Effect of chronic treatment with bark of Terminalia arjuna: a study on the isolated ischemic-reperfused rat heart

Therapeutic potential and industrial applications of Terminalia arjuna bark

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia arjuna (Roxb. ex DC.) Wight & Arnot (Combretaceae) is one of the most frequently used medicinal trees in Indian traditional medicinal systems. It is used for the treatment of a variety of diseases including cardiovascular disorders.

AIM OF THE STUDY

The purpose of this review was to provide a comprehensive overview of the phytochemistry, medicinal uses, toxicity, and industrial applications of T. arjuna bark (BTA), as well as to identify gaps in research and applications of this important tree. It also aimed to analyze trends and future research paths to utilize the full potential of this tree.

MATERIALS AND METHODS

Extensive bibliographic research on the T. arjuna tree was carried out using scientific research engines and databases such as Google Scholar, PubMed, and Web of Science, covering all relevant English-language articles. The database "World Flora Online (WFO)" (http://www.worldfloraonline.org) was used to confirm plant taxonomy.

RESULTS

To date, BTA has been traditionally employed for several disorders such as snakebites, scorpion stings, gleets, earaches, dysentery, sexual disorders, and urinary tract infections along with the cardioprotective activity. About 38 phytocompounds were identified from BTA and were classified as triterpenoids, tannins, flavonoids, and glycosides. A wide range of in vitro and in vivo pharmacological effects of BTA were reported such as anti-cancer, antimicrobial, antiviral, anti-inflammatory, antioxidant, hepatoprotective, anti-allergic, anti-diabetic, and wound healing activities. The oral administration of BTA (500 mg/kg) per day did not result in any toxicity in humans. The in vivo acute and sub-acute toxicity analysis of the methanol extract of BTA and one of its major compounds, 7-methyl gallate, did not produce any adverse effects up to a dose of 1000 mg/kg.

CONCLUSIONS

This comprehensive review highlights various aspects of traditional knowledge, phytochemicals, and pharmacological significance of BTA. The review covered safety information on employing BTA in pharmaceutical dosage forms. Despite its long history of medicinal benefit, more studies are needed to understand the molecular mechanisms, structure-activity relationship, and potential synergistic and antagonistic effects of its phytocompounds, drug administration, drug-drug interactions, and toxicological effects.

Multitarget Potential of Phytochemicals from Traditional Medicinal Tree, Terminalia arjuna (Roxb. ex DC.) Wight & Arnot as Potential Medicaments for Cardiovascular Disease: An In-Silico Approach

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide. Terminalia arjuna (Roxb. ex DC.) Wight & Arnot of the Combretaceae family is one of the most frequently approved and utilized medicinal trees in the traditional medicinal system, which was used for the treatment of a variety of diseases, including cardiovascular disorders. The present study aims to identify phytochemicals from T. arjuna, that do not exhibit any toxicity and have significant cardioprotective activity using an in-silico technique. Four different cardiovascular proteins, namely human angiotensin receptor (PDB ID: 4YAY), P38 mitogen-activated protein kinase (MAPK, PDB ID: 4DLI), 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-Co A) reductase (PDB ID: 1HW9), and human C-reactive protein (PDB ID: 1B09), were used as target proteins to identify potential inhibitors using a virtual screening of the phytochemicals in T. arjuna revealed casuarinin as a potential inhibitor of all selected target proteins with strong binding energy. Furthermore, MD simulations for a 100 ns time scale also revealed that most of the key protein contacts of all target proteins were retained throughout the simulation trajectories. Binding free energy calculations using the MM-GBSA approach also support a strong inhibitory effect of casuarinin on target proteins. Casuarinin's effective binding to these proteins lays the groundwork for the development of broad-spectrum drugs as well as the understanding of the underlying mechanism against cardiovascular diseases through in vivo and clinical studies.

Protective effect of aqueous extract of Nigella sativa on Oxidative Enzymes, Homocysteine, and Lipids in Methionine induced Hyperhomocysteinemic rats

Hyperhomocysteinemia has emerged as an independent risk factor for development of various diseases such as coronary, cerebrovascular and peripheral arterial occlusive diseases. Its association is found with atherosclerosis, cancer and some other aged-related illnesses including Alzheimer’s disease. The present study was designed to investigate the homocysteine lowering potential, effect on lipids and oxidative enzymes of standardized aqueous extract of Nigella sativa seeds (100 and 200 mg/kg body weight, p.o.) in hyperhomocysteinemia induced by L-methionine. Hyperhomocysteinemia was induced in wistar albino rats by methionine treatment (1 g/kg, p.o.) for 30 days. Folic acid (100 mg/kg, p.o.) given to rats as a standard drug treatment. Rats were fed with the aqueous extract of Nigella sativa (100 and 200 mg/kg, p.o.) for 30 days. The results of the present study after treatment with Nigella sativa aqueous extracts in two doses of 100 and 200 mg/kg body weight, showed lipid lowering, cardio- and neuro-protective potential of Nigella sativa. The results of test drug were compared with folic acid, a standard positive control. The present study results indicate that the aqueous extract of Nigella sativa seeds treatment protect the antioxidant defense against hyperhomocysteinemia, hyperlipidemia and oxidative stress in methionine-induced rat model.

A review of five traditionally used anti-diabetic plants of Bangladesh and their pharmacological activities

Plants are used traditionally throughout the globe to treat various diseases. Traditionally used medicinal plants are an essential part of the health sector in Bangladesh due to its abundance of a vast source of ethno-medicine. Rural people from developing country like Bangladesh are greatly dependent on traditional source of medicine. The prevalence of diabetes mellitus is increasing from recent years; therefore various researches are going on to discover better medicine to treat this disease. This study has focused on five plants which are Andrographis paniculata, Ageratum conyzoides, Swertia chirata, Terminalia arjuna, and Azadirachta indica to find out their traditional formulation as anti-diabetic medicine and their pharmacological activity has also been explored through literature search. The available information about traditional anti-diabetic uses of these plants and their pharmacological activities were collected from various electronic sources like Pubmed, SciFinder, Elsevier, Springer, Scopus, Scirus, Science Direct, Google Scholar and Web of Science apart from these locally available books and peer reviewed journal were also used to collect information. This study will help to strengthen the relation between traditional medicine, pharmacology and drug development. A clue may be found from the information provided this review to discover new and better anti-diabetic drugs.

Medicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: A review

Medicinal plants have been a main source of therapeutic agents from ancient time to cure diseases. Terminalia arjuna (Roxb.) Wight & Arn. (T. arjuna) is one of the most accepted and beneficial medicinal plants in indigenous system of medicine for the treatment of various critical diseases. This comprehensive review provides various aspects of its ethnomedical, phytochemical, pharmacognostical, pharmacological and clinical significance to different diseases particularly in cardiovascular conditions. This plant has a good safety outline when used in combination with other conventional drugs. This review highlights various medicinal properties of T. arjuna through different studies such as antioxidant, hypotensive, anti-atherogenic, anti-inflammatory, anti-carcinogenic, anti-mutagenic and gastro-productive effect.

