Nanochemoprevention by bioactive food components: a perspective

PLGA nanomedical consignation: A novel approach for the management of prostate cancer

The malignancy of the prostate is a complicated ailment which impacts millions of male populations around the globe. Despite the multitude of endeavour accomplished within this domain, modalities that are involved in the ameliorative management of predisposed infirmity are still relent upon non-specific and invasive procedures, thus imposing a detrimental mark on the living standard of the individual. Also, the orchestrated therapeutic interventions are still incompetent in substantiating a robust and unabridged therapeutic end point owing to their inadequate solubility, low bioavailability, limited cell assimilation, and swift deterioration, thereby muffling the clinical application of these existing treatment modalities. Nanotechnology has been employed in an array of modalities for the medical management of malignancies. Among the assortment of available nano-scaffolds, nanocarriers composed of a bio-decomposable and hybrid polymeric material like PLGA hold an opportunity to advance as standard chemotherapeutic modalities. PLGA-based nanocarriers have the prospect to address the drawbacks associated with conventional cancer interventions, owing to their versatility, durability, nontoxic nature, and their ability to facilitate prolonged drug release. This review intends to describe the plethora of evidence-based studies performed to validate the applicability of PLGA nanosystem in the amelioration of prostate malignancies, in conjunction with PLGA focused nano-scaffold in the clinical management of prostate carcinoma. This review seeks to explore numerous evidence-based studies confirming the applicability of PLGA nanosystems in ameliorating prostate malignancies. It also delves into the role of PLGA-focused nano-scaffolds in the clinical management of prostate carcinoma, aiming to provide a comprehensive perspective on these advancements.

Research Progress of Carrier-Free Antitumor Nanoparticles Based on Phytochemicals

Cancer is a major worldwide public health issue, responsible for millions of deaths every year. Cancer cases and deaths are expected to increase rapidly with population growth, age, and lifestyle behaviors that increase cancer risk. Long-term chemotherapy results in acquired drug resistance. Traditional treatment methods have limitations and cannot effectively treat distal metastatic cancers. Application of nanocarriers in multi-chemotherapy must be promoted. With research progress, the shortcomings of traditional nanocarriers have gradually become evident. Carrier-free nanodrugs with desirable bioactivity have attracted considerable attention. In this review, we provide an overview of recent reports on several carrier-free nanodrug delivery systems based on phytochemicals. This review focuses on the advantages of carrier-free nanodrugs, and provides new insights for establishment of ideal cancer treatment nanosystems.

Evaluation of the Antitumour and Antiproliferative Effect of Xanthohumol-Loaded PLGA Nanoparticles on Melanoma

Cutaneous melanoma is the deadliest type of skin cancer and current treatment is still inadequate, with low patient survival rates. The polyphenol xanthohumol has been shown to inhibit tumourigenesis and metastasization, however its physicochemical properties restrict its application. In this work, we developed PLGA nanoparticles encapsulating xanthohumol and tested its antiproliferative, antitumour, and migration effect on B16F10, malignant cutaneous melanoma, and RAW 264.7, macrophagic, mouse cell lines. PLGA nanoparticles had a size of 312 ± 41 nm and a PdI of 0.259, while achieving a xanthohumol loading of about 90%. The viability study showed similar cytoxicity between the xanthohumol and xanthohumol-loaded PLGA nanoparticles at 48 h with the IC50 established at 10 µM. Similar antimigration effects were observed for free and the encapsulated xanthohumol. It was also observed that the M1 antitumor phenotype was stimulated on macrophages. The ultimate anti-melanoma effect emerges from an association between the viability, migration and macrophagic phenotype modulation. These results display the remarkable antitumour effect of the xanthohumol-loaded PLGA nanoparticles and are the first advance towards the application of a nanoformulation to deliver xanthohumol to reduce adverse effects by currently employed chemotherapeutics.

Milk exosomes: A biogenic nanocarrier for small molecules and macromolecules to combat cancer

Exosomes are unique biogenic nanocarriers of endocytic origin that are generated from most of the cells and found in biofluids like milk, plasma, saliva, and urine. Bovine milk represents the largest and an economic source for the production of exosomes. In recent past, the utility of the milk exosomes as drug carriers is intensified. Exosomes are emerging for delivery of both small and large therapeutics due to their biocompatibility. In this article, we highlighted the various exosomal isolation techniques, physicochemical properties, their biodistribution, and utility of milk exosomes in delivering the small drug molecules and siRNA to combat cancer.

Enhanced Chemotherapeutic Efficacy of PLGA-Encapsulated Epigallocatechin Gallate (EGCG) Against Human Lung Cancer

Purpose

Currently, the clinical benefits of tea polyphenols have contributed to the development of efficient systemic delivery systems with adequate bioavailability and stability. In this study, we aimed to establish a nanoparticle model to overcome the shortcomings of epigallocatechin gallate (EGCG) in the treatment of lung cancer.

Materials and Methods

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with EGCG were prepared by the oil-in-water emulsion solvent evaporation technique. The characteristics of NPs, entrapment efficiency, and in vitro release were systematically evaluated. The cellular uptake, cytotoxic activity, and the effect of the formulation on cellular apoptosis of free-from EGCG and the NPs were compared. The interaction between protein-NF-κB and EGCG was detected by bio-layer interferometry (BLI). NF-κB signaling was evaluated by Western blotting and q-RT-PCR. The efficacy of the optimized nanoformulation was evaluated using a patient-derived tumor xenograft (PDX) model.

Results

EGCG-loaded NPs (175.8±3.8 nm in size) demonstrated its optimal efficacy, with approximately 86.0% of encapsulation efficiency and 14.2% of loading efficiency. Additionally, EGCG-encapsulated PLGA-NPs offered a 3-4-fold dose advantage compared to free EGCG in terms of exerting antiproliferative effects and inducing apoptosis at lower doses (12.5, 25 μM). Molecular interaction assays demonstrated that EGCG binds to NF-κB with high affnity (KD=4.8×10⁻⁵ M). EGCG-NPs were more effective at inhibiting NF-κB activation and suppressing the expression of NF-κB-regulated genes than free EGCG. Furthermore, EGCG-NPs showed superior anticancer activity in the PDX model than free EGCG.

