Metabolism and disposition of resveratrol in rats: extent of absorption, glucuronidation, and enterohepatic recirculation evidenced by a linked-rat model

Resveratrol-Loaded Polydimethylsiloxane-Silica Hybrid Materials: Synthesis, Characterization, and Antitumoral Activity

In this work, hybrid materials within the polydimethylsiloxane-silica (PDMS-SiO2) system, synthesized via the sol-gel method, were developed and characterized for their potential to incorporate and release the bioactive compound resveratrol (RES). RES was incorporated into the materials with a high loading efficiency (>75%) using the rotary evaporator technique. This incorporation induced the amorphization of RES, resulting in enhanced solubility and in vitro release when compared to the free polyphenolic compound. The release profiles displayed pH dependence, exhibiting notably faster release at pH 5.2 compared to pH 7.4. The gradual release of RES over time demonstrated an initial time lag of approximately 4 h, being well described by the Weibull model. In vitro cytotoxicity studies were conducted on human osteosarcoma cells (MG-63), revealing a concentration-dependent decrease in cell viability for RES-loaded samples (for concentrations >50 µg mL-1).

Resveratrol as sensitizer in colorectal cancer plasticity

Despite tremendous medical treatment successes, colorectal cancer (CRC) remains a leading cause of cancer deaths worldwide. Chemotherapy as monotherapy can lead to significant side effects and chemoresistance that can be linked to several resistance-activating biological processes, including an increase in inflammation, cellular plasticity, multidrug resistance (MDR), inhibition of the sentinel gene p53, and apoptosis. As a consequence, tumor cells can escape the effectiveness of chemotherapeutic agents. This underscores the need for cross-target therapeutic approaches that are not only pharmacologically safe but also modulate multiple potent signaling pathways and sensitize cancer cells to overcome resistance to standard drugs. In recent years, scientists have been searching for natural compounds that can be used as chemosensitizers in addition to conventional medications for the synergistic treatment of CRC. Resveratrol, a natural polyphenolic phytoalexin found in various fruits and vegetables such as peanuts, berries, and red grapes, is one of the most effective natural chemopreventive agents. Abundant in vitro and in vivo studies have shown that resveratrol, in interaction with standard drugs, is an effective chemosensitizer for CRC cells to chemotherapeutic agents and thus prevents drug resistance by modulating multiple pathways, including transcription factors, epithelial-to-mesenchymal transition-plasticity, proliferation, metastasis, angiogenesis, cell cycle, and apoptosis. The ability of resveratrol to modify multiple subcellular pathways that may suppress cancer cell plasticity and reversal of chemoresistance are critical parameters for understanding its anti-cancer effects. In this review, we focus on the chemosensitizing properties of resveratrol in CRC and, thus, its potential importance as an additive to ongoing treatments.

E-Stilbenes: General Chemical and Biological Aspects, Potential Pharmacological Activity Based on the Nrf2 Pathway

Stilbenes are phytoalexins, and their biosynthesis can occur through a natural route (shikimate precursor) or an alternative route (in microorganism cultures). The latter is a metabolic engineering strategy to enhance production due to stilbenes recognized pharmacological and medicinal potential. It is believed that in the human body, these potential activities can be modulated by the regulation of the nuclear factor erythroid derived 2 (Nrf2), which increases the expression of antioxidant enzymes. Given this, our review aims to critically analyze evidence regarding E-stilbenes in human metabolism and the Nrf2 activation pathway, with an emphasis on inflammatory and oxidative stress aspects related to the pathophysiology of chronic and metabolic diseases. In this comprehensive literature review, it can be observed that despite the broad number of stilbenes, those most frequently explored in clinical trials and preclinical studies (in vitro and in vivo) were resveratrol, piceatannol, pterostilbene, polydatin, stilbestrol, and pinosylvin. In some cases, depending on the dose/concentration and chemical nature of the stilbene, it was possible to identify activation of the Nrf2 pathway. Furthermore, the use of some experimental models presented a challenge in comparing results. In view of the above, it can be suggested that E-stilbenes have a relationship with the Nrf2 pathway, whether directly or indirectly, through different biological pathways, and in different diseases or conditions that are mainly related to inflammation and oxidative stress.

Pharmacodynamic, pharmacokinetic, toxicity, and recent advances in Eugenol's potential benefits against natural and chemical noxious agents: A mechanistic review

The active biological phytochemicals, crucial compounds employed in creating hundreds of medications, are derived from valuable and medicinally significant plants. These phytochemicals offer excellent protection from various illnesses, including inflammatory disorders and chronic conditions caused by oxidative stress. A phenolic monoterpenoid known as eugenol (EUG), it is typically found in the essential oils of many plant species from the Myristicaceae, Myrtaceae, Lamiaceae, and Lauraceae families. One of the main ingredients of clove oil (Syzygium aromaticum (L.), Myrtaceae), it has several applications in industry, including flavoring food, pharmaceutics, dentistry, agriculture, and cosmeceuticals. Due to its excellent potential for avoiding many chronic illnesses, it has lately attracted attention. EUG has been classified as a nonmutant, generally acknowledged as a safe (GRAS) chemical by the World Health Organization (WHO). According to the existing research, EUG possesses notable anti-inflammatory, antioxidant, analgesic, antibacterial, antispasmodic, and apoptosis-promoting properties, which have lately gained attention for its ability to control chronic inflammation, oxidative stress, and mitochondrial malfunction and dramatically impact human wellness. The purpose of this review is to evaluate the scientific evidence from the most significant research studies that have been published regarding the protective role and detoxifying effects of EUG against a wide range of toxins, including biological and chemical toxins, as well as different drugs and pesticides that produce a variety of toxicities, throughout view of the possible advantages of EUG.

Fabrication of resveratrol-loaded soy protein isolate-glycyrrhizin nanocomplex for improving bioavailability via pH-responsive hydrogel properties

Resveratrol (RES) is a functional polyphenol that suffers from low water solubility and poor bioavailability. A novel RES-loaded soy protein isolate-dipotassium glycyrrhizinate (SPI-DG) nanocomplex (RES@SPI-DG) was designed and evaluated in this study. RES@SPI-DG was prepared using a simple but novel self-assembly ultrasonic-assisted pH-driven method. The interactions between RES and SPI-DG were non-covalent bonds, including hydrophobic interactions, hydrogen bonds, and van der Waals interactions. RES@SPI-DG exhibited high encapsulation efficiency (97.60 ± 0.38 %) and loading capacity (8.74 ± 0.03 %) of RES with a uniform small size (68.39 ± 1.10 nm). RES in RES@SPI-DG was in an amorphous state and demonstrated a 24-h apparent solubility 482.53-fold higher than bare RES. RES@SPI-DG also showed strong in vitro antioxidant properties. The pH-responsive hydrogel character of SPI-DG makes it an effective intestine-targeted delivery system that could retard the release of RES in a simulated stomach and accelerate it in a simulated intestine. In animal experiments, the bioavailability of RES@SPI-DG was 5.17 times higher than that of bare RES, and the biodistribution was also significantly improved. RES@SPI-DG demonstrated a strong hepatoprotective effect against overdose acetaminophen-induced liver injury. The SPI-DG complex might be a promising nano-platform for enhancing the bioavailability and efficacy of hydrophobic polyphenols such as RES.

