Curcumin, Gut Microbiota, and Neuroprotection

Phytonutrients: Sources, bioavailability, interaction with gut microbiota, and their impacts on human health

Phytonutrients are natural bioactive components present in the daily diet that can exert a positive impact on human health. Studies have shown that phytonutrients may act as antioxidants and improve metabolism after being ingested, which help to regulate physiological processes and prevent metabolic disorders and diseases. However, their efficacy is limited by their low bioavailability. The gut microbiota is symbiotic with humans and its abundance and profile are related to most diseases. Interestingly, studies have shown that the gut microbiota is associated with the metabolism of phytonutrients by converting them into small molecules that can be absorbed by the body, thereby enhancing their bioavailability. Furthermore, phytonutrients can modulate the composition of the gut microbiota, and therefore improve the host's health. Here, we focus on uncovering the mechanisms by which phytonutrients and gut microbiota play roles in health, and the interrelationships between phytonutrients and gut microbiota were summarized. We also reviewed the studies that reported the efficacy of phytonutrients in human health and the future directions.

Updated design strategies for oral delivery systems: maximized bioefficacy of dietary bioactive compounds achieved by inducing proper digestive fate and sensory attributes

Interest in the application of dietary bioactive compounds (DBC) in healthcare and pharmaceutical industries has motivated researchers to develop functional delivery systems (FDS) aiming to maximize their bioefficacy. As the direct and indirect health benefiting effects of DBC are acknowledged, traditional design principle of FDS aiming at improving the bioavailability of intact DBC is challenged by the updated one, where the maximized bioefficacy of DBC delivered by FDS will be achieved via rationally absorbed at target sites with proper metabolism pathways. This article briefly summarized the absorption and metabolic fates of orally digested DBC along with their direct and indirect mechanisms to perform health benefiting effects. Current strategies in designing the next generation FDS with an emphasis on their modulation effects on the distribution portion between the upper and lower digestive tract, portal vein and lymphatic absorption, human digestive and gut microbiota enzymatic mediated metabolism were highlighted. Updated research progresses of FDS in adjusting sensory attributes of food end products and inducing synergistic effects rooting from matrix materials and co-delivered cargos were also discussed. Challenges as well as future perspectives concerning the precise nutrition and the critical role of delivery systems in dietary intervention were proposed.

A Review of In Silico Research, SARS-CoV-2, and Neurodegeneration: Focus on Papain-Like Protease

Since the appearance of SARS-CoV-2 and the COVID-19 pandemic, the search for new approaches to treat this disease took place in the scientific community. The in silico approach has gained importance at this moment, once the methodologies used in this kind of study allow for the identification of specific protein–ligand interactions, which may serve as a filter step for molecules that can act as specific inhibitors. In addition, it is a low-cost and high-speed technology. Molecular docking has been widely used to find potential viral protein inhibitors for structural and non-structural proteins of the SARS-CoV-2, aiming to block the infection and the virus multiplication. The papain-like protease (PLpro) participates in the proteolytic processing of SARS-CoV-2 and composes one of the main targets studied for pharmacological intervention by in silico methodologies. Based on that, we performed a systematic review about PLpro inhibitors from the perspective of in silico research, including possible therapeutic molecules in relation to this viral protein. The neurological problems triggered by COVID-19 were also briefly discussed, especially relative to the similarities of neuroinflammation present in Alzheimer’s disease. In this context, we focused on two molecules, curcumin and glycyrrhizinic acid, given their PLpro inhibitory actions and neuroprotective properties and potential therapeutic effects on COVID-19.

Neuroprotective Effects of Curcumin against Oxygen-Glucose Deprivation/Reoxygenation-Induced Injury in Cultured Primary Rat Astrocyte by Improving Mitochondrial Function and Regulating the ERK Signaling Pathway

Objectives

Curcumin (Cur) is a natural polyphenol isolated from turmeric and has potent anti-inflammatory and antioxidant activities. This study aimed to explore the effects and possible mechanisms of curcumin on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced injury in cultured rat astrocyte primary cells.

Methods

After screening for effective doses, the cultured rat astrocyte primary cells were divided into three groups: control, OGD/R, and OGD/R + curcumin (10 μM, 20 μM, and 40 μM). Cell viability was detected using CCK8 assays. The level of malondialdehyde and superoxide dismutase activity was determined using commercial kits. The endothelial nitric oxide synthase and adenosine triphosphate concentrations were determined by enzyme-linked immunosorbent assay. The mRNA levels of the inflammatory indexes interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1β were evaluated by quantitative reverse-transcription polymerase chain reaction. Annexin V-fluorescein isothiocyanate/propidium iodide was used to detect apoptosis. JC-1 was used to assess the mitochondrial membrane potential. The protein expression of apoptosis-related proteins (B-cell lymphoma-2 (Bcl-2), BCL-2-associated X (Bax), and cleaved caspase 3), mitochondria-related proteins (dynamin-related protein 1 (DRP1), phosphorylated DRP1 (p-DRP1), and mitofusin 2), and essential proteins of the extracellular signal-regulated kinase (ERK) signaling pathway (ERK1/2, p-ERK1/2) were analyzed by western blot.

Results

Our data indicated that curcumin reversed OGD/R-induced cell viability loss, oxidative stress, inflammatory cytokine production, and cell apoptosis in a dose-dependent manner. Furthermore, curcumin attenuated OGD/R-induced mitochondrial dysfunction and ERK1/2 phosphorylation in a dose-dependent manner.

Conclusions

Curcumin protected against OGD/R-induced injury in rat astrocyte primary cells through improving mitochondrial function and regulating the ERK signaling pathway.

Herbs as an Active Ingredient in Sport: Availability and Information on the Internet

The use of supplements containing herbal active ingredients in sport has increased in recent years. Their consumption is explained by the benefits they may provide and because their natural origin do not involve health complications, from the point of view of the consumers. The aim of this study is to analyze the availability of four supplements (caffeine, turmeric, ginseng, cannabidiol) on the internet and understand the nature of these websites. A descriptive, observational, and cross-sectional study design was used. A detailed search was carried out with specifically developed software. The searches and data evaluation took 10 days. The websites consulted correspond to those that sell supplements, or some sport websites in the case of the Spanish ones, whereas those in English belong to pharmacies, parapharmacies, or herbalists. It is concluded that the websites do not provide adequate information to ensure proper consumption and lack advice on the choices of supplements and their administration guidelines.