Conclusion

These findings indicated that the prepared EGCG-NPs were more effective than free EGCG in inhibiting lung cancer tumors in the PDX model.

Switching from Conventional to Nano-natural Phytochemicals to Prevent and Treat Cancers: Special Emphasis on Resveratrol

BACKGROUND

Natural phytochemicals and their derivatives have been used in medicine since prehistoric times. Natural phytochemicals have potential uses against various disorders, including cancers. However, due to low bioavailability, their success in clinical trials has not been reproduced. Nanotechnology has played a vital role in providing new directions for diagnosis, prevention, and treatment of different disorders, and of cancer in particular. Nanotechnology has demonstrated the capability to deliver conventional natural products with poor solubility or a short half-life to target specific sites in the body and regulate the release of drugs. Among the natural products, the phytoalexin resveratrol has demonstrated therapeutic effects, including antioxidant, antiinflammatory, and anti-proliferative effects, as well as the potential to inhibit the initiation and promotion of cancer. However, low water solubility and extensive first-pass metabolism lead to poor bioavailability of resveratrol, hindering its potential. Conventional dosage forms of resveratrol, such as tablets, capsules, dry powder, and injections, have met with limited success. Nanoformulations are now being investigated to improve the pharmacokinetic characteristics, as well as to enhance the bioavailability and targetability of resveratrol.

OBJECTIVES

This review details the therapeutic effectiveness, mode of action, and pharmacokinetic limitations of resveratrol, as well as discusses the successes and challenges of resveratrol nanoformulations. Modern nanotechnology techniques to enhance the encapsulation of resveratrol within nanoparticles and thereby enhance its therapeutic effects are emphasized.

CONCLUSION

To date, no resveratrol-based nanosystems are in clinical use, and this review would provide a new direction for further investigations on innovative nanodevices that could consolidate the anticancer potential of resveratrol.

Nanotechnologies in Food Science: Applications, Recent Trends, and Future Perspectives

Nanotechnology is a key advanced technology enabling contribution, development, and sustainable impact on food, medicine, and agriculture sectors. Nanomaterials have potential to lead qualitative and quantitative production of healthier, safer, and high-quality functional foods which are perishable or semi-perishable in nature. Nanotechnologies are superior than conventional food processing technologies with increased shelf life of food products, preventing contamination, and production of enhanced food quality. This comprehensive review on nanotechnologies for functional food development describes the current trends and future perspectives of advanced nanomaterials in food sector considering processing, packaging, security, and storage. Applications of nanotechnologies enhance the food bioavailability, taste, texture, and consistency, achieved through modification of particle size, possible cluster formation, and surface charge of food nanomaterials. In addition, the nanodelivery-mediated nutraceuticals, synergistic action of nanomaterials in food protection, and the application of nanosensors in smart food packaging for monitoring the quality of the stored foods and the common methods employed for assessing the impact of nanomaterials in biological systems are also discussed.

Neurotheranostics as personalized medicines

The discipline of neurotheranostics was forged to improve diagnostic and therapeutic clinical outcomes for neurological disorders. Research was facilitated, in largest measure, by the creation of pharmacologically effective multimodal pharmaceutical formulations. Deployment of neurotheranostic agents could revolutionize staging and improve nervous system disease therapeutic outcomes. However, obstacles in formulation design, drug loading and payload delivery still remain. These will certainly be aided by multidisciplinary basic research and clinical teams with pharmacology, nanotechnology, neuroscience and pharmaceutic expertise. When successful the end results will provide "optimal" therapeutic delivery platforms. The current report reviews an extensive body of knowledge of the natural history, epidemiology, pathogenesis and therapeutics of neurologic disease with an eye on how, when and under what circumstances neurotheranostics will soon be used as personalized medicines for a broad range of neurodegenerative, neuroinflammatory and neuroinfectious diseases.

Evaluation of Carum-loaded Niosomes on Breast Cancer Cells:Physicochemical Properties, In Vitro Cytotoxicity, Flow Cytometric, DNA Fragmentation and Cell Migration Assay

Thymoquinone (TQ), a phytochemical compound found in Carum carvil seeds (C. carvil), has a lot of applications in medical especially cancer therapy. However, TQ has a hydrophobic nature, and because of that, its solubility, permeability and its bioavailability in biological mediums are poor. To diminish these drawbacks, we have designed a herbal carrier composed of Ergosterol (herbal lipid), Carum carvil extract (Carum) and nonionic surfactants for herbal cancer treatment. C. carvil was extracted and characterized by GC/Mass. Two different formulations containing TQ and Carum were encapsulated into niosomes (Nio/TQ and Nio/Carum, respectively) and their properties were compared together. Morphology, size, zeta potential, encapsulation efficiency (EE%), profile release rate, in vitro cytotoxicity, flow cytometric, DNA fragmentation and cell migration assay of formulations were evaluated. Results show that both loaded formulations have a spherical morphology, nanometric size and negative zeta potential. EE% of TQ and Carum loaded niosomes was about 92.32% ± 2.32 and 86.25% ± 1.85, respectively. Both loaded formulations provided a controlled release compared with free TQ. MTT assay showed that loaded niosomes have more anti-cancer activity compared with Free TQ and free Carum against MCF-7 cancer cell line and these results were confirmed by flow cytometric analysis. Cell cycle analysis showed G2/M arrest in TQ, Nio/TQ and Nio/Carum formulations. TQ, Nio/TQ and Nio/Carum decreased the migration of MCF7 cells remarkedly. These results show that the TQ and Carum loaded niosomes are novel carriers with high efficiency for encapsulation of low soluble phytochemicals and also would be favourable systems for breast cancer treatment.

