Tangeretin ameliorates oxidative stress in the renal tissues of rats with experimental breast cancer induced by 7,12-dimethylbenz[a]anthracene

Verapamil and tangeretin enhances the M1 macrophages to M2 type in lipopolysaccharide-treated mice and inhibits the P-glycoprotein expression by downregulating STAT1/STAT3 and upregulating SOCS3

LPS induced sepsis is a complex process involving various immune cells and signaling molecules. Dysregulation of macrophage polarization and ROS production contributed to the pathogenesis of sepsis. PGP is a transmembrane transporter responsible for the efflux of a number of drugs and also expressed in murine macrophages. Natural products have been shown to decrease inflammation and expression of efflux transporters. However, no treatment is currently available to treat LPS induced sepsis. Verapamil and Tangeretin also reported to attenuate lipopolysaccharide-induced inflammation. However, the effects of verapamil or tangeretin on lipopolysaccharide (LPS)-induced sepsis and its detailed anti-inflammatory mechanism have not been reported. Here, we have determined that verapamil and tangeretin protects against LPS-induced sepsis by suppressing M1 macrophages populations and also through the inhibition of P-glycoprotein expression via downregulating STAT1/STAT3 and upregulating SOCS3 expression in macrophages. An hour before LPS (10 mg/kg) was administered; mice were given intraperitoneal injections of either verapamil (5 mg/kg) or tangeretin (5 mg/kg). The peritoneal macrophages from different experimental groups of mice were isolated. Hepatic, pulmonary and splenic morphometric analyses revealed that verapamil and tangeretin decreased the infiltration of neutrophils into the tissues. Verapamil and tangeritin also enhanced the activity of SOD, CAT, GRX and GSH level in all the tissues tested. verapamil or tangeretin pre-treated mice shifted M1 macrophages to M2 type possibly through the inhibition of P-glycoprotein expression via downregulating STAT1/STAT3 and upregulating SOCS3 expression. Hence, both these drugs have shown protective effects in sepsis via suppressing iNOS, COX-2, oxidative stress and NF-κB signaling in macrophages. Therefore, in our study we can summarize that mice were treated with either Vera or Tan before LPS administration cause an elevated IL-10 by the macrophages which enhances the SOCS3 expression, and thereby able to limits STAT1/STAT3 inter-conversion in the macrophages. As a result, NF-κB activity is also getting down regulated and ultimately mitigating the adverse effect of inflammation caused by LPS in resident macrophages. Whether verapamil or tangeretin offers such protection possibly through the inhibition of P-glycoprotein expression in macrophages needs clarification with the bio availability of these drugs under PGP inhibited conditions is a limitation of this study.

An Update on the Potential of Tangeretin in the Management of Neuroinflammation-Mediated Neurodegenerative Disorders

Neuroinflammation is the major cause of neurodegenerative disorders such as Alzheimer's and Parkinson's disease. Currently available drugs present relatively low efficacy and are not capable of modifying the course of the disease or delaying its progression. Identifying well-tolerated and brain-penetrant agents of plant origin could fulfil the pressing need for novel treatment techniques for neuroinflammation. Attention has been drawn to a large family of flavonoids in citrus fruits, which may function as strong nutraceuticals in slowing down the development and progression of neuroinflammation. This review is aimed at elucidating and summarizing the effects of the flavonoid tangeretin (TAN) in the management of neuroinflammation-mediated neurodegenerative disorders. A literature survey was performed using various resources, including ScienceDirect, PubMed, Google Scholar, Springer, and Web of Science. The data revealed that TAN exhibited immense neuroprotective effects in addition to its anti-oxidant, anti-diabetic, and peroxisome proliferator-activated receptor-γ agonistic effects. The effects of TAN are mainly mediated through the inhibition of oxidative and inflammatory pathways via regulating multiple signaling pathways, including c-Jun N-terminal kinase, phosphoinositide 3-kinase, mitogen-activated protein kinase, nuclear factor erythroid-2-related factor 2, extracellular-signal-regulated kinase, and CRE-dependent transcription. In conclusion, the citrus flavonoid TAN has the potential to prevent neuronal death mediated by neuroinflammatory pathways and can be developed as an auxiliary therapeutic agent in the management of neurodegenerative disorders.

Citrus reticulata peel extract mitigates oxidative stress and liver injury induced by abamectin in rats

The prevalent use of abamectin (ABM) has latterly raised safety attention as it has different toxicities to non-target living organisms. Citrus fruits are widely renowned for their nutritional and health-promoting qualities, and their peels are full of phenolic constituents. The purpose of the current study was to evaluate the modulatory effectiveness of Citrus reticulata peel extract (CPE) against abamectin-induced hepatotoxicity and oxidative injury. Rats were distributed into 4 groups as follows: control, CPE (400 mg/kg bw orally for 14 days), ABM (2 mg/kg bw for 5 days), and CPE + ABM at the doses mentioned above. Results revealed that GC-MS analysis of CPE has 19 identified components with significant total phenolic and flavonoid contents. Treatment with ABM in rats displayed significant variations in enzymatic and non-enzymatic antioxidants, oxidative stress markers (MDA, H2O2, PCC), liver and kidney function biomarkers, hematological parameters, lipids, and protein profile as well as histopathological abnormalities, inflammation and apoptosis (TNF-α, Caspase-3, NF-κB, and Bcl-2 genes) in rats' liver. Supplementation of CPE solo dramatically improved the antioxidant state and reduced oxidative stress. C. reticulata peel extract pretreatment alleviated ABM toxicity by modulating most of the tested parameters compared to the ABM group. Conclusively, CPE had potent antioxidant activity and could be used in the modulation of ABM hepatotoxicity presumably due to its antioxidant, anti-inflammatory, and gene-regulating capabilities.