Dietary essential oils improves the growth performance, antioxidant properties and intestinal permeability by inhibiting bacterial proliferation and altering the gut microbiota of yellow-feather broilers

This experiment was conducted to investigate the antibacterial effects of essential oils (EO) in vitro and the influence of EO on growth performance, intestinal morphology and oxidation resistance and cecal microflora of yellow-feathered broilers. A total of 720 one-day-old male yellow feather broilers were randomly assigned into 4 treatments with 6 replicate cages of 30 broilers each. The groups were as follows: CON group (basal diet), EO200 group (basal diet + 200 mg/kg EO), EO400 group (basal diet + 400 mg/kg EO), and EO600 group (basal diet + 600 mg/kg EO). The experiment lasted for 48 d. Results showed that the growth and biofilm formation of avian pathogenic E. coli O78 and Salmonella pullorum were limited by adding EO to the diet (P < 0.05). Besides, birds fed with EO had greater (P < 0.05) average daily feed intake (ADFI), average daily gain (ADG), and body weight (BW) during d 1 to 21, 22 to 42, and 1 to 48 and lower (P < 0.05) feed: gain (F:G) than those fed with basal diet during d 22 to 42 and 1 to 48. Moreover, the activity of antioxidant enzyme and the intestinal permeability were improved in the EO400 and EO600 groups rather than the CON group on d 21 (P < 0.05). There were significant differences in cecal microbial composition and enrichment of metabolic pathways of birds among all groups by 16S-based sequencing. In summary, some dose of EO improved bacteriostatic ability, antioxidant ability, and intestinal health of broilers which contributed to the growth performance improvement of yellow-feathered broilers, which can be a promising antibiotic alternative for improving poultry production.

Regulation of Gene Expression through Food—Curcumin as a Sirtuin Activity Modulator

The sirtuin family comprises NAD⁺-dependent protein lysine deacylases, mammalian sirtuins being either nuclear (SIRT1, SIRT2, SIRT6, and SIRT7), mitochondrial (SIRT3, SIRT4, and SIRT5) or cytosolic enzymes (SIRT2 and SIRT5). They are able to catalyze direct metabolic reactions, thus regulating several physiological functions, such as energy metabolism, stress response, inflammation, cell survival, DNA repair, tissue regeneration, neuronal signaling, and even circadian rhythms. Based on these data, recent research was focused on finding molecules that could regulate sirtuins’ expression and/or activity, natural compounds being among the most promising in the field. Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) can induce, through SIRT, modulation of cancer cell senescence, improve endothelial cells protection against atherosclerotic factors, enhance muscle regeneration in atrophy models, and act as a pro-longevity factor counteracting the neurotoxicity of amyloid-beta. Although a plethora of protective effects was reported (antioxidant, anti-inflammatory, anticancer, etc.), its therapeutical use is limited due to its bioavailability issues. However, all the reported effects may be explained via the bioactivation theory, which postulates that curcumin’s observed actions are modulated via its metabolites and/or degradation products. The present article is focused on bringing together the literature data correlating the ability of curcumin and its metabolites to modulate SIRT activity and its consequent beneficial effects.

Health benefits of polyphenols: A concise review

Plants produce polyphenols, which are considered highly essential functional foods in our diet. They are classified into several groups according to their diverse chemical structures. Flavanoids, lignans, stilbenes, and phenolic acids are the four main families of polyphenols. Several in vivo and in vitro research have been conducted so far to evaluate their health consequences. Polyphenols serve a vital function in the protection of the organism from external stimuli and in eliminating reactive oxygen species (ROS), which are instigators of several illnesses. Polyphenols are present in tea, chocolate, fruits, and vegetables with the potential to positively influence human health. For instance, cocoa flavan-3-ols have been associated with a decreased risk of myocardial infarction, stroke, and diabetes. Polyphenols in the diet also help to improve lipid profiles, blood pressure, insulin resistance, and systemic inflammation. Quercetin, a flavonoid, and resveratrol, a stilbene, have been linked to improved cardiovascular health. Dietary polyphenols potential to elicit therapeutic effects might be attributed, at least in part, to a bidirectional association with the gut microbiome. This is because polyphenols are known to affect the gut microbiome composition in ways that lead to better human health. Specifically, the gut microbiome converts polyphenols into bioactive compounds that have therapeutic effects. In this review, the antioxidant, cytotoxicity, anti-inflammatory, antihypertensive, and anti-diabetic actions of polyphenols are described based on findings from in vivo and in vitro experimental trials. PRACTICAL APPLICATIONS: The non-communicable diseases (NCDs) burden has been increasing worldwide due to the sedentary lifestyle and several other factors such as smoking, junk food, etc. Scientific literature evidence supports the use of plant-based food polyphenols as therapeutic agents that could help to alleviate NCD's burden. Thus, consuming polyphenolic compounds from natural sources could be an effective solution to mitigate NCDs concerns. It is also discussed how natural antioxidants from medicinal plants might help prevent or repair damage caused by free radicals, such as oxidative stress.

Ketogenic and Modified Mediterranean Diet as a Tool to Counteract Neuroinflammation in Multiple Sclerosis: Nutritional Suggestions

Ketogenic Diet is a nutritional pattern often used as dietotherapy in inflammatory diseases, including neurological disorders. Applied on epileptic children since 1920, in recent years it has been taken into account again as a tool to both reduce inflammatory burdens and ameliorate the nutritional status of patients affected by different pathologies. Multiple sclerosis (MS) is considered an immune-mediated neuro-inflammatory disease and diet is a possible factor in its pathogenesis. The aim of this work is to investigate the main potential targets of MS-related impairments, in particular the cognitive deficits, focusing on the alteration of biomarkers such as the Brain Derived-Neurotrophic Factor and the Tryptophan/Kynurenine ratio that could play a role on neuroprotection and thus on MS progression. Furthermore, we here propose nutritional suggestions which are useful in the development of a ketogenic diet protocol that takes advantage of the anti-inflammatory properties of low-carbohydrate foods from the Mediterranean diet to be applied to subjects with MS. In conclusion, this approach will allow one to develop the ketogenic diet combined with a modified Mediterranean diet as a possible tool to improve neuroinflammation in multiple sclerosis.

Dietary regulations for microbiota dysbiosis among post-menopausal women with type 2 diabetes

Type 2 diabetes (T2D) and T2D-associated comorbidities, such as obesity, are serious universally prevalent health issues among post-menopausal women. Menopause is an unavoidable condition characterized by the depletion of estrogen, a gonadotropic hormone responsible for secondary sexual characteristics in women. In addition to sexual dimorphism, estrogen also participates in glucose-lipid homeostasis, and estrogen depletion is associated with insulin resistance in the female body. Estrogen level in the gut also regulates the microbiota composition, and even conjugated estrogen is actively metabolized by the estrobolome to maintain insulin levels. Moreover, post-menopausal gut microbiota is different from the pre-menopausal gut microbiota, as it is less diverse and lacks the mucolytic Akkermansia and short-chain fatty acid (SCFA) producers such as Faecalibacterium and Roseburia. Through various metabolites (SCFAs, secondary bile acid, and serotonin), the gut microbiota plays a significant role in regulating glucose homeostasis, oxidative stress, and T2D-associated pro-inflammatory cytokines (IL-1, IL-6). While gut dysbiosis is common among post-menopausal women, dietary interventions such as probiotics, prebiotics, and synbiotics can ease post-menopausal gut dysbiosis. The objective of this review is to understand the relationship between post-menopausal gut dysbiosis and T2D-associated factors. Additionally, the study also provided dietary recommendations to avoid T2D progression among post-menopausal women.

