Formation and Characterization of Green Tea Extract Loaded Liposomes

Differential effects of theasinensins and epigallocatechin-3-O-gallate on phospholipid bilayer structure and liposomal aggregation

(-)-Epigallocatechin-3-O-gallate (EGCg), the major catechin responsible for the health-enhancing and disease-preventive effects of green tea, is susceptible to auto-oxidation at physiological pH levels. However, whether the oxidized EGCg resulting from its oral consumption possesses any bioactive functions remains unclear. This study presents a differential analysis of intact and oxidized EGCg regarding their interactions with phosphatidylcholine liposomes, serving as a simple biomembrane model. In the presence of ascorbic acid, pre-oxidized EGCg induced liposomal aggregation in a dose-dependent manner, whereas intact EGCg did not. Toxicity evaluation using calcein-loaded liposomes revealed that liposomal aggregation is associated with minimal membrane damage. Through fractionation of the oxidized EGCg sample, the fraction containing theasinensins showed high liposomal aggregation activity. Overall, these results suggest that oxidatively condensed EGCg dimers may stimulate various cells by altering the plasma membrane in a manner different from that of EGCg monomers.

Rosehip Extract-Loaded Liposomes for Potential Skin Application: Physicochemical Properties of Non- and UV-Irradiated Liposomes

In the present study, rosehip (Rosa canina L.) extract was successfully encapsulated in phospholipid liposomes using a single-step procedure named the proliposome method. Part of the obtained liposomes was subjected to UV irradiation and non-treated (native) and UV-irradiated liposomes were further characterized in terms of encapsulation efficiency, chemical composition (HPLC analysis), antioxidant capacity, particle size, PDI, zeta potential, conductivity, mobility, and antioxidant capacity. Raman spectroscopy as well as DSC analysis were applied to evaluate the influence of UV irradiation on the physicochemical properties of liposomes. The encapsulation efficiency of extract-loaded liposomes was higher than 90%; the average size was 251.5 nm; the zeta potential was -22.4 mV; and the conductivity was found to be 0.007 mS/cm. UV irradiation did not cause a change in the mentioned parameters. In addition, irradiation did not affect the antioxidant potential of the liposome-extract system. Raman spectroscopy indicated that the extract was completely covered by the lipid membrane during liposome entrapment, and the peroxidation process was minimized by the presence of rosehip extract in liposomes. These results may guide the potential application of rosehip extract-loaded liposomes in the food, pharmaceutical, or cosmetic industries, particularly when liposomal sterilization is needed.

Encapsulation of Hydrophobic Apigenin into Small Unilamellar Liposomes Coated with Chitosan Through Ethanol Injection and Spray Drying

Despite the multiple health benefits, natural flavonoid apigenin has poor aqueous solubility that restricts its delivery in foods. This study investigated the potential of spray-dried chitosan-coated liposomes prepared from scalable methods for the food industry as the delivery carriers for apigenin. Apigenin-loaded small unilamellar liposomes produced from ethanol injection had an encapsulation efficiency of 74.88 ± 5.31%. They were electrostatically stabilised via chitosan coating (0.25% w/v) and spray-dried. Spray-dried chitosan-coated apigenin liposomes (SCAL) exhibited the following powder characteristics: yield 66.62 ± 3.08%, moisture content 4.33 ± 0.56%, water activity 0.2242 ± 0.0548, particle size 10.97 ± 1.55 μm, nearly spherical morphology with wrinkles and dents under microscopic observation. Compared with the unencapsulated apigenin, SCAL demonstrated improved aqueous solubility (10.22 ± 0.18 mg/L), higher antioxidant capacity, and stability against simulated gastrointestinal digestion. The chitosan coating gave a slower in-vitro release of apigenin in SCAL (77.0 ± 6.2%) than that of uncoated apigenin liposomes (94.0 ± 5.3%) at 12 h. The apigenin release kinetics from SCAL could be represented by the Korsmeyer-Peppas model (R2 = 0.971). These findings suggest that SCAL could be a promising delivery system of apigenin for functional food applications.