Comparative pharmacokinetics and tissue distribution of polydatin, resveratrol, and emodin after oral administration of Huzhang and Huzhang-Guizhi herb-pair extracts to rats

ETHNOPHARMACOLOGICAL RELEVANCE

Huzhang-Guizhi herb pair (HGHP), composed of Polygonum cuspidatum (Huzhang [HZ] in Chinese, the root of Polygonum cuspidatum Sieb. & Zucc.) and Ramulus Cinnamomi (Guizhi [GZ] in Chinese, the dried twig of Cinnamomum cassia Presl.), is a popular herb pair commonly used to treat arthritis and involved in many Chinese prescriptions. In order to reveal the influence of GZ on HZ on bioavailability, the pharmacokinetic behaviors and tissue distribution variations of the three analytes from HZ were detected between oral administration of HZ and HGHP extracts to rats.

MATERIALS AND METHODS

Male Sprague-Dawley rats were randomly assigned to two groups for pharmacokinetics study and eight groups for tissues distribution research with the equivalent dose of 18 g crude HZ/kg. Assays for analytes from HZ (polydatin, resveratrol, emodin) were developed and validated using high performance liquid chromatography with ultraviolet detection (HPLC-UV).

RESULTS

Part pharmacokinetic parameters including area under the concentration-time curve (AUC), the maximum plasma concentration (Cmax), biological half-life (t1/2), mean residence time (MRT), time to peak concentration (Tmax), clearance rate/bioavailability (CL/F) and volume of distribution/bioavailability (Vd/F) showed significant difference (P < 0.05) after oral administration of HGHP, as compared to those of HZ. The three analytes could be detected in heart, liver, spleen, lung, kidney and brain. Compared with the HZ group, AUC0-t of polydatin in heart, liver and kidney increased significantly (p < 0.05) while that in spleen decreased significantly (p < 0.05); AUC0-t of resveratrol in all detected tissues increased conspicuously (p < 0.05) in the HGHP group; AUC0-t of emodin in heart, liver, spleen, lung, and kidney increased conspicuously (p < 0.05), and decreased obviously (p < 0.05) in brain in the HGHP group.

CONCLUSIONS

GZ could strongly influence the pharmacokinetic parameters and tissue distribution characteristics of polydatin, resveratrol and emodin in rats when administrated with HZ or HGHP extracts. It might provide a reference for further explanation of the compatibility mechanism and the clinical application of HGHP.

Structural Changes Induced by Resveratrol in Monounsaturated and Polyunsaturated Phosphatidylcholine-Enriched Model Membranes

Resveratrol (Resv) is considered to exert a beneficial impact due to its radical scavenger, anti-microbial and anti-inflammatory properties through several mechanisms that could include its interaction with the cell plasma membrane. To address this issue, we investigated the influence of Resv on membrane lipid order and organization in large unilamellar vesicles composed of different lipids and ratios. The studied lipid membrane models were composed of phosphatidylcholine (PC) species (either palmitoyl-docosahexaenoyl phosphatidylcholine (PDPC) or palmitoyl-oleoyl phosphatidylcholine (POPC)), sphingomyelin (SM) and cholesterol (Chol). This study found that the addition of Resv resulted in complex membrane reorganization depending on the degree of fatty acid unsaturation at the sn-2 position, and the Lipid/Resv and SM/Chol ratios. Resv rigidified POPC-containing membranes and increased liquid-ordered (Lo) domain formation in 40/40/20 POPC/SM/Chol mixtures as this increase was lower at a 33/33/34 ratio. In contrast, Resv interacted with PDPC/SM/Chol mixtures in a bimodal manner by fluidizing/rigidifying the membranes in a dose-dependent way. Lo domain formation upon Resv addition occurred via the following bimodal mode of action: Lo domain size increased at low Resv concentrations; then, Lo domain size decreased at higher ones. To account for the variable effect of Resv, we suggest that it may act as a "spacer" at low doses, with a transition to a more "filler" position in the lipid bulk. We hypothesize that one of the roles of Resv is to tune the lipid order and organization of cell plasma membranes, which is closely linked to important cell functions such as membrane sorting and trafficking.

Unlocking the therapeutic potential of natural stilbene: Exploring pterostilbene as a powerful ally against aging and cognitive decline

The therapeutic potential of natural stilbenes, with a particular focus on pterostilbene (PTE), has emerged as a promising avenue of research targeting age-associated conditions encompassing cardiovascular diseases (CVD), diabetes mellitus (DM), and cognitive decline. This comprehensive investigation delves into the intricate mechanisms through which PTE, a polyphenolic compound abundant in grapes and blueberries, exerts its advantageous effects as an anti-aging agent. Central to its action is the modulation of hallmark aging processes, including oxidative damage, inflammatory responses, telomere attrition, and cellular senescence. PTE's ability to effectively penetrate the blood-brain barrier amplifies its potential for safeguarding neural health, thereby facilitating the regulation of neuronal signalling cascades, synaptic plasticity, and mitochondrial functionality. Through engagement with sirtuin proteins, it orchestrates cellular resilience, longevity, and metabolic equilibrium. Encouraging findings from preclinical studies portray PTE as a robust candidate for counteracting age-linked cognitive decline, augmenting memory consolidation, and potentially ameliorating neurodegenerative maladies such as Alzheimer's disease (AD). The synthesis of current scientific insights accentuates the promising translational prospects of PTE as a potent, naturally derived therapeutic agent against cognitive impairments associated with aging. Consequently, these collective findings lay a solid groundwork for forthcoming clinical inquiries and innovative therapeutic interventions in this realm.

Resveratrol and its analogs suppress HIV replication, oxidative stress, and inflammation in macrophages

Objectives

HIV suppression in brain viral reservoirs, especially macrophages, and microglia is critical to suppress HIV neuropathogenesis and subsequently HIV-associated neurocognitive disorders (HAND). Since most antiretroviral therapy (ART) drugs do not achieve optimal therapeutic concentrations in the brain and can cause neurotoxicity, an alternative/adjuvant therapy is needed to suppress HIV neuropathogenesis. In this study, our objectives were to examine the anti-HIV, antioxidant, and anti-inflammatory potential of resveratrol (RES) and its synthetic analogs 4-(E)-{(p-tolylimino)-methylbenzene-1,2-diol} (TIMBD) and 4-(E)-{(4-hydroxyphenylimino)-methylbenzene,1,2-diol} (HPIMBD) in HIV-infected macrophages.

Methods

We used HIV replication (viral load), oxidative stress (reactive oxygen species and antioxidant enzymes), and inflammatory response (pro- and anti-inflammatory cytokines/chemokines) assays to achieve the objectives of the study.

Results

Our results showed that RES and its analogs HPIMBD and TIMBD at 25 µM concentration significantly decrease HIV replication in both primary monocyte-derived macrophages and U1-differentiated macrophages. Moreover, RES and its analogs do not induce any cytotoxicity for up to 3 days in these cells. Further, treatment with RES and TIMBD (25 µM) also reduced the levels of reactive oxygen species without affecting the expression of antioxidant enzymes, SOD1, and catalase in U1 macrophages. Besides, RES and HPIMBD treatment inhibited the proinflammatory cytokines and chemokines in U1 macrophages, which was associated with decreased levels of anti-inflammatory cytokines. Importantly, our western blot experiments show that RES also decreases cellular proinflammatory cytokine IL-1β, which is usually elevated in both myeloid and neuronal cells upon HIV infection.

Conclusions

Taken together, our results suggest that RES and/or its analogs are important adjuvants that may be used not only to suppress HIV but also oxidative stress and inflammation in brain viral reservoirs.

