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Dipak K. Das

Bio: Dipak K. Das is an academic researcher from University of Connecticut. The author has contributed to research in topics: Ischemia & Resveratrol. The author has an hindex of 75, co-authored 327 publications receiving 17708 citations. Previous affiliations of Dipak K. Das include Jawaharlal Nehru University & Baystate Medical Center.


Papers
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Journal ArticleDOI
TL;DR: It is demonstrated that GSPE is highly bioavailable and provides significantly greater protection against free radicals and free radical-induced lipid peroxidation and DNA damage than vitamins C, E and beta-carotene.

1,028 citations

Journal ArticleDOI
16 Jun 2011-PLOS ONE
TL;DR: The published evidence is not sufficiently strong to justify a recommendation for the administration of resveratrol to humans, beyond the dose which can be obtained from dietary sources, and animal data are promising in prevention of various cancer types, coronary heart diseases and diabetes which strongly indicate the need for human clinical trials.
Abstract: Background: Resveratrol is a natural compound suggested to have beneficial health effects. However, people are consuming resveratrol for this reason without having the adequate scientific evidence for its effects in humans. Therefore, scientific valid recommendations concerning the human intake of resveratrol based on available published scientific data are necessary. Such recommendations were formulated after the Resveratrol 2010 conference, held in September 2010 in Helsingor, Denmark. Methodology: Literature search in databases as PubMed and ISI Web of Science in combination with manual search was used to answer the following five questions: 1 Can resveratrol be recommended in the prevention or treatment of human diseases?; 2 Are there observed ‘‘side effects’’ caused by the intake of resveratrol in humans?; 3 What is the relevant dose of resveratrol?; 4 What valid data are available regarding an effect in various species of experimental animals?; 5 Which relevant (overall) mechanisms of action of resveratrol have been documented? Conclusions/Significance: The overall conclusion is that the published evidence is not sufficiently strong to justify a recommendation for the administration of resveratrol to humans, beyond the dose which can be obtained from dietary sources. On the other hand, animal data are promising in prevention of various cancer types, coronary heart diseases and diabetes which strongly indicate the need for human clinical trials. Finally, we suggest directions for future research in resveratrol regarding its mechanism of action and its safety and toxicology in human subjects.

413 citations

Journal ArticleDOI
TL;DR: It is demonstrated that IH636 grape seed proanthocyanidin extract (GSPE) provides superior antioxidant efficacy as compared to Vitamins C, E and beta-carotene and may serve as a potential therapeutic tool in promoting cardiovascular health via a number of novel mechanisms.
Abstract: Free radicals and oxidative stress play a crucial role in the pathophysiology of a broad spectrum of cardiovascular diseases including congestive heart failure, valvular heart disease, cardiomyopathy, hypertrophy, atherosclerosis and ischemic heart disease. We have demonstrated that IH636 grape seed proanthocyanidin extract (GSPE) provides superior antioxidant efficacy as compared to Vitamins C, E and beta-carotene. A series of studies were conducted using GSPE to demonstrate its cardioprotective ability in animals and humans. GSPE supplementation improved cardiac functional assessment including post-ischemic left ventricular function, reduced myocardial infarct size, reduced ventricular fibrillation (VF) and tachycardia, decreased the amount of reactive oxygen species (ROS) as detected by ESR spectroscopy and reduced malondialdehyde (MDA) formation in the heart perfusate. Cardiomyocyte apoptosis detected by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) staining. In concert, the proapoptotic signals mediated by JNK-l and c-fos proteins were also reduced suggesting that the novel cardioprotective properties of GSPE may be at least partially attributed to its ability to block anti-death signaling mediated through the proapoptotic transcription factors and genes such as JNK-1 and c-JUN. In a separate study, GSPE pretreatment significantly inhibited doxorubicin-induced cardiotoxicity as demonstrated by reduced serum creatine kinase (CK) activity, DNA damage and histopathological changes in the cardiac tissue of mice. Concentration-dependent efficacy of GSPE was also assessed in a hamster atherosclerosis model. Approximately 49 and 63% reduction in foam cells, a biomarker of early stage atherosclerosis, were observed following supplementation of 50 and 100 mg GSPE/kg body weight, respectively. A human clinical trial was conducted on hypercholesterolemic subjects. GSPE supplementation significantly reduced oxidized LDL, a biomarker of cardiovascular diseases. Finally, a cDNA microarray study demonstrated significant inhibition of inducible endothelial CD36 expression, a novel cardioregulatory gene, by GSPE. These results demonstrate that GSPE may serve as a potential therapeutic tool in promoting cardiovascular health via a number of novel mechanisms.