TRAIL mediated apoptosis ruling and anticancer trigger by fine-tuned nano spheres of Fagonia cretica methanolic extracts as novel cancer regime

Fagonia cretica L. is a tropical plant of family Zygophyllaceae with wide range of medicinally important secondary metabolites. The low cellular uptake of the polar compounds in the extract of the plant limits its biological application. In present study efficacy of F. cretica modified bioactive nano-formulations for in vitro modulation of TRAIL mediated extrinsic apoptotic pathway as cancer therapy was investigated. F. cretica methanolic extracts were formulated at nano-scale for green synthesis of silver nanoparticles, albumin conjugation and liposomes encapsulation to enhance targeted bioactivity against cancer. Physical characterization of the synthesized nanoparticles was done by SEM, EDX and Zeta potential analyzer. In vitro cell viability assay MTT was done for MCF-7, Hep-2, HUH-7 and HCEC cell lines. Relative expression variation of the apoptotic pathway-associated genes was done by qRT-PCR. SEM revealed spherical shape of 56.62 ± 8.04, 143 ± 11.54 and 83.36 ± 38.73 nm size and zeta potential - 18.6, - 15.5 and - 18.3 mV for liposomes, silver and albumin nanoparticles. Silver nanoparticles showed highest anticancer activity in vitro than albumin and liposomes nanoparticles with IC₅₀ 0.101 ± 0.004, 0.177 ± 0.03 and 0.434 ± 0.022 mg/mL in MCF-7, Hep-2 and HUH-7 respectively. F. cretica albumin and silver nanoparticles upregulated the in vitro TRAIL, DR4, DR5 and FADD gene expression at statistically significant levels in Hep-2 cell lines. Nano-formulations of F. cretica proved therapeutically important biomolecules in vitro. The hypothesized modulation of extrinsic apoptosis pathway genes through the plant nanoparticles proved novel medicinal options for effective treatment of cancer and enhancing the bioavailability of the active plant metabolites.

Encapsulation of bioactive compounds extracted from date palm seeds (Phoenix dactylifera L.) and their use in functional food

Liposomes have been used as a novel phytoconstituent delivery system to encapsulate lyophilized palm seed phenolic extract (PSPE) and incorporate it into yogurt as a food model to enhance the bioavailability of PSPE. Phenolic compounds were extracted with aqueous ethanol from palm seed powder using the solvent-maceration approach assisted by ultrasonication. Lyophilized PSPE (0.2-1% w/v) was enclosed in a liposome structure coated with or without chitosan (primary/secondary liposome). Particle size, zeta potential, encapsulation efficiency (EE), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were applied to investigate the primary and secondary liposomes. To assess the in vitro bioaccessibility of PSPE and primary/secondary liposomes, the total phenolic content (TPC) and the antioxidant activity were studied during the oral, gastric, and intestinal digestion stages. Three concentrations of lyophilized secondary liposomes (1.25, 2.5, and 3.75% w/v) were added to the yogurt food model. During the 14 days of storage, the physical, chemical, and sensory properties were assessed. Compared to the primary liposomes (87%), the secondary liposomes (91%) showed a higher encapsulation efficiency. Comparing the secondary liposomes to the original liposomes and the non-encapsulated PSPE, the bioaccessibility of phenolic compounds was improved. Fortified yogurt with secondary liposomes had a lower syneresis and viscosity than the reference yogurt. The encapsulated PSPE provided a good level of protection, and its release increased throughout the intestinal phase. Thus, PSPE in a microencapsulated form has been proven to be a rich and cost-effective source of phenolics that can be used successfully to produce functional yogurt.