Curcumin can improve Parkinson's disease via activating BDNF/PI3k/Akt signaling pathways

Parkinson's disease is a common progressive neurodegenerative disease, and presently has no curative agent. Curcumin, as one of the natural polyphenols, has great potential in neurodegenerative diseases and other different pathological settings. The brain-derived neurotrophic factor (BDNF) and phosphatidylinositol 3 kinase (PI3k)/protein kinase B (Akt) signaling pathways are significantly involved nerve regeneration and anti-apoptotic activities. Currently, relevant studies have confirmed that curcumin has an optimistic impact on neuroprotection via regulating BDNF and PI3k/Akt signaling pathways in neurodegenerative disease. Here, we summarized the relationship between BDNF and PI3k/Akt signaling pathway, the main biological functions and neuroprotective effects of curcumin via activating BDNF and PI3k/Akt signaling pathways in Parkinson's disease. This paper illustrates that curcumin, as a neuroprotective agent, can delay the progression of Parkinson's disease by protecting nerve cells.

Fabrication and characterization of octenyl succinic anhydride modified pullulan micelles for encapsulating curcumin

BACKGROUND

Curcumin has become increasingly popular in functional foods and beverages field as a result of its high biological activity. Nevertheless, the application of curcumin is usually limited by its poor water solubility, low absorption, rapid metabolism and instability. Accordingly, the development of an appropriate wall material is crucial for its effective use. In the present study, curcumin-octenyl succinic anhydride modified pullulan (Cur-OSAP) micelles were successfully prepared by an anti-solvent co-precipitation method.

RESULTS

Octenyl succinic anhydride modified pullulan (OSAP) micelles exhibited the highest encapsulation efficiency (57.31%) and loading capacity (5.73%) of curcumin when the mass ratio of OSAP to curcumin was 10:1 and the degree of substitution of OSAP was 0.0469, at which point Cur-OSAP micelles formed via hydrogen binding and hydrophobic interactions, as confirmed by Fourier transform infrared and fluorescence techniques. The transmission electron microscopy results showed that the Cur-OSAP micelles were roughly spherical in shape with diameters in the approximate range 30-60 nm.

CONCLUSION

The encapsulation of OSAP greatly improved photostability and sustained release properties of curcumin in Cur-OSAP micelles. These findings suggest that OSAP can be used as a carrier to encapsulate and protect hydrophobic food ingredients. © 2021 Society of Chemical Industry.

Curcumin-Rich Curry Consumption and Neurocognitive Function from 4.5-Year Follow-Up of Community-Dwelling Older Adults (Singapore Longitudinal Ageing Study)

The potential neurocognition protective effects of dietary curcumin in curry consumed with food was investigated in this study of 2734 community-dwelling adults (aged ≥ 55, mean ± SD: 65.9 ± 7.4). We analyzed longitudinal data of baseline curry consumption (“never or rarely”, “occasionally”: <once a month, “often”: >once a month and <once a week, “very often”: >once a week or daily) and baseline and 4.5-year follow-up cognitive function in mixed model analyses controlling for confounding risk factors. Significant between-exposure differences were found for Digit Span-Backward (DS-B), Verbal Fluency-Animals (VF-A) and Block Design (BD). Compared to “never or rarely” consumption, “very often” and “often” consumptions were associated with higher DS-B performance; “very often”—with higher VF-A, and “occasional”, “often” and “very often” consumptions—with higher BD: Cohen’s d: from 0.130 to 0.186. Among participants with cardiometabolic and cardiac diseases (CMVD), curry consumption was associated with significantly higher DS-B and VF-A. Among CMVD-free participants, curry consumption was associated with significantly higher DS-B, VF-A and BD: Cohen’s d: from 0.098 to 0.305. The consumption of dietary curcumin was associated with the maintenance over time of higher functioning on attention, short-term working memory, visual spatial constructional ability, language and executive function among community-dwelling older Asian adults.

An Update on the Exploratory Use of Curcumin in Neuropsychiatric Disorders

Curcumin is a polyphenol extracted from the rhizome of the turmeric plant. Beyond its common use as a culinary spice in Eastern Asia, curcumin has been proposed as a therapeutic compound due to its antioxidant, anti-inflammatory and neuroprotective properties. Thus, its efficacy has been evaluated in various inflammatory-based psychiatric disorders, such as schizophrenia, depression, or autism. Our aim is to review those preclinical and clinical studies carried out in psychiatric disorders whose therapeutic approach has involved the use of curcumin and, therefore, to discern the possible positive effect of curcumin in these disorders. Preclinical studies and completed clinical trials of curcumin for psychiatric disorders published from January 2005 to October 2021 were identified through searching relevant databases until 31st October 2021. Sixty-five preclinical studies and 15 clinical trials and open-label studies were selected. Results showed a bias toward studies in depression and, to a lesser extent, schizophrenia. In all disorders, the results were positive in reducing psychiatric deficits. Despite the considerable number of beneficial outcomes reported, the small number of trials and the heterogeneity of protocols make it difficult to draw solid conclusions about the real potency of curcumin in psychiatric disorders.

Dietary Supplements in Chemotherapy-Induced Peripheral Neuropathy: A New Hope?

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the main and most prevalent side effects of chemotherapy, significantly affecting the quality of life of patients and the course of chemotherapeutic treatment. Nevertheless, despite its prevalence, the management of the CIPN is considered particularly challenging, with this condition often being perceived as very difficult or even impossible to prevent with currently available agents. Therefore, it is imperative to find better options for patients diagnosed with this condition. While the search for the new agents must continue, another opportunity should be taken into consideration—repurposing of the already known medications. As proposed, acetyl-L-carnitine, vitamins (group B and E), extracts of medical plants, including goshajinkigan, curcumin and others, unsaturated fatty acids, as well as the diet composed of so-called “sirtuin-activating foods”, could change the typical way of treatment of CIPN, improve the quality of life of patients and maintain the continuity of chemotherapy. This review summarizes currently available data regarding mentioned above agents and evaluates the rationale behind future research focused on their efficacy in CIPN.

Identification of G protein-coupled receptor 55 (GPR55) as a target of curcumin

The identification of molecular targets of bioactive food components is important to understand the mechanistic aspect of their physiological functions. Here, we have developed a screening system that enables us to determine the activation of G protein-coupled receptors (GPCRs) by food components and have identified GPR55 as a target for curcumin. Curcumin activated GPR55 and induced serum-response element- and serum-response factor-mediated transcription, which were inhibited by Rho kinase and GPR55 antagonists. Both the methoxy group and the heptadienone moiety of curcumin were required for GPR55 activation. The F190^5.47 residue of GPR55 was important for the interaction with curcumin. The curcumin-induced secretion of glucagon-like peptide-1 in GLUTag cells was inhibited by a GPR55 antagonist. These results indicate that expression screening is a useful system to identify GPCRs as targets of food components and strongly suggest that curcumin activates GPR55 as an agonist, which is involved in the physiological function of curcumin.

Fragile X Premutation: Medications, Therapy and Lifestyle Advice

The fragile X premutation is characterized by 55–200 CGG repeats in the 5ʹ untranslated region of FMR1, whereas full fragile X mutation has greater than 200 repeats and full methylation, which manifests as fragile X syndrome (FXS). The premutation spectrum of clinical involvement includes fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND). In addition, premutation carriers also suffer from various other health problems such as endocrine abnormalities and autoimmune problems. In this paper, we have discussed different health issues faced by the carriers and interventions including medications, therapy and lifestyle changes that could improve their health.

Curcumin and Weight Loss: Does It Work?

