The oral bioavailability of curcumin from micronized powder and liquid micelles is significantly increased in healthy humans and differs between sexes

Steatosis induced by nonylphenol in HepG2 cells and the intervention effect of curcumin

Non-alcoholic fatty liver disease (NAFLD) has increasingly become a serious public health problem. There is growing evidence that nonylphenol (NP) exposure may cause steatosis, but the underlying mechanism is not fully understood. Curcumin (CUR) improves NAFLD-related lipid metabolism disorders and oxidative stress, but its preventive and therapeutic effects on NP-induced steatosis have not been reported. The objective of this investigation was to determine the capability and potential mechanism of NP to induce steatosis in vitro and the intervention of curcumin. HepG2 cells were treated with 0 μM, 20 μM, 30 μM, 40 μM NP for 24 h. Lipid droplets accumulated significantly in HepG2 cells after NP treatment, and the concentration of triglyceride (TG) and total cholesterol (T-CHO) increased significantly. Simultaneously, lipogenesis gene expression was up-regulated significantly, fatty acid oxidation (FAO) gene expression was significantly down-regulated, and reactive oxygen species (ROS) were overproduced. Meanwhile, the expression of p-AMPK/AMPK in the AMPK/mTOR signaling pathway was significantly down-regulated and the expression of p-mTOR/mTOR was markedly up-regulated. However, blocking ROS production with N-acetyl-L-cysteine (NAC) can reverse these phenomena. In addition, our study found that curcumin effectively ameliorated the effects of NP-induced steatosis. Our study indicates that NP can induce steatosis in HepG2 cells, and may be implicated in inhibiting the ROS-dependent AMPK/mTOR pathway, and that curcumin ameliorates the NAFLD-like changes induced by NP in HepG2 cells.

Drug Delivery Strategies for Curcumin and Other Natural Nrf2 Modulators of Oxidative Stress-Related Diseases

Oxidative stress is associated with a wide range of diseases characterised by oxidant-mediated disturbances of various signalling pathways and cellular damage. The only effective strategy for the prevention of cellular damage is to limit the production of oxidants and support their efficient removal. The implication of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the cellular redox status has spurred new interest in the use of its natural modulators (e.g., curcumin, resveratrol). Unfortunately, most natural Nrf2 modulators are poorly soluble and show extensive pre-systemic metabolism, low oral bioavailability, and rapid elimination, which necessitates formulation strategies to circumvent these limitations. This paper provides a brief introduction on the cellular and molecular mechanisms involved in Nrf2 modulation and an overview of commonly studied formulations for the improvement of oral bioavailability and in vivo pharmacokinetics of Nrf2 modulators. Some formulations that have also been studied in vivo are discussed, including solid dispersions, self-microemulsifying drug delivery systems, and nanotechnology approaches, such as polymeric and solid lipid nanoparticles, nanocrystals, and micelles. Lastly, brief considerations of nano drug delivery systems for the delivery of Nrf2 modulators to the brain, are provided. The literature reviewed shows that the formulations discussed can provide various improvements to the bioavailability and pharmacokinetics of natural Nrf2 modulators. This has been demonstrated in animal models and clinical studies, thereby increasing the potential for the translation of natural Nrf2 modulators into clinical practice.

The Inhibitory Activity of Curcumin on P-Glycoprotein and Its Uptake by and Efflux from LS180 Cells Is Not Affected by Its Galenic Formulation

The biological activities of curcumin in humans, including its antioxidative and anti-inflammatory functions, are limited by its naturally low bioavailability. Different formulation strategies have been developed, but the uptake of curcumin from these galenic formulations into and efflux from intestinal cells, which may be critical processes limiting bioavailability, have not been directly compared. Furthermore, little is known about their effect on P-glycoprotein activity, an important determinant of the pharmacokinetics of potentially co-administered drugs. P-glycoprotein activity was determined in LS180 cells, incubated with 30 or 60 µmol/L of curcumin in the form of seven different formulations or native curcuma extract for 1 h. All formulations inhibited P-glycoprotein activity at both concentrations. Curcumin uptake, after 1 h incubation of LS180 cells with the formulations (60 µmol/L), showed significant variability but no consistent effects. After 1 h pre-treatment with the formulations and further 8 h with curcumin-free medium, curcumin in cell culture supernatants, reflecting the efflux, differed between individual formulations, again without a clear effect. In conclusion, curcumin inhibits P-glycoprotein activity independently of its formulation. Its uptake by and efflux from intestinal cells was not significantly different between formulations, indicating that these processes are not important regulatory points for its bioavailability.

Curcumin and Radiotherapy Exert Synergistic Anti-Glioma Effect In Vitro

Curcumin, a bioactive polyphenol, is known to have anticancer properties. In this study, the effectiveness of curcumin pretreatment as a strategy for radio-sensitizing glioblastoma cell lines was explored. For this, U87 and T98 cells were treated with curcumin, exposed to 2 Gy or 4 Gy of irradiation, and the combined effect was compared to the antiproliferative effect of each agent when given individually. Cell viability and proliferation were evaluated with the trypan blue exclusion assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The synergistic effects of the combination treatment were analyzed with CompuSyn software. To examine how the co-treatment affected different phases of cell-cycle progression, a cell-cycle analysis via flow cytometry was performed. Treatment with curcumin and radiation significantly reduced cell viability in both U87 and T98 cell lines. The combination treatment arrested both cell lines at the G2/M phase to a higher extent than radiation or curcumin treatment alone. The synergistic effect of curcumin when combined with temozolomide resulted in increased tumor cell death. Our results demonstrate for the first time that low doses of curcumin and irradiation exhibit a strong synergistic anti-proliferative effect on glioblastoma cells in vitro. Therefore, this combination may represent an innovative and promising strategy for the treatment of glioblastoma, and further studies are needed to fully understand the molecular mechanism underlying this effect.

Cross-kingdom regulation by dietary plant miRNAs: an evidence-based review with recent updates

As non-coding RNA molecules, microRNAs (miRNAs) are widely known for their critical role in gene regulation. Recent studies have shown that plant miRNAs obtained through dietary oral administration can survive in the gastrointestinal (GI) tract, enter the circulatory system and regulate endogenous mRNAs. Diet-derived plant miRNAs have 2'-O-methylated modified 3'ends and high cytosine and guanine (GC) content, as well as exosomal packaging, which gives them high stability even in the harsh environment of the digestive system and circulatory system. The latest evidence shows that dietary plant miRNAs can not only be absorbed in the intestine, but also be absorbed and packaged by gastric epithelial cells and then secreted into the circulatory system. Alternatively, these biologically active plant-derived miRNAs may also affect the health of the host by affecting the function of the microbiome, while not need to be taken into the host's circulatory system and transferred to remote tissues. This cross-kingdom regulation of miRNAs gives us hope for exploring their therapeutic potential and as dietary supplements. However, doubts have also been raised about the cross-border regulation of miRNAs, suggesting that technical flaws in the experiments may have led to this hypothesis. In this article, we summarize the visibility of dietary plant miRNAs in the development of human health and recent research data on their use in therapeutics. The regulation of plant miRNAs across kingdoms is a novel concept. Continued efforts in this area will broaden our understanding of the biological role of plant miRNAs and will open the way for the development of new approaches to prevent or treat human diseases.

Increasing Post-Digestive Solubility of Curcumin Is the Most Successful Strategy to Improve its Oral Bioavailability: A Randomized Cross-Over Trial in Healthy Adults and In Vitro Bioaccessibility Experiments

SCOPE

Different mechanistic approaches to improve the low oral bioavailability of curcumin have been developed, but not yet directly compared in humans.