Dynamic high pressure treatments: current advances on mechanistic-cum-transport phenomena approaches and plant protein functionalization

Dynamic high pressure treatment (DHPT) either by high pressure homogenization or microfluidisation, is an emerging concept used in the food industry for new products development through macromolecules modifications in addition to simple mixing and emulsification action. Mechanistic understanding of droplets breakup during high pressure homogenization is used to understand how these compact and high molecular weight-sized globular plant proteins are affected during DHPTs. Plant protein needs to be functionalized for advanced use in food formulation. DHPTs brought changes in plant proteins' secondary, tertiary, and quaternary structures through alterations in intermolecular and intramolecular interactions, sulfhydryl groups, and disulfide bonds. These structural changes in plant proteins affected their functional and physicochemical properties like solubility, oil and water holding capacity, gelation, emulsification, foaming, and rheological properties. These remarkable changes made utilization of this concept in novel food system applications like in plant-based dairy analogues. Overall, this review provides a comprehensive and critical understanding of DHPTs on their mechanistic and transport approaches for droplet breakup, structural and functional modification of plant macromolecules. This article also explores the potential of DHPT for formulating plant-based dairy analogues to meet healthy and sustainable food consumption needs. HIGHLIGHTSIt critically reviews high pressure homogenization (HPH) and microfluidisation (DHPM).It explores the mechanistic and transport phenomena approaches of HPH and DHPMHPH and DHPM can induce conformational and structural changes in plant proteins.Improvement in the functional properties of HPH and DHPM treated plant proteins.HPH and DHPM are potentially applicable for plant based dairy alternatives food system.

Green Tea Epigallocatechin-3-Gallate Regulates Autophagy in Male and Female Reproductive Cancer

With a rich abundance of natural polyphenols, green tea has become one of the most popular and healthiest nonalcoholic beverages being consumed worldwide. Epigallocatechin-3-gallate (EGCG) is the predominant catechin found in green tea, which has been shown to promote numerous health benefits, including metabolic regulation, antioxidant, anti-inflammatory, and anticancer. Clinical studies have also shown the inhibitory effects of EGCG on cancers of the male and female reproductive system, including ovarian, cervical, endometrial, breast, testicular, and prostate cancers. Autophagy is a natural, self-degradation process that serves important functions in both tumor suppression and tumor cell survival. Naturally derived products have the potential to be an effective and safe alternative in balancing autophagy and maintaining homeostasis during tumor development. Although EGCG has been shown to play a critical role in the suppression of multiple cancers, its role as autophagy modulator in cancers of the male and female reproductive system remains to be fully discussed. Herein, we aim to provide an overview of the current knowledge of EGCG in targeting autophagy and its related signaling mechanism in reproductive cancers. Effects of EGCG on regulating autophagy toward reproductive cancers as a single therapy or cotreatment with other chemotherapies will be reviewed and compared. Additionally, the underlying mechanisms and crosstalk of EGCG between autophagy and other cellular processes, such as reactive oxidative stress, ER stress, angiogenesis, and apoptosis, will be summarized. The present review will help to shed light on the significance of green tea as a potential therapeutic treatment for reproductive cancers through regulating autophagy.

Flavonoids: Food associations, therapeutic mechanisms, metabolism and nanoformulations

Flavonoids possess an impressive therapeutic potential, thereby imparting them a nutraceutical character. As it becomes increasingly common to consume foods associated with healing properties, it is imperative to understand the associations of different foods with different classes of nutraceutic compounds, and their mechanisms of therapeutic action. At the same time, it is important to address the limitations thereof so that plausible future directions may be drawn. This review summarizes the food associations of flavonoids, and discusses the mechanisms responsible for imparting them their nutraceutic properties, detailing the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway, inhibition of inflammatory signaling pathways such as toll-like receptor (TLR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), cyclooxygenase 2 (COX-2) and lipoxygenase-2 (LOX-2) mediators. Further on, the review explains the mechanism of flavonoids metabolism, reasons for low bioavailability and thereafter recapitulates the role of technological interventions to overcome the limitations, with a particular focus on nanoformulations that utilize the synergy between flavonoids and biocompatible materials used as nanocarriers, as reported in works spanning over a decade. It is the Generally Recognized as Safe (GRAS) classified carriers that will become the basis for developing functional formulations. It is promisingly noteworthy that some flavonoid formulations have been commercialized and mentioned therein. Such commercially viable and safe for consumption technological applications pave way for bringing science to the table, and add value to the innate properties of flavonoids.