Obesity is a global health problem needing urgent research. Synthetic anti-obesity drugs show side effects and variable effectiveness. Thus, there is a tendency to use natural compounds for the management of obesity. There is a considerable body of knowledge, supported by rigorous experimental data, that natural polyphenols, including curcumin, can be an effective and safer alternative for managing obesity. Curcumin is a is an important compound present in Curcuma longa L. rhizome. It is a lipophilic molecule that rapidly permeates cell membrane. Curcumin has been used as a pharmacological traditional medicinal agent in Ayurvedic medicine for ∼6000 years. This plant metabolite doubtless effectiveness has been reported through increasingly detailed in vitro, in vivo and clinical trials. Regarding its biological effects, multiple health-promoting, disease-preventing and even treatment attributes have been remarkably highlighted. This review documents the status of research on anti-obesity mechanisms and evaluates the effectiveness of curcumin for management of obesity. It summarizes different mechanisms of anti-obesity action, associated with the enzymes, energy expenditure, adipocyte differentiation, lipid metabolism, gut microbiota and anti-inflammatory potential of curcumin. However, there is still a need for systematic and targeted clinical studies before curcumin can be used as the mainstream therapy for managing obesity.

New Promising Therapeutic Avenues of Curcumin in Brain Diseases

Curcumin, the dietary polyphenol isolated from Curcuma longa (turmeric), is commonly used as an herb and spice worldwide. Because of its bio-pharmacological effects curcumin is also called "spice of life", in fact it is recognized that curcumin possesses important proprieties such as anti-oxidant, anti-inflammatory, anti-microbial, antiproliferative, anti-tumoral, and anti-aging. Neurodegenerative diseases such as Alzheimer's Diseases, Parkinson's Diseases, and Multiple Sclerosis are a group of diseases characterized by a progressive loss of brain structure and function due to neuronal death; at present there is no effective treatment to cure these diseases. The protective effect of curcumin against some neurodegenerative diseases has been proven by in vivo and in vitro studies. The current review highlights the latest findings on the neuroprotective effects of curcumin, its bioavailability, its mechanism of action and its possible application for the prevention or treatment of neurodegenerative disorders.

Role of nutraceuticals on neurodegenerative diseases: neuroprotective and immunomodulant activity

Neurodegeneration is a degenerative process characterized by the progressive loss of the structure and function of neurons that involves several immune cells. It is the primary cause of dementia and other several syndromes, known as neurodegenerative diseases. These disorders are age-related and it is estimated that by 2040 there will be approximately 81.1 million people suffering from these diseases. In addition to the traditional pharmacological therapy, in recent years nutraceuticals, naturally based compounds with a broad spectrum of biological effects: anti-aging, antioxidants, hypoglycaemic, hypocholesterolemic, anticancer, anxiolytic, antidepressant, etc., assumed an important role in counteracting these pathologies. In particular, several compounds such as astaxanthin, baicalein, glycyrrhizin, St. John's wort, and Ginkgo biloba L. extracts show particular neuroprotective and immunomodulatory abilities, involving several immune cells and some neurotransmitters that play a critical role in neurodegeneration, making them particularly useful in improving the symptoms and progression of neurodegenerative diseases.

Curcumin β-D-Glucuronide Modulates an Autoimmune Model of Multiple Sclerosis with Altered Gut Microbiota in the Ileum and Feces

We developed a prodrug type of curcumin, curcumin monoglucuronide (CMG), whose intravenous/intraperitoneal injection achieves a high serum concentration of free-form curcumin. Although curcumin has been reported to alter the gut microbiota and immune responses, it is unclear whether the altered microbiota could be associated with inflammation in immune-mediated diseases, such as multiple sclerosis (MS). We aimed to determine whether CMG administration could affect the gut microbiota at three anatomical sites (feces, ileal contents, and the ileal mucosa), leading to suppression of inflammation in the central nervous system (CNS) in an autoimmune model for MS, experimental autoimmune encephalomyelitis (EAE). We injected EAE mice with CMG, harvested the brains and spinal cords for histological analyses, and conducted microbiome analyses using 16S rRNA sequencing. CMG administration modulated EAE clinically and histologically, and altered overall microbiota compositions in feces and ileal contents, but not the ileal mucosa. Principal component analysis (PCA) of the microbiome showed that principal component (PC) 1 values in ileal contents, but not in feces, correlated with the clinical and histological EAE scores. On the other hand, when we analyzed the individual bacteria of the microbiota, the EAE scores correlated with significant increases in the relative abundance of two bacterial species at each anatomical site: Ruminococcus bromii and Blautia (Ruminococcus) gnavus in feces, Turicibacter sp. and Alistipes finegoldii in ileal contents, and Burkholderia spp. and Azoarcus spp. in the ileal mucosa. Therefore, CMG administration could alter the gut microbiota at the three different sites differentially in not only the overall gut microbiome compositions but also the abundance of individual bacteria, each of which was associated with modulation of neuroinflammation.

Curcumin supplementation improves biomarkers of oxidative stress and inflammation in conditions of obesity, type 2 diabetes and NAFLD: updating the status of clinical evidence

Oxidative stress and inflammation remain the major complications implicated in the development and progression of metabolic complications, including obesity, type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD). In fact, due to their abundant antioxidant and anti-inflammatory properties, there is a general interest in understanding the therapeutic effects of some major food-derived bioactive compounds like curcumin against diverse metabolic diseases. Hence, a systematic search, through prominent online databases such as MEDLINE, Scopus, and Google Scholar was done focusing on randomized controlled trials (RCTs) reporting on the impact of curcumin supplementation in individuals with diverse metabolic complications, including obesity, T2D and NAFLD. Summarized findings suggest that curcumin supplementation can significantly reduce blood glucose and triglycerides levels, including markers of liver function like alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in patients with T2D and NAFLD. Importantly, this effect was consistent with the reduction of predominant markers of oxidative stress and inflammation, such as the levels of malonaldehyde (MDA), tumor necrosis factor-alpha (TNF-α), high sensitivity C-reactive protein (hs-CRP) and monocyte chemoattractant protein-1 (MCP-1) in these patients. Although RCTs suggest that curcumin is beneficial in ameliorating some metabolic complications, future research is still necessary to enhance its absorption and bioavailability profile, while also optimizing the most effective therapeutic doses.

The Interplay of the Unfolded Protein Response in Neurodegenerative Diseases: A Therapeutic Role of Curcumin

Abnormal accumulation of misfolded proteins in the endoplasmic reticulum and their aggregation causes inflammation and endoplasmic reticulum stress. This promotes accumulation of toxic proteins in the body tissues especially brain leading to manifestation of neurodegenerative diseases. The studies suggest that deregulation of proteostasis, particularly aberrant unfolded protein response (UPR) signaling, may be a common morbific process in the development of neurodegeneration. Curcumin, the mixture of low molecular weight polyphenolic compounds from turmeric, Curcuma longa has shown promising response to prevents many diseases including current global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and neurodegenerative disorders. The UPR which correlates positively with neurodegenerative disorders were found affected by curcumin. In this review, we examine the evidence from many model systems illustrating how curcumin interacts with UPR and slows down the development of various neurodegenerative disorders (ND), e.g., Alzheimer's and Parkinson's diseases. The recent global increase in ND patients indicates that researchers and practitioners will need to develop a new pharmacological drug or treatment to manage and cure these neurodegenerative diseases.