Mandarin peel ethanolic extract attenuates diclofenac sodium induced hepatorenal toxicity in rats by mitigating oxidative stress and inflammation

Nonsteroidal anti-inflammatory drugs (NSAIDs) constitute approximately one-third of the global pharmaceutical market and are the first drugs of choice when treating fever and pain. Furthermore, among NSAIDs, the use of diclofenac sodium (DS) is preferred as it is a strong inhibitor of cyclooxygenase enzyme. However, despite its strong efficacy, DS is known for its potential to cause hepatorenal damage. Currently, to mitigate the adverse effects of certain drugs, medically effective agricultural products are often preferred as they are inexpensive, effective and safe. One such agricultural product-mandarin-is noteworthy for its high phenolic contents. The purpose of the present study was to assess the efficacy of mandarin peel ethanolic extract (MPEE) in protecting against hepatorenal damage induced by DS. Four groups (six/group) of adult male albino rats received oral administration of physiological saline (control group), DS (10 mg/kg body weight), MPEE (200 mg/kg body weight), and DS + MPEE for 7 days. Rats in the DS group showed increased serum levels of ALT, AST, ALP, BUN, CRE, and UA. Furthermore, the hepatic and renal tissue levels of MDA, TNF-α and IL-1β increased, whereas those of GSH, SOD, GP-x and IL-10 decreased (p < 0.05). Investigation of MPEE in terms of its effects on biochemical, oxidative and inflammatory parameters, it exerted protective and healing effects. Therefore, MPEE can be used to ameliorate DS-induced hepatorenal damage.

Allyl isothiocyanate regulates oxidative stress, inflammation, cell proliferation, cell cycle arrest, apoptosis, angiogenesis, invasion and metastasis via interaction with multiple cell signaling pathways

Cancer growth is a molecular mechanism initiated by genetic and epigenetic modifications that are involved in cell proliferation, differentiation, apoptosis, and senescence pathways. Chemoprevention is an important strategy for cancer treatment that leads to blocking, reversing, or impeding the multistep process of tumorigenesis, including the blockage of its vital morphogenetic milestones viz. normal, preneoplasia, neoplasia, and metastasis. Naturally occurring phytochemicals are becoming ever more popular compared to synthetic drugs for many reasons, including safety, bioavailability, efficacy, and easy availability. Allyl isothiocyanate (AITC) is a natural compound present in all plants of the Cruciferae family, such as Brussels sprouts, cauliflower, mustard, cabbage, kale, horseradish, and wasabi. In vitro and in vivo studies carried out over the decades have revealed that AITC inhibits tumorigenesis without any toxicity and undesirable side effects. The bioavailability of AITC is exceedingly high, as it was reported that nearly 90% of orally administered AITC is absorbed. AITC exhibits multiple pharmacological properties among which its anticancer activity is the most significant for cancer treatment. Its anticancer activity is exerted via selective modulation of multiple cell signaling pathways related to oxidative stress, inflammation, cell proliferation, cell cycle arrest, apoptosis, angiogenesis, invasion, and metastasis. This review highlights the current knowledge on molecular targets that are involved in the anticancer effect of AITC associated with (i) inhibition of carcinogenic activation and induction of antioxidants, (ii) suppression of pro-inflammatory and cell proliferative signals, (iii) induction of cell cycle arrest and apoptosis, and (iv) inhibition of angiogenic and invasive signals related to metastasis.

Polymethoxylated flavonoids in citrus fruits: absorption, metabolism, and anticancer mechanisms against breast cancer

Polymethoxylated flavonoids (PMFs) are a subclass of flavonoids found in citrus fruits that have shown multifunctional biological activities and potential anticancer effects against breast cancer. We studied the absorption, metabolism, species source, toxicity, anti-cancer mechanisms, and molecular targets of PMFs to better utilize their anticancer activity against breast cancer. We discuss the absorption and metabolism of PMFs in the body, including the methylation, demethylation, and hydroxylation processes. The anticancer mechanisms of PMFs against breast cancer were also reviewed, including the estrogen activity, cytochrome P-450 enzyme system, and arylhydrocarbon receptor (AhR) inhibition, along with various molecular targets and potential anticancer effects. Although PMFs may be advantageous in the prevention and treatment for breast cancer, there is a lack of clinical evidence and data to support their efficacy. Despite their promise, there is still a long way to go before PMFs can be applied clinically.

Anticancer Potential of Flavonoids: An Overview with an Emphasis on Tangeretin

Natural compounds with pharmacological activity, flavonoids have been the subject of an exponential increase in studies in the field of scientific research focused on therapeutic purposes due to their bioactive properties, such as antioxidant, anti-inflammatory, anti-aging, antibacterial, antiviral, neuroprotective, radioprotective, and antitumor activities. The biological potential of flavonoids, added to their bioavailability, cost-effectiveness, and minimal side effects, direct them as promising cytotoxic anticancer compounds in the optimization of therapies and the search for new drugs in the treatment of cancer, since some extensively antineoplastic therapeutic approaches have become less effective due to tumor resistance to drugs commonly used in chemotherapy. In this review, we emphasize the antitumor properties of tangeretin, a flavonoid found in citrus fruits that has shown activity against some hallmarks of cancer in several types of cancerous cell lines, such as antiproliferative, apoptotic, anti-inflammatory, anti-metastatic, anti-angiogenic, antioxidant, regulatory expression of tumor-suppressor genes, and epigenetic modulation.

Connexin43 is associated with the progression of clear cell renal carcinoma and is regulated by tangeretin to sygergize with tyrosine kinase inhibitors

BACKGROUND

The roles of Connexin43 (Cx43) in clear cell renal cell carcinoma (ccRCC) microenviroment remains to be poorly defined.

METHODS

The expression profile, prognosis and immune analysis of Cx43 in various cancers, particularly in ccRCC were performed using TCGA database, and various biological function assays were applied to explore the physiological role of Cx43 and tangeretin in ccRCC. Western blot were applied to examine the protein expression and Kunming mice were used to evaluate preliminary safety or anti-tumor activity of tangeretin and sunitinib.

RESULTS

Compared with the normal group, higher expression levels of Cx43 in ccRCC, and distinct associations between Cx43 expression and ccRCC prognosis or immune infiltration, were found. Notably, the expression of Cx43 was found to be highly correlated with that of receptor tyrosine kinases (RTKs), particularly with VEGFR1, VEGFR2 and VEGFR3. The expression of Cx43 and EGFR was also found to be higher in ccRCC than that in the para-cancerous specimens. Knocking down Cx43 expression decreased RCC cell viability, cell migration, p-EGFR, MMP-9 and survivin expression. Using 14 Chinese medicine monomers, tangeretin was screened and found to inhibit tumor cell viability and Cx43 expression. Tangeretin also enhanced the sensitivity of RCC cells to tyrosine kinase inhibitors (TKIs) sunitinib and sorafenib. However, the same concentration of tangeretin exerted a less prominent effect on normal renal cell viability.