Terminalia arjuna bark extract alleviates nickel toxicity by suppressing its uptake and modulating antioxidative defence in rice seedlings

Terminalia arjuna (Ta) bark contains various natural antioxidants and has been used to protect animal cells against oxidative stress. In the present study, we have examined alleviating effects of Ta bark aqueous extract against Ni toxicity in rice (Oryza sativa L.). When rice seedlings were raised for 8 days in hydroponics in Yoshida nutrient medium containing 200 μM NiSO₄, a decline in height, reduced biomass, increased Ni uptake, loss of root plasma membrane integrity, increase in the level of O₂˙^-, H₂O₂ and ˙OH, increased lipid peroxidation, decline in photosynthetic pigments, increase in the level of antioxidative enzymes superoxide dismutase, catalase and glutathione peroxidase and alterations in their isoenzyme profile patterns were observed. Transmission electron microscopy (TEM) showed damage to chloroplasts marked by disorganised enlarged starch granules and disrupted thylakoids under Ni toxicity. Exogenously adding Ta bark extract (3.2 mg ml^-1) to the growth medium considerably alleviated Ni toxicity in the seedlings by reducing Ni uptake, suppressing generation of reactive oxygen species, reducing lipid peroxidation, restoring level of photosynthesis pigments and ultrastructure of chloroplasts, and restoring levels of antioxidative enzymes. Results suggest that Ta bark extract considerably alleviates Ni toxicity in rice seedlings by preventing Ni uptake and reducing oxidative stress in the seedlings.

Clinical efficacy of water extract of stem bark of Terminalia arjuna (Roxb. ex DC.) Wight & Arn. in patients of chronic heart failure: a double-blind, randomized controlled trial

BACKGROUND

The stem bark of Terminalia arjuna (Roxb. ex DC.) Wight and Arn. (Arjuna) is used in Indian system of medicine (Ayurveda) for treatment of various cardiac diseases, including heart failure. However, well designed clinical trials exploring its efficacy and safety in chronic heart failure (CHF) are lacking.

PURPOSE

To ascertain the add-on efficacy and safety of a standardized water extract of stem bark of Arjuna (Arjuna extract) in CHF patients on standard pharmacotherapy.

STUDY DESIGN

Double-blind, parallel, randomized, placebo-controlled add-on clinical trial.

METHODS

After approval of institutional ethics committee, 100 patients of CHF of New York Heart Association (NYHA) functional class II on standard pharmacotherapy having an echocardiographic left ventricular ejection fraction (LVEF) ≤ 40% were consecutively recruited with informed consent and randomized 1:1 to Arjuna extract 750 mg or matching placebo twice daily. The primary outcome measure was change in LVEF at 12 weeks. Secondary outcome measures included changes in (i) NYHA functional class, (ii) distance covered in 6 min walk test (6MWT), (iii) quality of life (QoL), as determined by the Kansas City Cardiomyopathy Questionnaire (KCCQ), (iv) plasma brain natriuretic peptide, (v) plasma cytokines (interleukin-6, high sensitivity C-reactive protein and tumour necrosis factor-α) and (vi) oxidative stress markers [serum thiobarbituric acid reactive substances (TBARS), red blood cell (RBC) superoxide dismutase (SOD), RBC catalase and RBC glutathione (GSH)] at 6 and 12 weeks. Safety assessment was done by adverse event monitoring and laboratory investigations. Results were expressed as mean ± SD or median (interquartile range) and analysed with intention-to- treat principle using appropriate two-sided statistical tests. A p-value < 0.05 was considered significant.

RESULTS

Arjuna extract was well-tolerated, but did not change LVEF (24.3 ± 7.1 versus 25.5 ± 7.7%; p = 0.4) or secondary outcome measures except preservation of RBC catalase activity [1275(104, 10350) versus 1243.5(104, 10350) U/g haemoglobin; p = 0.01] compared to placebo. Significantly greater percentage increases occurred in distance covered in 6 MWT, RBC-SOD, RBC catalase, RBC GSH and in symptom severity and stability domains of KCCQ in patients on Arjuna extract versus those on placebo, on a post-hoc analysis, between subgroups of patients who improved in these outcomes.

CONCLUSION

Arjuna extract did not improve LVEF in CHF patients over 12 weeks, although there was improvement in functional capacity, antioxidant reserves and symptom-related QoL domains in some patients.

Protective Role of Ramipril and Candesartan against Myocardial Ischemic Reperfusion Injury: A Biochemical and Transmission Electron Microscopical Study

The present study was designed to investigate the role of combined administration of Ramipril and Candesartan against in vitro myocardial ischemic reperfusion injury in rat. Male Wistar albino rats were divided into five groups (n = 6) and treated with saline (10 mL/kg), Ramipril (2 mg/kg), Candesartan (1 mg/kg), and the combination of both drugs, respectively 24 h before induction of global ischemia (5 min of stabilization, 9 min of global ischemia, and 12 min of reflow). Combination of Ramipril and Candesartan when compared to the monotherapy significantly increased the levels of superoxide dismutase, reduced glutathione, catalase, and nitric oxide and decreased the levels of thiobarbituric acid reactive substances. In addition, the superior protective role of combination of Ramipril and Candesartan on ischemia induced myocardial damage was further confirmed by well preserved myocardial tissue architecture in light microscopy and transmission electron microscopy analysis studies. The combination was proved to be effective in salvaging the myocardial tissue against ischemic reperfusion injury when compared to the monotherapy of individual drugs and further investigations on protective mechanism of drugs by increasing the nitric oxide level at molecular levels are needed.

Cardioprotective role of methanolic extract of bark of Terminalia arjuna against in-vitro model of myocardial ischemic-reperfusion injury

BACKGROUND

The present study was designed to investigate the cardio protective role of chronic oral administration of methanolic extract of Terminalia arjuna bark in in-vitro myocardial ischemic reperfusion injury and the induction of HSP72.

MATERIALS AND METHODS

Rats, divided into three groups, and were administered with the methanolic extract of the bark powder of Terminalia arjuna (TAME) by oral gavage (6.75 and 9.75 mg/kg: 6 days/week for 12 weeks). Control and TAME extract treated rat hearts were subjected to in-vitro global ischemic reperfusion injury (5 min perfusion, 9 min noflow and 12 min reperfusion).

