Tannic acid elicits selective antitumoral activity in vitro and inhibits cancer cell growth in a preclinical model of glioblastoma multiforme

Elucidating the Antidepressant-Like Effect of Tannic Acid in Mice: Modulation of Serotonergic System and Pro-Inflammatory Mediators

This study aimed to evaluate the therapeutic action of tannic acid (TA) in male Swiss mice by investigating: i) the involvement of the serotonergic system in the acute TA antidepressant-like action per se using pharmacological tools, and ii) the neuroprotective activity of TA in a lipopolysaccharide (LPS)-induced depressive-like behavior. For mechanistic investigation of the acute TA antidepressant-like action, mice received i.p. the serotoninergic receptor antagonists: WAY-100135 (5-HT1 A antagonist), ketanserin (5-HT2 A/2 C antagonist), or ondansetron (5-HT3 antagonist); 15 min later, TA or water was given by gavage. After 1 h, mice were subjected to a tail suspension test (TST). TA in different doses was tested in acute open field test (OFT), TST, and forced swimming test (FST). In the LPS protocol, animals were pretreated once daily with TA (60 or 120 mg/kg), fluoxetine (20 mg/kg) or vehicle for 7 days. On the 7th day, mice received a single injection of LPS (830 μg/kg, i.p.). After 24 h, OFT and TST were assessed. Behavioral data concerning the acute antidepressant-like effects of TA demonstrated that this tannin acts via 5-HT1 A and 5-HT2 A/2 C receptors. Besides, monoamine oxidase A (MAO-A) in vitro activity was determined in total brain; the polyphenol action was able to decrease enzyme activity. In the LPS-induced depression model, TA prevented the increase in LPS-induced immobility time in the TST, downregulated the expression of NF-κB and IL-1β, and modulated MAO-A activity in the cerebral cortex. In conclusion, TA exhibited neuroprotective and antidepressant-like activities in mice, positioning it as a promising candidate for depression therapeutics.

Characterization of tannic acid-intravenous immunoglobulin (IVIG) protein complex and impact on drug-induced cytotoxicity in MDA-MB-468 breast cancer cells

In this study, we investigated the molecular interaction between intravenous immunoglobulin (IVIG) and tannic acid (TA), a natural polyphenol, to assess the potential impact of this interaction on cellular responses relevant to cancer. Binding analysis revealed that the IVIG-TA complex forms through a single binding site on the protein with lgKa = 3.08-4.20, driven by hydrogen bonding and van der Waals interactions. Spectroscopic studies, including CD, UV-visible, and fluorescence analysis, indicated that TA induces partial changes in the secondary structure of IVIG and alters the microenvironment around specific tyrosine residues (TYR33, TYR98, TYR99). Molecular dynamics simulations further supported these findings, showing that TA binding leads to partial folding of the protein's heavy chain. Functional assays in breast cancer cell lines demonstrated that the IVIG-TA complex, which exhibited IC50 values nearly comparable to those of TA, was associated with increased intracellular ROS and LDH release, indicating enhanced oxidative stress and membrane disruption. However, caspase-3 activity remained relatively unchanged, suggesting that the observed cellular damage was induced through non-apoptotic mechanisms, potentially sensitizing cells to further damage from TA or other treatments. Although the extent of anticancer modulation under the current conditions was limited due to the relatively weak interaction between TA and IVIG, these findings suggest that further exploration of the IVIG-ligand interaction could lead to enhanced specificity in binding and modulation of small molecule activity. This work lays the foundation for future studies investigating the structural and biological implications of IVIG-ligand interactions in therapeutic contexts.

Application of PLGA microspheres loaded with natural drug tannins in tumor treatment

Although conventional chemotherapeutic drugs exhibit broad-spectrum antitumor efficacy, their toxic effects on normal cells cannot be ignored, and there is an urgent need to develop novel drugs to improve therapeutic efficacy and reduce side effects. In this study, we prepared PLGA/TA microspheres with TA as the target drug and PLGA as the carrier, and evaluated their physicochemical properties, including particle size, morphology, and release behavior, with the aim of exploring the potential of PLGA/TA microspheres for tumor therapy. The results of RNA sequencing showed that PLGA/TA microspheres may act on tumor cells mainly through the pathway of PI3K-Akt, and do not interfere with the synthesis of DNA directly. Overall, PLGA/TA microspheres, as a novel drug delivery system, showed good anti-tumor potential and provided new ideas and directions for cancer therapy.

