Prevention of doxorubicin induced cardiotoxicity by catechin

Potential Role of Natural Antioxidant Products in Oncological Diseases

Nutrition has a significant effect and a crucial role in disease prevention. Low consumption of fruit and vegetables and a sedentary lifestyle are closely related with the onset and development of many types of cancer. Recently, nutraceuticals have gained much attention in cancer research due to their pleiotropic effects and relatively non-toxic behavior. In fact, although in the past there have been conflicting results on the role of some antioxidant compounds as allies against cancer, numerous recent clinical studies highlight the efficacy of dietary phytochemicals in the prevention and treatment of cancer. However, further investigation is necessary to gain a deeper understanding of the potential anticancer capacities of dietary phytochemicals as well as the mechanisms of their action. Therefore, this review examined the current literature on the key properties of the bioactive components present in the diet, such as carotenoids, polyphenols, and antioxidant compounds, as well as their use in cancer therapy. The review focused on potential chemopreventive properties, evaluating their synergistic effects with anticancer drugs and, consequently, the side effects associated with current cancer treatments.

The effect of propolis on 5-fluorouracil-induced cardiac toxicity in rats

5-Fluorouracil (5-FU) is one of the most common chemotherapeutic agents used in treating solid tumors, and the 5-FU-induced cardiotoxicity is the second cause of cardiotoxicity induced by chemotherapeutic drugs. Propolis (Pro) has vigorous anti-inflammatory activity. Its cardio-protective characteristic against doxorubicin-induced cardiotoxicity was previously proven. The current study aimed to appraise the effect of Pro on 5-FU-induced cardiotoxicity in rats. Twenty-four male Wistar rats were divided into four groups: Control, 5-FU, 5-FU + Pro 250 mg/kg, and 5-FU + Colchicine (CLC) 5 mg/kg. Different hematological, serological, biochemical, histopathological, and molecular assays were performed to assess the study’s aim. Moreover, a rat myocardium (H9C2(2–1)) cell line was also used to assess this protective effect in-vitro. 5-FU resulted in significant cardiotoxicity represented by an increase in malondialdehyde (MDA) levels, cyclooxygenase-2 (COX-2) and tumor necrosis factor-α (TNF-α) expression, cardiac enzyme levels, and histopathological degenerations. 5-FU treatment also decreased bodyweight, total anti-oxidant capacity (TAC), catalase (CAT) levels, blood cell counts, and hemoglobin (Hb) levels. In addition, 5-FU disrupted ECG parameters, including increased elevation in the ST-segment and increased QRS complex and QTc duration. Treating with Pro reduced oxidative stress, cardiac enzymes, histopathological degenerations, and COX-2 expression in cardiac tissue alleviated ECG disturbances and increased the number of blood cells and TAC levels. Moreover, 5-FU-induced bodyweight loss was ameliorated after treatment with Pro. Our results demonstrated that treatment with Pro significantly improved cardiotoxicity induced by 5-FU in rats.

Natural Products Counteracting Cardiotoxicity during Cancer Chemotherapy: The Special Case of Doxorubicin, a Comprehensive Review

Cardiotoxicity is a frequent undesirable phenomenon observed during oncological treatment that limits the therapeutic dose of antitumor drugs and thus may decrease the effectiveness of cancer eradication. Almost all antitumor drugs exhibit toxic properties towards cardiac muscle. One of the underlying causes of cardiotoxicity is the stimulation of oxidative stress by chemotherapy. This suggests that an appropriately designed diet or dietary supplements based on edible plants rich in antioxidants could decrease the toxicity of antitumor drugs and diminish the risk of cardiac failure. This comprehensive review compares the cardioprotective efficacy of edible plant extracts and foodborne phytochemicals whose beneficial activity was demonstrated in various models in vivo and in vitro. The studies selected for this review concentrated on a therapy frequently applied in cancer, anthracycline antibiotic-doxorubicin-as the oxidative stress- and cardiotoxicity-inducing agent.