Encapsulation of catechin into nano-cyclodextrin-metal-organic frameworks: Preparation, characterization, and evaluation of storage stability and bioavailability

This study, nanoscale α-, β-, γ-cyclodextrin (CD)-metal-organic frameworks (MOFs) were successfully prepared using solvothermal assisted ultrasound method. CD-MOFs were used as nanocarriers to encapsulate catechin (CA), and their encapsulation capacities were evaluated. Encapsulation capacities of CD-MOFs to incorporate CA followed the order: β-CD-MOFs > γ-CD-MOFs > α-CD-MOFs. CA/CD-MOFs were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). DSC and SEM results provided evidence for the formation of CA/CD-MOFs. XRD results indicated the new solid crystalline phases formed in CA/CD-MOFs complex. Results of FT-IR showed that CA was combined with CD-MOFs through hydrogen bonding and van der Waals forces. Current research demonstrated that encapsulation of CA within CD-MOFs provided it against light, oxygen and temperature. Moreover, encapsulation by CD-MOFs improved storage stability and bioavailability of CA. Thus, these CA/CD-MOFs have potential to be used as nutritional supplements and functional foods.

Chemico-biological aspects of (-)-epigallocatechin-3-gallate (EGCG) to improve its stability, bioavailability and membrane permeability: Current status and future prospects

Natural products have been a bedrock for drug discovery for decades. (-)-Epigallocatechin-3-gallate (EGCG) is one of the widely studied natural polyphenolic compounds derived from green tea. It is the key component believed to be responsible for the medicinal value of green tea. Significant studies implemented in in vitro, in cellulo, and in vivo models have suggested its anti-oxidant, anti-cancer, anti-diabetic, anti-inflammatory, anti-microbial, neuroprotective activities etc. Despite having such a wide array of therapeutic potential and promising results in preclinical studies, its applicability to humans has encountered with rather limited success largely due to the poor bioavailability, poor membrane permeability, rapid metabolic clearance and lack of stability of EGCG. Therefore, novel techniques are warranted to address those limitations so that EGCG or its modified analogs can be used in the clinical setup. This review comprehensively covers different strategies such as structural modifications, nano-carriers as efficient drug delivery systems, synergistic studies with other bioactivities to improve the chemico-biological aspects (e.g., stability, bioavailability, permeability, etc.) of EGCG for its enhanced pharmacokinetics and pharmacological properties, eventually enhancing its therapeutic potentials. We think this review article will serve as a strong platform with comprehensive literature on the development of novel techniques to improve the bioavailability of EGCG so that it can be translated to the clinical applications.

Natural Compounds With Antimicrobial and Antiviral Effect and Nanocarriers Used for Their Transportation

Due to the increasing prevalence of life-threatening bacterial, fungal and viral infections and the ability of these human pathogens to develop resistance to current treatment strategies, there is a great need to find and develop new compunds to combat them. These molecules must have low toxicity, specific activity and high bioavailability. The most suitable compounds for this task are usually derived from natural sources (animal, plant or even microbial). In this review article, the latest and most promising natural compounds used to combat bacteria, filamentous fungi and viruses are presented and evaluated. These include plant extracts, essential oils, small antimicrobial peptides of animal origin, bacteriocins and various groups of plant compounds (triterpenoids; alkaloids; phenols; flavonoids) with antimicrobial and antiviral activity. Data are presented on the inhibitory activity of each natural antimicrobial substance and on the putative mechanism of action against bacterial and fungal strains. The results show that among the bioactive compounds studied, triterpenoids have significant inhibitory activity against coronaviruses, but flavonoids have also been shown to inhibit SARS-COV-2. The last chapter is devoted to nanocarriers used to improve stability, bioavailability, cellular uptake/internalization, pharmacokinetic profile and reduce toxicity of natural compunds. There are a number of nanocarriers such as liposomes, drug delivery microemulsion systems, nanocapsules, solid lipid nanoparticles, polymeric micelles, dendrimers, etc. However, some of the recent studies have focused on the incorporation of natural substances with antimicrobial/antiviral activity into polymeric nanoparticles, niosomes and silver nanoparticles (which have been shown to have intrinsic antimicrobial activity). The natural antimicrobials isolated from animals and microorganisms have been shown to have good inhibitory effect on a range of pathogens, however the plants remain the most prolific source. Even if the majority of the studies for the biological activity evaluation are in silico or in vitro, their internalization in the optimum nanocarriers represents the future of “green therapeutics” as shown by some of the recent work in the field.