METHODS AND RESULTS

In a randomized, double-blind, cross-over trial with 12 healthy adults, the 24 h pharmacokinetics of a single dose of 207 mg curcumin is compared from the following formulations: native, liposomes, with turmeric oils, with adjuvants (including piperine), submicron-particles, phytosomes, γ-cyclodextrin complexes, and micelles. No free, but only conjugated curcumin is detected in all subjects. Compared to native curcumin, a significant increase in the area under the plasma concentration-time curve is observed for micellar curcumin (57-fold) and the curcumin-γ-cyclodextrin complex (30-fold) only. In vitro digestive stability, solubility, and micellization efficiency of micellar curcumin (100%, 80%, and 55%) and curcumin-γ-cyclodextrin complex (73%, 33%, and 23%) are higher compared to all other formulations (<72%, <8%, and <4%). The transport efficiencies through Caco-2 cell monolayers of curcumin from the digested mixed-micellar fractions did not differ significantly.

CONCLUSION

The improved oral bioavailability of micellar curcumin, and to a lesser extent of γ-cyclodextrin curcumin complexes, appears to be facilitated by increased post-digestive stability and solubility, whereas strategies targeting post-absorptive processes, including inhibition of biotransformation, appear ineffective.

Improving Curcumin Bioavailability: Current Strategies and Future Perspectives

Curcumin possesses a plethora of interesting pharmacological effects. Unfortunately, it is also characterized by problematic drug delivery and scarce bioavailability, representing the main problem related to the use of this compound. Poor absorption, fast metabolism, and rapid systemic clearance are the most important factors contributing to low curcumin levels in plasma and tissues. Accordingly, to overcome these issues, numerous strategies have been proposed and are investigated in this article. Due to advances in the drug delivery field, we describe here the most promising strategies for increasing curcumin bioavailability, including the use of adjuvant, complexed/encapsulated curcumin, specific curcumin formulations, and curcumin nanoparticles. We analyze current strategies, already available in the market, and the most advanced technologies that can offer a future perspective for effective curcumin formulations. We focus the attention on the effectiveness of curcumin-based formulations in clinical trials, providing a comprehensive summary. Clinical trial results, employing various delivery methods for curcumin, showed that improved bioavailability corresponds to increased therapeutic efficacy. Furthermore, advances in the field of nanoparticles hold great promise for developing curcumin-based complexes as effective therapeutic agents. Summarizing, suitable delivery methods for this polyphenol will ensure the possibility of using curcumin-derived formulations in clinical practice as preventive and disease-modifying therapeutics.

Antitumoral Activities of Curcumin and Recent Advances to ImProve Its Oral Bioavailability

Curcumin, a main bioactive component of the Curcuma longa L. rhizome, is a phenolic compound that exerts a wide range of beneficial effects, acting as an antimicrobial, antioxidant, anti-inflammatory and anticancer agent. This review summarizes recent data on curcumin's ability to interfere with the multiple cell signaling pathways involved in cell cycle regulation, apoptosis and the migration of several cancer cell types. However, although curcumin displays anticancer potential, its clinical application is limited by its low absorption, rapid metabolism and poor bioavailability. To overcome these limitations, several curcumin-based derivatives/analogues and different drug delivery approaches have been developed. Here, we also report the anticancer mechanisms and pharmacokinetic characteristics of some derivatives/analogues and the delivery systems used. These strategies, although encouraging, require additional in vivo studies to support curcumin clinical applications.

Is Curcumin at the Threshold of Therapeutic Effectiveness on Patients with Colon Cancer?-A Systematic Review

Curcumin, obtained from curcuma longa, has been the subject of decades of scientific investigation on its therapeutic usefulness. It is reported to possess several therapeutic properties, of which anti-colon cancer is of interest in this review. Clinically however, curcumin has yet to firm up its place among established anti-colon cancer therapeutic contenders. We aimed to systematically review prevailing clinical evidence on the role of curcumin in colon cancer treatment. The review drawing from literature on clinical studies indicates fairly long term tolerability. No regression of tumor was reported when curcumin was the sole intervention. Increase in p53 level expression was reported in a placebo controlled study but no reduction in PGE2 or 5HETE. Pharmacokinetic data on healthy humans indicate that formulated curcumin delivery systems present significantly higher systemic bioavailability. It appears therefore that the clinical use of curcumin can potentially be realized only through appropriate formulation interventions. Systematic Review Registration: [website], identifier [registration number].

Current clinical developments in curcumin-based therapeutics for cancer and chronic diseases

The last decade has seen an unprecedented rise in the prevalence of chronic diseases worldwide. Different mono-targeted approaches have been devised to treat these multigenic diseases, still most of them suffer from limited success due to the off-target debilitating side effects and their inability to target multiple pathways. Hence a safe, efficacious, and multi-targeted approach is the need for the hour to circumvent these challenging chronic diseases. Curcumin, a natural compound extracted from the rhizomes of Curcuma longa, has been under intense scrutiny for its wide medicinal and biological properties. Curcumin is known to manifest antibacterial, antiinflammatory, antioxidant, antifungal, antineoplastic, antifungal, and proapoptotic effects. A plethora of literature has already established the immense promise of curcuminoids in the treatment and clinical management of various chronic diseases like cancer, cardiovascular, metabolic, neurological, inflammatory, and infectious diseases. To date, more than 230 clinical trials have opened investigations to understand the pharmacological aspects of curcumin in human systems. Still, further randomized clinical studies in different ethnic populations warrant its transition to a marketed drug. This review summarizes the results from different clinical trials of curcumin-based therapeutics in the prevention and treatment of various chronic diseases.

The Role of Curcumin in Cancer Treatment

Curcumin is a polyphenol extracted from the rhizomes of the turmeric plant, Curcuma longa which has anti-inflammatory, and anticancer properties. Chronic inflammation is associated with the development of cancer. Curcumin acts on the regulation of various immune modulators, including cytokines, cyclooxygenase-2 (COX-2), and reactive oxygen species (ROS), which partly explains its anticancer effects. It also takes part in the downregulation of growth factors, protein kinases, oncogenic molecules and various signaling pathways, such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), c-Jun N-terminal kinase (JNK) and signal transducer and activator of transcription 3 (STAT3) signaling. Clinical trials of curcumin have been completed or are ongoing for various types of cancer. This review presents the molecular mechanisms of curcumin in different types of cancer and the evidence from the most recent clinical trials.

Mechanistic Insight into the Effects of Curcumin on Neuroinflammation-Driven Chronic Pain

Chronic pain is a persistent and unremitting condition that has immense effects on patients' quality of life. Studies have shown that neuroinflammation is associated with the induction and progression of chronic pain. The activation of microglia and astrocytes is the major hallmark of spinal neuroinflammation leading to neuronal excitability in the projection neurons. Excessive activation of microglia and astrocytes is one of the major contributing factors to the exacerbation of pain. However, the current chronic pain treatments, mainly by targeting the neuronal cells, remain ineffective and unable to meet the patients' needs. Curcumin, a natural plant product found in the Curcuma genus, improves chronic pain by diminishing the release of inflammatory mediators from the spinal glia. This review details the role of curcumin in microglia and astrocytes both in vitro and in vivo and how it improves pain. We also describe the mechanism of curcumin by highlighting the major glia-mediated cascades in pain. Moreover, the role of curcumin on inflammasome and epigenetic regulation is discussed. Furthermore, we discuss the strategies used to improve the efficacy of curcumin. This review illustrates that curcumin modulating microglia and astrocytes could assure the treatment of chronic pain by suppressing spinal neuroinflammation.

Cytotoxic, Genotoxic and Senolytic Potential of Native and Micellar Curcumin

BACKGROUND

Curcumin, a natural polyphenol and the principal bioactive compound in Curcuma longa, was reported to have anti-inflammatory, anti-cancer, anti-diabetic and anti-rheumatic activity. Curcumin is not only considered for preventive, but also for therapeutic, purposes in cancer therapy, which requires a killing effect on cancer cells. A drawback, however, is the low bioavailability of curcumin due to its insolubility in water. To circumvent this limitation, curcumin was administered in different water-soluble formulations, including liposomes or embedded into nanoscaled micelles. The high uptake rate of micellar curcumin makes it attractive also for cancer therapeutic strategies. Native curcumin solubilised in organic solvent was previously shown to be cytotoxic and bears a genotoxic potential. Corresponding studies with micellar curcumin are lacking.