Antimicrobial activity and cytotoxic and epigenetic effects of tannic acid-loaded chitosan nanoparticles

Tannic acid (TA) is a potent antitumor agent, but its low bioavailability and absorption limit its use. In this study, it was loaded into chitosan-based nanoparticles (Chi-NPs) to overcome these limitations and to improve its antimicrobial and anticancer activities. TA-loaded Chi-NPs (Chi-TA-NPs) were synthesized using the ionic gelation method and physicochemically characterized by FE-SEM, FTIR, XRD, PDI, DLS, and zeta potential analysis. Additionally, the antimicrobial activity of Chi-TA-NPs against two G+ bacterial strains, two G- bacterial strains, and a fungal strain (Candida albicans) was investigated using the microbroth dilution method. MTT assay was used to examine the cytotoxic effects of Chi-TA-NPs on HepG2 cells. The expression of DNA methyltransferase 1 (DNMT1), DNMT3A, and DNMT3B was examined in HepG2 cells using RT-qPCR. The amount of 5-methylcytosine in the HepG2 cell-derived genomic DNA was measured using ELISA. FE-SEM micrographs showed the loading of TA into the chitosan-based formulation. The peaks detected in the XRD and FTIR analyses confirmed the formation of the Chi-TA-NPs. The PDI value (0.247 ± 0.03), size (567.0 ± 25.84 nm), and zeta potential (17.0 ± 5.86 mV) confirmed the relative stability of Chi-TA-NPs. A constant release profile in line with the Korsmeyer-Peppas model was detected for Chi-TA-NPs, such that approximately 44% of TA was released after 300 min. In addition, Chi-TA-NPs exhibited effective antimicrobial activity against the studied microbial strains, as manifested by MIC values ranging from 250 to 1000 µg/mL. Chi-TA-NPs induced cytotoxicity in liver tumor cell line, with an IC50 value of 500 µg/mL. Furthermore, Chi-TA-NPs considerably decreased the expression of DNMT1 (2.52-fold; p = 0.01), DNMT3A (2.96-fold; p = 0.004), and DNMT3B (2.94-fold; p < 0.0001). However, 5-methylcytosine levels in HepG2 cells were unaffected by Chi-TA-NPs treatment (p = 0.62). Finally, the antimicrobial, cytotoxic, and epigenetic effects of Chi-TA-NPs were more pronounced than those of free TA and the unloaded Chi-NPs. In conclusion, Chi-TA-NPs exhibit promising potential for reducing microbial growth and promoting cytotoxicity in liver cancer cells.

Current Combinatorial Therapeutic Aspects: The Future Prospect for Glioblastoma Treatment

There are several types of brain tumors but glioblastoma (GBM) is one of the highly malignant tumors. A primary concern with GBM is that the treatment is inadequate. Even after giving many multi-stacked combinations of therapies to patients, inclusive of chemotherapy, radiation, and surgery, the median survival rate remains poor. Due to its heterogeneous nature, the use of selective therapy for specific targeting of tumor cells is of particular importance. Although many treatment alternatives which include surgery with adjuvant chemotherapy and radiotherapy are available, the prognosis of the disease is very poor. Combination therapy is becoming the foundation of modern antitumor therapy and it is continuously evolving and developing innovative drug regimens as evidenced by ongoing preclinical and clinical trials. In this review, we discuss the current treatment options and emerging therapeutic approaches for the treatment of GBM. The prospects for alternative glioblastoma therapy are also discussed.

Tannic acid: A possible therapeutic agent for hypermethioninemia-induced neurochemical changes in young rats

This study explores the therapeutic benefits of tannic acid (TnA) in an experimental protocol of chronic hypermethioninemia in rats. Rats were categorized into four groups: Group I - control, Group II - TnA 30 mg/kg, Group III - methionine (Met) 0.2-0.4 g/kg + methionine sulfoxide (MS) 0.05-0.1 g/kg, Group IV - TnA/Met + MS. Saline was administered by subcutaneous pathway into groups I and II twice daily from postnatal day 6 (P6) to P28, whereas those in groups III and IV received Met + MS. From P28 to P35, groups II and IV received TnA orally. Animals from group III presented cognitive and memory impairment assessed through object recognition and Y-maze tests (p < 0.05). Elevated levels of reactive species, lipid peroxidation, and nitrites followed by a decline in sulfhydryl content, catalase activity, and superoxide dismutase activity were observed in animals treated with Met + MS (p < 0.05). However, TnA treatment reversed all these effects (p < 0.05). In group III, there was an increase in acetylcholinesterase activity and IL-6 levels, coupled with a reduction in Na+/K+-ATPase activity (p < 0.05). TnA was able to protect against these effects (p < 0.05). The gene expression of catalase, brain-derived neurotrophic factor, and nuclear factor erythroid 2-related factor 2 was decreased in the hippocampus and striatum from group III (p < 0.05). TnA reversed almost all of these alterations (p < 0.05). These findings suggest that TnA is a therapeutic target for patients with hypermethioninemia.

