Olive leaf extracts are rich in polyphenolic compounds. Their inclusion by impregnation in food solid matrices could improve the nutritional value and antioxidant capacity of dietary products, such ...as apple. Drying the food matrix is interesting not only because it speeds up the infusion but also because of its effect on the final stabilization of impregnated food. In this work, the influence of drying method on the retention of infused olive leaf polyphenols in a solid matrix (apple) was addressed. For this purpose, apple cubes (10 mm side) were initially dehydrated by freeze drying or hot air drying at 60 °C and then impregnated with the olive leaf extract. After the polyphenolic infusion, samples were dried for the final stabilization by means of three different methods: freeze drying and hot air drying at 60 °C both with and without ultrasound application. The retention of infused polyphenols in apple samples was evaluated by determining the total phenolic content and antioxidant capacity and quantifying the main olive leaf polyphenols by HPLC-DAD/MS–MS. The drying kinetics and the loss of apple solids during impregnation were modeled by using diffusion equations and the Weibull model, respectively. The role of fresh apple drying on the retention of infused olive leaf polyphenols was more significant than the further drying of the impregnated apple. Thus, hot air drying of fresh apple provided the highest antioxidant capacity (47.1 ± 2.6 mg Trolox/g d.m.), and oleuropein contents in the final dried apple of up to 1,928 mg/100 g d.m. were found.
•Impact of drying and storage on olive leaf polyphenols has been studied.•Drying of leaves determined the bioactive content of extracts during storage.•Extracts dehydration only meant a reduction in ...antioxidant potential of around 10%.•Extract form (liquid or powder) and storage temperature did not affect phenolic content.
There is an increasing demand for natural antioxidants in the food, cosmetics and pharmaceutical industries which has led to the search not only for natural extracts but also for strategies with which to increase long-term storage stability. The aim of this work was to assess the influence of the drying and storage of olive leaf extracts on the bioactive potential and stability of polyphenols. Olive leaves were hot air dried (120°C) and freeze dried. Then the extracts were obtained by maceration (ethanol–water, 80:20, v/v). Afterwards, a part of the extracts was hot air dried at 120°C and vacuum dehydrated at 55°C. Thus, the extracts, in liquid and powder forms, were stored at 4, 25 and 35°C for 4 weeks. During this period, the extracts were characterized by determining the antioxidant capacity (AC), the total phenolic content (TPC) and the concentration of the major phenolic compounds.
The experimental results highlighted that drying the raw material not only influenced the initial extract composition but also the bioactive potential evolution during storage. Regardless of the method used, extract dehydration reduced both the AC and TPC by around 10%. Finally, storage conditions (temperature and extract form) did not have a significant (p<0.05) effect on the extracts’ antioxidant potential.
Previous findings on the capacity of Hibiscus sabdariffa (HS) polyphenols to ameliorate metabolic disturbances justify the necessity of studies oriented to find the potential metabolites responsible ...for such an effect. The present study examined the intestinal epithelial membrane permeability of polyphenols present in a phenolic-enriched Hibiscus sabdariffa extract (PEHS), free and encapsulated, using the Caco-2 cell line. Additionally, selected polyphenols (quercetin, quercetin-3-glucoside, quercetin-3-glucuronide, and N-feruloyltyramine) were also studied in the same absorption model. The powerful analytical platform used ultra-high-performance liquid chromatography coupled with ultra-high-resolution quadrupole time-of-flight mass spectrometry (UHPLC-ESI-UHR-Qq-TOF-MS), and enabled the characterization of seven new compounds in PEHS. In the permeation study, only a few compounds were able to cross the cell monolayer and the permeability was lower when the extract was in an encapsulated form. Pure compounds showed a moderate absorption in all cases. Nevertheless, these preliminary results may need further research to understand the complete absorption mechanism of Hibiscus polyphenols.