The neuroprotective effect of curcumin against ATO triggered neurotoxicity through Nrf2 and NF-κB signaling pathway in the brain of ducks

Arsenic trioxide (ATO) has confirmed as a global pollutant, the toxic effect of which was not fully understood and lack effective therapies to against its associated toxicities. Curcumin (Cur) is a beneficial natural pigment for its antioxidant and anti-inflammatory properties. The purpose of this paper was to illustrate the antagonism of Cur against ATO-induced neurotoxicity. A total of 40 ducks were divided randomly into 4 groups and conducted via bite and sup for 28 days: control group (Control); 2 mg/kg ATO group (Low ATO); 4 mg/kg ATO group (Middle ATO); 8 mg/kg ATO group (High ATO); 400 mg/kg Cur group + 8 mg/kg ATO (Cur+ATO). The results showed that ATO exposure can hinder the duck growth and arsenic element accumulation rate increased in a dose-dependent manner. We observed neuronal shrinkage and vacuolize of HE staining in the ATO-treated group. In addition, SOD activity and T-AOC level reduced while MDA content increased in the ATO-exposed group. ATO exposure can decrease the expression of anti-oxidation related mRNA and proteins (Nrf2, SOD-1, GPX-1, CAT, Trx and HO-1) and anti-inflammatory makers (IL-4, IL-10), increased the expression of Keap1, NF-κB and pro-inflammatory makers (TNF-α, IL-1β, IL-18, IL-2, IL-6, INOS and COX-2). ATO treated might cause blood-brain barrier (BBB) damage through degradation of the tight junction proteins (TJs) occludin and ZO-1. Importantly, the experimental results also showed that Cur can alleviate oxidative stress, inflammatory response and BBB injury caused by ATO exposure through Nrf2 and NF-κB signaling pathway. The results suggested Cur exerted as a food additive and provided novel potential benefits of ATO toxicology in inflammation of the brain.

Curcumin and its derivatives in cancer therapy: Potentiating antitumor activity of cisplatin and reducing side effects

Curcumin is a phytochemical isolated from Curcuma longa with potent tumor-suppressor activity, which has shown significant efficacy in pre-clinical and clinical studies. Curcumin stimulates cell death, triggers cycle arrest, and suppresses oncogenic pathways, thereby suppressing cancer progression. Cisplatin (CP) stimulates DNA damage and apoptosis in cancer chemotherapy. However, CP has adverse effects on several organs of the body, and drug resistance is frequently observed. The purpose of the present review is to show the function of curcumin in decreasing CP's adverse impacts and improving its antitumor activity. Curcumin administration reduces ROS levels to prevent apoptosis in normal cells. Furthermore, curcumin can inhibit inflammation via down-regulation of NF-κB to maintain the normal function of organs. Curcumin and its nanoformulations can reduce the hepatoxicity, neurotoxicity, renal toxicity, ototoxicity, and cardiotoxicity caused by CP. Notably, curcumin potentiates CP cytotoxicity via mediating cell death and cycle arrest. Besides, curcumin suppresses the STAT3 and NF-ĸB as tumor-promoting pathways, to enhance CP sensitivity and prevent drug resistance. The targeted delivery of curcumin and CP to tumor cells can be mediated nanostructures. In addition, curcumin derivatives are also able to reduce CP-mediated side effects, and increase CP cytotoxicity against various cancer types.

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.

Standardized Astragalus Mongholicus Bunge-Curcuma Aromatica Salisb. Extract Efficiently Suppresses Colon Cancer Progression Through Gut Microbiota Modification in CT26-Bearing Mice

Altered gut microbiota and a damaged colon mucosal barrier have been implicated in the development of colon cancer. Astragalus mongholicus Bunge-Curcuma aromatica Salisb. (ACE) is a common herbal drug pair that widely used clinically to treat cancer. However, whether the anti-cancer effect of ACE is related to gut microbiota remains unclear yet. We standardized ACE and investigated the effects of ACE on tumour suppression and analyze the related mechanisms on gut microbiota in CT26 colon cancer-bearing mice in the present study. Firstly, four flavonoids (calycosin-7-glucoside, ononin, calycosin, formononetin) and three astragalosides (astragaloside A, astragaloside II, astragaloside I) riched in Astragalus mongholicus Bunge, three curcumins (bisdemethoxycurcumin, demethoxycurcumin, curcumin) and four essential oils (curdione, curzerene, germacrone and β-elemene) from Curcuma aromatica Salisb., in concentrations from 0.08 to 2.07 mg/g, were examined in ACE. Then the results in vivo studies indicated that ACE inhibited solid tumours, liver and spleen metastases of colon cancer while simultaneously reducing pathological tissue damage. Additionally, ACE regulated gut microbiota dysbiosis and the short chain fatty acid content in the gut, repaired intestinal barrier damage. ACE treatment suppressed the overgrowth of conditional pathogenic gut bacteria, including Escherichia-Shigella, Streptococcus and Enterococcus, while the probiotic gut microbiota like Lactobacillus, Roseburia, Prevotellaceae_UCG-001 and Mucispirillum were increased. More interestingly, the content level of SCFAs such as propionic acid and butyric acid was increased after ACE administration, which further mediates intestinal SDF-1/CXCR4 signalling pathway to repair the integrity of the intestinal barrier, decrease Cyclin D1 and C-myc expressions, eventually suppress the tumor the growth and metastasis of colon cancer. To sum up, the present study demonstrated that ACE could efficiently suppress colon cancer progression through gut microbiota modification, which may provide a new explanation of the mechanism of ACE against colon cancer.

Curcumin Reduces Adipose Tissue Inflammation and Alters Gut Microbiota in Diet-Induced Obese Male Mice

SCOPE

Obesity prevalence continues to increase and contribute to metabolic diseases, potentially by driving systemic inflammation. Curcumin is an anti-inflammatory spice with claimed health benefits. However, mechanisms by which curcumin may reduce obesity-associated inflammation are poorly understood; thus, it is hypothesized that benefits of curcumin consumption may occur through reduced white adipose tissue (WAT) inflammation and/or beneficial changes in gut bacteria.

METHODS AND RESULTS

Male B6 mice are fed high-fat diets (HFD, 45% kcal fat) or HFD supplemented with 0.4% (w/w) curcumin (HFC) for 14 weeks. Curcumin supplementation significantly reduces adiposity and total macrophage infiltration in WAT, compared to HFD group, consistent with reduced mRNA levels of M1 (Cd80, Cd38, Cd11c) and M2 (Arginase-1) macrophage markers. Moreover, curcumin supplementation reduces expression of other key pro-inflammatory genes, such as NF-κB p65 subunit (p65), Stat1, Tlr4, and Il6, in WAT (p < 0.05). Using microbial 16S RNA sequencing, it is demonstrated that the relative abundance of the Lactococcus, Parasutterella, and Turicibacter genera are increased in the HFC group versus HFD.

CONCLUSIONS

Curcumin exerts protective metabolic effects in dietary obesity, in part through downregulation of adipose tissue inflammation, which may be mediated by alterations in composition of gut microbiota, and metabolism of curcumin into curcumin-O-glucuronide.