RESULTS

Oxidative stress in MIRI was evidenced by, raised levels of myocardial TBARS and depletion of endogenous myocardial antioxidants GSH, SOD and catalase. Western blot analysis showed a single band corresponding to 72 kDa in homogenates of hearts from rat treated with both the doses. In the methanolic extract of the bark powder of Terminalia arjuna treatment groups, both the doses had better recovery of myocardial function, with significant reduction in TBARS, and rise in SOD, GSH, catalase were observed.

CONCLUSION

The results of the present study suggest that the methanolic extract of the bark powder of Terminalia arjuna in rat induces myocardial HSP72 and augments myocardial endogenous antioxidants, without causing any cellular injury and offers better cardioprotection against oxidative stress associated with myocardial IR injury.

Revisiting Terminalia arjuna - An Ancient Cardiovascular Drug

Terminalia arjuna, commonly known as arjuna, belongs to the family of Combretaceae. Its bark decoction is being used in the Indian subcontinent for anginal pain, hypertension, congestive heart failure, and dyslipidemia, based on the observations of ancient physicians for centuries. The utility of arjuna in various cardiovascular diseases needs to be studied further. Therefore, the present review is an effort to give a detailed survey of the literature summarizing the experimental and clinical studies pertinent to arjuna in cardiovascular disorders, which were particularly performed during the last decade. Systematic reviews, meta-analyses, and clinical studies of arjuna were retrieved through the use of PubMed, Google Scholar, and Cochrane databases. Most of the studies, both experimental and clinical, have suggested that the crude drug possesses anti-ischemic, antioxidant, hypolipidemic, and antiatherogenic activities. Its useful phytoconstituents are: Triterpenoids, β-sitosterol, flavonoids, and glycosides. Triterpenoids and flavonoids are considered to be responsible for its beneficial antioxidant cardiovascular properties. The drug has shown promising effect on ischemic cardiomyopathy. So far, no serious side effects have been reported with arjuna therapy. However, its long-term safety still remains to be elucidated. Though it has been found quite useful in angina pectoris, mild hypertension, and dyslipidemia, its exact role in primary/secondary coronary prevention is yet to be explored.

Terminalia arjuna in coronary artery disease: ethnopharmacology, pre-clinical, clinical & safety evaluation

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia arjuna (Roxb.) Wight & Arn. is one of the most popular and beneficial medicinal plants in indigenous system of medicine for the treatment of cardiovascular diseases. This comprehensive review provides latest updates on traditional use, phytochemistry, pharmacological and toxicological data, clinical efficacy and safety of Terminalia arjuna as well as outlined strategies for future research and development to scientifically validate the therapeutic potential of this plant.

MATERIALS AND METHODS

Information about Terminalia arjuna was collected via a systematic electronic and library search of various indexed and non-indexed journals, some local books and varied articles published on ethnopharmacology, phytochemistry and traditional uses. Various pre-clinical (2000-2014) and clinical studies (1990-2014) have also been considered regarding efficacy and safety profile of Terminalia arjuna.

RESULTS

Evidence from various in vitro, in vivo and clinical trials reveal the pleiotropic effects of Terminalia arjuna such as anti-atherogenic, hypotensive, inotropic, anti-inflammatory, anti-thrombotic and antioxidant actions for treatment of various cardiovascular disorders. It is clearly documented that this plant has a good safety profile when used in conjunction with other conventional drugs. However, there is a paucity of data regarding the exact molecular mechanism of its action, appropriate form of drug administration, whether whole crude drug or aqueous or alcoholic extract should be used, toxicological studies and its interaction with other drugs.

CONCLUSIONS

In conclusion, this review highlights the importance as well as pleiotropic actions and functional aspects of Terminalia arjuna especially in cardiovascular diseases. Though, various pharmacological studies and clinical trials support its benefit in the CVD as per traditional use, new clinical trials using more rigorous state of the art technology and in a larger population setup are warranted to assess the traditional putative efficacy of Terminalia arjuna.

Pre-treatment with α-tocopherol and Terminalia arjuna ameliorates, pro-inflammatory cytokines, cardiac and apoptotic markers in myocardial infracted rats

OBJECTIVE

This study was aimed to evaluate the cardioprotective potential of combination of T. arjuna and α-tocopherol in isoproterenol induced myocardial injury.

METHODS

Wistar albino rats were pre-treated with hydroalcoholic extract of T. arjuna (HETA) and α-tocopherol (100 mg/kg b. w) daily for 30 days. Isoproterenol (ISP, 85 mg/kg b.w) was administered on 28th and 29th days at an interval of 24 hr.

RESULTS

ISP treated rats showed significant increase in lipid peroxidation (MDA), cardiac markers (CK-MB, SGOT, Trop I and LDH), pro-inflammatory cytokine (IL-6, CRP, TNF-α) levels and apoptotic markers (Bcl-2/Bax) as compared to healthy group. Pre-treatment with HETA 100 mg/kg b. w, reduced the elevated levels of these markers and significant effect (p<0.05) were observed with the combination of HETA and α-tocopherol at a dose of 100 mg/kg b. w, which was further confirmed by histopathological studies.

CONCLUSION

The present study concluded that the combination of α-tocopherol (100 mg/kg b. w) and hydroalcoholic extract of T. arjuna (100 mg/kg b. w) augments endogenous antioxidant compounds of rat heart and also prevents the myocardium from ISP-induced myocardial injury and it may have therapeutic and prophylactic value in the treatment of ischemic heart disease.

Stem-bark of Terminalia arjuna attenuates human monocytic (THP-1) and aortic endothelial cell activation

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia arjuna - stem bark extract is traditionally used as cardiotonic in Ayurvedic medicine.

AIM OF THE STUDY

The present study was aimed to evaluate the molecular basis for cardioprotective potential of Terminalia arjuna (TA) stem bark, using cell cultures of human monocytic (THP-1) and human aortic endothelial cells (HAECs).

MATERIALS AND METHODS

Inhibitory effect of alcoholic (TAAE) and aqueous (TAWE) extracts of TA-stem bark was assessed on human 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, lipoprotein lipase (LpL) and lipid peroxidation in rat (wistar) liver and heart homogenates. The patterns of H2O2 induced reactive oxygen species (ROS) generation were observed by confocal microscopy. The activities of antioxidant enzymes and reducing power of the cells were measured in a microplate reader. Gene transcripts of proinflammatory markers in THP-1 and HAECs were assayed by real time PCR and levels of inflammatory protein markers by ELISA or flow cytometry. Phytochemical analyses of TAAE and TAWE were done using liquid chromatography, coupled to mass spectrometry (LC-MS).