Role of flavonoids against adriamycin toxicity

Doxorubicin (DOX), or adriamycin, is an anthracycline antineoplastic drug widely used in the chemotherapy of a large variety of cancers due to its potency and action spectrum. However, its use is limited by the toxicity on healthy cells and its acute and chronic side effects. One of the developed strategies to attenuate DOX toxicity is the combined therapy with bioactive compounds such as flavonoids. This review embraces the role of flavonoids on DOX treatment side effects. Protective properties of some flavonoidss against DOX toxicity have been investigated and observed mainly in heart but also in liver, kidney, brain, testis or bone marrow. Protective mechanisms involve reduction of oxidative stress by decrease of ROS levels and/or increase antioxidant defenses and interferences with autophagy, apoptosis and inflammation. Studies in cancer cells have reported that the anticancer activity of DOX was not compromised by the flavonoids. Moreover, some of them increased DOX efficiency as anti-cancer drug even in multidrug resistant cells.

Evaluating the protective potency of Acacia hydaspica R. Parker on histological and biochemical changes induced by Cisplatin in the cardiac tissue of rats

Background

Increase oxidative trauma is the main cause behind Cisplatin (CP) induced cardiotoxicity which restricts its clinical application as anti-neoplastic prescription. Acacia hydaspica is a natural shrub with diverse bioactivities. Acacia hydaspica ethyl acetate extract (AHE) ameliorated drug-induced cardiotoxicity in animals with anti-oxidative mechanisms. Current study aimed to evaluate the protective potential of A. hydaspica against cisplatin-induced myocardial injury.

Methods

Rats were indiscriminately distributed into six groups (n = 6). Group 1: control; Groups 2: Injected with CP (7.5 mg/kg bw, i.p, single dose) on day 16; Group 3: Treated for 21 days with AHE (400 mg/kg b.w, oral); Group 4: Received CP injection on day 16 and treated with AHE for 5 days post injection; Group 5: Received AHE (400 mg/kg b.w/day, p.o.) for 21 days and CP (7.5 mg/kg b.w., i.p.) on day 16; Group 6: Treated with silymarin (100 mg/kg b.w., p.o.) after 1 day interval for 21 days and CP injection (7.5 mg/kg b.w., i.p.) on day 16. On 22nd day, the animals were sacrificed and their heart tissues were removed. Cisplatin induced cardiac toxicity and the influence of AHE were evaluated by examination of serum cardiac function markers, cardiac tissue antioxidant enzymes, oxidative stress markers and histology.

Results

CP inoculation considerably altered cardiac function biomarkers in serum and diminished the antioxidant enzymes levels, while increased oxidative stress biomarkers in cardiac tissues AHE treatment attenuated CP-induced deteriorations in creatine kinase (CK), Creatine kinase isoenzymes MB (CK-MB), cardiac Troponin I (cTNI) and lactate dehydrogenase (LDH) levels and ameliorated cardiac oxidative stress markers as evidenced by decreasing lipid peroxidation, H₂O₂ and NO content along with augmentation in phase I and phase II antioxidant enzymes. Additionally, CP inoculation also induced morphological alterations which were ameliorated by AHE. In pretreatment group more significant protection was observed compared to post-treatment group indicating preventive potential of AHE. The protective potency of AHE was comparable to silymarin.

Conclusion

Results demonstrate that AHE attenuated CP induce cardiotoxicity. The polyphenolic metabolites and antioxidant properties of AHE might be responsible for its protective influence.

Acacia hydaspica R. Parker prevents doxorubicin-induced cardiac injury by attenuation of oxidative stress and structural Cardiomyocyte alterations in rats

BACKGROUND

The use of doxorubicin (DOX) an anthracycline antineoplastic agent is withdrawn due to its cardio-toxic side effects. Oxidative stress has been recognized as the primary cause of DOX induced cardiotoxicity. We have investigated whether polyphenol rich ethyl acetate extract of Acacia hydaspica (AHE) can attenuate doxorubicin-induced cardiotoxicity via inhibition of oxidative stress.

METHODS

AHE was administered orally to rats once daily for 6 weeks at doses of 200 and 400 mg/kg b.w. DOX (3 mg/kg b.w. i.p., single dose/week) was administered for 6 weeks (chronic model). The parameters studied to evaluate cardioprotective potential were the serum cardiac function biomarkers (CK, CKMB, AST and LDH), hematological parameters, cardiac tissue antioxidant enzymatic status and oxidative stress markers, and histopathological analysis to validate biochemical findings.