New Approaches to Profile the Microbiome for Treatment of Neurodegenerative Disease

Progressive neurodegenerative diseases represent some of the largest growing treatment challenges for public health in modern society. These diseases mainly progress due to aging and are driven by microglial surveillance and activation in response to changes occurring in the aging brain. The lack of efficacious treatment options for Alzheimer's disease (AD), as the focus of this review, and other neurodegenerative disorders has encouraged new approaches to address neuroinflammation for potential treatments. Here we will focus on the increasing evidence that dysbiosis of the gut microbiome is characterized by inflammation that may carry over to the central nervous system and into the brain. Neuroinflammation is the common thread associated with neurodegenerative diseases, but it is yet unknown at what point and how innate immune function turns pathogenic for an individual. This review will address extensive efforts to identify constituents of the gut microbiome and their neuroactive metabolites as a peripheral path to treatment. This approach is still in its infancy in substantive clinical trials and requires thorough human studies to elucidate the metabolic microbiome profile to design appropriate treatment strategies for early stages of neurodegenerative disease. We view that in order to address neurodegenerative mechanisms of the gut, microbiome and metabolite profiles must be determined to pre-screen AD subjects prior to the design of specific, chronic titrations of gut microbiota with low-dose antibiotics. This represents an exciting treatment strategy designed to balance inflammatory microglial involvement in disease progression with an individual's manifestation of AD as influenced by a coercive inflammatory gut.

Curcumin as Prospective Anti-Aging Natural Compound: Focus on Brain

The nutrients and their potential benefits are a new field of study in modern medicine for their positive impact on health. Curcumin, the yellow polyphenolic compound extracted from Curcuma longa species, is widely used in traditional Ayurvedic medicine to prevent and contrast many diseases, considering its antioxidant, immunomodulatory, anti-inflammatory, anti-microbial, cardio-protective, nephron-protective, hepato-protective, anti-neoplastic, and anti-rheumatic proprieties. In recent years, the investigations of curcumin have been focused on its application to aging and age-associated diseases. Aging is a physiological process in which there is a decreasing of cellular function due to internal or external stimuli. Oxidative stress is one of the most important causes of aging and age-related diseases. Moreover, many age-related disorders such as cancer, neuroinflammation, and infections are due to a low-grade chronic systemic inflammation. Curcumin acting on different proteins is able to contrast both oxidative stress than inflammation. In the brain, curcumin is able to modulate inflammation induced by microglia. Finally in brain tumors curcumin is able to reduce tumor growth by inhibition of telomerase activity. This review emphasizes the anti-aging role of curcumin focusing on its mechanism to counteract aging in the brain. Moreover, new formulations to increase the bioavailability of curcumin are discussed.

Curcumin nanoformulations to combat aging-related diseases

Aging increases the susceptibility to a diverse set of diseases and disorders, including neurodegeneration, cancer, diabetes, and arthritis. Natural compounds are currently being explored as alternative or complementary agents to treat or prevent aging-related malfunctions. Curcumin, a phytochemical isolated from the spice turmeric, has garnered great interest in recent years. With anti-oxidant, anti-inflammatory, anti-microbial, and other physiological activities, curcumin has great potential for health applications. However, the benefits of curcumin are restricted by its low bioavailability and stability in biological systems. Curcumin nanoformulations, or nano-curcumin, may overcome these limitations. This review discusses different forms of nano-curcumin that have been evaluated in vitro and in vivo to treat or prevent aging-associated health impairments. We describe current barriers for the routine use of curcumin nanoformulations in the clinic. Our review highlights outstanding questions and future work that is needed to ensure nano-curcumin is efficient and safe to lessen the burden of aging-related health problems.

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.

The Role of The Gut Microbiome in Parkinson's Disease

The gut microbiota is known to play a role in various disease states through inflammatory, immune and endocrinologic response. Parkinson's Disease is of particular interest as gastrointestinal involvement is one of the earlier features seen in this disease. This paper examines the relationship between gut microbiota and Parkinson's Disease, which has a growing body of literature. Inflammation caused by gut dysbiosis is thought to increase a-synuclein aggregation and worsen motor and neurologic symptoms of Parkinson's disease. We discuss potential treatment and supplementation to modify the microbiota. Some of these treatments require further research before recommendations can be made, such as cord blood transplant, antibiotic use, immunomodulation and fecal microbiota transplant. Other interventions, such as increasing dietary fiber, polyphenol and fermented food intake, can be made with few risks and may have some benefit for symptom relief and speed of disease progression.

Action Mechanisms of Curcumin in Alzheimer's Disease and Its Brain Targeted Delivery

AD is a chronic neurodegenerative disease. Many different signaling pathways, such as Wnt/β-catenin, Notch, ROS/JNK, and PI3K/Akt/mTOR are involved in Alzheimer’s disease and crosstalk between themselves. A promising treatment involves the uses of flavonoids, and one of the most promising is curcumin; however, because it has difficulty permeating the blood–brain barrier (BBB), it must be encapsulated by a drug carrier. Some of the most frequently studied are lipid nanocarriers, liposomes, micelles and PLGA. These carriers are further conjugated with brain-targeting agents such as lactoferrin and transferrin. In this review paper, curcumin and its therapeutic effects, which have been examined in vivo, are analyzed and then the delivery systems to the brain are addressed. Overall, the analysis of the literature revealed great potential for curcumin in treating AD and indicated the challenges that require further research.

An efficient enzyme-triggered controlled release system for colon-targeted oral delivery to combat dextran sodium sulfate (DSS)-induced colitis in mice

Oral route colon-targeted drug delivery systems (CDDSs) are desirable for the treatment of ulcerative colitis (UC). However, CDDSs are challenging owing to the physiological and anatomical barriers associated with the gastrointestinal tract (GIT). In this study, we developed an effective enzyme-triggered controlled release system using curcumin-cyclodextrin (CD-Cur) inclusion complex as core and low molecular weight chitosan and unsaturated alginate resulting nanoparticles (CANPs) as shell. The formed CD-Cur-CANPs showed a narrow particle-size distribution and a compact structure. In vitro drug release determination indicated that CD-Cur-CANPs showed pH-sensitive and α-amylase-responsive release characteristics. Furthermore, in vivo experiments demonstrated that oral administration of CD-Cur-CANPs had an efficient therapeutic efficacy, strong colonic biodistribution and accumulation, rapid macrophage uptake, promoted colonic epithelial barrier integrity and modulated production of inflammatory cytokines, reshaped the gut microbiota in mice with dextran sodium sulfate (DSS)-induced colitis. Taken together, our synthetic CD-Cur-CANPs are a promising synergistic colon-targeted approach for UC treatment.

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.

Role of Polyphenols on Gut Microbiota and the Ubiquitin-Proteasome System in Neurodegenerative Diseases

Today, neurodegenerative diseases have become a remarkable public health challenge due to their direct relation with aging. Accordingly, understanding the molecular and cellular mechanisms occurring in the pathogenesis of them is essential. Both protein aggregations as a result of the ubiquitin-proteasome system (UPS) inefficiency and gut microbiota alternation are the main pathogenic hallmarks. Polyphenols upregulating this system may decrease the developing rate of neurodegenerative diseases. Most of the dietary intake of polyphenols is converted into other microbial metabolites, which have completely different biological properties from the original polyphenols and should be thoroughly investigated. Herein, several prevalent neurodegenerative diseases are pinpointed to explain the role of gut microbiota alternations and the role of molecular changes, especially UPS down-regulation in their pathogenesis. Some of the most important polyphenols found in our diet are explained along with their microbial metabolites in the body.