RESULTS

TAAE and TAWE inhibited the lipid peroxidation and HMG-CoA reductase but had no effect on LpL. Both the extracts attenuated H2O2 mediated ROS generation in THP-1 cells by promoting catalase (CAT), glutathione peroxidase (GPx) activities, and by sustaining cellular reducing power. TAAE was highly effective in attenuating proinflammatory gene transcripts in THP-1 cells and HAECs, whereas the response to TAWE depended on the type of transcript and cell type. Both extracts decreased the levels of typical inflammatory marker proteins, viz. LPS induced tumor necrosis factor (TNF)-α secreted by THP-1 cells and TNF-α induced cell surface adhesion molecules on HAECs, namely vascular cell adhesion molecule-1 (VCAM-1) and E-selectin. Phytochemical analyses indicated the richness in phenolic compounds and terpenes of TAAE and TAWE, while revealing variability in their metabolite profile.

CONCLUSION

Our study scientifically validates the antioxidative and antiinflammatory properties of Terminalia arjuna stem bark. The marked effects on cultured human monocytic and aortic endothelial cells (HAEC) provide the biochemical and molecular basis for therapeutic potential of TA-stem bark against cardiovascular diseases (CVD).

Evidence-based antioxidant activity of the essential oil from Fructus A. zerumbet on cultured human umbilical vein endothelial cells' injury induced by ox-LDL

BACKGROUND

The essential oil from Fructus Alpiniae zerumbet (FAZ) is its principal bioactive ingredient, and is widely used in Miao folk herbs in Guizhou province for the treatment of gastrointestinal and cardiovascular diseases. Several studies have confirmed that FAZ ameliorates hyperlipidemia and atherosclerosis. Because endothelial dysfunction often accompanies cardiovascular diseases, especially hyperlipidemia and atherosclerosis, the present study concentrated on evaluating the endothelial protective effects of the essential oil from FAZ (EOFAZ) on oxidized low-density lipoprotein (ox-LDL)-induced injury of cultured human umbilical vein endothelial cells (HUVECs) and on the regulation of oxidative stress.

METHODS

Cell viability was analyzed with the MTT assay and trypan blue exclusion staining (TBES). Cell injury was assessed by lactate dehydrogenase (LDH) release. Biochemical enzymatic methods were used to evaluate the oxidative stress, including the lipid peroxidation product, malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px).

RESULTS

The redox status of HUVECs was significantly exacerbated after exposure to ox-LDL. EOFAZ protected HUVECs against ox-LDL injury as assessed by the MTT assay, TBES and LDH release. Furthermore, EOFAZ ameliorated the oxidative stress by elevating the activities of SOD, CAT and GSH-Px, and increasing the GSH levels, in addition to attenuating the MDA contents.

CONCLUSIONS

The present data provide the first experimental evidence that EOFAZ protects endothelial cells against ox-LDL-induced injury, and indicate that this protection involves ameliorating the redox status.

Therapeutic potential of Terminalia arjuna in cardiovascular disorders

The bark of the tree Terminalia arjuna (Roxb.) is widely used in Indian medicine (Ayurveda) for various cardiovascular ailments. The bark has been reported to contain several bioactive compounds. Many experimental studies have reported its antioxidant, anti-ischemic, antihypertensive, and antihypertrophic effects, which have relevance to its therapeutic potential in cardiovascular diseases in humans. Several clinical studies have reported its efficacy mostly in patients with ischemic heart disease, hypertension, and heart failure. However, a major shortcoming in all these experimental and clinical studies is the absence of phytochemical standardization of the extracts. In addition, many clinical studies are poor in terms of design and methods used for generating safety data. This review discusses how to address all these issues for a scientific validation of this medicinal plant.

Terminalia arjuna enhances baroreflex sensitivity and myocardial function in isoproterenol-induced chronic heart failure rats

Chronic heart failure (CHF) is characterized by left ventricular (LV) dysfunction along with impaired autonomic control functions. Herbal drugs are increasingly being used in the treatment of cardiovascular disorders. The present study was designed to examine the protective effect of Terminalia arjuna (T arjuna) bark extract on LV and baroreflex function in CHF and to elucidate the possible mechanistic clues in its cardioprotective action. The baroreflex was evaluated by measuring the changes in heart rate (HR) with changes in arterial blood pressure induced by bolus injections of phenylephrine (vasoconstrictor) and sodium nitroprusside (vasodilator). T arjuna bark extract and fluvastatin were tested/administered therapeutically and prophylactically in isoproterenol-induced rat model of CHF. Fifteen days after isoproterenol administration, rats exhibited cardiac dysfunction, hypertrophy, and LV remodeling along with reduced baroreflex sensitivity. Prophylactic and therapeutic treatment with T arjuna improved cardiac functions and baroreflex sensitivity. It also attenuated hypertrophy and fibrosis of the LV. Fluvastatin treatment exerted a similar protective effect against myocardial remodeling and heart failure. Further, T arjuna and fluvastatin significantly reduced oxidative stress and inflammatory cytokine level in CHF rats. In conclusion, T arjuna exerts beneficial effect on LV functions, myocardial remodeling, and autonomic control in CHF possibly through maintaining endogenous antioxidant enzyme activities, inhibiting lipid peroxidation and cytokine levels.

The aqueous extract, not organic extracts, of Terminalia arjuna bark exerts cardiotonic effect on adult ventricular myocytes

The bark of Terminalia arjuna (TA) has been used for centuries in ayurvedic medicine as cardiotonics for treatment of cardiac disorders. It became recently available as over-the-counter supplements marketed for maintaining a healthy heart. However, the cellular mechanism of its cardiotonic effect remains undefined. The present study was designed to investigate the physicochemical property and inotropic effect of the aqueous extract of TA bark (TA(AqE)) on adult rat ventricular myocytes in comparison with extracts prepared sequentially with organic solvents (organic extracts). The kinetics of myocyte contraction and caffeine-induced contraction were analyzed to assess the effect of TA(AqE) on sarcoplasmic reticular (SR) function. The inotropic effect of TA(AqE) was also compared with that of known cardiotonics, isoproterenol (ISO) and ouabain (Ouab). We found that TA(AqE) decoctions exerted positive inotropy, accelerated myocyte relaxation and increased caffeine-induced contraction concentration-dependently. In contrast, TA organic extracts caused interruption of excitability and arrhythmias without consistent inotropic action. In conclusion, TA(AqE)-induced cardiotonic action via enhancing SR function, a unique action minimizing the occurrence of arrhythmias, makes TA(AqE) a promising and relatively safe cardiotonic beneficial to the healthy heart and the treatment for chronic heart disease. The cardiotonic effect of TA(AqE) is consistent with the therapeutic property of TA bark used in ayurvedic medicine. The method of administration and/or selective omission of hydrophobic components from bark powder could be crucial to the efficacy and safety of TA bark in cardiac therapy and uses as over-the-counter supplements.