Marine compounds are a potential source of new anticancer drugs. In this study, the antiproliferative effects of 20 invertebrate marine extracts on three colon cancer cell models (HGUE-C-1, HT-29, ...and SW-480) were evaluated. Extracts from two nudibranchs (
, NA and
, NB), a holothurian (
, PS), and a soft coral (
sp., CR) were selected due to their potent cytotoxic capacities. The four marine extracts exhibited strong antiproliferative effects and induced cell cycle arrest at the G2/M transition, which evolved into early apoptosis in the case of the CR, NA, and NB extracts and necrotic cell death in the case of the PS extract. All the extracts induced, to some extent, intracellular ROS accumulation, mitochondrial depolarization, caspase activation, and DNA damage. The compositions of the four extracts were fully characterized via HPLC-ESI-TOF-MS analysis, which identified up to 98 compounds. We propose that, among the most abundant compounds identified in each extract, diterpenes, steroids, and sesqui- and seterterpenes (CR); cembranolides (PS); diterpenes, polyketides, and indole terpenes (NA); and porphyrin, drimenyl cyclohexanone, and polar steroids (NB) might be candidates for the observed activity. We postulate that reactive oxygen species (ROS) accumulation is responsible for the subsequent DNA damage, mitochondrial depolarization, and cell cycle arrest, ultimately inducing cell death by either apoptosis or necrosis.
It is estimated that over 60% of the approved drugs and new drug developments for cancer and infectious diseases are from natural origin. The use of natural compounds as a potential source of ...antitumor agents has been deeply studied in many cancer models, both in vitro and in vivo. Most of the Western medicine studies are based on the use of highly selective pure compounds with strong specificity for their targets such as colchicine or taxol. Nevertheless, approximately 60% of fairly specific drugs in their initial research fail because of toxicity or ineffectiveness in late-stage preclinical studies. Moreover, cancer is a multifaceted disease that in most cases deserves a polypharmacological therapeutic approach. Complex plant-derived mixtures such as natural extracts are difficult to characterize and hardly exhibit high pharmacological potency. However, in some cases, these may provide an advantage due to their multitargeted mode of action and potential synergistic behavior. The polypharmacology approach appears to be a plausible explanation for the multigargeted mechanism of complex natural extracts on different proteins within the same signalling pathway and in several biochemical pathways at once. This review focuses on the different aspects of natural extracts in the context of anticancer activity drug development, with special attention to synergy studies and xenohormesis.
► First time description of an AMP loaded-immunoliposome system targeted to virus. ► Direct inactivation of VHSV particles by melittin loaded-immunoliposomes in vitro. ► Melittin ...loaded-immunoliposomes also reduce VHSV spread in vitro.
In this study, melittin, a well-characterized pore-forming lytic amphiphilic peptide susceptible to be vehiculized in lipid membranes, has been utilized to study their antiviral properties. For this purpose, an assay based on melittin loaded-immunoliposomes previously described by our group was adapted to antiviral purposes by means of monoclonal antibodies targeting the surface G glycoprotein of the fish viral haemorrhagic septicemia rhabdovirus (VHSV). We also studied the antiviral action of these immunoliposomes in vitro and the results showed that they are capable of inhibiting the VHSV infectivity by 95.2% via direct inactivation of the virus. Furthermore, the inhibition of the infectivity when treatments were added at different times post-infection and the analysis of the infection foci sizes suggested altogether that they also act by reducing the VHSV spread in cell culture and by killing the infected cells which express the G glycoprotein in their plasmatic membranes.
There is growing evidence that natural products, mostly plant-derived polyphenols, are important in the relationship between nutrients and health in humans.
We aimed to investigate if verbascoside ...(VB) and other lemon verbena polyphenols could ameliorate obesity-induced metabolic disturbances, as well as their putative mechanism.
We used an insulin-resistant hypertrophic 3T3-L1-adipocyte model to test the effects of VB or lemon verbena extract on triglyceride accumulation, inflammation and oxidative stress and a murine model of diet-induced obesity to assess the in vivo metabolic response.
Polyphenols decreased triglyceride accumulation, the generation of reactive oxygen species (ROS) and restored mitochondrial membrane potential in adipocytes. The underlying mechanisms seemed to occur via ROS-mediated downregulation of nuclear factor kappa-B transcription factor (NF-κB) and peroxisome proliferator-activated receptor gamma (PPAR-γ)-dependent transcriptional upregulation of adiponectin. We also observed a potent activation of AMP-activated protein kinase (AMPK), the mRNA expression upregulation of PPAR-α and the mRNA expression downregulation of fatty acid synthase. Experiments in mice suggested a significant improvement in fat metabolism.