Antitumoral Activity of Cecropia Pachystachya Leaves Extract in Vitro and in Vivo Model of Rat Glioma: Brain and Blood Effects

The aim of this study was to investigate the antiglioma effect of Cecropia pachystachya Trécul (CEC) leaves extract against C6 and U87 glioblastoma (GB) cells and in a rat preclinical GB model. The CEC extract reduced in vitro cell viability and biomass. In vivo, the extract decreased the tumor volume approximately 62%, without inducing systemic toxicity. The deficit in locomotion and memory and an anxiolytic-like behaviors induced in the GB model were minimized by CEC. The extract decreased the levels of reactive oxygen species, nitrites and thiobarbituric acid reactive substances and increased the activity of antioxidant enzymes in platelets, sera and brains of GB animals. The activity of NTPDases, 5'-nucleotidase and adenosine deaminase (ADA) was evaluated in lymphocytes, platelets and serum. In platelets, ATP and AMP hydrolysis was reduced and hydrolysis of ADP and the activity of ADA were increased in the control, while in CEC-treated animals no alteration in the hydrolysis of ADP was detected. In serum, the reduction in ATP hydrolysis was reversed by CEC. In lymphocytes, the increase in the hydrolysis of ATP, ADP and in the activity of ADA observed in GB model was altered by CEC administration. The observed increase in IL-6 and decrease in IL-10 levels in the serum of GB animals was reversed by CEC. These results demonstrate that CEC extract is a potential complementary treatment to GB, decreasing the tumor size, while modulating aspects of redox and purinergic systems.

Molecular Insights on Coffee Components as Chemical Antioxidants

Coffee is not only a delicious beverage but also an important dietary source of natural antioxidants. We live in a world where it is impossible to avoid pollution, stress, food additives, radiation, and other sources of oxidants that eventually lead to severe health disorders. Fortunately, there are chemicals in our diet that counteract the hazards posed by the reactive species that trigger oxidative stress. They are usually referred to as antioxidants; some of them can be versatile compounds that exert such a role in many ways. This review summarizes, from a chemical point of view, the antioxidant effects of relevant molecules found in coffee. Their mechanisms of action, trends in activity, and the influence of media and pH in aqueous solutions, are analyzed. Structure-activity relationships are discussed, and the protective roles of these compounds are examined. A particular section is devoted to derivatives of some coffee components, and another one to their bioactivity. The data used in the analysis come from theoretical and computational protocols, which have been proven to be very useful in this context. Hopefully, the information provided here will pro-mote further investigations into the amazing chemistry contained in our morning coffee cup.   Resumen. El café no solo es una bebida deliciosa, sino también una importante fuente dietética de antioxidantes naturales. Vivimos en un mundo donde es imposible evitar la contaminación, el estrés, los aditivos alimentarios, la radiación y otras fuentes de oxidantes que eventualmente conducen a trastornos de salud graves. Afortunadamente, existen sustancias químicas en nuestra dieta que contrarrestan los peligros planteados por las especies reactivas que desencadenan el estrés oxidativo. Por lo general, se les denomina antioxidantes; algunos de ellos pueden ser compuestos versátiles que ejercen dicho papel de muchas maneras. Este artículo de revisión resume, desde un punto de vista químico, los efectos antioxidantes de moléculas relevantes encontradas en el café. Se analizan sus mecanismos de acción, tendencias en la actividad y la influencia del medio y el pH en soluciones acuosas. Se discuten las relaciones estructura-actividad, y se examinan los roles protectores de estos compuestos. Se dedica una sección particular a los derivados de algunos componentes del café, y otra a su bioactividad. Los datos utilizados en el análisis provienen de protocolos teóricos y computacionales, que han demostrado ser muy útiles en este contexto. Se espera que la información proporcionada aquí promueva investigaciones futuras sobre la química contenida en nuestra taza de café matutina.

Polyphenols: Secondary Metabolites with a Biological Impression

Polyphenols are natural compounds which are plant-based bioactive molecules, and have been the subject of growing interest in recent years. Characterized by multiple varieties, polyphenols are mostly found in fruits and vegetables. Currently, many diseases are waiting for a cure or a solution to reduce their symptoms. However, drug or other chemical strategies have limitations for using a treatment agent or still detection tool of many diseases, and thus researchers still need to investigate preventive or improving treatment. Therefore, it is of interest to elucidate polyphenols, their bioactivity effects, supplementation, and consumption. The disadvantage of polyphenols is that they have a limited bioavailability, although they have multiple beneficial outcomes with their bioactive roles. In this context, several different strategies have been developed to improve bioavailability, particularly liposomal and nanoparticles. As nutrition is one of the most important factors in improving health, the inclusion of plant-based molecules in the daily diet is significant and continues to be enthusiastically researched. Nutrition, which is important for individuals of all ages, is the key to the bioactivity of polyphenols.

Tannic Acid Impedes the Proliferation of Bladder Cancer Cells by Elevating Mitochondrial Pathways of Apoptosis

Bladder cancer stands as a prevailing neoplasm among men globally, distinguished for its pronounced malignancy attributed to invasiveness and metastatic proclivity. Tannic acid (TA), an organic compound in many plants, has garnered recent attention for its discernible anti-mutagenic attributes. This investigation endeavored to scrutinize the repercussions of TA on grade II bladder cancer, with a concerted focus on unraveling its anti-cancer mechanisms. The cytotoxic effects of TA on grade II bladder cancer cells were investigated using multiple techniques, including MTT assay, flow cytometry, TUNEL assay, and western blot. Our findings revealed that elevated concentrations of TA induced cytotoxic effects in grade II bladder cancer cells. Both flow cytometry and the TUNEL assay substantiated the dose-dependent capacity of TA to prompt apoptosis. Western blot analysis corroborated that TA treatment in bladder cancer cells resulted in the upregulation of cleaved caspase-3 expression and PARP. Furthermore, heightened TA dosage elicited an augmentation in the expression of pro-apoptotic proteins, namely Bax and Bak, alongside a reduction in the expression of the anti-apoptotic protein Bcl-2 within bladder cancer cells. This study confirms TA as a potential anticancer agent, demonstrably diminishing the viability of bladder cancer cells. TA exerts cytotoxicity through the activation of mitochondrial apoptotic pathways. Specifically, TA initiates the cleavage of PARP and caspase-3, concurrently augmenting the expression of pro-apoptotic proteins to facilitate apoptosis. Collectively, the present study indicates that TA effectively impedes the proliferation of bladder cancer cells by instigating apoptosis through the intrinsic mitochondrial pathway.