Phytochemicals: Current strategies for treating breast cancer

Females with early-stage metastatic, estrogen-dependent breast cancer are generally treated with surgery, radiation and chemotherapy, or with more targeted approaches such as aromatase inhibitors (anastrozole or letrozole) or anti-estrogens (tamoxifen). Despite widespread successful usage of these agents for the treatment of breast cancer, resistance, tumor relapse and metastasis remain the principal causes of mortality for patients with breast cancer. While numerous groups have made major contributions toward an improved understanding of resistance mechanisms, the currently insufficient grasp of the most critical pathways involved in resistance is evident in the inability to adequately treat and drastically improve patient outcomes in females with hormone-refractory breast cancer, including triple negative breast cancer. Therefore, further investigation of novel therapeutic approaches is paramount to reveal previously unconsidered agents that could be utilized to treat metastatic disease. Numerous naturally occurring phytochemicals have recently gained interest as potential therapeutic breast cancer agents appear to directly affect estrogen-dependent and estrogen-independent breast cancer cell proliferation, potentially via affecting breast cancer stem cell populations. While numerous natural compounds have exhibited promise, they are limited by their bioavailability. Therefore, to effectively treat future hormone-refractory breast tumors, it is critical to adequately refine and formulate these agents for effective therapeutic use and delivery. Herein, the literature on the current state of phytochemicals is reviewed, including their limitations and potential as targeted therapies for breast cancer.

Hydroxycinnamic acids loaded in lipid-core nanocapsules

Ferulic, caffeic, sinapic, and coumaric acids, belonging to the class of hydroxycinnamic acids (HAs), are bioactive polyphenols widespread in the plant kingdom and present in the human diet. Due to their biological properties and effects in the prevention of various diseases associated with oxidative stress, HAs can be exploited for attractive nutraceutical applications. Starting from this and in order to increase bioaccessibility, we encapsulated HAs in lipid-core nanocapsules (NCs) based on a biodegradable and biocompatible poly(ε-caprolactone) polymer. The results showed that nanoparticles loaded with hydroxycinnamic acids (HA-NCs) have diameter of 224-253 nm, encapsulation efficiency of 53-78%, and are stable over time (30 days). In vitro tests evidenced that NCs are able to preserve HAs in the gastric simulated fluid and release them in the intestinal simulated fluid. The delivery system developed could be employed to create novel functional foods.

Cancer Chemoprevention by Phytochemicals: Nature's Healing Touch

Phytochemicals are an important part of traditional medicine and have been investigated in detail for possible inclusion in modern medicine as well. These compounds often serve as the backbone for the synthesis of novel therapeutic agents. For many years, phytochemicals have demonstrated encouraging activity against various human cancer models in pre-clinical assays. Here, we discuss select phytochemicals—curcumin, epigallocatechin-3-gallate (EGCG), resveratrol, plumbagin and honokiol—in the context of their reported effects on the processes of inflammation and oxidative stress, which play a key role in tumorigenesis. We also discuss the emerging evidence on modulation of tumor microenvironment by these phytochemicals which can possibly define their cancer-specific action. Finally, we provide recent updates on how low bioavailability, a major concern with phytochemicals, is being circumvented and the general efficacy being improved, by synthesis of novel chemical analogs and nanoformulations.

Targeted nanoparticles encapsulating (-)-epigallocatechin-3-gallate for prostate cancer prevention and therapy

Earlier we introduced the concept of ‘nanochemoprevention’ i.e. the use of nanotechnology to improve the outcome of cancer chemoprevention. Here, we extended our work and developed polymeric EGCG-encapsulated nanoparticles (NPs) targeted with small molecular entities, able to bind to prostate specific membrane antigen (PSMA), a transmembrane protein that is overexpressed in prostate cancer (PCa), and evaluated their efficacy in preclinical studies. First, we performed a molecular recognition of DCL- and AG-PEGylation on ligand binding on PSMA active site. Next, the biocompatible polymers PLGA-PEG-A were synthesized and used as base to conjugate DCL or AG to obtain the respective copolymers, needed for the preparation of targeted NPs. The resulting EGCG encapsulating NPs led to an enhanced anti-proliferative activity in PCa cell lines compared to the free EGCG. The behavior of EGCG encapsulated in NPs in modulating apoptosis and cell-cycle, was also determined. Then, in vivo experiments, in mouse xenograft model of prostatic tumor, using EGCG-loaded NPs, with a model of targeted nanosystems, were conducted. The obtained data supported our hypothesis of target-specific enhanced bioavailability and limited unwanted toxicity, thus leading to a significant potential for probable clinical outcome.

Pharmacological Intervention through Dietary Nutraceuticals in Gastrointestinal Neoplasia

Neoplastic conditions associated with gastrointestinal (GI) tract are common worldwide with colorectal cancer alone accounting for the third leading rate of cancer incidence. Other GI malignancies such as esophageal carcinoma have shown an increasing trend in the last few years. The poor survival statistics of these fatal cancer diseases highlight the need for multiple alternative treatment options along with effective prophylactic strategies. Worldwide geographical variation in cancer incidence indicates a correlation between dietary habits and cancer risk. Epidemiological studies have suggested that populations with high intake of certain dietary agents in their regular meals have lower cancer rates. Thus, an impressive embodiment of evidence supports the concept that dietary factors are key modulators of cancer including those of GI origin. Preclinical studies on animal models of carcinogenesis have reflected the pharmacological significance of certain dietary agents called as nutraceuticals in the chemoprevention of GI neoplasia. These include stilbenes (from red grapes and red wine), isoflavones (from soy), carotenoids (from tomatoes), curcuminoids (from spice turmeric), catechins (from green tea), and various other small plant metabolites (from fruits, vegetables, and cereals). Pleiotropic action mechanisms have been reported for these diet-derived chemopreventive agents to retard, block, or reverse carcinogenesis. This review presents a prophylactic approach to primary prevention of GI cancers by highlighting the translational potential of plant-derived nutraceuticals from epidemiological, laboratory, and clinical studies, for the better management of these cancers through consumption of nutraceutical rich diets and their intervention in cancer therapeutics.