High resveratrol-loaded microcapsules with trehalose and OSA starch as the wall materials: Fabrication, characterization, and evaluation

To improve the solubility and stability of resveratrol (Res), Res nanocrystals (Res-ncs) as the capsule core were prepared by wet milling using hydroxypropyl methyl cellulose (HPMC_E5), sodium dodecyl sulfate (SDS), and polyvinylpyrrolidone (PVP_K30) as stabilizers, along with trehalose and octenyl succinic anhydride (OSA) modified starch were used as the wall material to produce Res microcapsules (Res-mcs) via spray drying. The fresh-prepared Res-ncs and rehydrated Res-mcs had mean particle sizes of 190.30 ± 3.43 and 204.70 ± 3.60 nm, zeta potentials of -13.90 ± 0.28 and - 11.20 ± 0.34 mV, and the loading capacities (LC) were as high as 73.03 % and 28.83 %. Particle morphology showed that Res-mcs had more regular and smooth spherical structures. FTIR indicated that Res may have hydrogen bonding with the walls. XRD and DSC exhibited that Res in nanocrystals and microcapsules existed mostly as amorphous structures. The solubility of Res-mcs and Res-ncs was increased, with excellent redispersibility and rapid dissolution of Res in vitro. The antioxidant properties of Res-mcs were protected and improved. With the walls acting as a physical barrier, Res-mcs have better photothermal stability than raw Res. Res-mcs have a relative bioavailability of 171.25 %, which is higher than that of raw Res.

A comprehensive perspective on the disposition, metabolism, and pharmacokinetics of representative multi-components of Dengzhan Shengmai in rats with chronic cerebral hypoperfusion after oral administration

ETHNOPHARMACOLOGICAL RELEVANCE

Dengzhan Shengmai capsule (DZSM), an evidence-based Chinese medicine comprising Erigeron breviscapus (Vaniot) Hand. -Mazz., Panax ginseng C.A.Mey., Ophiopogon japonicus (Thunb.) Ker Gawl., and Schisandra chinensis (Turcz.) Baill., exhibits an excellent efficacy in treating cardio- and cerebrovascular diseases. It contains caffeoyl compounds, flavonoids, saponins, and lignans as primary active components. However, so far, the characteristics of disposition, metabolism, and pharmacokinetics of its active components remain mostly unclear.

AIM OF STUDY

To elucidate disposition, metabolism, and pharmacokinetics of representative components of DZSM in rats with chronic cerebral hypoperfusion (CCH) by integrating ex vivo and in situ approaches.

MATERIALS AND METHODS

Exposure and distribution of absorbed prototypes and their metabolites were comprehensively investigated using sensitive LC-MS/MS and high-resolution LC-Q-TOF/MS. Pharmacokinetics of representative 16 components (12 prototypes and 4 metabolites) with different chemical categories, relatively high in vivo levels, wide tissue distribution, and reported neuroprotective activities were profiled. The ex vivo everted gut sac and in situ linked-rat models were adopted.

RESULTS

Representative 12 prototypes including 6 caffeoyl compounds (CA, 5-CQA, 3-CQA, 4-CQA, 1,3-CQA, and 3,4-CQA), 1 flavonoid (Scu), 2 saponins (Rd and Rg2), and 3 lignans (SchA, SchB, and SolA) presented characteristic absorption, disposition, and pharmacokinetics profiles in CCH rats. The caffeoyl compounds and flavonoid were well absorbed, exhibited wide distribution, and underwent extensive intestinal metabolism, such as methylation, isomerization, and sulfoconjugation. For CA, 5-CQA, Scu, and 4 related metabolites, the enterohepatic circulation was observed and resulted in bimodal or multimodal pharmacokinetic profiles. Saponins showed relatively low systemic exposure and limited distribution. The PPD-type ginsenoside Rd exhibited longer elimination half-life and systemic circulation than the PPT-type ginsenoside Rg2. No enterohepatic circulation was observed regarding saponins, suggesting that the multimodal pharmacokinetic profile of Rd could be due to its multi-site intestinal absorption. Lignans presented a low in vivo exposure and broad distribution. They were mainly transformed into hydroxylated metabolites. Corresponding to its bimodal pharmacokinetic profile, one metabolite of lignans completed the enterohepatic cycle.

CONCLUSION

The disposition, metabolism, and pharmacokinetic profiles of representative active components of DZSM were comprehensively characterized and elucidated.

Review of the Potential Therapeutic Effects and Molecular Mechanisms of Resveratrol on Endometriosis

Endometriosis is a hormone-dependent inflammatory disease characterized by the existence of endometrial tissues outside the uterine cavity. Pharmacotherapy and surgery are the current dominant management options for endometriosis. The greater incidence of recurrence and reoperation after surgical treatment as well as the adverse effects of medical approaches predispose patients to potential limitations for their long-term usage. Consequently, it is essential to explore novel supplementary and alternative drugs to ameliorate the therapeutic outcomes of endometriotic patients. Resveratrol is a phenolic compound that has attracted increasing interest from many researchers due to its pleiotropic biological activities. Here, we review the possible therapeutic efficacies and molecular mechanisms of resveratrol against endometriosis based on in vitro, animal, and clinical studies. The potential mechanisms of resveratrol include anti-proliferative, pro-apoptotic, anti-angiogenic, anti-oxidative stress, anti-invasive and anti-adhesive effects, thereby suggesting that resveratrol is a promising candidate for endometriosis. Because most studies have investigated the effectiveness of resveratrol on endometriosis via in vitro trials and/or experimental animal models, further high-quality clinical trials should be undertaken to comprehensively estimate the clinical application feasibility of resveratrol on endometriosis.

Determination of human FaFg of polyphenols using allometric scaling

Certain polyphenols exhibit low permeability; precise prediction of their intestinal absorption is important for understanding internal exposure in humans. Intestinal availability, which represents the fraction of administered compounds that reach the portal blood (F_aF_g), is calculated by dividing bioavailability (F) by hepatic availability (F_h), and F is obtained from pharmacokinetic data from both intravenous (i.v.) and oral (p.o.) administration. However, human F_aF_g of polyphenols is hardly reported, as human i.v. data are extremely scarce. In this study, we developed an estimation method for F_aF_g of polyphenols in humans based on the extrapolation of rat clearance using allometric scaling (allometric scaling-based F_aF_g calculation method, AS- F_aF_gCM). First, for quercetin, for which human i.v. data have been reported, we compared the F_aF_g obtained by AS-F_aF_gCM with the traditional approach using human i.v. and p.o. data. Less than two-fold difference in FaFg values was observed between the two approaches. Next, we obtained F_aF_g of structurally diverse polyphenols (genistein, baicalein, resveratrol, and epicatechin) using AS-F_aF_gCM, demonstrating that all of them were poorly absorbable. Furthermore, to utilize the pharmacokinetic data of the total concentration, including aglycones and metabolites, we modified the AS-F_aF_gCM to focus on their excretion. The F_aF_g value of naringenin was obtained using modified AS-F_aF_gCM and was nearly equal to that of baicalein, a structural isomer of naringenin. This study provides quantitative information on the intestinal absorption of polyphenols using comprehensive estimation methods.

Resveratrol: A potential therapeutic natural polyphenol for neurodegenerative diseases associated with mitochondrial dysfunction

Most polyphenols can cross blood-brain barrier, therefore, they are widely utilized in the treatment of various neurodegenerative diseases (ND). Resveratrol, a natural polyphenol contained in blueberry, grapes, mulberry, etc., is well documented to exhibit potent neuroprotective activity against different ND by mitochondria modulation approach. Mitochondrial function impairment is the most common etiology and pathological process in various neurodegenerative disorders, viz. Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and amyotrophic lateral sclerosis. Nowadays these ND associated with mitochondrial dysfunction have become a major threat to public health as well as health care systems in terms of financial burden. Currently available therapies for ND are limited to symptomatic cures and have inevitable toxic effects. Therefore, there is a strict requirement for a safe and highly effective drug treatment developed from natural compounds. The current review provides updated information about the potential of resveratrol to target mitochondria in the treatment of ND.