METHODS

We compared the cytotoxic and genotoxic activity of native curcumin solubilised in ethanol (Cur-E) with curcumin embedded in micells (Cur-M). We measured cell death by MTT assays, apoptosis, necrosis by flow cytometry, senolysis by MTT and C12FDG and genotoxicity by FPG-alkaline and neutral singe-cell gel electrophoresis (comet assay).

RESULTS

Using a variety of primary and established cell lines, we show that Cur-E and Cur-M reduce the viability in all cell types in the same dose range. Cur-E and Cur-M induced dose-dependently apoptosis, but did not exhibit senolytic activity. In the cytotoxic dose range, Cur-E and Cur-M were positive in the alkaline and the neutral comet assay. Genotoxic effects vanished upon removal of curcumin, indicating efficient and complete repair of DNA damage. For inducing cell death, which was measured 48 h after the onset of treatment, permanent exposure was required while 60 min pulse-treatment was ineffective. In all assays, Cur-E and Cur-M were equally active, and the concentration above which significant cytotoxic and genotoxic effects were observed was 10 µM. Micelles not containing curcumin were completely inactive.

CONCLUSIONS

The data show that micellar curcumin has the same cytotoxicity and genotoxicity profile as native curcumin. The effective concentration on different cell lines, including primary cells, was far above the curcumin concentration that can be achieved systemically in vivo, which leads us to conclude that native curcumin and curcumin administered as food supplement in a micellar formulation at the ADI level are not cytotoxic/genotoxic, indicating a wide margin of safety.

The enhanced bioavailability of free curcumin and bioactive-metabolite tetrahydrocurcumin from a dispersible, oleoresin-based turmeric formulation

BACKGROUND

Curcuminoids have been widely studied for human health and disease applications, yet bioavailability remains a hurdle to actualizing all the benefits ascribed to them. The lack of standardization in analysis method, confusion about what constitutes an ideal analyte, and conflicting thoughts around dosing strategies have made it difficult to draw parity between bioavailability and bioactivity and establish a baseline for formulation comparisons.

METHODS

This randomized double-blinded, 2-way cross over, single oral dose, comparative bioavailability study differentially evaluates curcumin at the time of its absorption and along various biotransformation pathways, to include free curcumin, the readily usable form of curcumin; individual and composite totals of curcumin and its analogues as exogenously cleaved conjugates, for example, total curcumin, total demethoxycurcumin (DMC), total bisdemethoxycurcumin (BDMC), and total curcuminoids respectively; and the bioactive metabolite of curcumin, total tetrahydrocurcumin (THC). As a primary study objective, the relative bioavailability of CURCUGEN, a novel dispersible, 50% curcuminoids-concentrated turmeric extract was compared to the standard curcumin reference product, curcuminoids 95% standardized extract (C-95), using the maximum concentration (Cmax), and area under the curve (AUC0-t) of free curcumin, total curcumin, total DMC, total BDMC and the curcumin active metabolite, as total THC.

RESULTS

The evaluation of free curcumin demonstrated that the Cmax and AUC0-t of the CURCUGEN was 16.1 times and 39 times higher than the Cmax and AUC0-t of C-95. Furthermore, total curcumin, total DMC, total BDMC, and total curcuminoids resulted in AUC0-t of the CURCUGEN at 49.5-, 43.5-, 46.8-, and 52.5-fold higher than C-95, respectively. The relative bioavailability of CURCUGEN for total THC was found to be 31 times higher when compared to C-95.

CONCLUSION

As the first human pharmacokinetics study to apply best-practice recommendations and pharmaceutically-aligned guidance in the comprehensive evaluation of a novel curcuminoids formulation, we have established the novelty of said formulation while better standardizing for the common variances and discrepancies between curcuminoids and their derivatives in the literature and commercial marketing, alike.

Putative role of natural products as Protein Kinase C modulator in different disease conditions

INTRODUCTION

Protein kinase C (PKC) is a promising drug target for various therapeutic areas. Natural products derived from plants, animals, microorganisms, and marine organisms have been used by humans as medicine from prehistoric times. Recently, several compounds derived from plants have been found to modulate PKC activities through competitive binding with ATP binding site, and other allosteric regions of PKC. As a result fresh race has been started in academia and pharmaceutical companies to develop an effective naturally derived small-molecule inhibitor to target PKC activities. Herein, in this review, we have discussed several natural products and their derivatives, which are reported to have an impact on PKC signaling cascade.

METHODS

All information presented in this review article regarding the regulation of PKC by natural products has been acquired by a systematic search of various electronic databases, including ScienceDirect, Scopus, Google Scholar, Web of science, ResearchGate, and PubMed. The keywords PKC, natural products, curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, protocatechuic acid, tannic acid, PKC modulators from marine organism, bryostatin, staurosporine, midostaurin, sangivamycin, and other relevant key words were explored.

RESULTS

The natural products and their derivatives including curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, bryostatin, staurosporine, and midostaurin play a major role in the management of PKC activity during various disease progression.

CONCLUSION

Based on the comprehensive literature survey, it could be concluded that various natural products can regulate PKC activity during disease progression. However, extensive research is needed to circumvent the challenge of isoform specific regulation of PKC by natural products.

Pharmacokinetics of a Single Dose of Turmeric Curcuminoids Depends on Formulation: Results of a Human Crossover Study

BACKGROUND

Curcuminoids from turmeric rhizome have significant health benefits but low bioavailability.

OBJECTIVES

To assess the pharmacokinetics of a novel natural turmeric dried colloidal suspension compared with 4 other turmeric formulations (including a standardized extract) at their respective recommended dosages.

METHODS

Thirty healthy men and women (18 to 45 y old) were enrolled in a randomized, open-labeled, crossover trial, and sequentially consumed single oral doses of standard turmeric extract (1500 mg), liquid micellar preparation (1000 mg), piperine-curcuminoid combination (1515 mg), phytosome formulation (1000 mg), or the dried colloidal suspension (300 mg). Eleven blood samples were obtained over 24 h, plasma was extracted with or without deconjugation with β-glucuronidase or sulfatase, and ultra-high-pressure liquid chromatography/tandem MS was used to quantify the 3 parent curcuminoids and 12 metabolites. Classical pharmacokinetics parameters were derived.

RESULTS

The total AUC values of unconjugated curcuminoids were highly variable within participants, with no significant differences between formulations. However, the AUC values for total curcuminoids (including all metabolites) showed significant product effects. Indeed, the micellar preparation delivered higher levels of total curcuminoids than any other formulation (8540 ng·h/mL), reaching significance when compared with the dried colloidal suspension and standard extract (6520 and 5080 ng·h/mL, respectively). After dose normalization, both micellar and dried colloidal formulations showed significantly higher AUC levels than the standard extract (respectively 136 and 72.9, compared with 3.7 ng·h/mL/mg). Total curcuminoid absorption levels were also significantly higher for the dried colloidal suspension when compared with either piperine or phytosome formulations. Interestingly, no significant differences were observed between the piperine-curcuminoid combination and the standard extract. No serious adverse events were reported.

CONCLUSIONS

The administration of a low dose of the novel natural dried colloidal suspension provided high unconjugated and conjugated curcuminoid absorption, with significant beneficial differences when compared with the high dose of standard extract.This trial was registered at clinicaltrials.gov as NCT03621865.