CONCLUSIONS

Cx43 is strongly associated with RTK expression and ccRCC progression, while tangeretin can inhibit RCC cell malignancy by inhibiting Cx43 expression and enhance the sensitivity of RCC cells to TKIs.

Characterization of tangeretin as an activator of nuclear factor erythroid 2-related factor 2/antioxidant response element pathway in HEK293T cells

Numerous studies have reported that tangeretin is a polymethoxylated flavone with a variety of biological activates, but little research has been done on the antioxidant mechanism of tangeretin. Hence, we investigated the effect of tangeretin on the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and its potential molecular mechanisms by in vitro and in silico research. The results of molecular docking suggested that tangeretin bound at the top of the central pore of Kelch-like ECH-associated protein 1 (Keap1) Kelch domain, and the hydrophobic and hydrogen bond interactions contributed to their stable binding. Herein, the regulation of Nrf2-ARE pathway by tangeretin was explored in the human embryonic kidney cell line HEK293T, which is relatively easy to be transfected. Upon binding to tangeretin, Nrf2 translocated to the nucleus of HEK293T cells, which in turn activated the Nrf2-ARE pathway. Luciferase reporter gene analysis showed that tangeretin significantly induced ARE-mediated transcriptional activation. Real-time PCR and Western blot assays showed that tangeretin induced the gene and protein expressions of Nrf2-mediated targets, including heme oxygenase 1 (HO-1), nicotinamide adenine dinucleotide phosphate (NADPH) quinone dehydrogenase 1 (NQO1), and glutamate-cysteine ligase (GCLM). In addition, tangeretin could effectively scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. In summary, tangeretin may be a potential antioxidant via activating the Nrf2-ARE pathway.

Mechanism of Citri Reticulatae Pericarpium as an Anticancer Agent from the Perspective of Flavonoids: A Review

Citri Reticulatae Pericarpium (CRP), also known as “chenpi”, is the most common qi-regulating drug in traditional Chinese medicine. It is often used to treat cough and indigestion, but in recent years, it has been found to have multi-faceted anti-cancer effects. This article reviews the pharmacology of CRP and the mechanism of the action of flavonoids, the key components of CRP, against cancers including breast cancer, lung cancer, prostate cancer, hepatic carcinoma, gastric cancer, colorectal cancer, esophageal cancer, cervical cancer, bladder cancer and other cancers with a high diagnosis rate. Finally, the specific roles of CRP in important phenotypes such as cell proliferation, apoptosis, autophagy and migration–invasion in cancer were analyzed, and the possible prospects and deficiencies of CRP as an anticancer agent were evaluated.

Poly (Thioether-Polyesters) Micelles Encapsulation Induces ROS-Triggered Targeted Release of Tangeretin

Tangeretin (Tan) possesses great anti-oxidation and anti-inflammation bioactivities; however, it is accompanied by poor water solubility, which leads to inefficient cellular internalization. To address this issue, a reactive oxygen species (ROS)-triggered poly (thioether-polyesters) micelle (PDHP, PEG-DTT) was designed and prepared via self-assembly, which consisted of poly (thioether-polyesters) as the hydrophilic shell, and the drug Tan as the hydrophobic inner core. The micelles (Tan@ PDHP), with a 63.15% loading efficiency of Tan, showed negligible cytotoxicity, high stability in phosphate-buffered saline buffer (pH  =  7.4), and continuous release of Tan with the stimulation of H2O2. In addition, this Tan loading micelle was more efficient in responding to the formation of ROS in the lipopolysaccharide-stimulated RAW264.7 cells compared to that of the free Tan. In short, the strategy of encapsulating the low solubility Tan in ROS-triggered poly (thioether-polyesters) micelles provides an effective assay of enhancing Tan's antioxidative activity.

Tangeretin promotes lifespan associated with insulin/insulin-like growth factor-1 signaling pathway and heat resistance in Caenorhabditis elegans

Tangeretin is a polymethoxylated flavonoid naturally occurred in citrus fruits with many pharmacological activities, such as anti-inflammatory, antiproliferative, and neuroprotective properties. A previous study reported that tangeretin-enriched orange extract could prolong the lifespan in Caenorhabditis elegans. However, the antiaging effect of tangeretin remains uncertain. In this study, we used the model organism C. elegans to conduct a lifespan test, observed the aging-related functional changes of nematodes, the fluorescence changes of stress-related proteins (DAF-16 and HSP-16.2) and its response to stress assay, and monitored the effect of tangeretin on the mRNA expression levels. The results showed that tangeretin supplementation (30 and 100 μM) extended the mean lifespan, slowed aging-related functional declines, and increased the resistance against heat-shock stress. Furthermore, tangeretin upregulated the mRNA expression of daf-16, hsp-16.2, and hsp-16.49, promoted the nuclear localization of DAF-16, and enhanced the fluorescence intensity of HSP-16.2, while it had no effect on the lifespan of daf-2, age-1, and daf-16 mutants. The current findings suggest that tangeretin can significantly extend the lifespan and enhance heat stress tolerance in an insulin/insulin-like growth factor signaling dependent manner.