A QbD Approach to Design and to Optimize the Self-Emulsifying Resveratrol-Phospholipid Complex to Enhance Drug Bioavailability through Lymphatic Transport

Objectives: Despite having profound therapeutic value, the clinical application of resveratrol is restrained due to its <1% bioavailability, arising from the extensive fast-pass effect along with enterohepatic recirculation. This study aimed to develop a self-emulsifying formulation capable of increasing the bioavailability of resveratrol via lymphatic transport. Methods: The resveratrol−phospholipid complex (RPC) was formed by the solvent evaporation method and characterized by FTIR, DSC, and XRD analyses. The RPC-loaded self-emulsifying drug delivery system (SEDDS) was designed, developed, and optimized using the QbD approach with an emphasis on resveratrol transport through the intestinal lymphatic pathway. The in vivo pharmacokinetic study was investigated in male Wister Albino rats. Results: The FTIR, DSC, and XRD analyses confirmed the RPC formation. The obtained design space provided robustness of prediction within the 95% prediction interval to meet the CQA specifications. An optimal formulation (desirability value of 7.24) provided Grade-A self-emulsion and exhibited a 48-fold bioavailability enhancement compared to the pure resveratrol. The cycloheximide-induced chylomicron flow blocking approach demonstrated that 91.14% of the systemically available resveratrol was transported through the intestinal lymphatic route. Conclusions: This study suggests that an optimal self-emulsifying formulation can significantly increase the bioavailability of resveratrol through lymphatic transport to achieve the desired pharmacological effects.

Short-term resveratrol treatment restored the quality of oocytes in aging mice

The quality of oocytes declines by aging, resulting in their low competences for fertility. Here, resveratrol treatment showed increases in the rates of implantation and live offspring as well as decreases in the abortion rate as short as one week after treatment, although the number of ovulated oocytes and the rates of fertilization and blastocyst formation were not changed following resveratrol treatment. Resveratrol treatment did not cause abnormalities mouse estrous cycles and body weights. No abnormality was detected in both fetuses and placentas after 22 weeks of resveratrol treatment and the fetuses had normal fertility. Positive correlations were found between serum resveratrol levels and pregnancy and live offspring rates as well as ovarian expression levels of Sirt1, Sirt3, Sirt4, Sirt5, and Sirt7. The mitochondrial membrane potential and ATP content but not copy number of mitochondrial DNA in oocytes was increased in aging mice with resveratrol treatment. In conclusion, we demonstrated the restoration of oocyte quality in aging mice in addition to the prevention of their quality decline during aging by restoring mitochondrial functions by resveratrol treatment without adverse effects in the animals and their offspring.

Impact of route-dependent phase-II gut metabolism and enterohepatic circulation on the bioavailability and systemic disposition of resveratrol in rats and humans: A comprehensive whole body physiologically-based pharmacokinetic modeling

Resveratrol, a natural polyphenolic phytoalexin, is a dietary supplement that improves the outcomes of metabolic, cardiovascular, and other age-related diseases due to its diverse pharmacological activities. Although there have been several preclinical and clinical investigations of resveratrol, the contributions of gut phase-II metabolism and enterohepatic circulation to the oral bioavailability and pharmacokinetics of resveratrol remain unclear. Furthermore, a physiologically-based pharmacokinetic (PBPK) model that accurately describes and predicts the systemic exposure profiles of resveratrol in clinical settings has not been developed. Experimental data were acquired from several perspectives, including in vitro protein binding and blood distribution, in vitro tissue S9 metabolism, in situ intestinal perfusion, and in vivo pharmacokinetics and excretion studies. Using these datasets, an in-house whole-body PBPK model incorporating route-dependent phase-II (glucuronidation and sulfation) gut metabolism and enterohepatic circulation processes was constructed and optimized for chemical-specific parameters. The developed PBPK model aligned with the observed systemic exposure profiles of resveratrol in single and multiple dosing regimens with an acceptable accuracy of 0.538-0.999-fold errors. Furthermore, the model simulations elucidated the substantial contribution of gut first-pass metabolism to the oral bioavailability of resveratrol and suggested differential effects of enterohepatic circulation on the systemic exposure of resveratrol between rats and humans. After partial modification and verification, our proposed PBPK model would be valuable to optimize dosage regimens and predict food-drug interactions with resveratrol-based natural products in various clinical scenarios.

Novel Insights on Dietary Polyphenols for Prevention in Early-Life Origins of Hypertension: A Review Focusing on Preclinical Animal Models

Polyphenols are the largest group of phytochemicals with health benefits. Early life appears to offer a critical window of opportunity for launching interventions focused on preventing hypertension, as increasing evidence supports the supposition that hypertension can originate in early life. Although polyphenols have antihypertensive actions, knowledge of the potential beneficial action of the early use of polyphenols to avert the development of hypertension is limited. Thus, in this review, we first provide a brief summary of the chemistry and biological function of polyphenols. Then, we present the current epidemiological and experimental evidence supporting the early-life origins of hypertension. We also document animal data on the use of specific polyphenols as an early-life intervention to protect offspring against hypertension in adulthood and discuss underlying mechanisms. Continued research into the use of polyphenols to prevent hypertension from starting early in life will have far-reaching implications for future health.

Enzymatic Synthesis of Resveratrol α-Glucoside by Amylosucrase of Deinococcus geothermalis

Glycosylation of resveratrol was carried out by using the amylosucrase of Deinococcus geothermalis, and the glycosylated products were tested for their solubility, chemical stability, and biological activities. We synthesized and identified these two major glycosylated products as resveratrol-4'-O-α-glucoside and resveratrol-3-O-α-glucoside by nuclear magnetic resonance analysis with a ratio of 5:1. The water solubilities of the two resveratrol-α-glucoside isomers (α-piceid isomers) were approximately 3.6 and 13.5 times higher than that of β-piceid and resveratrol, respectively, and they were also highly stable in buffered solutions. The antioxidant activity of the α-piceid isomers, examined by radical scavenging capability, showed it to be initially lower than that of resveratrol, but as time passed, the α-piceid isomers' activity reached a level similar to that of resveratrol. The α-piceid isomers also showed better inhibitory activity against tyrosinase and melanin synthesis in B16F10 melanoma cells than β-piceid. The cellular uptake of the α-piceid isomers, which was assessed by ultra-performance liquid chromatography (UPLC) analysis of the cell-free extracts of B16F10 melanoma cells, demonstrated that the glycosylated form of resveratrol was gradually converted to resveratrol inside the cells. These results indicate that the enzymatic glycosylation of resveratrol could be a useful method for enhancing the bioavailability of resveratrol.

Therapeutic potential of resveratrol in diabetic nephropathy according to molecular signaling

BACKGROUND

Diabetic nephropathy (DN) as a severe complication of diabetes mellitus (DM), is a crucial menace for human health and survival and remarkably elevates the healthcare systems' costs. Therefore, it is worth noting to identify novel preventive and therapeutic strategies to alleviate the disease conditions. Resveratrol, as a well-defined anti-diabetic/ antioxidant agent has capabilities to counteract diabetic complications. It has been predicted that resveratrol will be a fantastic natural polyphenol for diabetes therapy in the next few years.

OBJECTIVE

Accordingly, the current review aims to depict the role of resveratrol in the regulation of different signaling pathways that are involved in the reactive oxygen species (ROS) production, inflammatory processes, autophagy, and mitochondrial dysfunction, as critical contributors to DN pathophysiology.