Therapeutic effect of curcumin in gastrointestinal cancers: A comprehensive review

Gastrointestinal (GI) cancers with a high global prevalence are a leading cause of morbidity and mortality. Accordingly, there is a great need to develop efficient therapeutic approaches. Curcumin, a naturally occurring agent, is a promising compound with documented safety and anticancer activities. Recent studies have demonstrated the activity of curcumin in the prevention and treatment of different cancers. According to systematic studies on curcumin use in various diseases, it can be particularly effective in GI cancers because of its high bioavailability in the gastrointestinal tract. Nevertheless, the clinical applications of curcumin are largely limited because of its low solubility and low chemical stability in water. These limitations may be addressed by the use of relevant analogues or novel delivery systems. Herein, we summarize the pharmacological effects of curcumin against GI cancers. Moreover, we highlight the application of curcumin's analogues and novel delivery systems in the treatment of GI cancers.

A comprehensive review of the therapeutic potential of curcumin nanoformulations

Today, due to the prevalence of various diseases such as the novel coronavirus (SARS-CoV-2), diabetes, central nervous system diseases, cancer, cardiovascular disorders, and so on, extensive studies have been conducted on therapeutic properties of natural and synthetic agents. A literature review on herbal medicine and commercial products in the global market showed that curcumin (Cur) has many therapeutic benefits compared to other natural ingredients. Despite the unique properties of Cur, its use in clinical trials is very limited. The poor biopharmaceutical properties of Cur such as short half-life in plasma, low bioavailability, poor absorption, rapid metabolism, very low solubility (at acidic and physiological pH), and the chemical instability in body fluids are major concerns associated with the clinical applications of Cur. Recently, nanoformulations are emerging as approaches to develop and improve the therapeutic efficacy of various drugs. Many studies have shown that Cur nanoformulations have tremendous therapeutic potential against various diseases such as SARS-CoV-2, cancer, inflammatory, osteoporosis, and so on. These nanoformulations can inhibit many diseases through several cellular and molecular mechanisms. However, successful long-term clinical results are required to confirm their safety and clinical efficacy. The present review aims to update and explain the therapeutic potential of Cur nanoformulations.

Curcumin and Its Potential Impact on Microbiota

Curcumin is one of the most frequently researched herbal substances; however, it has been reported to have a poor bioavailability and fast metabolism, which has led to doubts about its effectiveness. Curcumin has antioxidant and anti-inflammatory effects, and has demonstrated favorable health effects. Nevertheless, well-reported in vivo pharmacological activities of curcumin are limited by its poor solubility, bioavailability, and pharmacokinetic profile. The bidirectional interactions between curcumin and gut microbiota play key roles in understanding the ambiguity between the bioavailability and biological activity of curcumin, including its wider health impact.

Curcumin nanoformulations for antimicrobial and wound healing purposes

The development and spread of resistance to antimicrobial drugs is hampering the management of microbial infectious and wound healing processes. Curcumin is the most active and effective constituent of Curcuma longa L., also known as turmeric, and has a very long and strong history of medicinal value for human health and skincare. Curcumin has been proposed as strong antimicrobial potentialities and many attempts have been made to determine its ability to conjointly control bacterial growth and promote wound healing. However, low aqueous solubility, poor tissue absorption and short plasma half-life due its rapid metabolism needs to be solved for made curcumin formulations as suitable treatment for wound healing. New curcumin nanoformulations have been designed to solve the low bioavailability problem of curcumin. Thus, in the present review, the therapeutic applications of curcumin nanoformulations for antimicrobial and wound healing purposes is described.

Comparative bioavailability of curcuminoids from a water-dispersible high curcuminoid turmeric extract against a generic turmeric extract: a randomized, cross-over, comparative, pharmacokinetic study

OBJECTIVES

The therapeutic utility of turmeric (Curcuma longa L., Zingiberaceae) is limited due to low bioavailability of its active principal curcuminoids. This study evaluates the pharmacokinetic characteristics of a natural, water-dispersible turmeric extract containing 60% curcuminoids (TurmXtra 60N), referred to as WDTE60N, compared to standard turmeric extract 95% (STE95).

METHODS

This open-label, two-way crossover, single oral dose, comparative pharmacokinetic study, randomized 14 subjects to receive one capsule of WDTE60N (150 mg curcuminoids) or three capsules of STE95 (500 mg curcuminoids each). The resulting dose ratio of actives for WDTE60N:STE95 was 1:10.

KEY FINDINGS

Peak plasma levels of free curcumin, total curcuminoids, tetrahydrocurcumin and demethoxycurcumin were similar (P > 0.05). Cmax of total curcumin was higher (P = 0.0253) for WDTE60N at a 10-fold lower dose compared to STE95 (43.5 ± 28.5 vs. 21.3 ± 10.7 ng/ml). Mean AUC0-t was higher (P < 0.001) for free curcumin and comparable for total curcumin and total curcuminoids with WDTE60N than with STE95. Five adverse events were reported in three subjects (mild in severity) and were unrelated to study products.

CONCLUSION

WDTE60N showed higher absorption and comparable exposure for free curcumin, total curcumin and total curcuminoids at a 10-fold lower dose than STE95.

Curcumin-loaded Pluronic® F-127 Micelles as a Drug Delivery System for Curcumin-mediated Photodynamic Therapy for Oral Application

Antimicrobial photodynamic therapy (aPDT) is promising for oral decontamination. Curcumin has been used as photosensitizer; however, the hydrophobic properties can negatively affect aPDT. This study evaluated the aPDT efficacy using Cur-loaded Pluronic^® F-127 micelles against Streptococcus mutans and Candida albicans biofilms. Micelles characterization was performed by zeta potential, dynamic light scattering, transmission electron microscopy, absorption and fluorescence spectroscopy. Cur concentrations, cell viability by CFU mL^-1 and confocal microscopy were determined. Data were analyzed by parametric and nonparametric tests under 5%. Cur-loaded Pluronic^® F-127 exhibited spherical shape, suitable particle size (≤100 nm), adequate polydispersity index, best stability, lower photodegradation and autoaggregation compared to unloaded-Cur. Both microorganisms were sensitive to Cur-loaded Pluronic^® F-127 micelles aPDT, with minimum inhibitory concentration (MIC) of 270 μm and 2.1093 μm for S. mutans and C. albicans suspended culture, respectively. Cur-loaded Pluronic^® F-127 aPDT exhibited antibacterial/antifungal effect against the biofilms (~3 log₁₀ reduction; P ≤ 0.05); however, similar to unloaded (P ≥ 0.05). Confocal images confirmed these results. Cur-loaded Pluronic^® F-127 micelles exhibited good photo-chemical properties and may be a viable alternative to deliver Cur and to improve aPDT effect during the treatment of dental caries. Moreover, Pluronic^® micelles can enhance the solubility, stability, permeability and control the release of Cur.

Nutraceuticals with anti-inflammatory and anti-oxidant properties as intervention for reducing the health effects of fine particulate matter: Potential and Prospects

Air pollution, especially particulate matter pollution adversely affects human health. A growing pool of evidence has emerged which underscores the potential of individual-level nutritional interventions in attenuating the adverse health impact of exposure to PM2.5. Although controlling emission and reducing the overall levels of air pollution remains the ultimate objective globally, the sustainable achievement of such a target and thus consequent protection of human health will require a substantial amount of time and concerted efforts worldwide. In the meantime, smaller-scale individual-level interventions that can counter the inflammatory or oxidative stress effects triggered by exposure to particulate matter may be utilized to ameliorate the health effects of PM2.5 pollution. One such intervention is incorporation of nutraceuticals in the diet. Here, we present a review of the evidence generated from various in vitro, in vivo and human studies regarding the effects of different anti-inflammatory and antioxidant nutraceuticals in ameliorating the health effects of particulate matter air pollution. The studies discussed in this review suggest that these nutraceuticals when consumed as a part of the diet, or as additional supplementation, can potentially negate the cellular level adverse effects of exposure to particulate pollution. The potential benefits of adopting a non-pharmacological diet-based approach to air pollution-induced disease management have also been discussed. We argue that before a nutraceuticals-based approach can be used for widespread public adoption, further research, especially human clinical trials, is essential to confirm the beneficial action of relevant nutraceuticals and to explore the safe limits of human supplementation and the risk of side effects. Future research should focus on systematically translating bench-based knowledge regarding nutraceuticals gained from in-vitro and in-vivo studies into clinically usable nutritional guidelines.