Citrus Flavone Tangeretin Inhibits CRPC Cell Proliferation by Regulating Cx26, AKT, and AR Signaling

Prostate cancer (PCa) progression depends on the action of androgen receptors (AR). Therefore, preventing ligand-mediated activation of AR is the first-line treatment strategy for metastatic PCa. Androgen deprivation therapy (ADT) can inhibit ligand binding to AR and alleviate PCa progression initially. However, due to the adaptation of PCa and recovery of AR signaling, castration-resistant prostate cancer (CRPC) eventually develops. Exploring novel dietary compounds that can target AR signaling appears to be a viable alternative therapeutic option for CRPC. In the present study, compounds from the citrus fruits were focused upon, which contain various flavonoid ingredients. Key components contained within orange peel, which is frequently used in traditional Chinese medicine, and downstream targets were first analyzed using network pharmacology approach. Notably, it was found that tangeretin, an active ingredient from orange peel, can significantly inhibit CRPC cell (C4-2 and Du145 cells) proliferation and migration whilst also synergistically increasing the sensitivity of CRPC cells to anti-tumor drugs sorafenib or cisplatin. Tangeretin also significantly reduced AR and AKT expressions in C4-2 cells and signal transducer and activator of transcription 3 expression in the androgen-insensitive cell line Du145. In addition, tangeretin increased the expression of both connexin26 (Cx26) and gap junction function, which may mediate the bystander effects of cisplatin or sorafenib. Taken together, the present study revealed a novel molecular mechanism by which tangeretin may inhibit the proliferation of CRPC cells, by affecting the Cx26/AKT/AR pathway, to synergistically increase the sensitivity of CRPC cells to sorafenib and cisplatin.

Aged Pericarpium Citri Reticulatae ‘Chachi’ Attenuates Oxidative Damage Induced by tert-Butyl Hydroperoxide (t-BHP) in HepG2 Cells

This study investigated the protective effects of aged Pericarpium Citri Reticulatae ‘Chachi’ (PCR-C) on tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in HepG2 cells. According to HPLC analysis, PCR-C aged 10 years (PCR-C10) had the highest flavonoids content, especially polymethoxyflavones (PMFs), compared with the fresh peel of Citrus reticulata cv. ‘Chachiensis’ and PCR-C aged 1, 3, and 5 years. Then, flavonoids-rich PCR-C samples and non-flavonoids-rich PCR-C samples (NF) were prepared by extracting and purifying PCR-C of different aging periods, for further cell experiments. Pretreatment with flavonoids-rich PCR-C samples (particularly PCR-C10) considerably reversed t-BHP-induced oxidative damage in HepG2 cells by improving cell viability, increasing SOD activity and GSH levels and reducing the overproduction of ROS and MDA. Correlation analysis further indicated that the accumulation of PMFs, mainly 5,6,7,4′-tetramethoxyflavone and nobiletin, was the main reason that PCR-C10 maintained the redox balance in HepG2 cells. These findings provided direct evidence for the cellular antioxidant activity of aged PCR-C and a guide for PCR-C’s classification, authentication and rational use.

Redox Activity of Flavonoids: Impact on Human Health, Therapeutics, and Chemical Safety

The cost-effectiveness of presently used therapies is a problem in overall redox-based management, which is posing a significant financial burden on communities across the world. As a result, sophisticated treatment models that provide notions of predictive diagnoses followed by targeted preventive therapies adapted to individual patient profiles are gaining global acclaim as being beneficial to patients, the healthcare sector, and society as a whole. In this context, natural flavonoids were considered due to their multifaceted antioxidant, anti-inflammatory, and anticancer effects as well as their low toxicity and ease of availability. The aim of this review is to focus on the capacity of flavonoids to modulate the responsiveness of various diseases and ailments associated with redox toxicity. The review will also focus on the flavonoids' pathway-based redox activity and the advancement of redox-based therapies as well as flavonoids' antioxidant characteristics and their influence on human health, therapeutics, and chemical safety. Research findings indicated that flavonoids significantly exhibit various redox-based therapeutic responses against several diseases such as inflammatory, neurodegenerative, cardiovascular, and hepatic diseases and various types of cancer by activating the Nrf2/Keap1 transcription system, suppressing the nuclear factor κB (NF-κB)/IκB kinase inflammatory pathway, abrogating the function of the Hsp90/Hsf1 complex, inhibiting the PTEN/PI3K/Akt pathway, and preventing mitochondrial dysfunction. Some flavonoids, especially genistein, apigenin, amentoflavone, baicalein, quercetin, licochalcone A, and biochanin A, play a potential role in redox regulation. Conclusions of this review on the antioxidant aspects of flavonoids highlight the medicinal and folk values of these compounds against oxidative stress and various diseases and ailments. In short, treatment with flavonoids could be a novel therapeutic invention in clinical trials, as we hope.

Nephroprotective activity of natural products against chemical toxicants: The role of Nrf2/ARE signaling pathway

Nephropathy can occur following exposure of the kidneys to oxidative stress. Oxidative stress is the result of reactive oxygen species (ROS) formation due to intracellular catabolism or exogenous toxicant exposure. Many natural products (NPs) with antioxidant properties have been used to demonstrate that oxidative damage-induced nephrotoxicity can be ameliorated or at least reduced through stimulation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Nrf2 is a basic leucine zipper (bZip) transcription factor that regulates gene expression of the antioxidant response elements (ARE). Nrf2 is involved in the cellular antioxidant-detoxification machinery. Nrf2 activation is a major mechanism of nephroprotective activity for these NPs, which facilitates its entry into the nucleus, primarily by inhibiting Kelch like-ECH-associated protein 1 (Keap1). The purpose of this article was to review the peer-reviewed literature of NPs that have shown mitigating effects on renal disorder by stimulating Nrf2 and thereby suggesting potential new therapeutic or prophylactic strategies against kidney-damaging xenobiotics.

Virtual Screening of Citrus Flavonoid Tangeretin: A Promising Pharmacological Tool for the Treatment and Prevention of Zika fever and COVID-19

It is of great importance for the pharmaceutical industry to find therapeutic substances extracted from natural sources, which are abundant, obtained with low costs and presenting the antiviral potential for the treatment of Zika virus (ZIKV) and COVID-19. Tangeretin (TAN) is a citrus polymethoxyflavone from Citrus reticulata peel oil with known antiviral activities, whose physico-chemical properties are not reported. The present study aimed to investigate by a theoretical screening of electronic, structural properties and pharmacodynamic and pharmacokinetic parameters that characterize TAN as a therapeutic drug in the treatment and prevention of zika fever and COVID-19. The molecule reached its minimum energy-forming state of [Formula: see text]795.85747[Formula: see text]kJ/mol and the HOMO and LUMO boundary orbitals reactivity descriptors suggest that the compound is stable and does not tend to be reactive in intermolecular interactions. The ligand connects to the NS1 ZIKV receptor with strong H-bond interactions, also connects with the NS5 ZIKV receptor in a competitive effect with the SAM inhibitor and acts in a supplementary effect with the N3 inhibitor and the BRT drug in the Mpro SARS-CoV-2 receptor. The properties of ADMET shows that the compound suffers few amounts of drug alterations because it inhibits the metabolic enzymes CYP2C9 and CYP3A4 and penetrates the central nervous system, without accumulation of drug residues in the blood or in the lumen in the gastrointestinal tract, without risk of toxicity to the patient. With the results obtained, it is possible to identify TAN as a promising pharmacological tool for the treatment and prevention of Zika fever and COVID-19.