Effects of Phytosterol Butyrate Ester on the Characteristics of Soybean Phosphatidylcholine Liposomes

The nutritional and structural properties of phytosterols (PS)/phytosterol esters (PEs) facilitate their use as substitutes for cholesterol in liposome encapsulation systems designed for oral drugs and health products. The purpose of this study was to determine the effect of phytosterol butyrate ester (PBE) on the properties of liposomes. PBE was encapsulated within liposomes (approximately 60 nm) prepared using soybean phosphatidylcholine using the thin-film hydration method. There was no significant change in the average particle diameter and zeta potential of these liposomal vesicles corresponding to the increasing amounts of encapsulated PBE. The incorporation of PBE increased the polydispersity index (PDI) independent of concentration. Additionally, we observed that the storage stability of PBE liposomes with uniform particle size and approximately spherical shape vesicle was better at low concentration. The results of Fourier-transform infrared (FTIR) spectroscopy and Raman spectroscopy showed that PBE was positioned at the water interface, which increased the order of hydrophobic alkyl chains in the lipid membranes. The incorporation of PBE led to an increase in the trans conformation of hydrophobic alkyl chain and consequently, the thermal stability of liposomes, which was confirmed by differential scanning calorimetry (DSC). The results of powder X-ray diffraction (XRD) analysis confirmed that PBE was present in an amorphous form in the liposomes. Additionally, the incorporation of PBE reduced the micropolarity of the lipid membrane. Thus, when preparing liposomes using thin-film hydration, the presence of PBE affected the characteristics of liposomes.

The interaction between tea polyphenols and host intestinal microorganisms: an effective way to prevent psychiatric disorders

Tea polyphenols (TP) are the most bioactive components in tea extracts. It has been reported that TP can regulate the composition and the function of the intestinal flora. Meanwhile, intestinal microorganisms improve the bioavailability of TP, and the corresponding metabolites of TP can regulate intestinal micro-ecology and promote human health more effectively. The dysfunction of the microbiota-gut-brain axis is the main pathological basis of depression, and its abnormality may be the direct cause and potential influencing factor of psychiatric disorders. The interrelationship between TP and intestinal microorganisms is discussed in this review, which will enable us to better evaluate the potential preventive effects of TP on psychiatric disorders by modulating host intestinal microorganisms.

Liposome Permeability to Essential Oil Components: A Focus on Cholesterol Content

Encapsulation in liposomes has been an efficient strategy to improve the stability of sensitive bioactive compounds such as essential oils (EOs). However, the stability of liposomal formulations remains a key parameter controlling the delivery of encapsulated ingredients. Cholesterol (Chol) modulates the membrane properties conferring stability to the lipid bilayer. Thus, the Chol content in the liposome formulations encapsulating EO components should be carefully chosen. In this work, various liposome formulations differing by Chol content (DPPC:Chol 100:10; 100:25; 100:50; 100:75; 100:100) were exposed to a series of 22 EO components at DPPC/EO 100/25. The formulations were characterized for their final composition and their permeability to the hydrophilic fluorophore, sulforhodamine B (SRB), was monitored. Results showed that the Chol content experimentally determined for the various formulations (above 10% Chol) was below the theoretical weighed Chol. Among the tested components, 13 molecules displayed a significant permeabilizing effect on 10% Chol membranes. Most of these possess a hydroxyl group. The EO induced permeability was dependent on the Chol content which affects the membrane phase: their effect was reduced upon increasing Chol content keeping five EOs components effective at 40% Chol. The EO's effect was also linked to the hydrophobicity of the molecule. Hence, the DPPC:Chol ratio of the formulation is chosen considering the structure of the compound, its hydrophobicity and its effect on the permeability at different Chol content: a formulation comprising 40% Chol is suggested for highly hydrophobic molecules whereas a formulation with higher Chol content could be selected for less hydrophobic compounds.