Non-invasive optical imaging of retinal Aβ plaques using curcumin loaded polymeric micelles in APPswe/PS1ΔE9 transgenic mice for the diagnosis of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease clinically characterized by impaired memory and progressive cognitive decline. Despite the advances in AD research, an effective method to timely diagnose AD has remained elusive, and until now, most AD patients receive the available symptomatic treatments late. Although the pathological hallmarks of AD have been traditionally described in the brain, recent studies have shown similar pathological changes in the retina which is developmentally an extension of the forebrain. Interestingly, retinal beta-amyloid (Aβ) accumulation preceded that of the brain in a transgenic mouse model of AD. In the quest of finding an early reliable biomarker for AD, researchers have targeted the optical imaging of retinal Aβ plaques as a method of diagnosing AD. One promising polyphenol compound that has found application in this area is curcumin due to its natural binding affinity to Aβ fibrils and oligomers while giving out a strong fluorescence signal. However, the clinical applications of curcumin have been difficult due to problems related to its bioavailability and retention in the body since it is a hydrophobic molecule. To address these limitations, we herein report the development of anionic and water-soluble DSPE-PEG2000 curcumin polymeric micelles (also referred to as curcumin micelles) that can label both brain and retinal Aβ plaques ex vivo. Following their intravitreal injection in the APPswe/PS1ΔE9 transgenic mouse model of AD, green-labeled retinal deposits were optically imaged live using a rodent retinal microscope. Furthermore, these micelles had excellent intraocular biocompatibility, low hemolytic ratio, and were safe for use in two key retinal cell lines (ARPE-19 and 661W cells). Taken together, these findings provide an alternative insight into the optical imaging of Aβ plaques for the diagnosis of AD using the eyes. More importantly, this study can be translated to humans in the future to improve on early diagnosis and timely management of the disease.

The protective role of glutathione in osteoarthritis

It is currently understood that osteoarthritis (OA) is a major chronic inflammatory musculoskeletal disease. While this disease has long been attributed to biomechanical trauma, recent evidence establishes a significant correlation between osteoarthritic progression and unbridled oxidative stress, responsible for prolonged inflammation. Research describes this as a disturbance in the balanced production of reactive oxygen species (ROS) and antioxidant defenses, generating macromolecular damage and disrupted redox signaling and control. Since ROS pathways are being considered new targets for OA treatment, the development of antioxidant therapy to counteract exacerbated oxidative stress is being continuously researched and enhanced in order to fortify the cellular defenses. Experiments with glutathione and its precursor molecule, N-acetylcysteine (NAC), have shown interesting results in the literature for the management of OA, where they have demonstrated efficacy in reducing cartilage degradation and inflammation markers as well as significant improvements in pain and functional outcomes. Glutathione remains a safe, effective and overall cheap treatment alternative in comparison to other current therapeutic solutions and, for these reasons, it may prove to be comparably superior under particular circumstances.

METHODS

Literature was reviewed using PubMed and Google Scholar in order to bring up significant evidence and illustrate the defensive mechanisms of antioxidant compounds against oxidative damage in the onset of musculoskeletal diseases. The investigation included a combination of keywords such as: oxidative stress, oxidative damage, inflammation, osteoarthritis, antioxidant, glutathione, n-acetylcysteine, redox, and cell signaling.

CONCLUSION

Based on the numerous studies included in this literature review, glutathione and its precursor N-acetylcysteine have demonstrated significant protective effects in events of prolonged, exacerbated oxidative stress as seen in chronic inflammatory musculoskeletal disorders such as osteoarthritis.

Graphene-Based Sensors for the Detection of Bioactive Compounds: A Review

Over the last years, different nanomaterials have been investigated to design highly selective and sensitive sensors, reaching nano/picomolar concentrations of biomolecules, which is crucial for medical sciences and the healthcare industry in order to assess physiological and metabolic parameters. The discovery of graphene (G) has unexpectedly impulsed research on developing cost-effective electrode materials owed to its unique physical and chemical properties, including high specific surface area, elevated carrier mobility, exceptional electrical and thermal conductivity, strong stiffness and strength combined with flexibility and optical transparency. G and its derivatives, including graphene oxide (GO) and reduced graphene oxide (rGO), are becoming an important class of nanomaterials in the area of optical and electrochemical sensors. The presence of oxygenated functional groups makes GO nanosheets amphiphilic, facilitating chemical functionalization. G-based nanomaterials can be easily combined with different types of inorganic nanoparticles, including metals and metal oxides, quantum dots, organic polymers, and biomolecules, to yield a wide range of nanocomposites with enhanced sensitivity for sensor applications. This review provides an overview of recent research on G-based nanocomposites for the detection of bioactive compounds, providing insights on the unique advantages offered by G and its derivatives. Their synthesis process, functionalization routes, and main properties are summarized, and the main challenges are also discussed. The antioxidants selected for this review are melatonin, gallic acid, tannic acid, resveratrol, oleuropein, hydroxytyrosol, tocopherol, ascorbic acid, and curcumin. They were chosen owed to their beneficial properties for human health, including antibiotic, antiviral, cardiovascular protector, anticancer, anti-inflammatory, cytoprotective, neuroprotective, antiageing, antidegenerative, and antiallergic capacity. The sensitivity and selectivity of G-based electrochemical and fluorescent sensors are also examined. Finally, the future outlook for the development of G-based sensors for this type of biocompounds is outlined.

Curcumin from Turmeric Rhizome: A Potential Modulator of DNA Methylation Machinery in Breast Cancer Inhibition

One of the most systematically studied bioactive nutraceuticals for its benefits in the management of various diseases is the turmeric-derived compounds: curcumin. Turmeric obtained from the rhizome of a perennial herb Curcuma longa L. is a condiment commonly used in our diet. Curcumin is well known for its potential role in inhibiting cancer by targeting epigenetic machinery, with DNA methylation at the forefront. The dynamic DNA methylation processes serve as an adaptive mechanism to a wide variety of environmental factors, including diet. Every healthy tissue has a precise DNA methylation pattern that changes during cancer development, forming a cancer-specific design. Hypermethylation of tumor suppressor genes, global DNA demethylation, and promoter hypomethylation of oncogenes and prometastatic genes are hallmarks of nearly all types of cancer, including breast cancer. Curcumin has been shown to modulate epigenetic events that are dysregulated in cancer cells and possess the potential to prevent cancer or enhance the effects of conventional anti-cancer therapy. Although mechanisms underlying curcumin-mediated changes in the epigenome remain to be fully elucidated, the mode of action targeting both hypermethylated and hypomethylated genes in cancer is promising for cancer chemoprevention. This review provides a comprehensive discussion of potential epigenetic mechanisms of curcumin in reversing altered patterns of DNA methylation in breast cancer that is the most commonly diagnosed cancer and the leading cause of cancer death among females worldwide. Insight into the other bioactive components of turmeric rhizome as potential epigenetic modifiers has been indicated as well.

Effect of Polyphenols on Cognitive Function: Evidence from Population-Based Studies and Clinical Trials

Due to progressive population aging, a new dementia case occurs at every 3 seconds, placing a heavy burden of disease. Identifying potential risk or preventive factors is emphasized owing to a lack of effective treatment for dementia. There has been emerging evidence on the link of certain dietary components, particularly polyphenols, to brain wellness and cognitive outcomes. Findings from animal and in vitro studies appear more consistent and conclusive. However, such an association has not been investigated in depth in human beings. In this review, we examined studies on the effect of dietary polyphenols (including flavonoids, curcumin, and resveratrol) on cognitive function. Intervention in early stages of dementia/Alzheimer's disease might be a target to slow down age-related cognitive decline before disease onset. We summarized 28 epidemiological studies (8 cross-sectional and 20 cohort studies) and 55 trials in this review. Preliminary evidence from epidemiological data provides the necessity for intervention trials, even though the measures of polyphenol intake tend to be less precise. Clinical trials are in favor of the role of some polyphenols in benefiting specific domains of cognition. This review also describes the divergence of results and current limitations of research in this field.