Therapeutic Implications of a Polymethoxylated Flavone, Tangeretin, in the Management of Cancer via Modulation of Different Molecular Pathways

Chemotherapeutics can induce oxidative stress, inflammation, apoptosis, mitochondrial dysfunction, and abnormalities in neurotransmitter metabolism leading to toxicity. Because there have been no therapeutic strategies developed to target inflammation and oxidative stress, there is a continuing need for new and improved therapy. As a result, there has been increasing interest in complementary and alternative medicine with anticancer potential. Studies have shown that the antioxidant activities and anti-inflammatory effects of citrus fruits are promising natural phytochemicals in the development of new anticancer agents. Tangeretin is a naturally polymethoxylated flavone compound extracted from the citrus peel that has shown significant intestinal absorption and adequate bioavailability, with the added benefit of promoting longevity. In addition, tangeretin is known to exhibit considerable selective toxicity to many types of cancer cell proliferation such as ovarian, brain, blood, and skin cancer. Evidence indicates that tangeretin acts through several mechanisms including growth inhibition, induction of apoptosis, autophagy, antiangiogenesis, and estrogenic-like effects. Furthermore, tangeretin works through mitigating levels of inflammatory mediators in the immune system. Using tangeretin in combination with clinically applied anticancer drugs could be a good strategy for increasing the efficiency of these agents and protecting noncancerous cells from damage caused by chemotherapy. The purpose of this review is to highlight the protective effects of a novel natural product, tangeretin against chemotherapeutic-induced toxicity. The development of chemoprevention strategies can lead to significant health care improvement in cancer survivors. Thus, study outcomes may attract more investigators to conduct tangeretin-related research and find out potentially significant impacts on health care of cancer patients and decreased health problems associated with chemotherapeutics-induced toxicity.

Citrus flavonoids and their antioxidant evaluation

The antioxidant ability is the link and bridge connecting a variety of biological activities. Citrus flavonoids play an essential role in regulating oxidative stress and are an important source of daily intake of antioxidant supplements. Many studies have shown that citrus flavonoids promote health through antioxidation. In this review, the biosynthesis, composition and distribution of citrus flavonoids were concluded. The detection methods of antioxidant capacity of citrus flavonoids were divided into four categories: chemical, cellular, animal and clinical antioxidant capacity evaluation systems. The modeling methods, applicable scenarios, and their relative merits were compared based on these four systems. The antioxidant functions of citrus flavonoids under different evaluation systems were also discussed, especially the regulation of the Nrf2-antioxidases pathway. Some shortcomings in the current research were pointed out, and some suggestions for progress were put forward.

The combined effect of pomegranate extract and tangeretin on the DMBA-induced breast cancer model

The aim of this study was to investigate the protective effects of pomegranate extract and tangeretin alone or in combination in DMBA-induced rat breast cancer model. A total of 68 female rats were randomly divided into 8 groups. The first 4 groups were designed as controls for cancer and treatment groups, and the control groups were composed of only control (C), Pomegranate (P), Tangeretin (T), and Pomegranate+Tangeretin (P+T) groups. The other four groups were designed as cancer and treatment groups and were composed of DMBA (D) and DMBA+Pomegranate (D+P), DMBA+Tangeretin (D+T), DMBA+Pomegranate+Tangeretin (D+P+T) groups. Tumor markers and angiogenesis parameters were studied from plasma samples obtained from rats. Histopathological, immunohistochemical, and TUNEL analyses and expressions of proteins affecting apoptosis and cell cycle were determined in breast tissue samples. In the DMBA group, plasma CA15-3, CEA, VEGF, MMP-9, and NF-κB levels were significantly increased compared to the controls, but significant decreases were observed in these parameters except MMP-9 in the treatment groups. It was observed that p53 and Bax expressions significantly increased in both D+P and D+P+T groups compared to the DMBA group, and these findings were supported by Tunel and immunohistochemical findings. Cyclin D1 expressions were found to be significantly decreased only in the D+T group and supported by TUNEL and immunohistochemical findings. Immunohistochemical ER-α and Ki-67 immune reactivities were significantly decreased in all treatment groups compared to the DMBA group. Our results showed that combined application of pomegranate extract and tangeretin may be more beneficial in preventing breast cancer development.

Calliandra portoricensis ameliorates ovarian and uterine oxido-inflammatory responses in N-methyl-N-nitrosourea and benzo[a]pyrene-treated rats

IMPACT STATEMENT

Infertility resulting from reproductive impairment is traumatic in families. Exposure to chemicals may play insidious roles not easily connected to infertility. We examined benzo[a]pyrene (BaP), and N-methyl nitrosourea (NMU)-induced ovarian and uterine toxicity and the role of Calliandra portoricensis in mitigating toxicity. In a bid to illuminate folk medical claims cloaked in mystery, unearthing lost knowledge, advance natural chemopreventive agents, and report new evidence lacking in the literature attributed to CP. Although CP is known to exhibit anticonvulsant, antidiarrheal, antipyretic, antirheumatic, and analgesic effects in humans, its possible roles for mitigating toxicity stemming from inadvertent chemical exposures are reported here. Our findings affirm and further show that CP abates toxic response incumbent on oxidative damage and inflammatory responses associated with NMU and BaP exposure. Development of phytochemical derived from CP may serve as a potential natural therapy against chemical toxicities in individuals inadvertently exposed, and promote human health and reproductive satiety.