Phytochemicals in Chemoprevention: A Cost-Effective Complementary Approach

Cancer is one of the leading causes of death across the world. Although conventional cancer treatments such as chemotherapy and radiotherapy have effectively decreased cancer progression, they come with many dose-limiting side-effects. Phytochemicals that naturally occur in spices, fruits, vegetables, grains, legumes, and other common foods are surprisingly effective complements to conventional cancer treatments. These biologically active compounds demonstrate anticancer effects via cell signaling pathway interference in cancerous cells. In addition, phytochemicals protect non-cancerous cells from chemotherapy-induced side-effects. This paper addresses the not only the potential of phytochemicals quercetin, isoflavones, curcumin, catechins, and hesperidin in terms of cancer treatment and protection against side-effects of chemotherapy, but also methods for increasing phytochemical bioavailability.

Physicochemical characteristics of liposome encapsulation of stingless bees' propolis

Nutraceuticals from natural sources have shown potential new leads in functional food products. Despite a broad range of health-promoting effects, these compounds are easily oxidized and unstable, making their utilization as nutraceutical ingredients limited. In this study, the encapsulated stingless bees' propolis in liposome was prepared using soy phosphatidylcholine and cholesterol by thin-film hydration technique. Three different formulations of phosphatidylcholine composition and cholesterol prepared by weight ratio was conducted to extract high propolis encapsulation. Physicochemical changes in the result of the encapsulation process are briefly discussed using scanning electron microscopy and Fourier Transform Infrared Spectroscopy. A dynamic light-scattering instrument was used to measure the hydrodynamic diameter, polydispersity index, and zeta potential. The increment of the liposomal size was observed when the concentration of extract loaded increased. In comparing three formulations, F2 (8:1 w/w) presented the best formulation as it yielded small nanoparticles of 275.9 nm with high encapsulation efficiency (66.9%). F1 (6:1 w/w) formed large particles of liposomes with 422.8 nm, while F3 (10:1 w/w) showed low encapsulation efficiency with (by) 38.7%. The liposome encapsulation will provide an effective nanocarrier system to protect and deliver the flavonoids extracted from stingless bees' propolis.

Phenolic compounds: current industrial applications, limitations and future challenges

Phenolic compounds are natural bioactive molecules found mainly in plant tissues that have shown interesting bioactivities, such as antioxidant, antimicrobial, anti-inflammatory, and antiproliferative activities, among others, which has led to great interest in their use by several industries. However, despite the large number of scientific studies on this topic, some issues still need to be studied and solved, such as the understanding of the main actions of these compounds in organisms. Besides their large potential applicability in industry, phenolic compounds still face some issues making it necessary to develop strategies to improve bioavailability, sustainable technologies of extraction and refinement, and stability procedures to increase the range of applicability. This review focuses on the most recent advances in the applications of phenolic compounds in different technological and medicinal areas. In addition, techniques to improve their sustainable resourcing, stability and bioavailability will be presented and discussed.