Electrospraying and electrospinning of tannic acid-loaded zein: Characterization and antioxidant effects in astrocyte culture exposed to E. coli lipopolysaccharide

Tannic acid (TA) exhibits low bioavailability in the gastrointestinal tract, limiting its benefits due to small amounts reaching the CNS. Thus, the objective of this study was to develop zein capsules and fibers by electrospraying/electrospinning for encapsulation of TA. Polymeric solutions were evaluated by electrical conductivity, density, and viscosity. In zein capsules, up to 2 % TA was added, and in fibers, up to 1 % TA was added. Zein capsule and fiber with TA were evaluated by morphology, size distribution, encapsulation efficiency, thermal and thermogravimetric properties, and functional groups. Zein capsule with 1.5 % TA was evaluated in astrocyte culture for cytotoxicity and antioxidant activity. TA zein capsules and fibers exhibited high encapsulation efficiency and homogeneous morphology. TA encapsulated in zein presented higher thermal stability than free TA. TA zein capsule did not present toxicity and elicited antioxidant action in lipopolysaccharide-induced astrocyte culture. Capsules and fibers were successfully produced by electrospraying/electrospinning techniques.

New Avenues and Major Achievements in Phytocompounds Research for Glioblastoma Therapy

Phytocompounds have been evaluated for their anti-glioblastoma actions for decades, with promising results from preclinical studies but only limited translation into clinics. Indeed, by targeting multiple signaling pathways deregulated in cancer, they often show high efficacy in the in vitro studies, but their poor bioavailability, low tumor accumulation, and rapid clearance compromise their efficacy in vivo. Here, we present the new avenues in phytocompound research for the improvement of glioblastoma therapy, including the ways to enhance the response to temozolomide using phytochemicals, the current focus on phytocompound-based immunotherapy, or the use of phytocompounds as photosensitizers in photodynamic therapy. Moreover, we present new, intensively evaluated approaches, such as chemical modifications of phytochemicals or encapsulation into numerous types of nanoformulations, to improve their bioavailability and delivery to the brain. Finally, we present the clinical trials evaluating the role of phytocompounds or phytocompound-derived drugs in glioblastoma therapy and the less studied phytocompounds or plant extracts that have only recently been found to possess promising anti-glioblastoma properties. Overall, recent advancements in phytocompound research are encouraging; however, only with more 3D glioblastoma models, in vivo studies, and clinical trials it is possible to upgrade the role of phytocompounds in glioblastoma treatment to a satisfactory level.

Tannic acid ameliorates the hazards effect of beryllium induced neuro-alterations and oxidative stress in adult male rats

Background

Tannic acid (TA) is one of the most consumed and famous polyphenols with a widespread attention in the medical field according to its unique structural, pharmaceutical, physicochemical, antioxidant and other biological features. A rare study was conducted on the hazard effect of beryllium (Be) on the central nervous system.

Aims

This study aims to show the ability of beryllium to cross the blood brain barrier. Demonstrate the effect of beryllium and tannic acid separately or with each other on brain ions (Na+, K+, Ca++) and on norepinephrine, dopamine, serotonin, finally on the glutathione and malondialdehyde.

Animals grouping

Seventy-two rats were divided into four groups as control, Be, TA, and Be+TA where Be was injected intraperitoneally as 1 mg/Kg b. wt, TA was orally administrated as 5% in aquas solution.

Results

The administration of beryllium showed its ability to cross the blood brain barrier and accumulated in cortex > cerebellum>hypothalamus also, a significant increase in Na+, Ca++ cooperated with a significant decrease in K+ ions content was observed. Norepinephrine, dopamine, and serotonin showed a general significant decrease in their content joined with a significant decrease in glutathione (GSH) and elevation in malondialdehydes (MDA) because of Be intoxication. On the other hands the daily oral administration of tannic acid showed a general significant decrease in Na+, Ca++ ions content parallel with a significant increase K+ also, a non-significant change in the three measured neurotransmitters was noticed.

Conclusion

Tannic acid showed a mitigation effect against Be intoxication which may regarded to the tannic acid antioxidant, chelating effect.