Tangeretin: a mechanistic review of its pharmacological and therapeutic effects

To date, a large number of synthetic drugs have been developed for the treatment and prevention of different disorders, such as neurodegenerative diseases, diabetes mellitus, and cancer. However, these drugs suffer from a variety of drawbacks including side effects and low efficacy. In response to this problem, researchers have focused on the plant-derived natural products due to their valuable biological activities and low side effects. Flavonoids consist of a wide range of naturally occurring compounds exclusively found in fruits and vegetables and demonstrate a number of pharmacological and therapeutic effects. Tangeretin (TGN) is a key member of flavonoids that is extensively found in citrus peels. It has different favorable biological activities such as antioxidant, anti-inflammatory, antitumor, hepatoprotective, and neuroprotective effects. In the present review, we discuss the various pharmacological and therapeutic effects of TGN and then, demonstrate how this naturally occurring compound affects signaling pathways to exert its impacts.

Natural Products Derived from the Mediterranean Diet with Antidiabetic Activity: from Insulin Mimetic Hypoglycemic to Nutriepigenetic Modulator Compounds

BACKGROUND

The Mediterranean diet is a healthy eating pattern that protects against the development of Type 2 diabetes mellitus (T2DM), a metabolic disease characterized by elevated blood sugar levels due to pancreatic beta-cell functional impairment and insulin resistance in various tissues. Inspired by the ancient communities, this diet emphasizes eating primarily plant-based foods, including vegetables, legumes, fruits, cereals, and nuts. Importantly, virgin olive oil is used as the principal source of fat. Red meat is consumed in low amounts while wine and fish are consumed moderately.

OBJECTIVE

Here, we review the most beneficial components of the Mediterranean Diet and tentative mechanisms of action for prevention and/or management of T2DM, based on research conducted within the last decade.

METHODS

The references over the last five years have been reviewed and they have been selected properly according to inclusion/ exclusion criteria.

RESULTS

Several bioactive diet components were evaluated to prevent inflammation and cytokine-induced oxidative damage, reduce glucose concentration, carbohydrate absorption and increase insulin sensitivity and related gene expression.

CONCLUSION

The adherence to a healthy lifestyle, including diet, exercise and habits remains the best approach for the prevention of diabetes as well as frequent check-ups and education. Though diabetes has a strong genetic component, in recent years many reports strongly point to the critical role of lifestyle specific epigenetic modifications in the development of T2DM. It remains to be established how different components of the Mediterranean Diet interact and influence the epigenetic landscape to prevent or treat the disease.

Recent Advances of Natural Polyphenols Activators for Keap1-Nrf2 Signaling Pathway

The Keap1-Nrf2/ARE signaling pathway is an important defense system against exogenous and endogenous oxidative stress injury. The dysregulation of the signaling pathway is associated with many diseases, such as cancer, diabetes, and respiratory diseases. Over the years, a wide range of natural products has provided sufficient resources for the discovery of potential therapeutic drugs. Among them, polyphenols possess Nrf2 activation, not only inhibit the production of ROS, inhibit Keap1-Nrf2 protein-protein interaction, but also degrade Keap1 and regulate the Nrf2 related pathway. In fact, with the continuous improvement of natural polyphenols separation and purification technology and further studies on the Keap1-Nrf2 molecular mechanism, more and more natural polyphenols monomer components of Nrf2 activators have been gradually discovered. In this view, we summarize the research status of natural polyphenols that have been found with apparent Nrf2 activation and their action modes. On the whole, this review may guide the design of novel Keap1-Nrf2 activator.

Proteomics Analysis of Tangeretin-Induced Apoptosis through Mitochondrial Dysfunction in Bladder Cancer Cells

Tangeretin is one of the most abundant compounds in citrus peel, and studies have shown that it possesses anti-oxidant and anti-cancer properties. However, no study has been conducted on bladder cancer cells. Bladder cancer has the second highest mortality rate among urological cancers and is the fifth most common malignancy in the world. Currently, combination chemotherapy is the most common approach by which to treat patients with bladder cancer, and thus identifying more effective chemotherapeutic agents that can be safely administered to patients is a very important research issue. Therefore, this study investigated whether tangeretin can induce apoptosis and identified the signaling pathways of tangeretin-induced apoptosis in human bladder cancer cells using two-dimensional gel electrophoresis (2DGE). The results of the study demonstrated that 60 μM tangeretin reduced the cell survival of a BFTC-905 bladder carcinoma cell line by 42%, and induced early and late apoptosis in the cells. In this study 2DGE proteomics technology identified 41 proteins that were differentially-expressed in tangeretin-treated cells, and subsequently LC–MS/MS analysis was performed to identify the proteins. Based on the functions of the differentially-expressed proteins, the results suggested that tangeretin caused mitochondrial dysfunction and further induced apoptosis in bladder cancer cells. Moreover, western blotting analysis demonstrated that tangeretin treatment disturbed calcium homeostasis in the mitochondria, triggered cytochrome C release, and activated caspase-3 and caspase-9, which led to apoptosis. In conclusion, our results showed that tangeretin-induced apoptosis in human bladder cancer cells is mediated by mitochondrial inactivation, suggesting that tangeretin has the potential to be developed as a new drug for the treatment of bladder cancer.

The Inhibitory Effect of Flavonoid Aglycones on the Metabolic Activity of CYP3A4 Enzyme

Flavonoids are natural compounds that have been extensively studied due to their positive effects on human health. There are over 4000 flavonoids found in higher plants and their beneficial effects have been shown in vitro as well as in vivo. However, data on their pharmacokinetics and influence on metabolic enzymes is scarce. The aim of this study was to focus on possible interactions between the 30 most commonly encountered flavonoid aglycones on the metabolic activity of CYP3A4 enzyme. 6β-hydroxylation of testosterone was used as marker reaction of CYP3A4 activity. Generated product was determined by HPLC coupled with diode array detector. Metabolism and time dependence, as well as direct inhibition, were tested to determine if inhibition was reversible and/or irreversible. Out of the 30 flavonoids tested, 7 significantly inhibited CYP3A4, most prominent being acacetin that inhibited 95% of enzyme activity at 1 µM concentration. Apigenin showed reversible inhibition, acacetin, and chrysin showed combined irreversible and reversible inhibition while chrysin dimethylether, isorhamnetin, pinocembrin, and tangeretin showed pure irreversible inhibition. These results alert on possible flavonoid–drug interactions on the level of CYP3A4.