Physicochemical mechanisms of different biopolymers' (lysozyme, gum arabic, whey protein, chitosan) adsorption on green tea extract loaded liposomes

Having various domains of applicability, liposomes have been the issue of many studies since 1960s. Kinetically stable nature of liposomes required incorporation of other substituents to gain storage stability and interaction of liposomes with polymers, electrolytes, proteins or lipids still requires further investigation to explain the underlying mechanism. In this study, polyphenol-rich green tea extract was encapsulated into liposomes by means of microfluidization in two different aqueous media (pH = 3.8 acetate buffer and pH = 6.5 distilled water). Antioxidant loaded vesicles were further mixed with anionic biopolymers (gum arabic, whey protein) and cationic biopolymers (lysozyme, chitosan) separately. The physical and chemical interactions between liposomes and biopolymers were rationalized by particle size, zeta potential, transmission electron microscopy, total phenolic content and antioxidant activity measurements during 28-days storage at 4 °C. Experimental results indicated that the biopolymer incorporated liposomes showed better stability compared to control liposomes during storage, developing resistance against changes in particle size and zeta potential. On the other hand, biopolymer interaction mechanisms were shown to be different for different biopolymers. As was also proved by transmission electron microscopy, lysozyme was absorbed into the liposomes while gum arabic, whey protein and chitosan were adsorbed on the vesicle surface to shield green tea extract loaded liposomes.

Interactions of tea polyphenols with intestinal microbiota and their implication for cellular signal conditioning mechanism

Tea polyphenols (TP) is the main functional substances in tea. It has been reported that TP can modulate the composition of gut microbes in the human body, in addition, after the bio-transformation by intestinal flora, the metabolites of TP also have positive effects on the health of the host. Lots of researches have shown that TP have possible therapeutic effect against high fat diet induced obesity, which is closely related to the gut flora of the host. Therefore, this review focused on the interactions of TP with intestinal microbiota and their implication for cellular signal conditioning mechanism that will enable us to better study the two-way effects of TP and intestinal microbiota on host health improvement. PRACTICAL APPLICATIONS: TP have been widely concerned for their health care properties. As the functional food components, TP have strong antioxidant and physiological activities for human body. A better understanding on the interactions of TP with intestinal microbiota and their implication for cellular signal conditioning mechanism will lead us to better evaluate the contribution of the microbial metabolites of TP, as well as the regulation of intestinal bacterial diversity and abundance for host health.

Encapsulation of antioxidant sea fennel (Crithmum maritimum) aqueous and ethanolic extracts in freeze-dried soy phosphatidylcholine liposomes

Soy phosphatidylcholine liposomes encapsulating increasing concentrations of two sea fennel extracts (aqueous and ethanolic) prepared by ultrasonication were freeze-dried, using glycerol as lyoprotectant. Particle properties, water dispersibility, colour, thermal properties and antioxidant capacity (radical scavenging capacity, ferric ion reducing power, Folin-reactive substances) of the liposomal preparations were determined. The freeze-drying process caused an overall increase in particle size and polydispersity index, while the zeta-potential became more electronegative. Both sea fennel extracts were rich in chlorogenic acid (42.61 and 58.48 mg/g for the aqueous and ethanolic extracts, respectively) and showed great antioxidant activity. Vitamin C was identified in the aqueous extract, whereas rutin and rosmarinic acid in the ethanolic one. The entrapment efficiency, determined in the liposomes prepared at the highest extract concentration, was 65.6% and 49.1% for the aqueous extract and the ethanolic extract, respectively. The liposomal antioxidant activity and total phenolic content followed a linear increasing tendency as a result of increasing the extract concentration, irrespective of the type of extract. Higher antioxidant activity was found in the liposomes loaded with the ethanolic extract, in a clear relationship to the greater amount of highly antioxidant phenolic compounds extracted, and also to their lower entrapment efficiency, which caused a greater amount of extract to remain outside the liposome. Both extracts were suitable for producing liposomes with antioxidant properties which could be dried and used to design functional foods.