Challenges in Biomaterial-Based Drug Delivery Approach for the Treatment of Neurodegenerative Diseases: Opportunities for Extracellular Vesicles

Biomaterials have been the subject of numerous studies to pursue potential therapeutic interventions for a wide variety of disorders and diseases. The physical and chemical properties of various materials have been explored to develop natural, synthetic, or semi-synthetic materials with distinct advantages for use as drug delivery systems for the central nervous system (CNS) and non-CNS diseases. In this review, an overview of popular biomaterials as drug delivery systems for neurogenerative diseases is provided, balancing the potential and challenges associated with the CNS drug delivery. As an effective drug delivery system, desired properties of biomaterials are discussed, addressing the persistent challenges such as targeted drug delivery, stimuli responsiveness, and controlled drug release in vivo. Finally, we discuss the prospects and limitations of incorporating extracellular vesicles (EVs) as a drug delivery system and their use for biocompatible, stable, and targeted delivery with limited immunogenicity, as well as their ability to be delivered via a non-invasive approach for the treatment of neurodegenerative diseases.

Hydroxypropyl-β-cyclodextrin as an effective carrier of curcumin - piperine nutraceutical system with improved enzyme inhibition properties

The nutraceutical system of curcumin-piperine in 2-hydroxypropyl-β-cyclodextrin was prepared by using the kneading technique. Interactions between the components of the system were defined by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR). Application of hydroxypropyl-β-cyclodextrin as a carrier-solubiliser improved solubility of the curcumin-piperine system, its permeability through biological membranes (gastrointestinal tract, blood-brain barrier) as well as the antioxidant, antimicrobial and enzyme inhibitory activities against acetylcholinesterase and butyrylcholinesterase.

Curcumin Oligosaccharides (Gluco-oligosaccharides) Penetrate the Blood-Brain Barrier in Mouse Brain: Glycoside (Polysaccharide) Modification Approach for Brain Drug Delivery Across the Blood-Brain Barrier and Tumor Drug Delivery

In order to expand our drug delivery technique by glycosylation of chemical into brain delivery, it was demonstrated that oligosaccharide and monosaccharide modifications of curcumin enhanced its crossing ability of the blood-brain barrier (BBB) in mice. The brain sample prepared by glycosidase-catalyzed hydrolysis of brain tissue homogenates of mice, to which curcumin gluco-oligosaccharides were intraperitoneally injected, contained curcumin at 116 ng/1 g of tissue of brain, indicating that curcumin modified with gluco-oligosaccharides residues can smoothly cross the BBB in mouse brain. The brain samples of mice, which were treated with curcumin monosaccharide or curcumin itself, contained curcumin at 18 ng and 0 ng per 1 g of tissue of brain, respectively. On the other hand, after the administration of curcumin gluco-oligosaccharides to C57BL mouse with a large tumor for 5 days, the tumor disappeared.

Experimental and clinical studies on radiation and curcumin in human glioma

Purpose

There is progressing evidence for the anti-cancer potential of the natural compound and dietary spice curcumin. Curcumin has been ascribed to be cytotoxic for various tumour cell types, to inhibit cell proliferation and to interfere with the cellular oxidant status. The compound has been notified as a therapeutic agent with radiosensitizing potential in brain tumour therapy. We considered the rationale to combine curcumin with radiation in the treatment of human glioblastoma multiforme (GBM).

Method

Determination of clonogenic cell survival following exposure of U251 human glioma cells to single dose (1–6 Gy) and fractionated irradiation (5 daily fractions of 2 Gy) without and with curcumin. Additional literature search focused on the interaction between curcumin and radiotherapy in experimental and clinical studies on human glioma.

Results

No interaction was found on the survival of U251 human glioma cells after irradiation in combination with curcumin at clinically achievable concentrations. Experimental in vitro and in vivo data together with clinical bioavailability data from the literature do not give evidence for a radiosensitizing effect of curcumin. Reported GBM intratumoural curcumin concentrations are too low to either exert an own cytotoxic effect or to synergistically interact with radiation. Novel approaches are being explored to increase the bioavailability of curcumin and to facilitate transport over the blood–brain barrier, aimed to reach therapeutic curcumin levels at the tumour site.

Conclusion

There is neither a biological nor clinical rationale for using curcumin as radiosensitizer in the therapy of GBM patients.

Obstacles against the Marketing of Curcumin as a Drug

Among the extensive public and scientific interest in the use of phytochemicals to prevent or treat human diseases in recent years, natural compounds have been highly investigated to elucidate their therapeutic effect on chronic human diseases including cancer, cardiovascular disease, and neurodegenerative disease. Curcumin, an active principle of the perennial herb Curcuma longa, has attracted an increasing research interest over the last half-century due to its diversity of molecular targets, including transcription factors, enzymes, protein kinases, growth factors, inflammatory cytokines, receptors, and it's interesting pharmacological activities. Despite that, the clinical effectiveness of the native curcumin is weak, owing to its low bioavailability and rapid metabolism. Preclinical data obtained from animal models and phase I clinical studies done in human volunteers confirmed a small amount of intestinal absorption, hepatic first pass effect, and some degree of intestinal metabolism, might explain its poor systemic availability when it is given via the oral route. During the last decade, researchers have attempted with new pharmaceutical methods such as nanoparticles, liposomes, micelles, solid dispersions, emulsions, and microspheres to improve the bioavailability of curcumin. As a result, a significant number of bioavailable curcumin-based formulations were introduced with a varying range of enhanced bioavailability. This manuscript critically reviews the available scientific evidence on the basic and clinical effects and molecular targets of curcumin. We also discuss its pharmacokinetic and problems for marketing curcumin as a drug.

An Update on the Pharmacological Usage of Curcumin: Has it Failed in the Drug Discovery Pipeline?

The pharmacological propensities of curcumin have been reported in a plethora of pre-clinical and clinical studies. However, innate attributes account for extremely low oral bioavailability which impedes its development as a therapeutic agent. Regardless, these drawbacks have not deterred researchers from optimizing its potentials. This review discussed the pharmacokinetic properties of curcumin relative to its outlook as a lead compound in drug discovery. Also, we highlighted therapeutic strategies that have expedited improvements in curcumin oral bioavailability and delivery to target sites over the years. Recent implementations of these strategies were also covered. More research efforts should be directed towards investigating the pharmacokinetic impacts of these novel curcumin formulations in human clinical studies since inter-species disparities could limit the accuracies of animal studies. We envisaged that integrative-clinical research would help determine 'actual' improvements in curcumin pharmacokinetics coupled with suitable administrative routes, optimal dosing, and drug-enzyme or drug-drug interactions. In addition, this could help determine formulations for achieving higher systemic exposure of parent curcumin thereby providing a strong impetus towards the development of curcumin as a drug candidate in disease treatment.

Flavonoids and Related Members of the Aromatic Polyketide Group in Human Health and Disease: Do They Really Work?

Some aromatic polyketides such as dietary flavonoids have gained reputation as miraculous molecules with preeminent beneficial effects on human health, for example, as antioxidants. However, there is little conclusive evidence that dietary flavonoids provide significant leads for developing more effective drugs, as the majority appears to be of negligible medicinal importance. Some aromatic polyketides of limited distribution have shown more interesting medicinal properties and additional research should be focused on them. Combretastatins, analogues of phenoxodiol, hepatoactive kavalactones, and silymarin are showing a considerable promise in the advanced phases of clinical trials for the treatment of various pathologies. If their limitations such as adverse side effects, poor water solubility, and oral inactivity are successfully eliminated, they might be prime candidates for the development of more effective and in some case safer drugs. This review highlights some of the newer compounds, where they are in the new drug pipeline and how researchers are searching for additional likely candidates.