RESULTS

The pathogenesis of DN can be multifactorial; hyperglycemia is one of the prominent risk factors of DN development that is closely related to oxidative stress. Resveratrol, as a well-defined polyphenol, has various biological and medicinal properties, including anti-diabetic, anti-inflammatory, and anti-oxidative effects.

CONCLUSION

Resveratrol prevents kidney damages that are caused by oxidative stress, enhances antioxidant capacity, and attenuates the inflammatory and fibrotic responses. For this reason, resveratrol is considered an interesting target in DN research due to its therapeutic possibilities during diabetic disorders and renal protection.

Efficacy of resveratrol in male urogenital tract dysfunctions: an evaluation of pre-clinical data

Resveratrol is a polyphenol found naturally in fruits and plants. Recently, studies in humans and animal models have suggested beneficial properties of this polyphenol, such as improvements to metabolic and lipid profiles, along with antioxidant, anti-inflammatory and anti-proliferative effects. In the urogenital tract (UGT), resveratrol has also been tested clinically and experimentally as a therapeutic drug in several diseases; however, the translational efficacy of resveratrol, especially in UGT, is still a matter of debate. In the present review, we address the pre-clinical efficacy of resveratrol in UGT-related dysfunctions, focusing on lower urinary tract symptoms, non-cancerous prostatic disease (benign prostatic hyperplasia and prostatitis) and erectile dysfunction. In vitro studies indicate that resveratrol reduces inflammatory markers and oxidative stress, and improves endothelial function in UGT organs and cells isolated from humans and animals. Despite displaying low oral bioavailability, in vivo administration of resveratrol largely improves erectile dysfunction, benign prostatic hyperplasia, prostatitis and voiding impairments, as evidenced in different animal models. Resveratrol also acts as a microbiota modulator, which may explain some of its beneficial effects in vivo. In contrast to the large amount of pre-clinical data, there are insufficient clinical trials to establish resveratrol treatment efficacy in human UGT-related diseases. In summary, we provide an overview of the in vivo and in vitro efficacy of resveratrol in animal and human UGT dysfunctions, which may support future clinical trials.

Comparative Study on Inhibition of Pancreatic Cancer Cells by Resveratrol Gold Nanoparticles and a Resveratrol Nanoemulsion Prepared from Grape Skin

Resveratrol, a phenolic compound possessing vital biological activities such as anti-cancer, is present abundantly in grape skin, a waste produced during the processing of grape juice. The objectives of this study were to prepare resveratrol-gold nanoparticles and a resveratrol nanoemulsion from grape skin and study their inhibition effects on pancreatic cancer cells BxPC-3. The spherical-shaped citrate gold nanoparticles (GNPs) and resveratrol-gold nanoparticles (R-GNPs) were, respectively, prepared with a surface plasmon resonance peak at 528 and 538 nm, mean particle size of 20.8 and 11.9 nm, and zeta-potential at −32.7 and −66.7 mV, by controlling an appropriate concentration of citrate/resveratrol and gold chloride as well as stirring time and temperature. The resveratrol nanoemulsion, composed of soybean oil, Tween 80, and sucrose fatty acid ester in glycerol and water, possessed a high storage stability with a mean particle size of 14.1 nm, zeta-potential of −49.7 mV, and encapsulation efficiency of 95.5%. An antiproliferation study revealed that both R-GNPs and resveratrol nanoemulsion could effectively inhibit the growth of pancreatic cancer cells BxPC-3, with the latter showing a higher inhibition effect. Western blot analysis implied that both can down-regulate expressions of cyclin A, cyclin B, CDK1, and CDK2 and up-regulate expressions of p53 and p21, accompanied by enhancing cytochrome C expression, decreasing BcL-2 expression, increasing Bax expression, and leading to the elevation of caspase-8, caspase-9, and caspase-3 activities for cell apoptosis execution. Future research is needed to study the inhibition of pancreatic tumors in vivo by R-GNPs and resveratrol nanoemulsions.

Depuration Kinetics and Growth Dilution of Caribbean Ciguatoxin in the Omnivore Lagodon rhomboides: Implications for Trophic Transfer and Ciguatera Risk

Modeling ciguatoxin (CTX) trophic transfer in marine food webs has significant implications for the management of ciguatera poisoning, a circumtropical disease caused by human consumption of CTX-contaminated seafood. Current models associated with CP risk rely on modeling abundance/presence of CTX-producing epi-benthic dinoflagellates, e.g., Gambierdiscus spp., and are based on studies showing that toxin production is site specific and occurs in pulses driven by environmental factors. However, food web models are not yet developed and require parameterizing the CTX exposure cascade in fish which has been traditionally approached through top-down assessment of CTX loads in wild-caught fish. The primary goal of this study was to provide critical knowledge on the kinetics of C-CTX-1 bioaccumulation and depuration in the marine omnivore Lagodon rhomboides. We performed a two-phase, 17 week CTX feeding trial in L. rhomboides where fish were given either a formulated C-CTX-1 (n = 40) or control feed (n = 37) for 20 days, and then switched to a non-toxic diet for up to 14 weeks. Fish were randomly sampled through time with whole muscle, liver, and other pooled viscera dissected for toxin analysis by a sodium channel-dependent MTT-based mouse neuroblastoma (N2a) assay. The CTX levels measured in all tissues increased with time during the exposure period (days 1 to 20), but a decrease in CTX-specific toxicity with depuration time only occurred in viscera extracts. By the end of the depuration, muscle, liver, and viscera samples had mean toxin concentrations of 189%, 128%, and 42%, respectively, compared to fish sampled at the start of the depuration phase. However, a one-compartment model analysis of combined tissues showed total concentration declined to 56%, resulting in an approximate half-life of 97 d (R² = 0.43). Further, applying growth dilution correction models to the overall concentration found that growth was a major factor reducing C-CTX concentrations, and that the body burden was largely unchanged, causing pseudo-elimination and a half-life of 143-148 days (R² = 0.36). These data have important implications for food web CTX models and management of ciguatera poisoning in endemic regions where the frequency of environmental algal toxin pulses may be greater than the growth-corrected half-life of C-CTX in intermediate-trophic-level fish with high site fidelity.

PD-1/PD-L1 Checkpoints and Resveratrol: A Controversial New Way for a Therapeutic Strategy

Simple Summary

Over the last decade, immunotherapies using antibodies targeting the programmed cell death 1 (PD-1) checkpoint or its ligand, programmed death ligand 1 (PD-L1), have emerged as promising therapeutic strategies against cancer. However, some current limitations include a relatively low rate of “responders”, the high cost of the treatment, and a rare risk of hyper-progression. Currently, the main challenge is, therefore, to improve these therapies, for instance, by using combined approaches. Here, we summarize the accumulating evidence that resveratrol (RSV) plays a role in the modulation of the PD-1/PD-L1 axis in cancer cells, suggesting the potential of therapeutic strategies combining RSV with PD-L1 or anti-PD-1 inhibitors. We then discuss the therapeutic potential of polyphenols such as RSV to be used in combination with PD-L1 or PD-1 inhibitors for the management of cancer patients.