RESULTS

Chronic 6 week treatment of DOX significantly deteriorated cardiac function biomarkers and decreased the activities of antioxidant enzymes, whereas significant increase in oxidative stress biomarkers was noticed in comparison to control group. AHE dose dependently protected DOX-induced leakage of cardiac enzymes in serum and ameliorated DOX-induced oxidative stress; as evidenced by decreasing lipid peroxidation, H₂O₂ and NO content with increase in phase I and phase II antioxidant enzymes. Doxorubicin treatment produced severe morphological lesions, leucopenia, decrease in red blood cell counts and hemoglobin concentrations. AHE co-treatment protected the heart and blood elements from the toxic effects of doxorubicin as indicated by the recovery of hematological parameters to normal values and prevention of myocardial injuries in a dose dependent way. The protective potency of AHE (400 mg/kg b.w) was equivalent to silymarin.

CONCLUSION

Results revealed that AHE showed protective effects against DOX induce cardiotoxicity. The protective effect might attribute to its polyphenolic constituents and antioxidant properties. AHE might be helpful in combination therapies as safer and efficient.

Protective effects of green tea and its main constituents against natural and chemical toxins: A comprehensive review

Toxins are natural or chemical poisonous substances with severe side effects on health. Humans are generally exposed by widespread toxic contaminations via air, soil, water, food, fruits and vegetables. Determining a critical antidote agent with extensive effects on different toxins is an ultimate goal for all toxicologists. Traditional medicine is currently perceived as a safe and natural approach against toxins. In this regard, we focused on the protective effects of green tea (Camellia sinensis) and its main components such as catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin and epigallocatechin gallate as a principal source of antioxidants against both natural and chemical toxins. This literate review demonstrates that protective effects of green tea and its constituents were mainly attributed to their anti-oxidative, radical scavenging, chelating, anti-apoptotic properties and modulating inflammatory responses. Although, some studies reveal they have protective effects by increasing toxin metabolism and neutralizing PLA₂, proteases, hyaluronidase and l-amino acid oxidase enzymes.

The Protective Role of Phenolic Compounds Against Doxorubicin-induced Cardiotoxicity: A Comprehensive Review

Although doxorubicin (DOX) is among the most widely used anticancer agents, its clinical application is hampered owing to its cardiotoxicity. Adjuvant therapy with an antioxidant has been suggested as a promising strategy to reduce DOX-induced adverse effects. In this context, many phenolic compounds have been reported to protect against DOX-induced cardiotoxicity. The cardioprotective effects of phenolic compounds are exerted via multiple mechanisms including inhibition of reactive oxygen species generation, apoptosis, NF-κB, p53, mitochondrial dysfunction, and DNA damage. In this review, we present a summary of the in vitro, in vivo, and clinical findings on the protective mechanisms of phenolic compounds against DOX-induced cardiotoxicity.

Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance.

Oxidative stress, redox signaling, and metal chelation in anthracycline cardiotoxicity and pharmacological cardioprotection

SIGNIFICANCE

Anthracyclines (doxorubicin, daunorubicin, or epirubicin) rank among the most effective anticancer drugs, but their clinical usefulness is hampered by the risk of cardiotoxicity. The most feared are the chronic forms of cardiotoxicity, characterized by irreversible cardiac damage and congestive heart failure. Although the pathogenesis of anthracycline cardiotoxicity seems to be complex, the pivotal role has been traditionally attributed to the iron-mediated formation of reactive oxygen species (ROS). In clinics, the bisdioxopiperazine agent dexrazoxane (ICRF-187) reduces the risk of anthracycline cardiotoxicity without a significant effect on response to chemotherapy. The prevailing concept describes dexrazoxane as a prodrug undergoing bioactivation to an iron-chelating agent ADR-925, which may inhibit anthracycline-induced ROS formation and oxidative damage to cardiomyocytes.

RECENT ADVANCES

A considerable body of evidence points to mitochondria as the key targets for anthracycline cardiotoxicity, and therefore it could be also crucial for effective cardioprotection. Numerous antioxidants and several iron chelators have been tested in vitro and in vivo with variable outcomes. None of these compounds have matched or even surpassed the effectiveness of dexrazoxane in chronic anthracycline cardiotoxicity settings, despite being stronger chelators and/or antioxidants.

CRITICAL ISSUES

The interpretation of many findings is complicated by the heterogeneity of experimental models and frequent employment of acute high-dose treatments with limited translatability to clinical practice.

FUTURE DIRECTIONS

Dexrazoxane may be the key to the enigma of anthracycline cardiotoxicity, and therefore it warrants further investigation, including the search for alternative/complementary modes of cardioprotective action beyond simple iron chelation.