Neuroprotective effect of Hibiscus rosa sinensis in an oxidative stress model of cerebral post-ischemic reperfusion injury in rats

CONTEXT

The ischemic brain lesions induced in rats by temporary occlusion of the bilateral common carotid arteries and restoration of blood flow to an ischemic brain region is associated with generation of reactive oxygen species with consequent reperfusion injury.

OBJECTIVE

The present study investigated the neuroprotective potential of Hibiscus rosa sinensis L. (Malvaceae) in a bilateral common carotid artery (BCCA) occlusion model of global cerebral ischemic reperfusion.

MATERIALS AND METHODS

The animals underwent 30 min BCCA occlusion and 45 min reperfusion. The methanol extract of H. sinensis (100, 200, 300 mg/kg/day for 6 days, p.o.) was administered 30 min before induction of BCCA occlusion.

RESULTS

The bilateral common carotid artery occlusion resulted in increase in lipid peroxidation, and reduction in superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GSH) activity. The extract attenuated the ischemic reperfusion-induced increase in lipid peroxidation and fall in SOD, CAT, and GSH levels. The cerebral hypoperfusion caused a propensity towards anxiety and was accompanied by deficits of learning and memory. The extract ameliorated anxiety and there was improvement of learning and memory.

DISCUSSION

The administration of H. sinensis prevented the oxidative stress and the biochemical changes associated with cerebral ischemic reperfusion injury. The mechanism of such protection of H. sinensis may be due to cerebral adaptation, through augmentation of cellular antioxidants such as GSH, SOD and CAT. The results suggest the protective role of H. sinensis in ischemic reperfusion injury.

CONCLUSION

This study indicates the beneficial role of H. sinensis in cerebrovascular insufficiency states and dementia.

ACE inhibitors - angiotensin II receptor antagonists: A useful combination therapy for ischemic heart disease

Morbidity and mortality from cardiovascular diseases are still high, even with the use of the best available therapies. There is mounting evidence that excessive renin-angiotensin system activation triggers much of the damaging and progressive nature of cardiovascular and kidney diseases through expression of angiotensin II. Moreover, angiotensin II play a major role in the development of end organ damage through a variety of inflammatory mechanisms. Today, angiotensins-converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists have clearly demonstrated their efficacy in preventing target organ damage and in reducing cardiovascular morbidity and mortality in ischemic heart disease (IHD). Moreover, the development of angiotensin II receptor antagonists has enabled a large gain in tolerability and safety. Several clinical trials have firmly established that these drugs act on the renin–angiotensin system, reducing the incidence of coronary events with monotherapy and combination therapy. In this review we summarize the role mono- and combined therapy of ACE inhibitors and angiotensin II receptor antagonists play in ischemic heart disease. In this respect the review will improve ideas for developing new formulations with combinations of these drugs in the future.

Methanol extract of Desmodium gangeticum roots preserves mitochondrial respiratory enzymes, protecting rat heart against oxidative stress induced by reperfusion injury

Ischaemia and reperfusion result in mitochondrial dysfunction, with decreased oxidative capacity, loss of cytochrome c and generation of reactive oxygen species. The aim of this study was to evaluate the effect of a methanol extract of Desmodium gangeticum (L) DC (Fabaceae) (DG) on lipid per-oxidation and antioxidants in mitochondria and tissue homogenates of normal, ischaemic and ischaemia-reperfused rats. Myocardial lipid peroxidation products (thiobarbituric acid reactive substances; TBARS) in cardiac tissue homogenates and mitochondrial fractions were significantly increased during ischaemia reperfusion. Antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase (GPx) and glutathione reductase) in the myocardial tissue homogenate and mitochondria decreased significantly during ischaemia reperfusion, accompanied by a decreased activity of mitochondrial respiratory enzymes. Daily pretreatment of rats with DG (50 or 100 mgkg−1) orally for 30 days had a significant effect on the activity of mitochondrial and antioxidant enzymes. In-vitro studies showed that DG inhibited lipid peroxidation, and also scavenged hydroxyl and superoxide radicals. The concentrations required to scavenge 50% of the superoxide and hydroxyl radicals were 21 and 50.5 μgmL−1, respectively. Administration of DG to normal rats did not have any significant effect on any of the parameters studied. The results of our study showed that DG possesses the ability to scavenge the free radicals generated during ischaemia and ischaemia reperfusion and thereby preserves the mitochondrial respiratory enzymes that eventually lead to cardioprotection.

Chronic oral administration of Ocimum sanctum Linn. augments cardiac endogenous antioxidants and prevents isoproterenol-induced myocardial necrosis in rats

Wistar rats (200–250 g) of either sex were fed with fresh leaf homogenate of Ocimum sanctum by oral gavage in two different doses, 50 mg kg−1 (Os 50) and 100 mg kg−1 (Os 100), daily for 30 days. This was followed by isoproterenol administration (85 mg kg−1 s.c. two doses at 24 h intervals) in both control and O. sanctum-fed rats to induce myocardial necrosis. Hearts were isolated for estimation of endogenous myocardial antioxidants (superoxide dismutase (SOD), catalase, reduced glutathione (GSH) and glutathione peroxidase (GPx) and myocardial lipid peroxidation) and light microscopic study. Increased basal myocardial antioxidant SOD (9.3 ± 1.2 vs 3.7 ± 0.7 units mg−1 protein; P &lt; 0.05) and catalase activities (34.3 ± 5.4 vs 17.9 ± 5.1 units mg−1 protein; P &lt; 0.05) were observed in the Os 50 group only without any evidence of cellular injury in both the groups. In control rats, isoproterenol administration caused significant depletion of myocardial SOD (1.7 ± 0.2 units mg−1 protein) and GPx (104 ± 2 mU mg−1 protein) activities and increase in GSH (551.7 ± 30.9 μg g−1 wet weight of tissue) level, with evidence of myocardial necrosis. Isoproterenol-induced changes in myocardial SOD, GPx and GSH were prevented by both the doses of O. sanctum, however cellular injury was minimal only with 50 mg kg−1. The results indicate that long-term feeding of O. sanctum offered significant protection against isoproterenol-induced myocardial necrosis through a unique property of enhancement of endogenous antioxidants.