Tangeretin inhibits streptozotocin-induced cell apoptosis via regulating NF-κB pathway in INS-1 cells

Oxidative stress is considered to play an important role in inducing the pancreatic β-cells apoptosis and promoting the development of diabetes mellitus. Tangeretin is a plant-derived flavonoid that retains antidiabetic effects. However, the role of tangeretin in streptozotocin (STZ)-induced β-cell apoptosis remains unclear. In this study, we aimed to examine the effects of tangeretin on STZ-induced cell apoptosis and the underlying mechanisms implicated in vitro. Our results showed that tangeretin improved the cell viability in STZ-induced INS-1 cells. Tangeretin reduced the increase of apoptosis ratio and revered the altered expressions of Bax and Bcl-2 caused by STZ induction. Furthermore, the impairment of insulin secretion ability as well as a reduction in messenger RNA levels of insulin 1 and 2 was significantly attenuated by tangeretin in STZ-induced INS-1 cells. Moreover, tangeretin resulted in a significant decrease in reactive oxygen species content, accompanied by an evident increase in the activities of superoxide dismutase, catalase, and glutathione peroxidase. Mechanistic studies further revealed that tangeretin inhibited the NF-κB pathway in STZ-induced INS-1 cells. These data indicated that tangeretin improved the cell apoptosis induced by STZ in INS-1 cells, which might be partly due to its antioxidant potential. Furthermore, NF-κB was found to be involved in the protective effect of tangeretin. Collectively, the results indicated that tangeretin could be used as a therapeutic approach for diabetes mellitus treatment.

Attenuation of tert-Butyl Hydroperoxide ( t-BHP)-Induced Oxidative Damage in HepG2 Cells by Tangeretin: Relevance of the Nrf2-ARE and MAPK Signaling Pathways

The current study evaluates the protective effects of tangeretin, a representative polymethoxyflavone (PMF) mainly isolated from the peels of citrus fruits, against tert-butyl hydroperoxide ( t-BHP)-induced oxidative damage in HepG2 cells and the potential mechanisms of this protection. Tangeretin suppressed t-BHP-induced oxidative damage, as evaluated by cell viability, reactive-oxygen-species (ROS) levels, lactate dehydrogenase (LDH) leakage and glutathione (GSH) levels. Further mechanistic studies showed that tangeretin up-regulated the expression of heme oxygenase 1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). Moreover, tangeretin induced antioxidant-responsive-element (ARE)-dependent luciferase activation, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nuclear translocation, and mitogen-activated-protein-kinase (MAPK) phosphorylation. Results in the study indicate that the protective effects of tangeretin may be at least partly due to its capacity to up-regulate the antioxidant enzymes NQO1 and HO-1 via the MAPK-Nrf2-ARE signaling pathway. Tangeretin may play an effective protective role in liver injury.

Tangeretin inhibits high glucose-induced extracellular matrix accumulation in human glomerular mesangial cells

Tangeretin (5, 6, 7, 8, 4'-pentamethoxyflavone), a natural compound extracted from citrus plants, has been shown to possess a variety of pharmacological activities, including anti-oxidant, anti-tumor, cytostatic and anti-diabetic properties. However, the role of tangeretin in diabetic nephropathy (DN) has not yet been investigated. This study was undertaken to elucidate the effects of tangeretin on high glucose (HG)-induced oxidative stress and extracellular matrix (ECM) accumulation in human glomerular mesangial cells (MCs) and explore the underlying mechanisms. Our results showed that tangeretin significantly inhibited HG-induced the proliferation of MCs. In addition, tangeretin dramatically reduced the levels of reactive oxygen species (ROS) and malondialdhyde (MDA), and induced SOD activity, as well as inhibited the expression of fibronectin (FN) and collagen IV in HG-stimulated MCs. Furthermore, tangeretin efficiently prevented the activation of ERK signaling pathway in HG-stimulated MCs. Taken together, these data indicated that tangeretin inhibits HG-induced cell proliferation, oxidative stress and ECM expression in glomerular MCs, at least in part, through the inactivation of ERK signaling pathway. Therefore, tangeretin may be a potential agent in the treatment of DN.

Effect of allyl isothiocyanate on NF-κB signaling in 7,12-dimethylbenz(a)anthracene and N-methyl-N-nitrosourea-induced mammary carcinogenesis

BACKGROUND

Inflammation plays a pivotal role in the process of carcinogenesis and phytochemicals have anti-inflammatory properties gaining more importance in cancer chemoprevention. The present study aimed to investigate the anti-inflammatory effect of allyl isothiocyanate (AITC) on 7,12-dimethylbenz(a)anthracene (DMBA)- and N-methyl-N-nitrosourea (MNU)-induced mammary carcinogenesis in female Sprague-Dawley rats.

METHODS

RT-PCR and western blot analysis showed that inflammatory markers such as NF-κB p65, TNF-α, and IL-6 were overexpressed in mammary tumor tissues. Histological analysis of tumor tissues shows abnormality in hematoxylin and eosin (H&E) staining and toluidine blue (TB) staining of mast cell content, and lipid accumulation in oil red O staining.

RESULTS

Administration of AITC (20 mg/kg bw) to carcinogen-injected rats significantly decreased the expression of NF-κB p65, TNF-α, and IL-6 in mammary tissues. Further, molecular docking study demonstrates the binding of AITC to NF-κB p65. Remarkably, AITC treatments control the growth of cancer cells as clearly evidenced by histopathological analysis. Staining of mammary tissues for mast cells and lipids indicates that AITC treatment to carcinogen-administrated rats significantly reduced mammary tumorigenesis.

CONCLUSIONS

The result suggests that AITC has anti-inflammatory potential to prevent DMBA- and MNU-induced mammary carcinogenesis in rats.