Polyphenols of the Mediterranean Diet and Their Metabolites in the Prevention of Colorectal Cancer

The Mediterranean diet is a central element of a healthy lifestyle, where polyphenols play a key role due to their anti-oxidant properties, and for some of them, as nutripharmacological compounds capable of preventing a number of diseases, including cancer. Due to the high prevalence of intestinal cancer (ranking second in causing morbidity and mortality), this review is focused on the beneficial effects of selected dietary phytophenols, largely present in Mediterranean cooking: apigenin, curcumin, epigallocatechin gallate, quercetin-rutine, and resveratrol. The role of the Mediterranean diet in the prevention of colorectal cancer and future perspectives are discussed in terms of food polyphenol content, the effectiveness, the plasma level, and the importance of other factors, such as the polyphenol metabolites and the influence of the microbiome. Perspectives are discussed in terms of microbiome-dependency of the brain-second brain axis. The emergence of polyphenol formulations may strengthen the efficiency of the Mediterranean diet in the prevention of cancer.

Phytochemicals as modifiers of gut microbial communities

A healthy gut microbiota (GM) is paramount for a healthy lifestyle. Alterations of the GM have been involved in the aetiology of several chronic diseases, including obesity and type 2 diabetes, as well as cardiovascular and neurodegenerative diseases. In pathological conditions, the diversity of the GM is commonly reduced or altered, often toward an increased Firmicutes/Bacteroidetes ratio. The colonic fermentation of dietary fiber has shown to stimulate the fraction of bacteria purported to have beneficial health effects, acting as prebiotics, and to increase the production of short chain fatty acids, e.g. propionate and butyrate, while also improving gut epithelium integrity such as tight junction functionality. However, a variety of phytochemicals, often associated with dietary fiber, have also been proposed to modulate the GM. Many phytochemicals possess antioxidant and anti-inflammatory properties that may positively affect the GM, including polyphenols, carotenoids, phytosterols/phytostanols, lignans, alkaloids, glucosinolates and terpenes. Some polyphenols may act as prebiotics, while carotenoids have been shown to alter immunoglobulin A expression, an important factor for bacteria colonization. Other phytochemicals may interact with the mucosa, another important factor for colonization, and prevent its degradation. Certain polyphenols have shown to influence bacterial communication, interacting with quorum sensing. Finally, phytochemicals can be metabolized in the gut into bioactive constituents, e.g. equol from daidzein and enterolactone from secoisolariciresinol, while bacteria can use glycosides for energy. In this review, we strive to highlight the potential interactions between prominent phytochemicals and health benefits related to the GM, emphasizing their potential as adjuvant strategies for GM-related diseases.

Regional Diets Targeting Gut Microbial Dynamics to Support Prolonged Healthspan

In the last 150 years, we have seen a significant increase in average life expectancy, associated with a shift from infectious to non-communicable diseases. The rising incidence of these diseases, for which age is often the largest risk factor, highlights the need for contemporary societies to improve healthy ageing for their growing silver generations. As ageing is an inevitable, non-reversing and highly individualised process, we need to better understand how non-genetic factors like diet choices and commensal gut microbes can modulate the biology of ageing. In this review, we discuss how geographical and ethnic variations influence habitual dietary patterns, nutrient structure, and gut microbial profiles with potential impact on the human healthspan. Several gut microbial genera have been associated with healthy elderly populations but are highly variable across populations. It seems unlikely that a universal pro-longevity gut microbiome exists. Rather, the optimal microbiome appears to be conditional on the microbial functionality acting on regional- and ethnicity-specific trends driven by cultural food context. We also highlight dietary and microbial factors that have been observed to elicit individual and clustered biological responses. Finally, we identify next generation avenues to modify otherwise fixed host functions and the individual ageing trajectory by manipulating the malleable gut microbiome with regionally adapted, personalised food intervention regimens targeted at prolonging human healthspan.

Curcumin alleviates high-fat diet-induced hepatic steatosis and obesity in association with modulation of gut microbiota in mice

Curcumin (Cur) is a natural polyphenol with beneficial effect against obesity and related metabolic disorders, but its precise mechanisms of action remain to be defined due to its limited systemic bioavailability. We hypothesized that gut microbiota may be a prospective therapeutic target for Cur-induced metabolic benefits. This study aimed to investigate whether the metabolic adaptations resulting from Cur supplementation were mediated by the gut microbiota in high-fat diet (HFD)-fed obese mice. C57BL/6 mice were fed a control diet or a HFD diet with or without 0.2% Cur for 10 weeks. Lipid profiles, insulin sensitivity, hepatic metabolism, gut microbiota composition and short-chain fatty acid (SCFA) production were determined. Dietary Cur reduced fat mass, hepatic steatosis and circulating lipopolysaccharide levels and improved the insulin sensitivity in HFD-fed mice. More importantly, Cur supplementation modulated the gut microbiota composition and ameliorated intestinal dysbiosis by decreasing the ratio of Firmicutes/Bacteroidetes and endotoxin-producing Desulfovibrio bacteria and increasing the abundance of Akkermansia population and SCFA-producing bacteria, such as Bacteroides, Parabacteroides, Alistipes and Alloprevotella, along with increases in caecal and colonic SCFA concentrations. These dominant bacterial genera altered by Cur showed strong correlations with the obesity-related metabolic parameters in HFD-fed mice. In conclusion, our data suggest that Cur alleviated metabolic features of hepatic steatosis and insulin resistance in HFD-fed obese mice, which might be associated with the modulation of gut microbiota composition and metabolites.

Young at Gut-Turning Back the Clock with the Gut Microbiome

Over the past century, we have witnessed an increase in life-expectancy due to public health measures; however, we have also seen an increase in susceptibility to chronic disease and frailty. Microbiome dysfunction may be linked to many of the conditions that increase in prevalence with age, including type 2 diabetes, cardiovascular disease, Alzheimer's disease, and cancer, suggesting the need for further research on these connections. Moreover, because both non-modifiable (e.g., age, sex, genetics) and environmental (e.g., diet, infection) factors can influence the microbiome, there are vast opportunities for the use of interventions related to the microbiome to promote lifespan and healthspan in aging populations. To understand the mechanisms mediating many of the interventions discussed in this review, we also provide an overview of the gut microbiome's relationships with the immune system, aging, and the brain. Importantly, we explore how inflammageing (low-grade chronic inflammation that often develops with age), systemic inflammation, and senescent cells may arise from and relate to the gut microbiome. Furthermore, we explore in detail the complex gut-brain axis and the evidence surrounding how gut dysbiosis may be implicated in several age-associated neurodegenerative diseases. We also examine current research on potential interventions for healthspan and lifespan as they relate to the changes taking place in the microbiome during aging; and we begin to explore how the reduction in senescent cells and senescence-associated secretory phenotype (SASP) interplay with the microbiome during the aging process and highlight avenues for further research in this area.