Dietary palm olein oil augments cardiac antioxidant enzymes and protects against isoproterenol-induced myocardial necrosis in rats

Wistar rats, 150–200g, of either sex, were fed daily with commercial rat diet supplemented with palm olein oil in two doses (5% v/w (n = 16) and 10% v/w (n = 16) of diet) for 30 days. Control rats (n = 16) were fed with normal diet. On the 29th and 30th days, 8 rats from each group were administred isoproterenol (85 mg/kg, s.c., 24-h interval). On the 31st day, all rats were sacrificed and myocardial tissues were studied for thiobarbituric acid reactive substances (TBARS), antioxidant enzymes and light microscopic changes, along with the ferric-reducing ability of plasma (FRAP). A significant rise in myocardial superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activity and FRAP level were observed in rats fed with palm olein oil. Isoproterenol caused an increase in myocardial oxidative stress in control rats, as evidenced by an increase in myocardial TBARS level, reduction in FRAP and myocardial SOD, catalase and GPx activity, along with focal necrosis of cardiac muscle fibres on light microscopy. The rise in myocardial TBARS and depletion of SOD and catalase activity following isoproterenol administration were prevented in palm-olein-oil-supplemented diet-fed rats at both doses. Isoproterenol-induced myocardial light-microscopic changes were also prevented in the treated groups. The results suggest that dietary palm olein oil caused augmentation of myocardial antioxidant enzymes and protected against isoproterenol-induced myocardial necrosis and associated oxidative stress.

Catecholamine-induced myocardial fibrosis and oxidative stress is attenuated by Terminalia arjuna (Roxb.)

Objectives

Myocardial fibrosis and oxidative stress accompany a number of cardiac disorders such as hypertrophic cardiomyopathy, hypertensive heart disease and cardiac failure. Stem bark of Terminalia arjuna has been advocated for cardiac ailments. The present study evaluated the effects of T. arjuna bark extract on myocardial fibrosis and oxidative stress induced by chronic beta-adrenoceptor stimulation.

Methods

Aqueous extract of T. arjuna bark was evaluated at 63, 125 and 250 mg/kg given orally for antifibrotic and antioxidant effects in rats given the selective β-adrenoceptor agonist isoprenaline (5 mg/kg s.c.) for 28 days. Captopril (50 mg/kg per day, given orally), an inhibitor of angiotensin-converting enzyme used as a standard cardioprotective drug, was used as a positive control.

Key findings

Isoprenaline caused fibrosis, increased oxidative stress and cardiac hypertrophy (increased heart weight: body weight ratio and cardiomyocyte diameter). The T. arjuna bark extract and captopril significantly prevented the isoprenaline-induced increase in oxidative stress and decline in endogenous antioxidant level. Both also prevented fibrosis but not the increase in heart weight: body weight ratio.

Conclusions

T. arjuna protects against myocardial changes induced by chronic beta-adrenoceptor stimulation.

Arjunolic acid attenuates arsenic-induced nephrotoxicity

Arsenic is highly toxic naturally occurring element that affects numerous organ systems in humans. Present study was designed to investigate the preventive role of a triterpenoid saponin, arjunolic acid (AA) against arsenic-induced nephrotoxicity in mouse model. For this study, NaAsO(2) was chosen as the source of arsenic. Oral administration of NaAsO(2) at a dose of 10mg/kg body weight for 2 days caused significant accumulation of arsenic in renal tissues as well as altered the activities of serum markers, urea nitrogen (UN) and creatinine, antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx), level of cellular metabolites, reduced glutathione (GSH), oxidized glutathione (GSSG) and total thiols, level of lipid peroxidation end products and protein carbonyl content. Treatment with AA at a dose of 20mg/kg body weight for 4 days almost normalized above indices. Histological studies also indicated preventive role of AA against NaAsO(2)-induced nephrotoxicity. The radical scavenging activity and in vivo antioxidant power of AA were determined from its DPPH radical scavenging ability and ferric reducing/antioxidant power (FRAP), respectively. A well-known antioxidant, vitamin C was used as positive control throughout the study. Combining all, results suggest that arsenic could cause kidney damage by inducing oxidative stress in mice and that could be prevented by AA.

Protective effects of Terminalia arjuna against Doxorubicin-induced cardiotoxicity

Terminalia arjuna has been marked as a potential cardioprotective agent since vedic period. The present study was aimed to investigate the effects of butanolic fraction of Terminalia arjuna bark (TA-05) on Doxorubicin (Dox)-induced cardiotoxicity. Male wistar rats were used as in vivo model for the study. TA-05 was administered orally to Wistar rats at different doses (0.42 mg/kg, 0.85 mg/kg, 1.7 mg/kg, 3.4 mg/kg and 6.8 mg/kg) for 6 days/week for 4 weeks. Thereafter, all the animals except saline and TA-05-treated controls were administered 20 mg/kg Dox intraperitonially. There was a significant decrease in myocardial superoxide dismutase (38.94%) and reduced glutathione (23.84%) in animals treated with Dox. Concurrently marked increase in serum creatine kinase-MB (CKMB) activity (48.11%) as well as increase in extent of lipid peroxidation (2.55-fold) was reported. Co-treatment of TA-05 and Dox resulted in an increase in the cardiac antioxidant enzymes, decrease in serum CKMB levels and reduction in lipid peroxidation as compared to Dox-treated animals. Electron microscopic studies in Dox-treated animals revealed mitochondrial swelling, Z-band disarray, focal dilatation of smooth endoplasmic reticulum (SER) and lipid inclusions, whereas the concurrent administration of TA-05 led to a lesser degree of Dox-induced histological alterations. These findings suggest that butanolic fraction of Terminalia arjuna bark has protective effects against Dox-induced cardiotoxicity and may have potential as a cardioprotective agent.

Terminalia arjuna Wight & Arn.--a useful drug for cardiovascular disorders

Ancient Indian physicians used the powdered tree bark of Terminalia arjuna Wight & Arn. for alleviating "hritshool" (angina) and other cardiovascular conditions. Its stem bark possesses glycosides, large quantities of flavonoids, tannins and minerals. Flavonoids have been detected to exert antioxidant, anti-inflammatory and lipid lowering effects while glycosides are cardiotonic, thus making Terminalia arjuna unique amongst currently used medicinal plants. In this review an attempt has been made to discuss various aspects of its ethnomedical, pharmacognostical, phytochemical, pharmacological and clinical relevance to cardiovascular conditions. Experimental studies have revealed its bark exerting significant inotropic and hypotensive effect, increasing coronary artery flow and protecting myocardium against ischemic damage. It has also been detected to have mild diuretic, antithrombotic, prostaglandin E(2) enhancing and hypolipidaemic activity. There is ample clinical evidence of its beneficial effect in coronary artery disease alone and along with statin. However, toxicological studies in experimental animals are lacking. Considering its anti-ischemic activity and its potential to correct dyslipidemia, reduce left ventricular mass and increase left ventricular ejection fraction, it is essential to examine the molecular mechanism of its action and its core constituents. Proposition to administer Terminalia arjuna along with statins deserves to be explored in depth for defining its place in the over all management and prevention of coronary artery disease.