Abstract

Immune checkpoints refer to a range of immunoregulatory molecules that modulate the immune response. For example, proteins expressed at the surface of T-cells (including PD-1 and CTLA-4) and their ligands (PD-L1 and B7-1/B7-2, respectively), expressed by cancer cells and antigen-presenting cells, are needed to prevent excessive immune responses. However, they dampen anti-tumor immunity by limiting T-cell activity, making them promising therapeutic targets in cancer. Although immunotherapies using checkpoint blocking/neutralizing antibodies targeting PD-L1 or PD-1 have proven their superiority over conventional chemotherapies or targeted therapies by enhancing T-cell-mediated anti-tumor immunity, some limitations have emerged. These include a relatively low rate of “responders” (<50%; irrespective of cancer type), the high cost of injections, and a rare risk of hyper-progression. For clinicians, the current challenge is thus to improve the existing therapies, potentially through combinatory approaches. Polyphenols such as resveratrol (RSV), a trihydroxystilbene found in various plants and an adjuvant in numerous nutraceuticals, have been proposed as potential therapeutic targets. Beyond its well-known pleiotropic effects, RSV affects PD-L1 and PD-1 expression as well as PD-L1 subcellular localization and post-translational modifications, which we review here. We also summarize the consequences of PD-1/PD-L1 signaling, the modalities of their blockade in the context of cancer, and the current status and limitations of these immunotherapies. Finally, we discuss their potential use in combination with chemotherapies, and, using RSV as a model, we propose polyphenols as adjuvants to enhance the efficacy of anti-PD-1/anti-PD-L1 immunotherapies.

Phytochemicals as Potential Chemopreventive and Chemotherapeutic Agents for Emerging Human Papillomavirus-Driven Head and Neck Cancer: Current Evidence and Future Prospects

Head and neck cancer (HNC) usually arises from squamous cells of the upper aerodigestive tract that line the mucosal surface in the head and neck region. In India, HNC is common in males, and it is the sixth most common cancer globally. Conventionally, HNC attributes to the use of alcohol or chewing tobacco. Over the past four decades, portions of human papillomavirus (HPV)-positive HNC are increasing at an alarming rate. Identification based on the etiological factors and molecular signatures demonstrates that these neoplastic lesions belong to a distinct category that differs in pathological characteristics and therapeutic response. Slow development in HNC therapeutics has resulted in a low 5-year survival rate in the last two decades. Interestingly, HPV-positive HNC has shown better outcomes following conservative treatments and immunotherapies. This raises demand to have a pre-therapy assessment of HPV status to decide the treatment strategy. Moreover, there is no HPV-specific treatment for HPV-positive HNC patients. Accumulating evidence suggests that phytochemicals are promising leads against HNC and show potential as adjuvants to chemoradiotherapy in HNC. However, only a few of these phytochemicals target HPV. The aim of the present article was to collate data on various leading phytochemicals that have shown promising results in the prevention and treatment of HNC in general and HPV-driven HNC. The review explores the possibility of using these leads against HPV-positive tumors as some of the signaling pathways are common. The review also addresses various challenges in the field that prevent their use in clinical settings.

The Interplay between Androgen and Gut Microbiota: Is There a Microbiota-Gut-Testis Axis

The gut microbiota, a large ecosystem interacting with the host, has been shown to affect the health and fitness of the host-microbial superorganism. Increasing evidence suggests that the gut microbiota communicates with distal organs of the host including the brain, liver, and muscle, as well as testis, through various complex mechanisms. So far, we know that the androgen can markedly remodel the gut microbiota and has initiated an interdisciplinary field termed "microgenderome." More recently, the gut microbiota has been found as a major regulator of androgen production and metabolism in turn and even could trespass the blood-testis barrier (BTB) to regulate spermatogenesis, which largely updates the current knowledge on male reproduction. In this review, we provided a brief overview of the context of the gender bias of diseases related to gut microbiota, the sex dimorphism of gut microbiota, and their relationships with androgen. We also summarized the known interaction between the testis and gut microbiota based on published animal studies and tentatively discussed the hypothesis of microbiota-gut-testis axis. Finally, we highlighted the opportunities and challenges underlying the ongoing research. This knowledge may extend our understanding of the role of gut microbiota in male health and microbiota-related diseases.

Solubilization of Trans-Resveratrol in Some Mono-Solvents and Various Propylene Glycol + Water Mixtures

This research deals with the determination of solubility, Hansen solubility parameters, dissolution properties, enthalpy-entropy compensation, and computational modeling of a naturally-derived bioactive compound trans-resveratrol (TRV) in water, methanol, ethanol, n-propanol, n-butanol, propylene glycol (PG), and various PG + water mixtures. The solubility of TRV in six different mono-solvents and various PG + water mixtures was determined at 298.2-318.2 K and 0.1 MPa. The measured experimental solubility values of TRV were regressed using six different computational/theoretical models, including van't Hoff, Apelblat, Buchowski-Ksiazczak λh, Yalkowsly-Roseman, Jouyban-Acree, and van't Hoff-Jouyban-Acree models, with average uncertainties of less than 3.0%. The maxima of TRV solubility in mole fraction was obtained in neat PG (2.62 × 10-2) at 318.2 K. However, the minima of TRV solubility in the mole fraction was recorded in neat water (3.12 × 10-6) at 298.2 K. Thermodynamic calculation of TRV dissolution properties suggested an endothermic and entropy-driven dissolution of TRV in all studied mono-solvents and various PG + water mixtures. Solvation behavior evaluation indicated an enthalpy-driven mechanism as the main mechanism for TRV solvation. Based on these data and observations, PG has been chosen as the best mono-solvent for TRV solubilization.

The Potential Role of Polyphenols in Modulating Mitochondrial Bioenergetics within the Skeletal Muscle: A Systematic Review of Preclinical Models

Polyphenols are naturally derived compounds that are increasingly being explored for their various health benefits. In fact, foods that are rich in polyphenols have become an attractive source of nutrition and a potential therapeutic strategy to alleviate the untoward effects of metabolic disorders. The last decade has seen a rapid increase in studies reporting on the bioactive properties of polyphenols against metabolic complications, especially in preclinical models. Various experimental models involving cell cultures exposed to lipid overload and rodents on high fat diet have been used to investigate the ameliorative effects of various polyphenols against metabolic anomalies. Here, we systematically searched and included literature reporting on the impact of polyphenols against metabolic function, particularly through the modulation of mitochondrial bioenergetics within the skeletal muscle. This is of interest since the skeletal muscle is rich in mitochondria and remains one of the main sites of energy homeostasis. Notably, increased substrate availability is consistent with impaired mitochondrial function and enhanced oxidative stress in preclinical models of metabolic disease. This explains the general interest in exploring the antioxidant properties of polyphenols and their ability to improve mitochondrial function. The current review aimed at understanding how these compounds modulate mitochondrial bioenergetics to improve metabolic function in preclinical models on metabolic disease.

Rational Design of Resveratrol O-methyltransferase for the Production of Pinostilbene

Pinostilbene is a monomethyl ether analog of the well-known nutraceutical resveratrol. Both compounds have health-promoting properties, but the latter undergoes rapid metabolization and has low bioavailability. O-methylation improves the stability and bioavailability of resveratrol. In plants, these reactions are performed by O-methyltransferases (OMTs). Few efficient OMTs that monomethylate resveratrol to yield pinostilbene have been described so far. Here, we report the engineering of a resveratrol OMT from Vitis vinifera (VvROMT), which has the highest catalytic efficiency in di-methylating resveratrol to yield pterostilbene. In the absence of a crystal structure, we constructed a three-dimensional protein model of VvROMT and identified four critical binding site residues by applying different in silico approaches. We performed point mutations in these positions generating W20A, F24A, F311A, and F318A variants, which greatly reduced resveratrol's enzymatic conversion. Then, we rationally designed eight variants through comparison of the binding site residues with other stilbene OMTs. We successfully modified the native substrate selectivity of VvROMT. Variant L117F/F311W showed the highest conversion to pinostilbene, and variant L117F presented an overall increase in enzymatic activity. Our results suggest that VvROMT has potential for the tailor-made production of stilbenes.