Rational design of food-grade polyelectrolyte complex coacervate for encapsulation and enhanced oral delivery of oenothein B

Controlled release of OeB through GI tract using CPP–CS nanoparticles cross-linked with genipin was achievable.

The bounty of nature for changing the cancer landscape

The landscape of cancer has changed considerably in past several years, due mainly to aggressive screening, accumulation of data from basic and epidemiological studies, and the advances in translational research. Natural anticancer agents have always been a part and parcel of cancer research. The initial focus on natural anticancer agents was in context of their cancer chemopreventive properties but their ability to selectively target oncogenic signaling pathways has also been recognized. In light of the rapid advancements in our understanding of the role of microRNAs, cancer stem cells, and epigenetic events in cancer initiation and progression, a number of natural anticancer agents are showing promise in vitro, in vivo as well as in preclinical studies. Moreover, parent structures of natural agents are being extensively modified with the hope of improving efficacy, specificity, and bioavailability. In this article, we focus on two natural agents, 3,3'-diindolylmethane and garcinol, along with 3,4-difluorobenzo curcumin, a synthetic analog of natural agent curcumin. We showcase how these anticancer agents are changing cancer landscape by modulating novel microRNAs, epigenetic factors, and cancer stem cell markers. These activities are relevant and being appreciated for overcoming drug resistance and inhibition of metastases, the two overarching clinical challenges in modern medicine.

Recent trends in nano-based drug delivery systems for efficient delivery of phytochemicals in chemotherapy

The phytochemicals were found to become more soluble when delivered by the nanocarriers and exhibited a remarkable effect on the cancer cells compared to its free form.

Nanoencapsulation of natural triterpenoid celastrol for prostate cancer treatment

Celastrol (CL), a triterpenoid extracted from the Chinese herb Tripterygium wilfordii, has recently attracted interest for its potential antitumor effects. However, unfavorable physicochemical and pharmacokinetics properties such as low solubility, poor bioavailability, and systemic toxicity, are limiting its therapeutic application. In this context, the development of innovative nanocarriers can be useful to overcome these issues, and nanoencapsulation would represent a powerful strategy. In this study, we developed novel CL-loaded poly(ε-caprolactone) nanoparticles (NPs), and investigated their antiproliferative efficacy on prostate cancer cells. CL-NPs were prepared using a nanoprecipitation method and fully characterized by physicochemical techniques. The antiproliferative effects on LNCaP, DU-145, and PC3 cell lines of CL-NPs, compared to those of free CL at different concentrations (0.5, 1.0, and 2.0 µM), were investigated. Moreover, fluorescence microscopy was utilized to examine the cellular uptake of the nanosystems. Furthermore, to elucidate impact of nanoencapsulation on the mechanism of action, Western analyses were conducted to explore apoptosis, migration, proliferation, and angiogenesis alteration of prostate cancer cells. The results confirmed that CL-NPs inhibit proliferation dose dependently in all prostate cancer cells, with inhibitory concentration₅₀ less than 2 µM. In particular, the NPs significantly increased cytotoxicity at lower/medium dose (0.5 and 1.0 µM) on DU145 and PC3 cell lines with respect to free CL, with modulation of apoptotic and cell cycle machinery proteins. To date, this represents the first report on the development of biocompatible polymeric NPs encapsulating CL. Our findings offer new perspectives for the exploitation of developed CL-NPs as suitable prototypes for prostate cancer treatment.

Gold-conjugated green tea nanoparticles for enhanced anti-tumor activities and hepatoprotection--synthesis, characterization and in vitro evaluation

Green tea (GT)-based chemoprevention has shown promising results in various cancer models. However, the effective dose may not be far from the toxic dose because of inefficient systemic delivery and limited bio-availability of GT polyphenols. We have used GT polyphenols to successfully reduce gold to corresponding gold nanoparticles (NPs) in a single step; a process that fulfils all criteria of green nanotechnology as no "man-made" chemical other than gold acids are used. GT and (-) - epigallocatechin-3-gallate (EGCG) conjugated gold NPs (diameters <50 nm), showed remarkable stability, significantly rapid cellular uptake and excellent in vitro anti-oxidant activities. These NPs were observed to be selectively toxic towards cancer cells (Ehrlich's Ascites Carcinoma and MCF-7) while showing absolutely no lethality towards normal primary mouse hepatocytes. In cancer cells, NPs altered the redox status and limited Nrf2 activation by almost 50%. These NPs significantly decreased nuclear translocation of NF-κB, coupled with decreased phosphorylation of IĸB and down-regulation of NF-κB-dependent anti-apoptotic proteins Bcl2 and Akt in a dose-dependent manner, triggering onset of apoptosis. Culturing normal hepatocytes with tumor-conditioned media prompted apoptosis by increasing reactive oxygen species (ROS) and depleting the anti-oxidant defense mechanism of hepatocytes. Pre-treatment with NPs protected hepatocytes from tumor-induced cellular damage by scavenging excess ROS, increasing the levels of reduced glutathione and anti-oxidant enzymes. There was evidence of decreased Bax/Bcl2 ratio and active Caspase 3 levels in these hepatocytes, indicating apoptosis escape. Nanoformulations of GT-based polyphenols might serve as an operative platform for effective delivery, increased bio-availability, enhanced effects and minimal chemotherapy-associated toxicities.

Dietary phytochemicals alter epigenetic events and signaling pathways for inhibition of metastasis cascade: phytoblockers of metastasis cascade

Cancer metastasis is a multistep process in which a cancer cell spreads from the site of the primary lesion, passes through the circulatory system, and establishes a secondary tumor at a new nonadjacent organ or part. Inhibition of cancer progression by dietary phytochemicals (DPs) offers significant promise for reducing the incidence and mortality of cancer. Consumption of DPs in the diet has been linked to a decrease in the rate of metastatic cancer in a number of preclinical animal models and human epidemiological studies. DPs have been reported to modulate the numerous biological events including epigenetic events (noncoding micro-RNAs, histone modification, and DNA methylation) and multiple signaling transduction pathways (Wnt/β-catenin, Notch, Sonic hedgehog, COX-2, EGFR, MAPK-ERK, JAK-STAT, Akt/PI3K/mTOR, NF-κB, AP-1, etc.), which can play a key role in regulation of metastasis cascade. Extensive studies have also been performed to determine the molecular mechanisms underlying antimetastatic activity of DPs, with results indicating that these DPs have significant inhibitory activity at nearly every step of the metastatic cascade. DPs have anticancer effects by inducing apoptosis and by inhibiting cell growth, migration, invasion, and angiogenesis. Growing evidence has also shown that these natural agents potentiate the efficacy of chemotherapy and radiotherapy through the regulation of multiple signaling pathways. In this review, we discuss the variety of molecular mechanisms by which DPs regulate metastatic cascade and highlight the potentials of these DPs as promising therapeutic inhibitors of cancer.