411 citations

Journal ArticleDOI
TL;DR: Evidence is provided that resveratrol exhibits potent anti-inflammatory activity and the mechanisms discussed address foremost mechanisms for the anti- inflammatory activity which, in turn, is responsible for cardioprotection.
Abstract: Resveratrol (trans-3,4',5-trihydroxystilbene), a natural polyphenolic, non-flavonoid antioxidant, is a phytoalexin found in many plants including grapes, nuts and berries. Recent studies have documented that resveratrol has various health benefits, such as cardiovascular and cancer preventive properties. However, the experimental basis for such health benefit is not fully understood. One of the possible mechanisms for its protective activities is by down regulation of the inflammatory responses. That includes the inhibition of synthesis and release of pro-inflammatory mediators, modifications of eicosanoid synthesis, inhibition of some activated immune cells, or inhibiting the enzymes, such as cyclooxygenase-1 (COX-1) or cyclooxygenase-2 (COX-2), which are responsible for the synthesis of pro-inflammatory mediators through the inhibitory effect of resveratrol on transcription factors like nuclear factor kappaB (NFkappaB) or activator protein-1 (AP-1). Being a phenolic compound, resveratrol certainly possesses a low bioavailability and most importantly, a rapid clearance from the plasma. Recent growing interest in varying protective nature of resveratrol may clinically also hold a respectable position as a better alternative for anti-inflammatory drugs. The purpose of this review is to provide evidence that resveratrol exhibits potent anti-inflammatory activity and also to explain the underling mechanism for both resveratrol- induced cardioprotective and anti-inflammatory properties. While it is true that the cardioprotective properties of resveratrol are likely attributable, at least in part, to its anti-inflammatory properties, the mechanisms discussed address foremost mechanisms for the anti-inflammatory activity which, in turn, is responsible for cardioprotection.

350 citations

Journal ArticleDOI
TL;DR: The results of this study demonstrate that resveratrol possesses cardioprotective effects which may be attributed to its peroxyl radical scavenging activity and suggest a probable mechanism involved in the protective ability of RVT.

349 citations


Cited by
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Journal ArticleDOI
TL;DR: Attention is focussed on the ROS/RNS-linked pathogenesis of cancer, cardiovascular disease, atherosclerosis, hypertension, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative diseases, rheumatoid arthritis, and ageing.

12,240 citations

Journal ArticleDOI
TL;DR: There is growing evidence that aging involves, in addition, progressive changes in free radical-mediated regulatory processes that result in altered gene expression.
Abstract: At high concentrations, free radicals and radical-derived, nonradical reactive species are hazardous for living organisms and damage all major cellular constituents. At moderate concentrations, how...

9,131 citations

Journal Article
TL;DR: Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional, and suggestions are made where such possibilities may be worth pursuing.
Abstract: Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

4,663 citations

Journal ArticleDOI
TL;DR: A comprehensive and critical review of the in vivo data on resveratrol is provided, and its potential as a therapeutic for humans is considered.
Abstract: Resveratrol, a constituent of red wine, has long been suspected to have cardioprotective effects. Interest in this compound has been renewed in recent years, first from its identification as a chemopreventive agent for skin cancer, and subsequently from reports that it activates sirtuin deacetylases and extends the lifespans of lower organisms. Despite scepticism concerning its bioavailability, a growing body of in vivo evidence indicates that resveratrol has protective effects in rodent models of stress and disease. Here, we provide a comprehensive and critical review of the in vivo data on resveratrol, and consider its potential as a therapeutic for humans.

3,509 citations

Journal ArticleDOI
TL;DR: Once MMP has been induced, it causes the release of catabolic hydrolases and activators of such enzymes (including those of caspases) from mitochondria, meaning that mitochondria coordinate the late stage of cellular demise.
Abstract: Irrespective of the morphological features of end-stage cell death (that may be apoptotic, necrotic, autophagic, or mitotic), mitochondrial membrane permeabilization (MMP) is frequently the decisive event that delimits the frontier between survival and death. Thus mitochondrial membranes constitute the battleground on which opposing signals combat to seal the cell's fate. Local players that determine the propensity to MMP include the pro- and antiapoptotic members of the Bcl-2 family, proteins from the mitochondrialpermeability transition pore complex, as well as a plethora of interacting partners including mitochondrial lipids. Intermediate metabolites, redox processes, sphingolipids, ion gradients, transcription factors, as well as kinases and phosphatases link lethal and vital signals emanating from distinct subcellular compartments to mitochondria. Thus mitochondria integrate a variety of proapoptotic signals. Once MMP has been induced, it causes the release of catabolic hydrolases and activators of such enzymes (including those of caspases) from mitochondria. These catabolic enzymes as well as the cessation of the bioenergetic and redox functions of mitochondria finally lead to cell death, meaning that mitochondria coordinate the late stage of cellular demise. Pathological cell death induced by ischemia/reperfusion, intoxication with xenobiotics, neurodegenerative diseases, or viral infection also relies on MMP as a critical event. The inhibition of MMP constitutes an important strategy for the pharmaceutical prevention of unwarranted cell death. Conversely, induction of MMP in tumor cells constitutes the goal of anticancer chemotherapy.

3,340 citations