Preventive Aspects of Early Resveratrol Supplementation in Cardiovascular and Kidney Disease of Developmental Origins

The increase in the incidence of cardiovascular diseases (CVDs) and kidney disease has stimulated research for strategies that could prevent, rather than just treat, both interconnected disorders. Resveratrol, a polyphenolic compound with pleiotropic biofunctions, has shown health benefits. Emerging epidemiological data supports that early life environmental insults are regarded as increased risks of developing CVDs and kidney disease in adulthood. Conversely, both disorders could be reversed or postponed by shifting interventions from adulthood to earlier stage by so-called reprogramming. The purpose of this review is first to highlight current epidemiological studies linking cardiovascular and renal programming to resulting CVD and kidney disease of developmental origins. This will be followed by a summary of how resveratrol could exert a positive influence on CVDs and kidney disease. This review also presents an overview of the evidence documenting resveratrol as a reprogramming agent to protect against CVD and kidney disease of developmental origins from animal studies and to outline the advances in understanding the underlying molecular mechanisms. Overall, this review reveals the need for future research to further clarify the reprogramming effects of resveratrol before clinical translation.

Resveratrol and Its Analogs as Functional Foods in Periodontal Disease Management

Periodontitis is a common chronic inflammatory disease driven by the interaction between a dysbiotic oral microbiome and the dysregulated host immune-inflammatory response. Naturally derived nutraceuticals, such as resveratrol and its analogs, are potential adjunctive therapies in periodontal treatment due to their antimicrobial and anti-inflammatory properties. Furthermore, different analogs of resveratrol and the choice of solvents used may lead to varying effects on therapeutic properties. This review presents the current findings and gaps in our understanding on the potential utility of resveratrol and its analogs in periodontal treatment.

In Vivo Genotoxicity Evaluation of a Stilbene Extract Prior to Its Use as a Natural Additive: A Combination of the Micronucleus Test and the Comet Assay

Genotoxic data of substances that could be used as food additives are required by the European Food Safety Authority. In this sense, the use of an extract from grapevine shoots containing a stilbene richness of 99% (ST-99), due to its antioxidant and antibacterial activities, has been proposed as an alternative to sulfur dioxide in wine. The aim of this work was to study, for the first time, the in vivo genotoxic effects produced in rats orally exposed to 90, 180, or 360 mg ST-99/kg body weight at 0, 24, and 45 h. The combination of micronucleus assay in bone marrow (OECD 474) and standard (OECD 489) and enzyme-modified comet assay was used to determine the genotoxicity on cells isolated from stomach, liver, and blood of exposed animals. The ST-99 revealed no in vivo genotoxicity. These results were corroborated by analytical studies that confirm the presence of stilbenes and their metabolites in plasma and tissues. Moreover, to complete these findings, a histopathological study was performed under light microscopy in liver and stomach showing only slight modifications in both organs at the highest concentration used. The present work confirms that this extract is not genotoxic presenting a good profile for its potential application as a preservative in the wine industry.

Resveratrol and cardiac fibrosis prevention and treatment

Cardiovascular diseases are some of the major causes of morbidity and mortality in developed or developing countries but in developed countries as well. Cardiac fibrosis is one of the most often pathological changes of heart tissues. It occurs as a result of extracellular matrix proteins accumulation at myocardia. Cardiac fibrosis results in impaired cardiac systolic and diastolic functions and is associated with other effects. Therapies with medicines have not been sufficiently successful in treating chronic diseases such as CVD. Therefore, the interest for therapeutic potential of natural compounds and medicinal plants has increased. Plants such as grapes, berries and peanuts contain a polyphenolic compound called "resveratrol" which has been reported to have various therapeutic properties for a variety of diseases. Studies on laboratory models that show that resveratrol has beneficial effects on cardiovascular diseases including myocardial infarction, high blood pressure cardiomyopathy, thrombosis, cardiac fibrosis, and atherosclerosis. In vitro animal models using resveratrol indicated protective effects on the heart by neutralizing reactive oxygen species, preventing inflammation, increasing neoangiogenesis, dilating blood vessels, suppressing apoptosis and delaying atherosclerosis. In this review, we are presenting experimental and clinical results of studies concerning resveratrol effects on cardiac fibrosis as a CVD outcome in humans.

Enhanced Oral Bioavailability of Resveratrol by Using Neutralized Eudragit E Solid Dispersion Prepared via Spray Drying

In this study, we designed amorphous solid dispersions based on Eudragit E/HCl (neutralized Eudragit E using hydrochloric acid) to maximize the dissolution of trans-resveratrol. Solid-state characterization of amorphous solid dispersions of trans-resveratrol was performed using powder X-ray diffraction, scanning electron microscopy, and particle size measurements. In addition, an in vitro dissolution study and an in vivo pharmacokinetic study in rats were carried out. Among the tested polymers, Eudragit E/HCl was the most effective solid dispersion for the solubilization of trans-resveratrol. Eudragit E/HCl significantly inhibited the precipitation of trans-resveratrol in a pH 1.2 dissolution medium in a dose-dependent manner. The amorphous Eudragit E/HCl solid dispersion at a trans-resveratrol/polymer ratio of 10/90 exhibited a high degree of supersaturation without trans-resveratrol precipitation for at least 48 h by the formation of Eudragit E/HCl micelles. In rats, the absolute oral bioavailability (F%) of trans-resveratrol from Eudragit E/HCl solid dispersion (10/90) was estimated to be 40%. Therefore, trans-resveratrol-loaded Eudragit E/HCl solid dispersions prepared by spray drying offer a promising formulation strategy with high oral bioavailability for developing high-quality health supplements, nutraceutical, and pharmaceutical products.

Resveratrol: nanocarrier-based delivery systems to enhance its therapeutic potential

Resveratrol (3,5,4'-trihydroxystilbene) is a polyphenolic compound existing in trees, peanuts and grapes and exhibits a broad spectrum of promising therapeutic activities, but it is unclear whether this entity targets the sites of action after oral administration. In vivo applicability of resveratrol has limited success so far, mainly due to its incompetent systemic delivery resulting from its low water solubility, poor bioavailability and short biological half-life. First-pass metabolism and presence of enterohepatic recirculation create doubt on the biological application of high doses typically used for in vitro trials. To augment bioavailability, absorption and uptake of resveratrol by cellular internalization, countless approaches have been implemented which involve the use of nanocarriers. Nanocarriers are a well-known delivery system used to reduce first-pass hepatic metabolism, overcome enterohepatic recirculation and accelerate the absorption of drugs via lymphatic pathways.

Resveratrol Metabolites Are Able to Reduce Steatosis in Cultured Hepatocytes

Steatosis is characterized primarily by excessive lipid accumulation in the form of triglycerides in the liver. Although resveratrol shows a low bioavailability, it has significant positive effects on steatosis. The aim of this study was to analyze whether some phase II and microbial resveratrol metabolites (trans-resveratrol-4'-O-glucuronide (R-4G); trans-resveratrol-3-O-glucuronide (R-3G); trans-resveratrol-3-O-sulfate (R-S) and dihydro-resveratrol (DH-R) were effective in reducing hepatocyte fat accumulation. An in vitro model mimicking the hepatocyte situation in fatty liver was developed by incubating mouse AML12 hepatocytes with palmitic acid (PA). For cell treatments, hepatocytes were incubated with 1, 10, or 25 µM resveratrol or its metabolites. Triglycerides and cell viability were assessed using commercial kits. Protein expression of enzymes and transporters involved in triglyceride metabolism were analyzed by western blot. We show for the first time that resveratrol and all the tested metabolites, at 1 µM, partially prevented lipid accumulation induced by the saturated fatty acid PA in AML12 hepatocytes. This effect was mainly due to the inhibition of de novo lipogenesis. This demonstrates that the low bioavailability of resveratrol is not as big a problem as it was thought to be, because resveratrol metabolites contribute to the delipidating effects of the parent compound.