Merits of non-invasive rat models of left ventricular heart failure

Heart failure (HF) is characterized as a limitation to cardiac output that prevents the heart from supplying tissues with adequate oxygen and predisposes individuals to pulmonary edema. Impaired cardiac function is secondary to either decreased contractility reducing ejection (systolic failure), diminished ventricular compliance preventing filling (diastolic failure), or both. To study HF etiology, many different techniques have been developed to elicit this condition in experimental animals, with varying degrees of success. Among rats, surgically induced HF models are the most prevalent, but they bear several shortcomings, including high mortality rates and limited recapitulation of the pathophysiology, etiology, and progression of human HF. Alternatively, a number of non-invasive HF induction methods avoid many of these pitfalls, and their merits in technical simplicity, reliability, survivability, and comparability to the pathophysiologic and pathogenic characteristics of HF are reviewed herein. In particular, this review focuses on the primary pathogenic mechanisms common to genetic strains (spontaneously hypertensive and spontaneously hypertensive heart failure), pharmacological models of toxic cardiomyopathy (doxorubicin and isoproterenol), and dietary salt models, all of which have been shown to induce left ventricular HF in the rat. Additional non-invasive techniques that may potentially enable the development of new HF models are also discussed.

A major green tea component, (-)-epigallocatechin-3-gallate, ameliorates doxorubicin-mediated cardiotoxicity in cardiomyocytes of neonatal rats

Cardiac injury is a major complication of the oxidative stress-generating anticancer drug doxorubicin (DOX). The green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) has been reported to play a cardioprotective role in diseases associated with oxidative stress. The objective of this study was to investigate whether EGCG can protect against DOX-induced toxicity in cardiomyocytes. The data showed that EGCG protected the cardiomyocytes from DOX-mediated cardiotoxicity, as evidenced by decreased lactate dehydrogenase (LDH) activity and increased cell viability in a dose-dependent manner. EGCG treatment also decreased malondialdehyde content and increased protein expression and activities of manganese superoxide dismutase (MnSOD), catalase, and glutathione peroxidase. Furthermore, treatment with EGCG decreased reactive oxygen species (ROS) production and apoptosis. This study suggests that EGCG could protect cardiomyocytes from DOX-induced oxidative stress by attenuating ROS production, apoptosis, and increasing activities and protein expression of endogenous antioxidant enzymes.

Screening of antioxidants from medicinal plants for cardioprotective effect against doxorubicin toxicity

Doxorubicin is an important and effective anticancer drug widely used for the treatment of various types of cancer but its clinical use is limited by dose-dependent cardiotoxicity. Elevated tissue levels of cellular superoxide anion/oxidative stress are a mechanism by which doxorubicin-induced cardiotoxicity. Selected medicinal plant extracts were tested for their antioxidant capacity and cardioprotective effect against doxorubicin-induced cardiotoxicity. The cardiac myoblasts H9c2 were incubated with the antioxidants ascorbic acid, trolox, N-acetylcysteine or selected medicinal plant extracts including; 1) ethanolic extracts from Curcuma longa L-EtOH Phyllanthus emblica L-EtOH, and Piper rostratum Roxb-EtOH; and 2) water extracts from Curcuma longa L-H2O and Morus alba L-H2O. The cardioprotective effects of these extracts were evaluated by crystal violet cytotoxicity assay. IC50s of doxorubicin were compared in the presence or absence of ascorbic acids, trolox, N-acetylcysteine or plant extracts. Morus alba L-H2O showed the highest antioxidant properties evaluated by ferric reducing/antioxidant power assay. Ascorbic acid and N-acetylcysteine had modest effects on the protection of doxorubicin-induced cytotoxicity while trolox showed insignificant protective effect. All plant extracts protected cardiac toxicity at different degrees except that Curcuma longa L-EtOH had no protective effect. Phyllanthus emblica-EtOH (100 microg/ml) showed the highest cardioprotective effect (approximately 12-fold doxorubicin IC50 increase). The data demonstrate that antioxidants from natural sources may be useful in the protection of cardiotoxicity in patients who receive doxorubicin.