Arjunolic acid, a triterpenoid saponin, ameliorates arsenic-induced cyto-toxicity in hepatocytes

Arsenic is a well-established environmental toxin, which damages various organs of the body. A triterpenoid saponin, arjunolic acid (AA) has been isolated from the bark of Terminalia arjuna. The present study was conducted to investigate the preventive role of AA against arsenic-induced cytotoxicity in isolated murine hepatocytes. Sodium arsenite (NaAsO(2)) was chosen as the source of arsenic. Incubation of the hepatocytes with NaAsO(2) (1 mM) for 2 h caused reduction in the cell viability and activities of the intracellular enzymatic as well as non-enzymatic antioxidants. Treatment of NaAsO(2) enhanced lipid peroxidation and also increased the activities of the membrane leakage enzymes. Administration of AA (100 microg/ml) before and with the toxin almost normalized the altered activities of antioxidant indices. AA possesses free radical scavenging activity and could enhance the cellular anti-oxidant capability against NaAsO(2)-induced cyto-toxicity. The cytoprotective activity of AA was found to be comparable to that of a known antioxidant, vitamin C. Experimental results, therefore, suggest that AA protects arsenic-induced cytotoxicity in murine hepatocytes.

Cardioprotective effect of the Hibiscus rosa sinensis flowers in an oxidative stress model of myocardial ischemic reperfusion injury in rat

BACKGROUND

The present study investigates the cardioprotective effects of Hibiscus rosa sinensis in myocardial ischemic reperfusion injury, particularly in terms of its antioxidant effects.

METHODS

The medicinal values of the flowers of Hibiscus rosa sinensis (Chinese rose) have been mentioned in ancient literature as useful in disorders of the heart. Dried pulverized flower of Hibiscus rosa sinensis was administered orally to Wistar albino rats (150-200 gms) in three different doses [125, 250 and 500 mg/kg in 2% carboxy methyl cellulose (CMC)], 6 days per week for 4 weeks. Thereafter, rats were sacrificed; either for the determination of baseline changes in cardiac endogenous antioxidants [superoxide dismutase, reduced glutathione and catalase] or the hearts were subjected to isoproterenol induced myocardial necrosis.

RESULTS

There was significant increase in the baseline contents of thiobarbituric acid reactive substances (TBARS) [a measure of lipid per oxidation] with both doses of Hibiscus Rosa sinensis. In the 250 mg/kg treated group, there was significant increase in superoxide dismutase, reduced glutathione, and catalase levels but not in the 125 and 500 mg/kg treated groups. Significant rise in myocardial thiobarbituric acid reactive substances and loss of superoxide dismutase, catalase and reduced glutathione (suggestive of increased oxidative stress) occurred in the vehicle treated hearts subjected to in vivo myocardial ischemic reperfusion injury.

CONCLUSION

It may be concluded that flower of Hibiscus rosa sinensis (250 mg/kg) augments endogenous antioxidant compounds of rat heart and also prevents the myocardium from isoproterenol induced myocardial injury.

Anti-oxidative stress effects of Herba leonuri on ischemic rat hearts

Our current study was to test the hypothesis that the extract of Herba leonuri (HL) would have antioxidant and cardioprotective effects on ischemic myocardium. The extract of HL (400 mg/kg/day) was administered orally (daily) starting from 1 week before and continuing until 3 weeks after myocardial infarction (MI). Surviving rats were sacrificed at different time points to obtain left ventricles for biochemical assays. Our study demonstrates for the first time that HL does have antioxidant effects both in vitro and in vivo. The antioxidant effects of HL are exerted only under the condition of oxidative stress, by selectively preserving the activities of superoxide dismutase and glutathione peroxidase, as well as depressing the formation of malondialdehyde, especially in the acute phase of acute MI. Its effects of scavenging free radicals and inhibiting the formation of reactive oxygen species may play a key role in protecting the endogenous antioxidant system from oxidative stress in vivo.

Terminalia arjuna (Roxb.) protects rabbit heart against ischemic-reperfusion injury: role of antioxidant enzymes and heat shock protein

The bark of Terminalia arjuna Roxb. (TA) is widely recommended for the treatment of ischemic heart disease (IHD) in Indian system of medicine. Oral administration of TA for 12 weeks in rabbits caused augmentation of myocardial antioxidants; superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) along with induction of heat shock protein72 (HSP72). In vivo ischemic-reperfusion injury induced oxidative stress, tissue injury of heart and haemodynamic effects were prevented in the TA treated rabbit hearts. The study provides scientific basis for the putative therapeutic effect of TA in ischemic heart disease.

Effect of dietary palm olein oil on oxidative stress associated with ischemic-reperfusion injury in isolated rat heart

Background

Palm olein oil (PO), obtained from refining of palm oil is rich in monounsaturated fatty acid and antioxidant vitamins and is widely used as oil in diet in many parts of the world including India. Palm oil has been reported to have beneficial effects in oxidative stress associated with hypertension and arterial thrombosis. Oxidative stress plays a major role in the etiopathology of myocardial ischemic-reperfusion injury (IRI) which is a common sequel of ischemic heart disease. Antioxidants have potent therapeutic effects on both ischemic heart disease and ischemic-reperfusion injury. Information on the effect of PO on ischemic-reperfusion injury is, however, lacking. In the present study, the effect of dietary palm olein oil on oxidative stress associated with IRI was investigated in an isolated rat heart model. Wistar rats (150–200 gm) of either sex were divided into three different groups (n = 16). Rats were fed with palm olein oil supplemented commercial rat diet, in two different doses [5% v / w (PO 5) and 10% v / w (PO 10) of diet] for 30 days. Control rats (C) were fed with normal diet. After 30 days, half the rats from each group were subjected to in vitro myocardial IRI (20 min of global ischemia, followed by 40 min of reperfusion). Hearts from all the groups were then processed for biochemical and histopathological studies. One way ANOVA followed by Bonferroni test was applied to test for significance and values are expressed as mean ± SE (p < 0.05).

Results

There was a significant increase in myocardial catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities with no significant change in myocardial thiobarbituric acid reactive substances (TBARS) only in group PO 5 as compared to group C. There was no light microscopic evidence of tissue injury. A significant rise in myocardial TBARS and depletion of myocardial endogenous antioxidants (SOD, CAT and GPx) along with significant myocyte injury was observed in control rats subjected to ischemia-reperfusion (C IR). Hearts from palm olein oil fed rats subjected to ischemia-reperfusion (PO 5 IR and PO 10 IR) were protected from increase in TBARS and depletion of endogenous antioxidants as compared to C IR group. No significant myocyte injury was present in the treated groups.

Conclusions

The present study demonstrated for the first time that dietary palm olein oil protected rat heart from oxidative stress associated with ischemic-reperfusion injury.