Tannic Acid and Ethyl Gallate Potentialize Paclitaxel Effect on Microtubule Dynamics in Hep3B Cells

Among broad-spectrum anticancer agents, paclitaxel (PTX) has proven to be one of the most effective against solid tumors for which more specific treatments are lacking. However, drawbacks such as neurotoxicity and the development of resistance reduce its therapeutic efficacy. Therefore, there is a need for compounds able to improve its activity by synergizing with it or potentiating its effect, thus reducing the doses required. We investigated the interaction between PTX and tannins, other compounds with anticancer activity known to act as repressors of several proteins involved in oncological pathways. We found that both tannic acid (TA) and ethyl gallate (EG) strongly potentiate the toxicity of PTX in Hep3B cells, suggesting their utility in combination therapy. We also found that AT and EG promote tubulin polymerization and enhance the effect of PTX on tubulin, suggesting a direct interaction with tubulin. Biochemical experiments confirmed that TA, but not EG, binds tubulin and potentiates the apparent binding affinity of PTX for the tubulin binding site. Furthermore, the molecular docking of TA to tubulin suggests that TA can bind to two different sites on tubulin, one at the PTX site and the second at the interface of α and β-tubulin (cluster 2). The binding of TA to cluster 2 could explain the overstabilization in the tubulin + PTX combinatorial assay. Finally, we found that EG can inhibit PTX-induced expression of pAkt and pERK defensive protein kinases, which are involved in resistance to PXT, by limiting cell death (apoptosis) and favoring cell proliferation and cell cycle progression. Our results support that tannic acid and ethyl gallate are potential chemotherapeutic agents due to their potentiating effect on paclitaxel.

Quaternary nanoparticles enable sustained release of bortezomib for hepatocellular carcinoma

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) represents the third leading cause of cancer-related mortality in the world. Over the past two decades, there has been minimal improvement in therapies as well as clinical outcomes for patients with Barcelona Clinic Liver Cancer (BCLC)-B. These patients are treated with local interventions, including transarterial chemoembolization. Current methodologies only allow sustained intratumoral release measured in hours. Methodologies to allow sustained local release of the drug cargo over days to weeks are acutely needed. We hypothesize that tumor response as well as outcomes of patients with BCLC-B can be improved through utilization of a highly cytotoxic agent delivered with a sustained release platform.

APPROACH AND RESULTS

High-throughput drug screening across 40 HCC patient-derived organoids identified bortezomib (BTZ) as a highly cytotoxic small molecule for HCC. We designed and manufactured sustained release BTZ nanoparticles (BTZ-NP) using a flash nanocomplexation/nanoprecipitation process. We quantified the release profile and tested the anti-tumoral effects in vivo. The BTZ-NP formulation demonstrated a sustained release of BTZ of 30 days. This BTZ-NP formulation was highly effective in controlling tumor size and improved survival in vivo in three animal models of HCC, including when delivered via the hepatic artery, as we envision its delivery in patients. In addition, the BTZ-NP formulation was superior to treatment with doxorubicin-drug eluting beads.

CONCLUSIONS

The BTZ-NP formulation provides a potent and safe treatment of HCC via a localized delivery approach. These results warrant additional preclinical studies to advance this technology to human clinical trials.

Impact of gallic acid on tumor suppression: Modulation of redox homeostasis and purinergic response in in vitro and a preclinical glioblastoma model

Glioblastoma (GBM) is the deadliest primary brain tumor in adults due to the high rate of relapse with current treatment. Therefore, the search for therapeutic alternatives is urgent. Gallic acid (GA), a potent natural antioxidant, has antitumor and modulatory actions on purinergic signaling. In this study, we investigated the cytotoxic effects of GA on the rat GBM (C6) cell line and on astrocyte culture and analyzed its role in regulating oxidative stress and purinergic enzymes involved in GBM proliferation. Cells were exposed to GA from 50 to 400 µM for 24 and/or 48 h. Next, the effect of GA was evaluated in the preclinical model of GBM. Wistar rats were treated with 50 or 100 mg/kg of GA for 15 days, and cerebral and systemic redox status and degradation of adenine nucleotides and nucleosides in circulating platelets, lymphocytes, and serum were evaluated. Our results demonstrated that GA has selective anti-glioma activity in vitro, without inducing cytotoxicity in astrocyte. Furthermore, GA prevented oxidative stress and changes in the hydrolysis of nucleotides in GBM cells. The anti-glioma effect was also observed in vivo, as GA reduced tumor volume by 90%. Interestingly, GA decreased the oxidative damage induced by a tumor in the brain, serum, and platelets, and, also prevented changes in the degradation of nucleotides and nucleosides in lymphocytes, platelets, and serum. These results indicate, for the first time, the therapeutic potential of GA in a preclinical model of GBM, whose effects may be related to its role in redox and purinergic modulation.

Pharmacological effects and mechanisms of tannic acid

In recent years, increasing attention has been paid to the pharmacological efficacy of tannins. Tannic acid (TA), the simplest hydrolysable tannin that has been approved by the FDA as a safe food additive, is one of the most important components of these traditional medicines. Studies have shown that TA displays a wide range of pharmacological activities, such as anti-inflammatory, neuroprotective, antitumor, cardioprotective, and anti-pathogenic effects. Here, we summarize the known pharmacological effects and associated mechanisms of TA. We focus on the effect and mechanism of TA in various animal models of inflammatory disease and organ, brain, and cardiovascular injury. Moreover, we discuss the possible molecular targets and signaling pathways of TA, in addition to the pharmacological effects of TA-based nanoparticles and TA in combination with chemotherapeutic drugs.