Decreased lipogenesis, enhanced fatty acid oxidation and the activation of the energy sensor AMPK, probably through activating transcriptional factors, are involved in the observed beneficial effects. VB effects were less potent than those observed with the extract, so a potential synergistic, multi-targeted action is proposed. The polypharmacological effects of plant-derived polyphenols from lemon verbena may have the potential for clinical applications in obesity.
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Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammation and impaired airway immunity, providing an opportunistic platform for nontypeable
(NTHi) infection. In this ...context, therapies targeting not only overactive inflammation without significant adverse effects, but also infection are of interest. Increasing evidence suggests that polyphenols, plant secondary metabolites with anti-inflammatory and antimicrobial properties, may be protective. Here, a
plant extract containing quercetin, myricetin, and punicalagin was shown to reduce NTHi viability. Analysis of these polyphenols revealed that quercetin has a bactericidal effect on NTHi, does not display synergies, and that bacteria do not seem to develop resistance. Moreover, quercetin lowered NTHi airway epithelial invasion through a mechanism likely involving inhibition of Akt phosphorylation, and reduced the expression of bacterially-induced proinflammatory markers
,
,
,
, and
. We further tested quercetin's effect on NTHi murine pulmonary infection, showing a moderate reduction in bacterial counts and significantly reduced expression of proinflammatory genes, compared to untreated mice. Quercetin administration during NTHi infection on a zebrafish septicemia infection model system showed a bacterial clearing effect without signs of host toxicity. In conclusion, this study highlights the therapeutic potential of the xenohormetic molecule quercetin against NTHi infection.
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► Cistus extracts exhibit antimicrobial activity against E. coli and S. aureus. ► C. salviifolius phenolic fraction exhibits bacteriostatic and bactericidal activity. ► Galloylated ...flavanols, ellagitannins and flavonols may be the responsible compounds. ► C. salviifolius extracts may be antimicrobial ingredients for hygiene or cosmetics. ► Potential synergistic effects among Cistus polyphenols may deserve further studies.
Cistaceae is a large family of shrubs commonly distributed in the Mediterranean ecosystem. The aim of this study was to explore the potential antimicrobial properties against Escherichia coli and/or Staphylococcus aureus of different extracts obtained from four Cistaceae species that are especially abundant in Spanish semi-arid regions. MIC50 values of the extracts of C. salviifolius exhibited potent bacteriostatic effects against S. aureus compared with the other Cistus species tested. Spray-drying had less impact on the antimicrobial activities and polyphenolic contents than did evaporation followed by freeze-drying. When C. salviifolius extract was concentrated and the polar fraction was removed, its bacteriostatic and bactericidal activities against both strains were significantly enhanced. Seasonal influences on the composition have also been found. Up to 48 compounds were found in the aqueous extract of C. salviifolius using RRLC–ESI–TOF–MS. The analysis of the composition of the extracts revealed that the inhibitory activity against E. coli may be related to the presence of galloylated flavanols and specific flavonols, whereas the inhibitory capacity against S. aureus may be related primarily to polar compounds and to other flavonols. Potential synergistic effects among polyphenols may deserve further studies. These extracts may serve as an alternative source of antimicrobial ingredients focused on medical devices or cosmetics.
Cistus albidus L. (Cistaceae) is a medicinal plant that has been used therapeutically since ancient times in the Mediterranean basin for its important pharmacological properties. The ability of C. ...albidus to produce large quantities of a wide range of natural metabolites makes it an attractive source of raw material. The main constituents with bioactive functions that exert pharmacological effects are terpenes and polyphenols, with more than 200 identified compounds. The purpose of this review is to offer a detailed account of the botanical, ethnological, phytochemical, and pharmacological characteristics of C. albidus with the aim of encouraging additional pharmaceutical investigations into the potential therapeutic benefits of this medicinal plant. This review was carried out using organized searches of the available literature up to July 2023. A detailed analysis of C. albidus confirms its traditional use as a medicinal plant. The outcome of several studies suggests a deeper involvement of certain polyphenols and terpenes in multiple mechanisms such as inflammation and pain, with a potential application focus on neurodegenerative diseases and disorders. Other diseases such as prostate cancer and leukemia have already been researched with promising results for this plant, for which no intoxication has been reported in humans.
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