Lipid reducing potential of liposomes loaded with ethanolic extract of purple pitanga (Eugenia uniflora) administered to Caenorhabditis elegans

The ethanolic extract obtained from purple pitanga fruit (Eugenia uniflora - PPE) has been previously described by its potential to reduce lipid accumulation in vitro. In this study, we aimed to study this potential in vivo using Caenorhabditis elegans as animal model. Considering the low pH of the extract, its hydrophilic characteristic, its absorption by the medium where the worms are cultivated and the need of a chronic exposure in the worms solid medium, we have loaded liposomes with PPE and investigated its potential for oral administration. Following 48 h exposure to the PPE-loaded liposomes on worms nematode growth medium, we did not observe any toxic effects of the formulation. Under high cholesterol diet, which increased worms total lipid and also triacylglycerides levels, liposomes containing PPE were able to significantly attenuate these alterations, which could not be observed when worms were treated with free PPE. Furthermore, we could evidence that liposomes were ingested by worms through their labelling to uranin fluorescence dye. Through total phenolic compounds quantification, we estimated an entrapment efficacy of PPE into liposomes of 87.7%. The high levels of phenolic compounds present in PPE, as previously described by our group, indicate that these antioxidants may interfere in worms lipid metabolism, which may occur through many and intricated mechanisms. Although the use of conventional liposomes for human consumption may not be pragmatic, its application for oral delivery of a hydrophilic substance in C. elegans was absolutely critical for our experimental design and has proven to be efficient.

Design, Fabrication, Characterization, and In Vitro Digestion of Alkaloid-, Catechin-, and Cocoa Extract-Loaded Liposomes

Liposomes containing theobromine, caffeine, catechin, epicatechin, and a cocoa extract were fabricated using microfluidization and sonication. A high encapsulation efficiency and good physicochemical stability were obtained by sonication (75% amplitude, 7 min). Liposomes produced at pH 5.0 had mean particle diameter ranging from 73.9 to 84.3 nm. The structural and physicochemical properties of the liposomes were characterized by transmission electron microscopy, confocal fluorescence microscopy, and antioxidant activity assays. The release profile was measured by ultra-high performance liquid chromatography coupled to diode array detection. The bioaccessibility of the bioactive compounds encapsulated in liposomes was determined after exposure to a simulated in vitro digestion model. Higher bioaccessibilities were measured for all catechins-loaded liposome formulations as compared to nonencapsulated counterparts. These results demonstrated that liposomes are capable of increasing the bioaccessibility of flavan-3-ols, which may be important for the development of nutraceutical-enriched functional foods.

Microfluidization trends in the development of nanodelivery systems and applications in chronic disease treatments

Plant bioactive compounds are known for their extensive health benefits and therefore have been used for generations in traditional and modern medicine to improve the health of humans. Processing and storage instabilities of the plant bioactive compounds, however, limit their bioavailability and bioaccessibility and thus lead researchers in search of novel encapsulation systems with enhanced stability, bioavailability, and bioaccessibility of encapsulated plant bioactive compounds. Recently many varieties of encapsulation methods have been used; among them, microfluidization has emerged as a novel method used for the development of delivery systems including solid lipid nanocarriers, nanoemulsions, liposomes, and so on with enhanced stability and bioavailability of encapsulated plant bioactive compounds. Therefore, the nanodelivery systems developed using microfluidization techniques have received much attention from the medical industry for their ability to facilitate controlled delivery with enhanced health benefits in the treatment of various chronic diseases. Many researchers have focused on plant bioactive compound-based delivery systems using microfluidization to enhance the bioavailability and bioaccessibility of encapsulated bioactive compounds in the treatment of various chronic diseases. This review focuses on various nanodelivery systems developed using microfluidization techniques and applications in various chronic disease treatments.

Bioavailability of Tea Catechins and Its Improvement

Many in vitro studies have shown that tea catechins had vevarious health beneficial effects. However, inconsistent results between in vitro and in vivo studies or between laboratory tests and epidemical studies are observed. Low bioavailability of tea catechins was an important factor leading to these inconsistencies. Research advances in bioavailability studies involving absorption and metabolic biotransformation of tea catechins were reviewed in the present paper. Related techniques for improving their bioavailability such as nanostructure-based drug delivery system, molecular modification, and co-administration of catechins with other bioactives were also discussed.