LPS-induced impairment of Na+/K+-ATPase activity: ameliorative effect of tannic acid in mice

Acetylcholine is an excitatory neurotransmitter that modulates synaptic plasticity and communication, and it is essential for learning and memory processes. This neurotransmitter is hydrolyzed by acetylcholinesterase (AChE), which plays other cellular roles in processes such as inflammation and oxidative stress. Ion pumps, such as Na⁺/K⁺-ATPase and Ca²⁺-ATPase, are highly expressed channels that derive energy for their functions from ATP hydrolysis. Impairment of the cholinergic system and ion pumps is associated with neuropsychiatric diseases. Major depressive disorder (MDD) is an example of a complex disease with high morbidity and a heterogenous etiology. Polyphenols have been investigated for their therapeutic effects, and tannic acid (TA) has been reported to show neuroprotective and antidepressant-like activities. Animal models of depression-like behavior, such as lipopolysaccharide (LPS)-induced models of depression, are useful for investigating the pathophysiology of MDD. In this context, effects of TA were evaluated in an LPS-induced mouse model of depression-like behavior. Animals received TA for 7 days, and on the last day of treatment, LPS (830 μg/kg) was administered intraperitoneally. In vitro exposure of healthy brain to TA decreased the AChE activity. Additionally, this enzyme activity was decreased in cerebral cortex of LPS-treated mice. LPS injection increased the activity of Ca²⁺-ATPase in the cerebral cortex but decreased the enzyme activity in the hippocampus. LPS administration decreased Na⁺/K⁺-ATPase activity in the cerebral cortex, hippocampus, and striatum; however, TA administration prevented these changes. In conclusion, tannins may affect Na⁺/K⁺-ATPase and Ca²⁺-ATPase activities, which is interesting in the context of MDD.

Tannic Acid Exhibits Antiangiogenesis Activity in Nonsmall-Cell Lung Cancer Cells

Nonsmall-cell lung cancer (NSCLC) is the most common type of lung cancer, with a dismal prognosis. NSCLC is a highly vascularized tumor, and chemotherapy is often hampered by the development of angiogenesis. Therefore, suppression of angiogenesis is considered a potential treatment approach. Tannic acid (TA), a natural polyphenol, has been demonstrated to have anticancer properties in a variety of cancers; however, its angiogenic properties have yet to be studied. Hence, in the current study, we investigated the antiproliferative and antiangiogenic effects of TA on NSCLC cells. The (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assay revealed that TA induced a dose- and time-dependent decrease in the proliferation of A549 and H1299 cells. However, TA had no significant toxicity effects on human bronchial epithelial cells. Clonogenicity assay revealed that TA suppressed colony formation ability in NSCLC cells in a dose-dependent manner. The anti-invasiveness and antimigratory potential of TA were confirmed by Matrigel and Boyden chamber studies, respectively. Importantly, TA also decreased the ability of human umbilical vein endothelial cells (HUVEC) to form tube-like networks, demonstrating its antiangiogenic properties. Extracellular vascular endothelial growth factor (VEGF) release was reduced in TA-treated cells compared to that in control cells, as measured by the enzyme-linked immunosorbent assay (ELISA). Overall, these results demonstrate that TA can induce antiproliferative and antiangiogenic effects against NSCLC.

Tannic Acid Attenuates Peripheral and Brain Changes in a Preclinical Rat Model of Glioblastoma by Modulating Oxidative Stress and Purinergic Signaling

Glioblastoma (GB) is a highly aggressive and invasive brain tumor; its treatment remains palliative. Tannic acid (TA) is a polyphenol widely found in foods and possesses antitumor and neuroprotective activities. This study aimed to investigate the effect of TA on oxidative stress parameters and the activity of ectonucleotidases in the serum, platelets, and lymphocytes and/or in the brain of rats with preclinical GB. Rats with GB were treated intragastrically with TA (50 mg/kg/day) for 15 days or with a vehicle. In the platelets of the animals with glioma, the adenosine triphosphate (ATP) and adenosine monophosphate (AMP) hydrolysis and the catalase (CAT) activity decreased. Besides, the adenosine diphosphate (ADP) hydrolysis, adenosine (Ado) deamination, and the reactive oxygen species (ROS) and nitrite levels were increased in glioma animals; however, TA reversed ROS and nitrite levels and AMP hydrolysis alterations. In lymphocytes from animals with glioma, the ATP and ADP hydrolysis, as well as Ado deamination were increased; TA treatment countered this increase. In the brain of the animals with glioma, the ROS, nitrite, and thiobarbituric acid reactive substance (TBARS) levels increased and the thiol (SH) levels and CAT and superoxide dismutase (SOD) activities were decreased; TA treatment decreased the ROS and TBARS levels and restored the SOD activity. In the serum of the animals with glioma, the ATP hydrolysis decreased; TA treatment restored this parameter. Additionally, the ROS levels increased and the SH and SOD activity decreased by glioma implant; TA treatment enhanced nitrite levels and reversed SOD activity. Altogether, our results suggest that TA is an important target in the treatment of GB, as it modulates purinergic and redox systems.