Tangeretin Alleviates Cisplatin-Induced Acute Hepatic Injury in Rats: Targeting MAPKs and Apoptosis

Despite its broad applications, cisplatin affords considerable nephro- and hepatotoxicity through triggering inflammatory and oxidative stress cascades. The aim of the current investigation was to study the possible protective effects of tangeretin on cisplatin-induced hepatotoxicity. The impact of tangeretin on cisplatin-evoked hepatic dysfunction and histopathologic changes along with oxidative stress, inflammatory and apoptotic biomarkers were investigated compared to silymarin. Tangeretin pre-treatment significantly improved liver function tests (ALT and AST), inhibited cisplatin-induced lipid profile aberrations (total cholesterol and triglycerides) and diminished histopathologic structural damage in liver tissues. Tangeretin also attenuated cisplatin-induced hepatic inflammatory events as indicated by suppression of tumor necrosis factor-α (TNF-α) and enhancement of interleukin-10 (IL-10). Meanwhile, it lowered malondialdehyde (MDA), nitric oxide (NO) and nuclear factor erythroid 2-related factor 2 (NRF-2) levels with restoration of glutathione (GSH), and glutathione peroxidase (GPx). Regarding mitogen-activated protein kinase (MAPK) pathway, tangeretin attenuated cisplatin-induced increase in phospho-p38, phospho-c-Jun N-terminal kinase (p-JNK) and phospho-extracellular signal-regulated kinase (p-ERK1/2) in liver tissues. In addition, tangeretin downregulated Bax expression with augmentation of Bcl-2 promoting liver cell survival. Our results highlight the protective effects of tangeretin against cisplatin-induced acute hepatic injury via the concerted modulation of inflammation, oxidative stress, MAPKs and apoptotic pathways.

Systems pharmacology-based dissection of mechanisms of Chinese medicinal formula Bufei Yishen as an effective treatment for chronic obstructive pulmonary disease

The present work adopted a systems pharmacology-based approach to provide new insights into the active compounds and therapeutic targets of Bufei Yishen formula (BYF) for the treatment of chronic obstructive pulmonary disease (COPD). In addition, we established a rat model of cigarette smoke- and bacterial infection-induced COPD to validate the mechanisms of BYF action that were predicted in systems pharmacology study. The systems pharmacology model derived 216 active compounds from BYF and 195 potential targets related to various diseases. The compound-target network showed that each herbal drug in the BYF formula acted on similar targets, suggesting potential synergistic effects among these herbal drugs. The ClueGo assay, a Cytoscape plugin, revealed that most targets were related to activation of MAP kinase and matrix metalloproteinases. By using target-diseases network analysis, we found that BYF had great potential to treatment of multiple diseases, such as respiratory tract diseases, immune system, and cardiovascular diseases. Furthermore, we found that BYF had the ability to prevent COPD and its comorbidities, such as ventricular hypertrophy, in vivo. Moreover, BYF inhibited the inflammatory cytokine, and hypertrophic factors expression, protease-antiprotease imbalance and the collagen deposition, which may be the underlying mechanisms of action of BYF.

A novel component from citrus, ginger, and mushroom family exhibits antitumor activity on human meningioma cells through suppressing the Wnt/β-catenin signaling pathway

Recurrent meningiomas constitute an uncommon but significant problem after standard (surgery and radiation) therapy failure. Current chemotherapies (hydroxyurea, RU-486, and interferon-α) are only of marginal benefit. There is an urgent need for more effective treatments for meningioma patients who have failed surgery and radiation therapy. Limonin, Tangeritin, Zerumbone, 6-Gingerol, Ganoderic Acid A, and Ganoderic Acid DM are some of the plant derivatives that have anti-tumorgenic properties and cause cell death in meningioma cells in vitro. Due to its ease of administration, long-term tolerability, and low incidence of long-term side effects, we explored its potential as a therapeutic agent against meningiomas by examining their efficacy in vitro against meningioma cells. Treatment effects were assessed using MTT assay, Western blot analysis, caspases assay, and DNA fragmentation assay. Results indicated that treatments of IOMM-Lee and CH157MN meningioma cells with Limonin, Tangeritin, Zerumbone, 6-Gingerol, Ganoderic Acid A, and Ganoderic Acid DM induced apoptosis with enhanced phosphorylation of glycogen synthase kinase 3 β (GSK3β) via inhibition of the Wnt5/β-catenin pathway. These drugs did not induce apoptosis in normal human neurons. Other events in apoptosis included downregulation of tetraspanin protein (TSPAN12), survival proteins (Bcl-XL and Mcl-1), and overexpression apoptotic factors (Bax and caspase-3). These results provide preliminary strong evidence that medicinal plants containing Limonin, Tangeritin, 6-Gingerol, Zerumbone, Ganoderic Acid A, and Ganoderic Acid DM can be applied to high-grade meningiomas as a therapeutic agent, and suggests that further in vivo studies are necessary to explore its potential as a therapeutic agent against malignant meningiomas.

Anti-tumor potential of nitroxyl derivative Pirolin in the DMBA-induced rat mammary carcinoma model: A comparison with quercetin

BACKGROUND

Considering the role of oxidative stress in carcinogenesis, we investigated the effect of synthetic antioxidant Pirolin (3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl) on breast cancer progression. Since the anticancer drugs may cause cardiotoxicity due to oxidative stress in the heart muscle, we also evaluated Pirolin performance in heart tissue and compared its effect with that of the natural dietary flavonoid quercetin.

METHODS

Sprague-Dawley rats were administered with 7,12-dimethylbenz(a)anthracene (DMBA) and then treated ip with an antioxidant (each at a dose of 10mg/kg b.w.) for 14 days. The histopathology of tumors, their size and multiplicity were assesed. The effect of antioxidants on heart tissue was evaluated by the oxidative stress markers and poly (ADP-ribose) polymerase 1 (PARP 1) cleavage.

RESULTS

The median number of tumors and their volume, at the end of the study, were considerably smaller in both antioxidant-treated groups. We found a better antioxidative performance of quercetin in the heart, since a restoration of the GSH pool and decreased amount of hydroperoxides were observed. Antioxidants did not prevent cardiomyocytes from apoptosis.

CONCLUSION

The attenuation of tumor progression by Pirolin was comparable with the action of quercetin. No negative changes were observed in the heart of animals after Pirolin treatment. Thus, its use in targeting deregulated redox pathways should be further studied.