Antioxidant supplements and endurance exercise: Current evidence and mechanistic insights

Antioxidant supplements are commonly consumed by endurance athletes to minimize exercise-induced oxidative stress, with the intention of enhancing recovery and improving performance. There are numerous commercially available nutritional supplements that are targeted to athletes and health enthusiasts that allegedly possess antioxidant properties. However, most of these compounds are poorly investigated with respect to their in vivo redox activity and efficacy in humans. Therefore, this review will firstly provide a background to endurance exercise-related redox signalling and the subsequent adaptations in skeletal muscle and vascular function. The review will then discuss commonly available compounds with purported antioxidant effects for use by athletes. N-acetyl cysteine may be of benefit over the days prior to an endurance event; while chronic intake of combined 1000 mg vitamin C + vitamin E is not recommended during periods of heavy training associated with adaptations in skeletal muscle. Melatonin, vitamin E and α-lipoic acid appear effective at decreasing markers of exercise-induced oxidative stress. However, evidence on their effects on endurance performance are either lacking or not supportive. Catechins, anthocyanins, coenzyme Q10 and vitamin C may improve vascular function, however, evidence is either limited to specific sub-populations and/or does not translate to improved performance. Finally, additional research should clarify the potential benefits of curcumin in improving muscle recovery post intensive exercise; and the potential hampering effects of astaxanthin, selenium and vitamin A on skeletal muscle adaptations to endurance training. Overall, we highlight the lack of supportive evidence for most antioxidant compounds to recommend to athletes.

The Use of Curcumin as a Complementary Therapy in Ulcerative Colitis: A Systematic Review of Randomized Controlled Clinical Trials

The objective of this study was to systematically review the literature to verify the efficacy and safety of curcumin as a complementary therapy for the maintenance or induction of remission in patients with inflammatory bowel disease (IBD). A comprehensive search was conducted by two independent authors in MEDLINE (PubMed), Scopus, Web of Science, the Cochrane Library, Lilacs, Food Science and Technology Abstracts, and ScienceDirect. The search terms “curcumin”, “curcuma”, “inflammatory bowel disease”, “proctocolitis”, “crohn disease”, and “inflammation” were combined to create search protocols. This study considered randomized controlled trials (RCTs) published in any language before March 2020 that evaluated the effects of curcumin on inflammatory activity and the maintenance or remission of IBD patients. After duplicates were removed, 989 trials were identified, but only 11 met the eligibility criteria. Five of these were considered to be biased and were excluded. Therefore, six trials were considered in this review. All the studies included in the systematic review were placebo-controlled RCTs conducted on individuals with ulcerative colitis (UC). All the RCTs reported that curcumin was well tolerated and was not associated with any serious side effects. Studies show that curcumin may be a safe, effective therapy for maintaining remission in UC when administered with standard treatments. However, the same cannot be stated for Crohn’s disease due to the lack of low bias risk studies. Further studies with larger sample sizes are needed before curcumin can be recommended as a complementary therapy for UC.

Formulation of More Efficacious Curcumin Delivery Systems Using Colloid Science: Enhanced Solubility, Stability, and Bioavailability

Curcumin is a bioactive constituent isolated from turmeric that has historically been used as a seasoning, pigment, and herbal medicine in food. Recently, it has become one of the most commonly studied nutraceuticals in the pharmaceutical, supplement, and food areas because of its myriad of potential health benefits. For instance, it is claimed to exhibit antioxidant, anti-inflammatory, antimicrobial, antiparasite, and anticancer activities when ingested as a drug, supplement, or food. Toxicity studies suggest that it is safe to consume, even at relatively high levels. Its broad-spectrum biological activities and low toxicity have meant that it has been widely explored as a nutraceutical ingredient for application in functional foods. However, there are several hurdles that formulators must overcome when incorporating curcumin into commercial products, such as its low water solubility (especially under acidic and neutral conditions), chemical instability (especially under neutral and alkaline conditions), rapid metabolism by enzymes in the human body, and limited bioavailability. As a result, only a small fraction of ingested curcumin is actually absorbed into the bloodstream. These hurdles can be at least partially overcome by using encapsulation technologies, which involve trapping the curcumin within small particles. Some of the most commonly used edible microparticles or nanoparticles utilized for this purpose are micelles, liposomes, emulsions, solid lipid particles, and biopolymer particles. Each of these encapsulation technologies has its own benefits and limitations for particular product applications and it is important to select the most appropriate one.

Antiviral Natural Products for Arbovirus Infections

Over the course of the last 50 years, the emergence of several arboviruses have resulted in countless outbreaks globally. With a high proportion of infections occurring in tropical and subtropical regions where arthropods tend to be abundant, Asia in particular is a region that is heavily affected by arboviral diseases caused by dengue, Japanese encephalitis, West Nile, Zika, and chikungunya viruses. Major gaps in protection against the most significant emerging arboviruses remains as there are currently no antivirals available, and vaccines are only available for some. A potential source of antiviral compounds could be discovered in natural products—such as vegetables, fruits, flowers, herbal plants, marine organisms and microorganisms—from which various compounds have been documented to exhibit antiviral activities and are expected to have good tolerability and minimal side effects. Polyphenols and plant extracts have been extensively studied for their antiviral properties against arboviruses and have demonstrated promising results. With an abundance of natural products to screen for new antiviral compounds, it is highly optimistic that natural products will continue to play an important role in contributing to antiviral drug development and in reducing the global infection burden of arboviruses.

Micellar solubilization enhances the anti-inflammatory effect of xanthohumol

BACKGROUND

Xanthohumol is known to exert anti-inflammatory properties but has poor oral bioavailability. Using advanced micellization technology, it has been possible to markedly enhance its bioavailability.

PURPOSE

In the present study, we compared the chronic anti-inflammatory activities of native and micellar xanthohumol in the rat adjuvant arthritis model, using diclofenac as a reference drug.

METHODS

Adjuvant arthritis was induced by injecting Freund's complete adjuvant into the right hind paw of rats and monitoring paw volume over 3 weeks. The drugs were given daily for 3 weeks, starting from the day of adjuvant inoculation. Serum was collected at the end of the experiment to measure inflammatory and oxidative stress parameters. Statistical comparisons between different groups were carried out by one-way analysis of variance followed by Tukey-Kramer multiple comparison test.

RESULTS

Micellar solubilized xanthohumol showed a better anti-inflammatory activity than its native form. The reduction in paw volume was reflected in corresponding changes in relevant mediators of inflammation like tumor necrosis factor-α, interleukin-6 and C-reactive protein, myloperoxidase and lipid peroxidation markers.

CONCLUSION

The findings confirm that micellar solubilization of xanthohumol enhances its anti-inflammatory activity, probably as a result of improving its bioavailabilty. The solubilized xanthohumol may prove to be a promising adjuvant tool for anti-inflammatory treatment and a potential anti-inflammatory alternative to synthetic drugs.

Curcumin Administered as Micellar Solution Suppresses Intestinal Inflammation and Colorectal Carcinogenesis

Colorectal cancer (CRC) is one of the most common cancers and preventive strategies based on natural compounds are highly desirable. Curcumin, the principal bioactive compound in Curcuma longa, was described to have multiple beneficial health effects. A drawback, however, is the low bioavailability due to its insolubility in water. Here, we studied whether nanoscaled micellar curcumin with improved bioavailability administered in drinking water reduces inflammation and CRC formation in a mouse model. C57BL6 wild-type (WT) mice and a strain defective in the DNA repair enzyme O⁶-methylguanine-DNA methyltransferase (MGMT) were used, in which tumors were induced by azoxymethane (AOM) followed by dextran sodium sulfate (DSS). Inflammation and tumor formation were determined by mini-colonoscopy. Micellar curcumin (mCur) administered in drinking water significantly reduced AOM/DSS-induced colorectal inflammation in both WT and MGMT-deficient mice as compared to animals receiving drinking water with micelles not containing curcumin. In line with this, the tumor yield and tumor score were significantly lower in mCur-treated mice compared to the control group. No adverse effects were observed in animals receiving mCur daily for at least three months. Overall, our data show that chronic oral administered micellar curcumin is well tolerated and reduces chemical-induced gut inflammation and CRC formation in mice.Impact: The study shows that micellar curcumin with high bioavailability chronically administered at low and physiologically relevant concentration suppresses inflammation and carcinogenesis in a mouse colorectal tumor model.