Molecular targets of naturopathy in cancer research: bridge to modern medicine

The relevance of naturopathy (defined as the practice of medicine for the treatment of human diseases with natural agents) in human cancer is beginning to be appreciated, as documented by renewed interest in nutraceutical research, the natural anticancer agents of dietary origin. Because of their pleiotropic effects and the ability to modulate multiple signaling pathways, which is a good attribute of natural agents, nutraceuticals have frequently been demonstrated to re-sensitize drug-resistant cancers. The effectiveness of nutraceuticals can be further enhanced if the tools for the relative assessment of their molecular targets are readily available. Such information can be critical for determining their most effective uses. Here, we discuss the anticancer potential of nutraceuticals and the associated challenges that have interfered with their translational potential as a naturopathic approach for the management of cancers. In the years to come, an efficient screening and assessment of molecular targets will be the key to make rapid progress in the area of drug design and discovery, especially focusing on evidence-based development of naturopathy for the treatment of human malignancies.

Epigallocatechin-3-gallate (EGCG)-stabilized selenium nanoparticles coated with Tet-1 peptide to reduce amyloid-β aggregation and cytotoxicity

Alzheimer's disease (AD), the most common neurodegenerative disease, is caused by an accumulation of amyloid-β (Aβ) plaque deposits in the brains. Evidence is increasingly showing that epigallocatechin-3-gallate (EGCG) can partly protect cells from Aβ-mediated neurotoxicity by inhibiting Aβ aggregation. In order to better understand the process of Aβ aggregation and amyloid fibril disaggregation and reduce the cytotoxicity of EGCG at high doses, we attached EGCG onto the surface of selenium nanoparticles (EGCG@Se). Given the low delivery efficiency of EGCG@Se to the targeted cells and the involvement of selenoprotein in antioxidation and neuroprotection, which are the key factors for preventing the onset and progression of AD, we synthesized EGCG-stabilized selenium nanoparticles coated with Tet-1 peptide (Tet-1-EGCG@Se, a synthetic selenoprotein analogue), considering the affinity of Tet-1 peptide to neurons. We revealed that Tet-1-EGCG@Se can effectively inhibit Aβ fibrillation and disaggregate preformed Aβ fibrils into nontoxic aggregates. In addition, we found that both EGCG@Se and Tet-1-EGCG@Se can label Aβ fibrils with a high affinity, and Tet-1 peptides can significantly enhance the cellular uptake of Tet-1-EGCG@Se in PC12 cells rather than in NIH/3T3 cells.

Resveratrol-loaded nanoparticles based on poly(epsilon-caprolactone) and poly(D,L-lactic-co-glycolic acid)-poly(ethylene glycol) blend for prostate cancer treatment

Nanoencapsulation of antiproliferative and chemopreventive phytoalexin trans-resveratrol (RSV) is likely to provide protection against degradation, enhancement of bioavailability, improvement in intracellular penetration and control delivery. In this study, polymeric nanoparticles (NPs) encapsulating RSV (nano-RSV) as novel prototypes for prostate cancer (PCa) treatment were designed, characterized and evaluated using human PCa cells. Nanosystems, composed of a biocompatible blend of poly(epsilon-caprolactone) (PCL) and poly(d,l-lactic-co-glycolic acid)-poly(ethylene glycol) conjugate (PLGA-PEG-COOH), were prepared by a nanoprecipitation method, and characterized in terms of morphology, particle size and zeta potential, encapsulation efficiency, thermal analyses, and in vitro release studies. Cellular uptake of NPs was then evaluated in PCa cell lines DU-145, PC-3, and LNCaP using confocal fluorescence microscopy, and antiproliferative efficacy was assessed using MTT assay. With encapsulation efficiencies ranging from 74% to 98%, RSV was successfully loaded in PCL:PLGA-PEG-COOH NPs, which showed an average diameter of 150 nm. NPs were able to control the RSV release at pH 6.5 and 7.4, mimicking the acidic tumoral microenvironment and physiological conditions, respectively, with only 55% of RSV released within 7 h. In gastrointestinal simulated fluids, NPs released about 55% of RSV in the first 2 h in acidic medium, and their total RSV content within the subsequent 5 h at pH 7.4. Confocal fluorescence microscopy observations revealed that NPs were efficiently taken up by PCa cell lines. Furthermore, nano-RSV significantly improved the cytotoxicity compared to that of free RSV toward all three cell lines, at all tested concentrations (from 10 μM to 40 μM), proving a consistent sensitivity toward both the androgen-independent DU-145 and hormone-sensitive LNCaP cells. Our findings support the potential use of developed nanoprototypes for the controlled delivery of bioactive RSV for PCa chemoprevention/chemotherapy.

Delivering flavonoids into solid tumors using nanotechnologies

INTRODUCTION

Long-term epidemiological studies have demonstrated that regular ingestion of flavonoids contained in dietary sources is associated with a reduced risk for many chronic diseases including cancer. However, although flavonoids are largely consumed in the diet and high concentrations may exist in the intestine after oral administration, the plasma/tissue concentrations of flavonoids are lower than their effective therapeutic doses due to poor bioavailability, resulting in the limited efficacy of flavonoids in various clinical studies. Therefore, the application of nanotechnology to deliver flavonoids to tumor sites has received considerable attention in recent years.

