by an Arrhenius type equation. The antioxidant potential was only mildly influenced by the drying temperature. However, long drying times at the highest temperature tested (150°C) significantly (p<0.05) increased the antioxidant potential.
Plant compounds are a potential source of new antimicrobial molecules against a variety of infections. Plant extracts suppose complex phytochemical libraries that may be used for the first stages of ...the screening process for antimicrobials. However, their large variability and complexity require fast and inexpensive methods that allow a rapid and adequate screening for antimicrobial activity against a variety of bacteria and fungi. In this study, a multi-well plate assay using the AlamarBlue registered fluorescent dye was applied to screen for antimicrobial activity of several botanical extracts and the data were correlated with microbial colony forming units (CFU). This correlation was performed for three pathogenic model microorganisms: Escherichia coli (Gram negative bacteria), Staphylococcus aureus (Gram positive bacteria) and for the yeast-like fungi Candida albicans. A total of ten plant extracts from different Mediterranean plants, including several Cistus and Hibiscus species, were successfully tested. HPLC-DAD-ESI-MS/MS analysis was utilized for the characterization of the extracts in order to establish structure-activity correlations. The results show that extracts enriched in ellagitannins and flavonols are promising antibacterial agents against both Gram positive and Gram negative bacteria. In contrast, phenolic acids, anthocyanidins and flavonols may be related to the observed antifungal activity.
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