Selective in vitro anticancer effect of blueberry extract (Vaccinium virgatum) against C6 rat glioma: exploring their redox status

The aim of this study was to investigate the anticancer potential of blueberry extract (Vaccinium virgatum) against a C6 rat glioma lineage. Cultures of the C6 cells were exposed to blueberry extract at concentrations of 50 to 600 µg/mL for 12, 24, 48, or 72 h and then evaluated for cell viability, proliferation, migration, colony formation and oxidative stress. We also evaluated the effects of blueberry extract on primary rat cortical astrocytes. Our results show that treatment with blueberry extract did not alter the viability or proliferation of normal primary astrocytes but it did significantly reduce the viability in 21.54 % after 48 h and proliferation in 8.59 % after 24 h of C6 cells at 200 µg/mL. We also observed a reduction in the size of the colonies of 29.99 % at 100 µg/mL when compared to the control cells and cell migration was also reduced at 50 µg/mL. After 72 h, there was a reduction in the reactive oxygen species levels ranging from 46.26 to 34.73 %, in addition to a 380.2 % increase in total thiol content. Superoxide dismutase, catalase, and glutathione S-transferase activities were also enhanced when compared to the control. Taken together this data suggests that blueberry extract exerts some selective anticancer activity in C6 glioma cells.

Bioadhesive metal-phenolic nanoparticles for enhanced NIR imaging-guided locoregional photothermal/antiangiogenic therapy

Locoregional drug delivery has emerged as a promising solution to the problems associated with intravenously administered antitumor agents, such as systemic toxicity and insufficient drug accumulation at tumor sites. Herein, we have developed an adhesive nanoparticle (NP)-based drug delivery system, using natural bioadhesive tannic acid (TA) and metal ions (Fe3+), for locoregional photothermal and antiangiogenic synergistic cancer therapy. In this study, a new near-infrared (NIR) photothermal agent indocyanine green (IR820) and an antiangiogenic agent sorafenib (SRF) were co-encapsulated in a TA-Fe complex (SIF@TA-Fe). The SIF@TA-Fe NPs exhibited super adhesion, antiangiogenesis, and efficient cellular uptake. Moreover, SIF@TA-Fe NPs showed a synergistic antitumor effect in vivo, including high tumor inhibition rate, excellent survival extension, and low risk of recurrence, resulting from the prolonged retention of the NPs in the tumor. Thus, this adhesive SIF@TA-Fe NP-based therapeutic system provides a promising approach for locoregional drug delivery of combined cancer therapy.

Tannic acid-based metal phenolic networks for bio-applications: a review

Tannic acid (TA), a large polyphenolic molecule, has long been known for use in food additives, antioxidants, bio-sorbents, animal feed and adhesives due to its intrinsic properties such as antioxidation, metal chelation, and polymerization. Recently, there has been a renewed interest in fabricating engineered advanced materials with TA modification for novel bio-applications. The modification process involves various interactions/reactions based on its diverse chemical structure, contributed by abundant aromatic rings and hydroxyl groups. In addition, the obtained composites are endowed with retained TA activity and novel enhanced properties. Therefore, the aim of this review is to highlight the recent biomedical application of TA-based metal phenolic networks (TA-MPNs) by focusing on their intrinsic properties and the endowed ability for novel engineered functional composites. The potential contributions of TA-MPNs in "Tumor Theranostics", "Anti-Bacterial Ability", "Wound Repair for Skin Regeneration" and "Bone Tissue Regeneration Applications" are summarized in this paper.

Natural Compounds in Glioblastoma Therapy: Preclinical Insights, Mechanistic Pathways, and Outlook

Simple Summary

Glioblastoma (GBM) is a tumor of the brain or spinal cord with poor clinical prognosis. Current interventions, such as chemotherapy and surgical tumor resection, are constrained by tumor invasion and cancer drug resistance. Dietary natural substances are therefore evaluated for their potential as agents in GBM treatment. Various substances found in fruits, vegetables, and other natural products restrict tumor growth and induce GBM cell death. These preclinical effects are promising but remain constrained by natural substances’ varying pharmacological properties. While many of the reviewed substances are available as over-the-counter supplements, their anti-GBM efficacy should be corroborated by clinical trials moving forward.

Abstract

Glioblastoma (GBM) is an aggressive, often fatal astrocyte-derived tumor of the central nervous system. Conventional medical and surgical interventions have greatly improved survival rates; however, tumor heterogeneity, invasiveness, and chemotherapeutic resistance continue to pose clinical challenges. As such, dietary natural substances—an integral component of the lifestyle medicine approach to chronic diseases—are examined as potential chemotherapeutic agents. These heterogenous substances exert anti-GBM effects by upregulating apoptosis and autophagy, inducing cell cycle arrest, interfering with tumor metabolism, and inhibiting proliferation, neuroinflammation, chemoresistance, angiogenesis, and metastasis. Although these beneficial effects are promising, natural substances’ efficacy in GBM is constrained by their bioavailability and blood–brain barrier permeability; various chemical formulations are proposed to improve their pharmacological properties. Many of the reviewed substances are available as over-the-counter dietary supplements, underscoring their viability as lifestyle interventions. However, clinical trials remain necessary to substantiate the in vitro and in vivo properties of natural substances.