The Influence of Piperine on the Radioprotective Effect of Curcumin in Irradiated Human Lymphocytes

Objectives

Ionizing radiation (IR) induces DNA damage in normal cells, leading to genotoxicity. The radioprotective effects of co-treatment with curcumin and piperine were investigated against genotoxicity induced by IR in human normal lymphocytes.

Materials and Methods

Human blood samples were pretreated with curcumin at different concentrations (5, 10, and 25 μg/mL) and/or piperine (2.5 μg/mL) and then were exposed to IR at a dose 1.5 Gy. The radioprotective effects of curcumin and piperine were assessed by micronucleus (MN) assay.

Results

Curcumin and piperine reduced the percentage of MN induced by IR in lymphocytes. Piperine alone significantly reduced genotoxicity induced by IR as compared to curcumin alone at all concentrations. An additive radioprotective effect was observed with combination of piperine and curcumin at the low concentration of 5 μg/mL, while this synergistic effect was not observed with curcumin at the higher concentrations of 10 and 25 μg/mL.

Conclusion

Piperine has a potent radioprotective effect at low concentration as compare to curcumin. However, an additive radioprotective effect was observed with co-treatment with piperine and curcumin at low concentration, while piperine increased the percentage of MN in normal lymphocytes when co-treated with curcumin at higher concentration.

Amelioration of Radiation-Induced Damages in Mice by Curcuminoids: The Role of Bioavailability

PURPOSE

The present study investigated the role of free curcuminoids bioavailability on the relative radioprotective efficacy of natural unformulated curcuminoids.

MATERIALS AND METHODS

A food-grade bioavailable formulation of curcuminoids as curcumagalactomannosides (CGM) and unformulated curcuminoids (UC) were employed for the study. Swiss albino mice were randomized into Normal control, Radiation control, Radiation + UC, and Radiation + CGM groups and irradiated with γ-radiation of 6, 8, 10 and 12 Gy. Survival rate, hematological and biochemical parameters, bone marrow cellularity, chromosomal aberrations and histopathology of intestine were followed as a measure of the relative efficacy.Results and Discussion: Oral administration with both UC and CGM at 100 mg/kg. b.wt. produced significant radioprotective effect over the untreated control group of animals. However, CGM treatment was found to provide better clastogenic and genotoxic potential as compared to UC. Further, the histopathology analysis of intestine confirmed the better protective effect of CGM over UC-treated animals.

CONCLUSION

The present study demonstrated the positive role of the bioavailability of curcuminoids in the amelioration of radiation-induced damages in mice since CGM treatment exerted better survival rate and radioprotective effect as compared with UC, despite the relatively low concentrations of curcuminoids in CGM (39% w/w).

Curcumin and neurological diseases

Objectives: The beneficial effects of many substances have been discovered because of regular dietary consumption. This is also the case with curcumin, whose effects have been known for more than 4,000 years in Eastern countries such as China and India. A curcumin-rich diet has been known to counteract many human diseases, including cancer and diabetes, and has been shown to reduce inflammation. The effect of a curcumin treatment for neurological diseases, such as spinal muscular atrophy; Alzheimer's disease; Parkinson's disease; amyotrophic lateral sclerosis; multiple sclerosis; and others, has only recently been brought to the attention of researchers and the wider population.Methods: In this paper, we summarise the studies on this natural product, from its isolation two centuries ago to its characterisation a century later.Results: We describe its role in the treatment of neurological diseases, including its cellular and common molecular mechanisms, and we report on the clinical trials of curcumin with healthy people and patients.Discussion: Commenting on the different approaches adopted by the efforts made to increase its bioavailability.

Lower concentrations of curcumin inhibit Her2-Akt pathway components in human breast cancer cells, and other dietary botanicals potentiate this and lapatinib inhibition

Her2-dependent breast cancer is treated with pharmacological drugs (eg, Herceptin, lapatinib) that target Her2 signaling. Curcumin has emerged as a potential co-treatment for this and other cancers, but prior studies have focused on non-attainable concentrations. Here we test the hypothesis that attainable in vivo levels of dietary curcumin can reduce Her2 signaling. Consistent with previous studies, higher dose curcumin (18 μmol/L) inhibits Her2-Akt pathway signaling (pHer2, total Her2 and pAkt levels) and cell growth using AU565 human breast cancer cells. We then examined lower, more physiologically relevant concentrations of curcumin, alone and in combination with other dietary botanicals (quercetin and OptiBerry fruit extract). At 4 μmol/L, curcumin reduced Her2 signaling, and even more when combined with quercetin or OptiBerry. At 1.5 μmol/L curcumin, pHer2 and Her2 (but not pAkt) were reduced, with all three pathway markers reduced more in the presence of quercetin. We also found that 1.5 μmol/L curcumin strongly potentiated lapatinib inhibition of Her2-Akt pathway signaling, and more so for pAkt, when combined with quercetin plus OptiBerry (CQO). Parallel analyses revealed cell growth inhibition at 18 and 4 μmol/L but not 1.5 μmol/L curcumin, and potentiation of 1.5 μmol/L curcumin growth arrest with other botanicals +/- lapatinib. These studies demonstrate that a physiological attainable level of curcumin (1.5 μmol/L) can reduce some components of the critical Her2-Akt pathway; that even more complete inhibition can be achieved by combination with other dietary botanicals; and that curcumin and other botanicals can potentiate the action of the Her2-cancer metastatic drug lapatinib, in turn suggesting the potential anti-cancer clinical use of these botanicals.

Nano Encapsulated Curcumin: And Its Potential for Biomedical Applications

Curcumin, a yellow-colored polyphenol extracted from the rhizome of turmeric root, is commonly used as a spice and nutritional supplement. It exhibits many pharmacological activities such as anti-inflammatory, anti-bacterial, anti-cancer, anti-Alzheimer, and anti-fungal. However, the therapeutic application of curcumin is limited by its extremely low solubility in aqueous buffer, instability in body fluids, and rapid metabolism. Nano delivery system has shown excellent potential to improve the solubility, biocompatibility and therapeutic effect of curcumin. In this review, we focus on the recent development of nano encapsulated curcumin and its potential for biomedical applications.

Modulatory effects of curcumin on the atherogenic activities of inflammatory monocytes: Evidence from in vitro and animal models of human atherosclerosis

Atherosclerosis is a complex and long-lasting disorder characterized by chronic inflammation of arteries that leads to the initiation and progression of lipid-rich plaques, in which monocytes/macrophages play the central role in endothelial inflammation and taking up these lipids. Circulating monocytes can adopt a long-term proinflammatory phenotype leading to their atherogenic activities. During atherogenic condition, inflammatory monocytes adhere to the surface of the activated endothelial cells and then transmigrate across the endothelial monolayer into the intima, where they proliferate and differentiate into macrophages and take up the lipoproteins, forming foam cells that derive atherosclerosis progression. Therefore, modulating the atherogenic activities of inflammatory monocytes can provide a valuable therapeutic approach for atherosclerosis prevention and treatment. Curcumin is a naturally occurring polyphenolic compound with numerous pharmacological activities and shows protective effects against atherosclerosis; however, underlying mechanisms are not clearly known yet. In the present review, on the basis of a growing body of evidence, we show that curcumin can exert antiatherosclerotic effect through inhibiting the atherogenic properties of monocytes, including inflammatory cytokine production, adhesion, and transendothelial migration, as well as intracellular cholesterol accumulation.