Antidyslipidemic and antioxidant activities of different fractions ofTerminalia arjuna stem bark

Terminalia arjuna (T. arjuna) stem bark was successively extracted with petroleum ether (A), solvent ether (B), ethanol (C) and water (D). The lipid lowering activity of these four fractions A, B, C, and D was evaluatedin vivo in two models viz., triton WR-1339 induced hyperlipemia in rats as well as fructose rich high fat diet (HFD) fed diabetic- dyslipidemic hamsters. Hyperlipidemia induced by triton caused marked increase in the plasma levels of total cholesterol (Tc), triglyceride (Tg) and phospholipids (PL) in rats. After treament withT. arjuna fractions A, B, C, and D at the doses of 250 mg/kg per oral (p.o.),only the ethanolic fraction (C) exerted significant lipid lowering effect as assessed by reversal of plasma levels of Tc, Tg and PL in hyperlipidemic rats. In another experiment, feeding with HFD produced marked dyslipidemia as observed by increased levels of plasma Tc, Tg, glucose (Glu), glycerol (Gly) and free fatty acids (FFA) in hamsters. After treatment withT. arjuna fractions at the doses of 250 mg/kg p.o. only two fraction (B and C) could exert significant lowering in the plasma levels of lipids and Glu. in dyslipidemic hamsters.In vitro experimentT. arjuna fractions at tested concentrations (50-500 μg/ml) inhibited the oxidative degradation of lipids in human low density lipoprotein and rat liver microsomes induced by metal ions. These fractions when tested against generation of oxygen free radicals at the concentrations (50-500 μg/ml), counteracted the formation of superoxide anions (O(-2)) and hydrodyl radicals (OH) in non enzymic test systems. The efficacy ofT. arjuna fractions as antidyslipidemic and antioxidant agents was found, fraction C> fraction B> fraction A.

Possible mechanisms of hypotension produced 70% alcoholic extract of Terminalia arjuna (L.) in anaesthetized dogs

Background

The bark of Terminalia arjuna L. (Combretaceae) is used in Ayurveda since ancient times for the treatment of cardiac disorders. Previous laboratory investigations have demonstrated the use of the bark in cardiovascular complications. The present study was aimed to find the effect of 70% alcoholic extract of Terminalia arjuna on anaesthetized dog blood pressure and probable site of action.

Methods

Six dogs were anaesthetized with intraperitoneal injection of thiopental sodium and the blood pressure of each dog (n = 6) was measured from the left common carotid artery connected to a mercury manometer on kymograph. The femoral vein was cannulated for administration of drug solutions. The extract of T. arjuna (dissolved in propylene glycol) in the dose range of 5 to 15 mg/kg were administered intravenously in a pilot study and the dose (6 mg/kg) which produced appreciable hypotension was selected for further studies.

Results

Intravenous administration of T. arjuna produced dose-dependent hypotension in anaesthetized dogs. The hypotension produced by 6 mg/kg dose of the extract was blocked by propranolol but not by atropine or mepyramine maleate. This indicates that muscarinic or histaminergic mechanisms are not likely to be involved in the hypotension produced by the extract. The blockade by propranolol of the hypotension produced by T. arjuna indicates that the extract might contain active compound(s) possessing adrenergic ß₂-receptor agonist action and/or that act directly on the heart muscle.

Conclusion

The results indicated the likely involvement of peripheral mechanism for hypotension produced by the 70% alcoholic extract of Terminalia arjuna and lends support for the claims of its traditional usage in cardiovascular disorders.

Cardioprotective effect of the alcoholic extract of Terminalia arjuna bark in an in vivo model of myocardial ischemic reperfusion injury

The present study was designed to investigate the effects of chronic administration of the alcoholic extract of Terminalia arjuna (TAAE) bark on isoproterenol induced myocardial injury. The TAAE was administered orally to Wistar albino rats (150-200 g) in three different doses, by gastric gavage [3.4 mg/kg: (T1), 6.75 mg/kg: (T2) and 9.75 mg/kg: (T3)] 6 days/week for 4 weeks. At the end of this period, all the animals, except the normal untreated rats that served as the control group, were administered isoproterenol (ISO) 85 mg/kg, S.C., for two consecutive days to induce in vivo myocardial injury. After 48 hours rats were anaesthetized with anaesthetic ether, then sacrificed and the hearts were harvested for biochemical and histological studies. A significant rise in myocardial thiobarbituric acid reactive substances (TBARS) and loss of reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (suggestive of increased oxidative stress) occurred in the hearts subjected to in vivo myocardial ischemic reperfusion injury. The 6.75 mg/kg TAAE treatment group (baseline) shows a significant increase in myocardial TBARS as well as endogenous antioxidants (GSH, SOD, and catalase), but not in the other treatment groups. In in vivo ischemic reperfusion injury of the TAAE treated rats there was a significant decrease in TBARS in all the groups. In 6.75 mg/kg treatment group, a significant rise in the levels of GSH, SOD and catalase were observed, and it shows better recovery profile than the other groups subjected to in vivo ischemic reperfusion injury. In histological studies, all the groups, except the isoproterenol treated group, showed preserved myocardium. The present study demonstrates that the 6.75 mg/kg TAAE augments endogenous antioxidant compounds of the rat heart and also prevents the myocardium from isoproterenol induced myocardial ischemic reperfusion injury.

Chronic garlic administration protects rat heart against oxidative stress induced by ischemic reperfusion injury

BACKGROUND

Oxidative stress plays a major role in the biochemical and pathological changes associated with myocardial ischemic-reperfusion injury (IRI). The need to identify agents with a potential for preventing such damage has assumed great importance. Chronic oral administration of raw garlic has been previously reported to augment myocardial endogenous antioxidants. In the present study, the effect of chronic oral administration of raw garlic homogenate on oxidative stress induced by ischemic-reperfusion injury in isolated rat heart was investigated.

RESULTS

Raw garlic homogenate (125, 250 and 500 mg/kg once daily for 30 days) was administered orally in Wistar albino rats. Thereafter, hearts were isolated and subjected to IRI (9 min. of global ischemia, followed by 12 min of reperfusion; perfusion with K-H buffer solution; 37 degrees C, 60 mm Hg.). Significant myocyte injury and rise in myocardial TBARS along with reduction in myocardial SOD, catalase, GSH and GPx were observed following IRI. Depletion of myocardial endogenous antioxidants and rise in TBARS were significantly less in the garlic-treated rat hearts. Oxidative stress induced cellular damage as indicated by ultrastructural changes, like disruption of myofilament, Z-band architecture along with mitochondrial changes were significantly less.

CONCLUSIONS

The study strongly suggests that chronic garlic administration prevents oxidative stress and associated ultrastructural changes, induced by myocardial ischemic-reperfusion injury.