The Impact of Microbiota on the Pathogenesis of Amyotrophic Lateral Sclerosis and the Possible Benefits of Polyphenols. An Overview

The relationship between gut microbiota and neurodegenerative diseases is becoming clearer. Among said diseases amyotrophic lateral sclerosis (ALS) stands out due to its severity and, as with other chronic pathologies that cause neurodegeneration, gut microbiota could play a fundamental role in its pathogenesis. Therefore, polyphenols could be a therapeutic alternative due to their anti-inflammatory action and probiotic effect. Thus, the objective of our narrative review was to identify those bacteria that could have connection with the mentioned disease (ALS) and to analyze the benefits produced by administering polyphenols. Therefore, an extensive search was carried out selecting the most relevant articles published between 2005 and 2020 on the PubMed and EBSCO database on research carried out on cell, animal and human models of the disease. Thereby, after selecting, analyzing and debating the main articles on this topic, the bacteria related to the pathogenesis of ALS have been identified, among which we can positively highlight the presence mainly of Akkermansia muciniphila, but also Lactobacillus spp., Bifidobacterium spp. or Butyrivibrio fibrisolvens. Nevertheless, the presence of Escherichia coli or Ruminococcus torques stand out negatively for the disease. In addition, most of these bacteria are associated with molecular changes also linked to the pathogenesis of ALS. However, once the main polyphenols related to improvements in any of these three ALS models were assessed, many of them show positive results that could improve the prognosis of the disease. Nonetheless, epigallocatechin gallate (EGCG), curcumin and resveratrol are the polyphenols considered to show the most promising results as a therapeutic alternative for ALS through changes in microbiota.

Nutraceutical Curcumin with Promising Protection against Herpesvirus Infections and Their Associated Inflammation: Mechanisms and Pathways

Herpesviruses are DNA viruses that infect humans and animals with the ability to induce latent and lytic infections in their hosts, causing critical health complications. The enrolment of nutraceutical anti-herpesvirus drugs in clinical investigations with promising levels of reduced resistance, free or minimal cellular toxicity, and diverse mechanisms of action might be an effective way to defeat challenges that hurdle the progress of anti-herpesvirus drug development, including the problems with drug resistance and recurrent infections. Therefore, in this review, we aim to hunt down all investigations that feature the curative properties of curcumin, a principal bioactive phenolic compound of the spice turmeric, in regard to various human and animal herpesvirus infections and inflammation connected with these diseases. Curcumin was explored with potent antiherpetic actions against herpes simplex virus type 1 and type 2, human cytomegalovirus, Kaposi’s sarcoma-associated herpesvirus, Epstein–Barr virus, bovine herpesvirus 1, and pseudorabies virus. The mechanisms and pathways by which curcumin inhibits anti-herpesvirus activities by targeting multiple steps in herpesvirus life/infectious cycle are emphasized. Improved strategies to overcome bioavailability challenges that limit its use in clinical practice, along with approaches and new directions to enhance the anti-herpesvirus efficacy of this compound, are also reviewed. According to the reviewed studies, this paper presents curcumin as a promising natural drug for the prevention and treatment of herpesvirus infections and their associated inflammatory diseases.

Curcumin, Quercetin, Catechins and Metabolic Diseases: The Role of Gut Microbiota

Polyphenols (PPs) are the naturally occurring bioactive components in fruits and vegetables, and they are the most abundant antioxidant in the human diet. Studies are suggesting that ingestion of PPs might be helpful to ameliorate metabolic syndromes that may contribute in the prevention of several chronic disorders like diabetes, obesity, hypertension, and colon cancer. PPs have structural diversity which impacts their bioavailability as they accumulate in the large intestine and are extensively metabolized through gut microbiota (GM). Intestinal microbiota transforms PPs into their metabolites to make them bioactive. Interestingly, not only GM act on PPs to metabolize them but PPs also modulate the composition of GM. Thus, change in GM from pathogenic to beneficial ones may be helpful to ameliorate gut health and associated diseases. However, to overcome the low bioavailability of PPs, various approaches have been developed to improve their solubility and transportation through the gut. In this review, we present evidence supporting the structural changes that occur after metabolic reactions in PPs (curcumin, quercetin, and catechins) and their effect on GM composition that leads to improving overall gut health and helping to ameliorate metabolic disorders.

Nutrition as Metabolic Treatment for Anxiety

Despite the overwhelming prevalence of anxiety disorders in modern society, medications and psychotherapy often fail to achieve complete symptom resolution. A complementary approach to medicating symptoms is to address the underlying metabolic pathologies associated with mental illnesses and anxiety. This may be achieved through nutritional interventions. In this perspectives piece, we highlight the roles of the microbiome and inflammation as influencers of anxiety. We further discuss the evidence base for six specific nutritional interventions: avoiding artificial sweeteners and gluten, including omega-3 fatty acids and turmeric in the diet, supplementation with vitamin D, and ketogenic diets. We attempt to integrate insights from the nutrition science-literature in order to highlight some practices that practitioners may consider when treating individual patients. Notably, this piece is not meant to serve as a comprehensive review of the literature, but rather argue our perspective that nutritional interventions should be more widely considered among clinical psychiatrists. Nutritional psychiatry is in its infancy and more research is needed in this burgeoning low-risk and potentially high-yield field.

Curcumin and Its Derivatives as Theranostic Agents in Alzheimer's Disease: The Implication of Nanotechnology

Curcumin is a polyphenolic natural compound with diverse and attractive biological properties, which may prevent or ameliorate pathological processes underlying age-related cognitive decline, Alzheimer's disease (AD), dementia, or mode disorders. AD is a chronic neurodegenerative disorder that is known as one of the rapidly growing diseases, especially in the elderly population. Moreover, being the eminent cause of dementia, posing problems for families, societies as well a severe burden on the economy. There are no effective drugs to cure AD. Although curcumin and its derivatives have shown properties that can be considered useful in inhibiting the hallmarks of AD, however, they have low bioavailability. Furthermore, to combat diagnostic and therapeutic limitations, various nanoformulations have also been recognized as theranostic agents that can also enhance the pharmacokinetic properties of curcumin and other bioactive compounds. Nanocarriers have shown beneficial properties to deliver curcumin and other nutritional compounds against the blood-brain barrier to efficiently distribute them in the brain. This review spotlights the role and effectiveness of curcumin and its derivatives in AD. Besides, the gut metabolism of curcumin and the effects of nanoparticles and their possible activity as diagnostic and therapeutic agents in AD also discussed.

Dietary polyphenols in lipid metabolism: A role of gut microbiome

Polyphenols are a class of non-essential phytonutrients, which are abundant in fruits and vegetables. Dietary polyphenols or foods rich in polyphenols are widely recommended for metabolic health. Indeed, polyphenols (i.e., catechins, resveratrol, and curcumin) are increasingly recognized as a regulator of lipid metabolism in host. The mechanisms, at least in part, may be highly associated with gut microbiome. This review mainly discussed the beneficial effects of dietary polyphenols on lipid metabolism. The potential mechanisms of gut microbiome are focused on the effect of dietary polyphenols on gut microbiota compositions and how gut microbiota affect polyphenol metabolism. Together, dietary polyphenols may be a useful nutritional strategy for manipulation of lipid metabolism or obesity care.