Ameliorative effect of tannic acid on hypermethioninemia-induced oxidative and nitrosative damage in rats: biochemical-based evidences in liver, kidney, brain, and serum

We investigated the ability of tannic acid (TA) to prevent oxidative and nitrosative damage in the brain, liver, kidney, and serum of a rat model of acute hypermethioninemia. Young Wistar rats were divided into four groups: I (control), II (TA 30 mg/kg), III (methionine (Met) 0.4 g/kg + methionine sulfoxide (MetO) 0.1 g/kg), and IV (TA/Met + MetO). Rats in groups II and IV received TA orally for seven days, and rats of groups I and III received an equal volume of water. After pretreatment with TA, rats from groups II and IV received a single subcutaneous injection of Met + MetO, and were euthanized 3 h afterwards. In specific brain structures and the kidneys, we observed that Met + MetO led to increased reactive oxygen species (ROS), nitrite, and lipid peroxidation levels, followed by a reduction in thiol content and antioxidant enzyme activity. On the other hand, pretreatment with TA prevented both oxidative and nitrosative damage. In the serum, Met + MetO caused a decrease in the activity of antioxidant enzymes, which was again prevented by TA pretreatment. In contrast, in the liver, there was a reduction in ROS levels and an increase in total thiol content, which was accompanied by a reduction in catalase and superoxide dismutase activities in the Met + MetO group, and pretreatment with TA was able to prevent only the reduction in catalase activity. Conclusively, pretreatment with TA has proven effective in preventing oxidative and nitrosative changes caused by the administration of Met + MetO, and may thus represent an adjunctive therapeutic approach for treatment of hypermethioninemia.

Antidepressant Effect and Modulation of the Redox System Mediated by Tannic Acid on Lipopolysaccharide-Induced Depressive and Inflammatory Changes in Mice

Depression is an emotional disorder that causes mental and physical changes, and has limited pharmacotherapy. Tannic acid (TA) is a polyphenol with previously described antioxidant and neuroprotective properties. The aim of this study was to evaluate the effects of TA on lipopolysaccharide (LPS)-induced depressive-like behavior, as well as oxidative stress parameters and TNF-α levels in the brains of mice. Animals were pretreated once daily, with TA (30 or 60 mg/kg), fluoxetine (20 mg/kg) or vehicle for 7 days. On the 7th day, the animals received a single injection of LPS (830 μg/kg). After 24 h, open field, forced swimming, tail suspension, and splash tests were conducted. The endotoxin induced depressive-like behavior in these mice and this was attenuated by TA. In the cerebral cortex, hippocampus, and striatum, LPS increased lipid peroxidation and reactive oxygen species production, and this was also prevented by TA administration. TA treatment also prevented a decrease in catalase activity within the striatum. Further, LPS administration caused increased levels of TNF-α in all brain structures, and this was prevented in the cortex by TA treatment. In conclusion, TA shows many neuroprotective properties, with demonstrated antioxidant, anti-inflammatory and antidepressant effects in this animal model of acute depressive-like behavior. Therefore, this compound could provide an alternative therapeutic approach for the treatment of depression.

Tannic Acid: Specific Form of Tannins in Cancer Chemoprevention and Therapy-Old and New Applications

Purpose of Review

This short review is aimed at providing an updated and comprehensive report on tannic acid biological activities and molecular mechanisms of action most important for cancer prevention and adjuvant therapy.

Recent Findings

Tannic acid (TA), a mixture of digallic acid esters of glucose, is a common ingredient of many foods. The early studies of its anti-mutagenic and anti-tumorigenic activity were mostly demonstrated in the mouse skin model. This activity has been explained by its ability to inhibit carcinogens activation, as well as antioxidant and anti-inflammatory properties. Recently, the cell cycle arrest, apoptosis induction, reduced rate of proliferation, and cell migration and adhesion of several cancer cell lines as a result of TA treatment were described. The underlining mechanisms include modulation of signaling pathways such as EGFR/Jak2/STATs, or inhibition of PKM2 glycolytic enzyme. Moreover, epithelial-to-mesenchymal transition prevention and decrease of cancer stem cells formation by TA were also reported. Besides, TA was found to be potent chemosensitizer overcoming multidrug resistance. Eventually, its specific physicochemical features were found useful for generation of drug-loaded nanoparticles.

Summary

TA was shown to be a very versatile molecule with possible application not only in cancer prophylaxis, as was initially thought, but also in adjuvant cancer therapy. The latter may refer to chemosensitization and its application as a part of drug delivery systems. More studies are required to better explore this subject. In addition, the effect of TA on normal cells and its bioavailability have to better characterized.