AREAS COVERED

In this review, after a general review of the potential benefits of flavonoids in cancer therapy and several key factors affecting their bioavailability, the current efforts in improving the delivery efficacy of promising candidates that are particularly important in the human diet, namely quercetin, epigallocatechin-3-gallate (EGCG) and genistein were focused on. Finally, the challenges of developing flavonoid delivery systems that improve flavonoid bioavailability and their anticancer therapy potentials were summarized.

EXPERT OPINION

The design of suitable molecular carriers for flavonoids is an area of research that is in rapid progress. A large number of unheeded promising favonoids are suffering from poor in vivo parameters, their potential benefits deserves further research. Furthermore, more effort should be placed on developing active targeting systems, evaluating the efficacy and toxicity of novel flavonoid delivery systems through small and large scale clinical trials.

Chemopreventive potential of flavonoids in oral squamous cell carcinoma in human studies

Evidence available from nutritional epidemiology has indicated an inverse association between regular consumption of fruits and vegetables and the risk of developing certain types of cancer. In turn, preclinical studies have attributed the health-promoting effects of plant foods to some groups of phytochemicals, by virtue of their many biological activities. In this survey, we briefly examine the chemopreventive potential of flavonoids and flavonoid-rich foods in human oral carcinogenesis. Despite the paucity of data from clinical trials and epidemiological studies, in comparison to in vitro/in vivo investigations, a high level of evidence has been reported for epigallocatechin gallate (EGCG) and anthocyanins. These flavonoids, abundant in green tea and black raspberries, respectively, represent promising chemopreventive agents in human oral cancer.

Anticancer activities of (-)-epigallocatechin-3-gallate encapsulated nanoliposomes in MCF7 breast cancer cells

The chemopreventive actions exerted by green tea are thought to be due to its major polyphenol, (-)-epigallocatechin-3-gallate (EGCG). However, the low level of stability and bioavailability in the body makes administering EGCG at chemopreventive doses unrealistic. We synthesized EGCG encapsulated chitosan-coated nanoliposomes (CSLIPO-EGCG), and observed their antiproliferative and proapoptotic effect in MCF7 breast cancer cells. CSLIPO-EGCG significantly enhanced EGCG stability, improved sustained release, increased intracellular EGCG content in MCF7 cells, induced apoptosis of MCF7 cells, and inhibited MCF7 cell proliferation compared to native EGCG and void CSLIPO. The CSLIPO-EGCG retained its antiproliferative and proapoptotic effectiveness at 10 μM or lower, at which native EGCG does not have any beneficial effects. This study portends a potential breakthrough in the prevention or even treatment of breast cancer by using biocompatible and biodegradable CSLIPO-EGCG with enhanced chemopreventive efficacy and minimized immunogenicity and side-effects.

Storage stability and physical characteristics of tea-polyphenol-bearing nanoliposomes prepared with milk fat globule membrane phospholipids

The objective of this work was to better understand the functional properties of milk phospholipids when used as ingredients to prepare liposomes. Liposomal dispersions (10%) were prepared using high-pressure homogenization, and their physical properties as well as their ability to encapsulate tea polyphenols were investigated. The extent of encapsulation, measured by HPLC, increased with tea polyphenol concentration up to about 4 mg·mL(-1). At polyphenol concentrations ≥ 6 mg·mL(-1), the liposome dispersions were no longer stable. The influence of pH (3-7), storage temperature (room temperature or refrigeration), and addition of sugars (0-15%) were studied for liposomes containing 4 mg·mL(-1) polyphenols. The liposomal dispersions were also stable in the presence of peptides. The storage stability of the systems prepared with milk phospholipids was compared to that of liposomes made with soy phospholipids. Soy liposomes were smaller in size than milk phospholipid liposomes, the encapsulation efficiency was higher, and the extent of release of tea polyphenols during storage was lower for milk phospholipid liposomes compared to soy liposomes. The results suggest that milk phospholipids could be employed to prepare tea-polyphenol-bearing liposomes and that the tea catechins may be incorporated in the milk phospholipid bilayer more efficiently than in the case of a soy phospholipid bilayer.

Bioactive peptides/chitosan nanoparticles enhance cellular antioxidant activity of (-)-epigallocatechin-3-gallate

(-)-Epigallocatechin-3-gallate (EGCG), one representative of the well-studied chemopreventive phytochemicals but with low bioavailability, was encapsulated in monodispersed nanoparticles that were assembled from bioactive caseinophosphopeptide (CPP) and chitosan (CS). The encapsulation efficiency of EGCG in CS-CPP nanoparticles ranged from 70.5 to 81.7%; meanwhile, the in vitro release of EGCG from CS-CPP nanoparticles was in a controllable manner. The EGCG-loaded CS-CPP nanoparticles exerted stronger activity of scavenging free radical than the free EGCG (p < 0.01) in the cellular antioxidant activity assay. Furthermore, cellular uptake of the EGCG-loaded CS-CPP nanoparticles was confirmed by the green fluorescence inside the human hepatocellular caricinoma (HepG2) cells, which was considered to play an important role in the improvement of the antioxidant activity of the nanoencapsulated EGCG. The results suggested that encapsulation of EGCG using CS-CPP nanoparticles should be a potential approach to enhance its antioxidant activity in biological systems.

Nanoformulation of natural products for prevention and therapy of prostate cancer

There is a need for developing improved therapeutic options for the management of prostate cancer, able to inhibit proliferation of precancerous and malignant lesions and/or to improve the effectiveness of conventional chemopreventive and chemotherapeutic agents. In this perspective, application of nanotechnology based strategies for the delivery of natural compounds for effective management of the disease is being actively researched. Here, after highlighting the most promising natural compounds for chemoprevention and chemotherapy of prostate cancer, the state of the art nanotherapeutics and the recent proof-of-concept of "nanochemoprevention", as well as the clinical development of promising targeted nanoprototypes for use in the prostate cancer treatment are being discussed.