Effect of PYCNOGENOL on the toxicity of heart, bone marrow and immune organs as induced by antitumor drugs

PYCNOGENOL is a mixture of water-soluble bioflavonoids extracted from the bark of pine trees growing in the southwest coastal region of France. In the present paper the effects of PYCNOGENOL (Pyc) on the toxicity of bone marrow, heart and immune organs induced by anticancer drugs were investigated, in mice. The following results were obtained: 1. Pyc at the orally-administered dose of 200 and 150 mg/kg body wt. markedly prevented the elevation of serum creatine phosphokinase (CPK) activity and the decrease of heart rate in mice treated with doxorubicin (Dox); 2. Pyc at 100 and 150 mg/kg body wt. significantly antagonized the inhibition of DNA synthesis in thymus induced by subcutaneous injection of cyclophosphamide (Cyc); 3. Pyc at 150 and 200 mg/kg body wt. markedly induced increase of erythrocytes and hemoglobin, but had no effect on leukopenia, in Cyc-treated mice; and 4. Pyc has no antagonizing effect on the anticancer activity of Dox and Cyc. All the results suggest that Pyc possesses a protective effect on the cardiotoxicity of Dox and the inhibition of thymus DNA synthesis induced by Cyc in mice.

Green tea extracts can counteract the modification of fatty acid composition induced by doxorubicin in cultured cardiomyocytes

Doxorubicin cardiotoxicity is associated with the generation of free radicals, and involves not only lipid peroxidation but also a decreased biosynthesis of highly unsaturated fatty acids, leading to significant modification in cardiomyocyte fatty acid composition. We have evaluated whether naturally occurring antioxidants could counteract this side-effect. Green tea is an excellent source of catechins; we supplemented cultured rat cardiomyocytes with different green tea extracts to relate their catechin content and composition to their ability in protecting cells against doxorubicin-induced damage. The determination of total lipid fatty acid composition, of conjugated diene production (indicator of lipid peroxidation), and of lactate dehydrogenase release revealed that supplementation with tea extracts could counteract significant modifications in the fatty acyl pattern due to doxorubicin exposure, although to different extents. These differences could be ascribed to the different total catechin content and to qualitative differences among the tea extracts, determined by HPLC analysis.

Catechin metabolism: glutathione conjugate formation catalyzed by tyrosinase, peroxidase, and cytochrome p450

The metabolic pathways of dietary flavonoids are still largely unknown. In the present work, mass spectrometry and UV-vis spectroscopy studies were used to show that the naturally occurring flavonoid catechin underwent enzymatic oxidation by tyrosinase in the presence of glutathione (GSH) to form mono-, bi-, and tri-glutathione conjugates of catechin and mono- and bi-glutathione conjugates of a catechin dimer. A hydroxylated catechin adduct was also detected. Using UV spectroscopy, it was shown that the catechol B-ring of catechin was oxidized by tyrosinase to form an o-quinone which could be reduced back to catechin with potassium borohydride or reacted with GSH to form glutathione conjugates. The catechin-glutathione conjugates formed had much lower distribution coefficient values than catechin itself. When peroxidase and hydrogen peroxide were used instead of tyrosinase, only mono-glutathione conjugates were formed but not bi-glutathione conjugates or hydroxylated adducts. (1)H NMR evidence showed that three different mono-glutathione conjugates on ring B of catechin were formed by peroxidase and hydrogen peroxide. Rat liver microsomes and NADPH or cumene hydroperoxide also catalyzed catechin-glutathione conjugate formation which was prevented by benzylimidazole, a P450 2E1 inhibitor. Catechin cytotoxicity toward isolated hepatocytes was also markedly enhanced by hydrogen peroxide or cumene hydroperoxide and was prevented by benzylimidazole, suggesting that catechin could be metabolically activated by P450 peroxidase activity to form cytotoxic quinoid species.

The therapeutic potential of flavonoids

Four most widely investigated flavonoids, flavopiridol, catechins, genistein and quercetin are reviewed in this article. Flavopiridol is a novel semisynthetic flavone analogue of rohitukine, a leading anticancer compound from an Indian tree. Flavopiridol inhibits most cyclin-dependent kinases and displays unique anticancer properties. It is the first cyclin-dependent kinase inhibitor to be tested in Phase II clinical trials. Catechin and its gallate are major ingredients in green tea and their anti-oxidant and cancer preventive effects have been widely investigated. A Phase I study of green tea extract GTE-TP91 has been conducted in adult patients with solid tumours. Similarly, genistein is a major ingredient in soybean and has been shown to prevent cancer and have antitumour, anti-oxidant and anti-inflammatory effects. Two antibody-genistein conjugates, B43-genistein and EGF-genistein, are currently in clinical development for the treatment of acute lymphoblastic leukaemia and breast cancer, respectively. Finally, most recent updates of quercetin are briefly described.