Resveratrol and Tumor Microenvironment: Mechanistic Basis and Therapeutic Targets

Resveratrol (3,4′,5 trihydroxystilbene) is a naturally occurring non-flavonoid polyphenol. It has various pharmacological effects including antioxidant, anti-diabetic, anti-inflammatory and anti-cancer. Many studies have given special attention to different aspects of resveratrol anti-cancer properties and proved its high efficiency in targeting multiple cancer hallmarks. Tumor microenvironment has a critical role in cancer development and progression. Tumor cells coordinate with a cast of normal cells to aid the malignant behavior of cancer. Many cancer supporting players were detected in tumor microenvironment. These players include blood and lymphatic vessels, infiltrating immune cells, stromal fibroblasts and the extracellular matrix. Targeting tumor microenvironment components is a promising strategy in cancer therapy. Resveratrol with its diverse biological activities has the capacity to target tumor microenvironment by manipulating the function of many components surrounding cancer cells. This review summarizes the targets of resveratrol in tumor microenvironment and the mechanisms involved in this targeting. Studies discussed in this review will participate in building a solid ground for researchers to have more insight into the mechanism of action of resveratrol in tumor microenvironment.

Resveratrol isoforms and conjugates: A review from biosynthesis in plants to elimination from the human body

The natural isomers of resveratrol, cis- and trans-resveratrol, are natural phenolic substances synthetized via the shikimate pathway and found in many sources, including grapes, peanuts, blackberries, pistachios, cacao, cranberries, and jackfruits. They have functional and pharmacological properties such as anticarcinogenic, antidiabetic, anti-inflammatory, and cardioprotective activities. The aim of this article is to review the data published on resveratrol and its isomers, and their biosynthesis in plants, food sources, health and toxic effects, and the excretion of their metabolites. Due to its contribution to the promotion of human health, it is convenient to gather more knowledge about its functional properties, food sources, and the interactions with the human body during the processes of eating, digestion, absorption, biotransformation, and excretion, to combine this information to improve the understanding of these substances.

Therapeutic Potential of Polyphenols-Loaded Polymeric Nanoparticles in Cardiovascular System

Numerous studies document an increased production of reactive oxygen species (ROS) with a subsequent decrease in nitric oxide (NO) bioavailability in different cardiovascular diseases, including hypertension, atherosclerosis, and heart failure. Many natural polyphenols have been demonstrated to decrease ROS generation and/or to induce the endogenous antioxidant enzymatic defense system. Moreover, different polyphenolic compounds have the ability to increase the activity/expression of endothelial nitric oxide synthase (eNOS) with a subsequent enhancement of NO generation. However, as a result of low absorption and bioavailability of natural polyphenols, the beneficial effects of these substances are very limited. Recent progress in delivering polyphenols to the targeted tissues revealed new possibilities for the use of polymeric nanoparticles in increasing the efficiency and reducing the degradability of natural polyphenols. This review focuses on the effects of different natural polyphenolic substances, especially resveratrol, quercetin, curcumin, and cherry extracts, and their ability to bind to polymeric nanoparticles, and summarizes the effects of polyphenol-loaded nanoparticles, mainly in the cardiovascular system.

Resveratrol-loaded hollow kafirin nanoparticles via gallic acid crosslinking: An evaluation compared with their solid and non-crosslinked counterparts

The possibility of combining the health benefits of kafirin and polyphenols and improving the bioavailability of resveratrol using hollow kafirin nanoparticles via gallic acid crosslinking was investigated. The size, morphology, charge state, loading efficiency, physicochemical stability, and redispersity after lyophilization of hollow resveratrol-loaded kafirin nanoparticles formed via gallic acid crosslinking were characterized and compared with their solid counterparts and those without crosslinking. The nanoparticles formed were anionic spheres with an average diameter of <100 nm when loading amounts of resveratrol were less than 20%. The hollow nanoparticles were homogenous and still achieved stable colloidal dispersion after lyophilization. The hollow nanoparticles crosslinked with gallic acid displayed stability against pancreatin and delayed release in stimulated digestion. The results suggested that hollow kafirin nanoparticles could be a favorable colloidal delivery system for incorporating resveratrol.

Pterostilbene complexed with cyclodextrin exerts antimicrobial and anti-inflammatory effects

Resveratrol (RES) is a natural polyphenol with potential as an adjunctive therapeutic modality for periodontitis. However, its inferior pharmacokinetics and toxicity concerns about its commonly used solvent dimethyl sulfoxide (DMSO) hinder translation to clinical applicability. Our study aimed to investigate the comparative antimicrobial properties of RES and its analogues (pterostilbene [PTS], oxyresveratrol [OXY] and piceatannol [PIC]), utilizing 2-hydroxypropyl-β-cyclodextrin (HPβCD) as a solubiliser, which has a well-documented safety profile and FDA approval. These properties were investigated against Fusobacterium nucleatum, a key periodontal pathogen. PTS demonstrated the most potent antibacterial effects in HPβCD, with MIC > 60-fold lower than that of RES, OXY and PIC. In addition, PTS inhibited F. nucleatum biofilm formation. PTS exerted antimicrobial effects by eliciting leakage of cellular contents, leading to loss of bacterial cell viability. PTS also conferred immunomodulatory effects on F. nucleatum-challenged macrophages via upregulation of antioxidant pathways and inhibition of NF-κB activation. Given the superior antimicrobial potency of PTS against F. nucleatum compared to RES and other analogues, and coupled with its immunomodulatory properties, PTS complexed with HPβCD holds promise as a candidate nutraceutical for the adjunctive treatment of periodontitis.

Comparative toxicokinetics of Trans-resveratrol and its major metabolites in Harlan Sprague Dawley rats and B6C3F1/N mice following oral and intravenous administration

Trans-resveratrol (RES) is a naturally occurring stilbene found in numerous plants and foods. Due to its widespread human exposure and lack of toxicity and carcinogenicity data, RES was nominated to the National Toxicology Program for testing. To aid the toxicology studies, the dose, sex, and species differences in RES toxicokinetics was investigated in Harlan Sprague Dawley rats and B6C3F1/N mice following single intravenous (IV) (10 mg/kg) or oral gavage administration (312.5, 625, and 1250 mg/kg and 625, 1250, and 2500 mg/kg in rats and mice, respectively). Following IV and gavage administration, systemic exposure of RES based on AUC was trans-resveratrol-3-O-β-D-glucuronide (R3G)> > trans-resveratrol-3-sulfate (R3S) > RES in both species. Following gavage administration Tmax_predicted values were ≤ 263 min for both species and sexes. RES elimination half-life was longer in rats than mice, and shortest in male mice. Clearance was slower in mice with no apparent sex difference in both species. In both rats and mice, following gavage administration AUC increased proportionally to the dose. After gavage administration, enterohepatic recirculation of RES was observed in both rats and mice with secondary peaks occurring around 640 min in the concentration-time profiles. RES was rapidly metabolized to R3S and R3G in both species. Extensive first pass conjugation and metabolism resulted in low levels of the parent compound RES which was confirmed by the low estimates for bioavailability. The bioavailability of RES was low, ~12-31% and ~2-6% for rats and mice, respectively, with no apparent difference between sexes.