Development of novel cationic chitosan-and anionic alginate-coated poly(D,L-lactide-co-glycolide) nanoparticles for controlled release and light protection of resveratrol

BACKGROUND

Resveratrol, like other natural polyphenols, is an extremely photosensitive compound with low chemical stability, which limits the therapeutic application of its beneficial effects. The development of innovative formulation strategies, able to overcome physicochemical and pharmacokinetic limitations of this compound, may be achieved via suitable carriers able to associate controlled release and protection. In this context, nanotechnology is proving to be a powerful strategy. In this study, we developed novel cationic chitosan (CS)- and anionic alginate (Alg)-coated poly(d,l-lactide-co-glycolide) nanoparticles (NPs) loaded with the bioactive polyphenolic trans-(E)-resveratrol (RSV) for biomedical applications.

METHODS

NPs were prepared by the nanoprecipitation method and characterized in terms of morphology, size and zeta potential, encapsulation efficiency, Raman spectroscopy, swelling properties, differential scanning calorimetry, and in vitro release studies. The protective effect of the nanosystems under the light-stressed RSV and long-term stability were investigated.

RESULTS

NPs turned out to be spherical in shape, with size ranging from 135 to about 580 nm, depending on the composition and the amount of polyelectrolytes, while the encapsulation efficiencies increased from 8% of uncoated poly(d,l-lactide-co-glycolide) (PLGA) to 23% and 32% of Alg- and CS-coated PLGA NPs, respectively. All nanocarriers are characterized by a biphasic release pattern, and more effective controlled release rates are obtained for NPs formulated with higher polyelectrolyte concentrations. Stability studies revealed that encapsulation provides significant protection against light-exposure degradation, by reducing the trans-cis photoisomerization reaction. Moreover, the nanosystems are able to prevent the degradation of trans isoform and the leakage of RSV from the carrier for a period of 6 months.

CONCLUSION

Our findings indicated that the newly developed CS- and Alg-coated PLGA NPs are suitable to be used for the delivery of bioactive RSV. The encapsulation of RSV into optimized polymeric NPs provides improved drug loading, effective controlled release, and protection against light-exposure degradation, thus opening new perspectives for the delivery of bioactive related phytochemicals to be used for (nano)chemoprevention/chemotherapy.

Polyphenols and health: current state and progress

During the 5th International Conference on Polyphenols and Health that was held in Sitges (Spain) in October 2011, the latest advances in this area of active research were presented. Sessions on polyphenol effects on cardiovascular disease, polyphenols as ingredients of functional foods, the role of polyphenols in preventing obesity and diabetes, the interaction of polyphenols with gut microbiota, bioavailability and metabolism of polyphenols in humans, the mechanisms of action of these metabolites in different models, new methodologies for the study of the role of polyphenols in health, polyphenols and cancer, recent developments in phenolic compounds and neuroscience, and polyphenols in epidemiology and public health were organized. This highlight issue presents a selection of papers from invited speakers, oral presentations, and poster prize winners. The perspectives for this exciting area of very active research were also discussed at the meeting and are summarized in this introductory paper.

Tea phenols in bulk and nanoparticle form modify DNA damage in human lymphocytes from colon cancer patients and healthy individuals treated in vitro with platinum-based chemotherapeutic drugs

BACKGROUND

Tea catechin epigallocatechin-3-gallate (EGCG) and other polyphenols, such as theaflavins (TFs), are increasingly proving useful as chemopreventives in a number of human cancers. They can also affect normal cells. The polyphenols in tea are known to have antioxidant properties that can quench free radical species, and pro-oxidant activities that appear to be responsible for the induction of apoptosis in tumor cells. The bioavailability of these natural compounds is an important factor that determines their efficacy. Nanoparticle (NP)-mediated delivery techniques of EGCG and TFs have been found to improve their bioavailability to a level that could benefit their effectiveness as chemopreventives.

AIM

The present study was conducted to compare the effects of TFs and EGCG, when used in the bulk form and in the polymer (poly[lactic-co-glycolic acid])-based NP form, in oxaliplatin- and satraplatin-treated lymphocytes as surrogate cells from colorectal cancer patients and healthy volunteers.

MATERIALS & METHODS

NPs were examined for their size distribution, surface morphology, entrapment efficiency and release profile. Lymphocytes were treated in the Comet assay with oxaliplatin and satraplatin, washed and treated with bulk or NP forms of tea phenols, washed and then treated with hydrogen peroxide to determine single-strand breaks after crosslinking.

RESULTS

The results of DNA damage measurements by the Comet assay revealed opposite trends in bulk and NP forms of TFs, as well as EGCG. Both the compounds in the bulk form produced statistically significant concentration-dependent reductions in DNA damage in oxaliplatin- or satraplatin-treated lymphocytes. In contrast, when used in the NP form both TFs and EGCG, although initially causing a reduction, produced a concentration-dependent statistically significant increase in DNA damage in the lymphocytes.

DISCUSSION

These observations support the notion that TFs and EGCG act as both antioxidants and pro-oxidants, depending on the form in which they are administered under the conditions of investigation.

Encapsulated nanoepigallocatechin-3-gallate and elemental selenium nanoparticles as paradigms for nanochemoprevention

Chemoprevention that impedes one or more steps in carcinogenesis, via long-term administration of naturally occurring or synthetic compounds, is widely considered to be a crucial strategy for cancer control. Selenium (Se) has chemopreventive effects, but its application is limited due to a low therapeutic index as shown in numerous animal experiments. In contrast to Se, which was known for its toxicity prior to the discovery of its beneficial effects, the natural compound epigallocatechin-3-gallate (EGCG) was originally considered to be nontoxic. Due to its preventive effects on many types of cancer in various animal models, EGCG has been regarded as a prime example of a promising chemopreventive agent without major toxicity concerns. However, very recently, evidence has accumulated showing that efficacious doses of EGCG used in health promotion may not be far from its toxic dose level. Therefore, both Se and EGCG need to be modified by novel pharmaceutical technologies to attain enhanced efficacy and/or reduced toxicity. Nanotechnology may be one of these technologies. In support of this hypothesis, the characteristics of polylactic acid and polyethylene glycol-encapsulated nano-EGCG and elemental Se nanoparticles dispersed by bovine serum albumin are reviewed in this article. Encapsulation of EGCG to form nano-EGCG leads to its enhanced stability in plasma and remarkably superior chemopreventive effects, with more than tenfold dose advantages in inducing apoptosis and inhibition of both angiogenesis and tumor growth. Se at nanoparticle size (“Nano-Se”), compared with Se compounds commonly used in dietary supplements, has significantly lower toxicity, without compromising its ability to upregulate selenoenzymes at nutritional levels and induce phase II enzymes at supranutritional levels.

Nanochemoprevention by encapsulation of (-)-epigallocatechin-3-gallate with bioactive peptides/chitosan nanoparticles for enhancement of its bioavailability

Nanochemoprevention by oral consumption was developed by the encapsulation of (-)-epigallocatechin-3-gallate (EGCG) with nanoparticles that were electrostatically assembled from bioactive caseinophosphopeptides and chitosan, which was highly biocompatible and able to enhance the bioavailability of EGCG.

Recent advances on tea polyphenols

Over the past decade many scientific and medical studies have focused on green tea for its long-purported health benefits. There is convincing evidence that tea is a cup of life. It has multiple preventive and therapeutic effects. This review thus focuses on the recent advances of tea polyphenols and their applications in the prevention and treatment of human cancers. Of the various polyphenols in tea, (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant, and active compound studied in tea research. EGCG inhibits several molecular targets to inhibit cancer initiation and modulates several essential survival pathways to block cancer progression. Herein, we describe the various mechanisms of action of EGCG and also discuss previous and current ongoing clinical trials of EGCG and green tea polyphenols in different cancer types.

Recent advances on tea polyphenols

Over the past decade many scientific and medical studies have focused on green tea for its long-purported health benefits. There is convincing evidence that tea is a cup of life. It has multiple preventive and therapeutic effects. This review thus focuses on the recent advances of tea polyphenols and their applications in the prevention and treatment of human cancers. Of the various polyphenols in tea, (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant, and active compound studied in tea research. EGCG inhibits several molecular targets to inhibit cancer initiation and modulates several essential survival pathways to block cancer progression. Herein, we describe the various mechanisms of action of EGCG and also discuss previous and current ongoing clinical trials of EGCG and green tea polyphenols in different cancer types.

Chemoprevention of colon cancer in a rat carcinogenesis model using a novel nanotechnology-based combined treatment system

Colorectal cancer (CRC) is the third most common cause of cancer death in the United States, accounting for approximately 51,000 deaths each year. We have previously shown in vitro chemopreventive effects of mixtures of aspirin, folic acid, and calcium (AFAC) on colon cancer cell lines. The objective of the present study was to evaluate the in vivo effects of orally administered, colon targeted chemopreventive combination regimens on the inhibition of aberrant crypt foci (ACF) in a rat model of colon carcinogenesis using (i) unmodified (free drug) combinations of AFAC and (ii) nanoparticle-encapsulated combinations of the same agents. A 14-week animal study was conducted in three phases to determine an optimal effective dose from AFAC combinations and evaluate the efficacy of nanotechnology-based chemopreventive regimens administered in combined (mixtures) and individual (single entity) forms. ACF inhibition when compared with azoxymethane-treated rat control group was significant in both the unmodified and the modified nanoparticle-mediated chemopreventive regimens, showing a range of 31% to 38% (P < 0.05) and 50% to 75% (P < 0.001) reduction, respectively, in the number of ACFs. In addition, the nanoparticulate combination regimens of AFAC showed a 2-fold increase in suppression of ACF compared with free drug mixtures. Individual administration of nanoparticle-encapsulated drugs showed no significant effect on the reduction of ACF. Histochemical analysis provided further confirmation of chemopreventive effects, showing a significant reduction in cell nuclear proliferation. Overall, our results provide a strong proof of concept using nanoparticle-mediated combination treatment in the chemoprevention of colon cancer.

Targeted biocompatible nanoparticles for the delivery of (-)-epigallocatechin 3-gallate to prostate cancer cells

Molecular targeted cancer therapy mediated by nanoparticles (NPs) is a promising strategy to overcome the lack of specificity of conventional chemotherapeutic agents. In this context, the prostate-specific membrane antigen (PSMA) has demonstrated a powerful potential for the management of prostate cancer (PCa). Cancer chemoprevention by phytochemicals is emerging as a suitable approach for the treatment of early carcinogenic processes. Since (-)-epigallocatechin 3-gallate (EGCG) has shown potent chemopreventive efficacy for PCa, we designed and developed novel targeted NPs in order to selectively deliver EGCG to cancer cells. Herein, to explore the recent concept of "nanochemoprevention", we present a study on EGCG-loaded NPs consisting of biocompatible polymers, functionalized with small molecules targeting PSMA, that exhibited a selective in vitro efficacy against PSMA-expressing PCa cells. This approach could be beneficial for high risk patients and would fulfill a significant therapeutic need, thus opening new perspectives for novel and effective treatment for PCa.

Delivery of antiinflammatory nutraceuticals by nanoparticles for the prevention and treatment of cancer

Extensive research within the last two decades has revealed that most chronic illnesses, including cancer, diabetes, and cardiovascular and pulmonary diseases, are mediated through chronic inflammation. Thus, suppressing chronic inflammation has the potential to delay, prevent, and even treat various chronic diseases, including cancer. Various nutraceuticals from fruits, vegetables, vitamins, spices, legumes, and traditional Chinese and Ayurvedic medicine have been shown to safely suppress proinflammatory pathways; however, their low bioavailability in vivo limits their use in preventing and treating cancer. We describe here the potential of nanotechnology to fill this gap. Several nutraceuticals, including curcumin, green tea polyphenols, coenzyme Q, quercetin, thymoquinone and others, have been packaged as nanoparticles and proven to be useful in "nanochemoprevention" and "nano-chemotherapy".