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Susmita Das

Bio: Susmita Das is an academic researcher from University of Calcutta. The author has contributed to research in topics: Arsenic toxicity & Arsenate. The author has an hindex of 9, co-authored 27 publications receiving 206 citations.

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Journal ArticleDOI
TL;DR: Cultivar- and dose-dependent alteration of parameters tested including the rate of accumulation showed that Kumargore, Binni, and Vijaya were characterized as arsenate tolerant and could be cultivated in arsenic-prone areas to minimize level of toxicity and potential health hazards.
Abstract: Arsenic toxicity is the most commonly experienced challenge of rice plants due to irrigation with arsenic-polluted groundwater and their cultivation in water logging environment which poses threat to human health, particularly in Bangladesh and West Bengal (India). In the present study, hydroponically grown eight rice cultivars, viz., Bhutmuri, Kumargore, Binni, Vijaya, Tulsibhog, Badshabhog, Pusa basmati, and Swarnadhan, were screened for arsenic tolerance by using physiological and molecular parameters. Treatment with 25 μM, 50 μM, and 75 μM arsenate resulted in dosage-based retardation in growth and water content in all the tested cultivars due to accumulation of total arsenic along with the enhanced activity of arsenate reductase with more severe effects exhibited in cvs. Swarnadhan, Pusa basmati, Badshabhog, and Tulsibhog. Arsenic sensitivity of rice cultivars was evaluated in terms of oxidative stress markers generation, antioxidant enzyme activities, and level of genotoxicity. Under arsenate-challenged conditions, the levels of oxidative stress markers, viz., H2O2, MDA, and proline, and activities of antioxidant enzymes, viz., SOD and CAT, along with the level of genotoxicity analyzed by RAPD profiling were altered in variable levels in all tested rice cultivars and showed a significant alteration in band patterns in arsenate-treated seedlings of cvs. Swarnadhan, Pusa basmati, Badshabhog, and Tulsibhog in terms of appearance of new bands and disappearance of normal bands that were presented in untreated seedlings led to reduction in genomic template stability due to their high susceptibility to arsenic toxicity. Cultivar- and dose-dependent alteration of parameters tested including the rate of As accumulation showed that cvs. Kumargore, Binni, and Vijaya, specially Bhutmuri, were characterized as arsenate tolerant and could be cultivated in arsenic-prone areas to minimize level of toxicity and potential health hazards.

32 citations

Journal ArticleDOI
TL;DR: Aqueous extracts of different seasonal as well as less popular but edible indigenous fruits of West Bengal, India were studied for their α-glucosidase and α-amylase inhibitory properties as discussed by the authors.
Abstract: Aqueous extracts of different seasonal as well as less popular but edible indigenous fruits of West Bengal, India were studied for their α-glucosidase and α-amylase inhibitory properties. Of the 22 different species of fruits, sixteen fruits inhibited both the carbohydrate digesting enzymes. Concentrations of the extracts are presented as fresh weight of fruit used to make extract / ml. Very high α-amylase (IC50 value = 5.0 μg/ml) and α-glucosidase (IC50 value = 9.0 μg/ml) inhibitory activity was shown by extracts of Phoenix sylvestris. Achras sapota also showed high α-amylase (IC50 value = 53.0 μg/ml) and α-glucosidase (IC50 value = 56.0 μg/ml) inhibitory activities. During the present study, no correlation could be established between total phenol / flavonoid content and α-amylase / α-glucosidase inhibitory activity. Unweighted pair-group average (UPGA) dendrogram showing interrelationships between the investigated species shows that the fruits can be grouped into two high level clusters. The cluster I brought together Borassus flabellifer and Physalis peruviana having very low α-glucosidase inhibitory activity. The cluster II included fruits with moderate to high α- glucosidase inhibitory activity.

30 citations

Journal ArticleDOI
28 Nov 2016-PLOS ONE
TL;DR: Oral administration of S. roxburghiana rhizome could reduce hyperglycemia, hyperlipidemia, membrane disintegration, oxidative stress, vascular inflammation and prevented the activation of oxidative stress induced signaling cascades leading to cell death.
Abstract: Background Sansevieria roxburghiana Schult. & Schult. F. (Family: Asparagaceae) rhizome has been claimed to possess antidiabetic activity in the ethno-medicinal literature in India. Therefore, present experiments were carried out to explore the protective role of edible (aqueous) extract of S. roxburghiana rhizome (SR) against experimentally induced type 2 diabetes mellitus (T2DM) and its associated cardiomyopathy in Wistar rats. Methods SR was chemically characterized by GC-MS analysis. Antidiabetic activity of SR (50 and 100 mg/kg, orally) was measured in high fat diets (ad libitum) + low-single dose of streptozotocin (35 mg/kg, intraperitoneal) induced type 2 diabetic (T2D) rat. Fasting blood glucose level was measured at specific intermissions. Serum biochemical and inflammatory markers were estimated after sacrificing the animals. Besides, myocardial redox status, expressions of signal proteins (NF-κB and PKCs), histological and ultrastructural studies of heart were performed in the controls and SR treated T2D rats. Results Phytochemical screening of the crude extract revealed the presence of phenolic compounds, sugar alcohols, sterols, amino acids, saturated fatty acids within SR. T2D rats exhibited significantly (p < 0.01) higher fasting blood glucose level with respect to control. Alteration in serum lipid profile (p < 0.01) and increased levels of lactate dehydrogenase (p < 0.01) and creatine kinase (p < 0.01) in the sera revealed the occurrence of hyperlipidemia and cell destruction in T2D rats. T2DM caused significant (p < 0.05–0.01) alteration in the biochemical markers in the sera. T2DM altered the redox status (p < 0.05–0.01), decreased (p < 0.01) the intracellular NAD and ATP concentrations in the myocardial tissues of experimental rats. While investigating the molecular mechanism, activation PKC isoforms was observed in the selected tissues. T2D rats also exhibited an up-regulation in nuclear NF-κB (p65) in the cardiac tissues. So, oral administration of SR (50 and 500 mg/kg) could reduce hyperglycemia, hyperlipidemia, membrane disintegration, oxidative stress, vascular inflammation and prevented the activation of oxidative stress induced signaling cascades leading to cell death. Histological and ultra-structural studies of cardiac tissues supported the protective characteristics of SR. Conclusions From the present findings it can be concluded that, SR could offer protection against T2DM and its associated cardio-toxicity via multiple mechanisms viz. hypoglycemic, antioxidant and anti-inflammatory actions.

27 citations

Journal ArticleDOI
TL;DR: The present experiment reports the importance of both primary and secondary metabolites for the bioactivity of plant extracts and identifies the inhibitors of α-amylase and α-glucosidase using metabolomics and chemometric approaches.
Abstract: Achras sapota L. fruit extracts have previously been reported to have activities against the carbohydrate-digesting enzymes α-amylase and α-glucosidase. The present work was aimed to identify the inhibitors of α-amylase and α-glucosidase using metabolomics and chemometric approaches. Metabolite profile of Achras sapota fruit extracts at different stages of post-harvest ripening was analyzed using GC–MS-based metabolomics approach. The extracts were also assayed for their properties to inhibit the carbohydrate-digesting enzymes α-amylase and α-glucosidase in vitro. The fruit extracts just after harvesting showed maximum activities against the enzymes α-amylase and α-glucosidase. The activities declined with post-harvest ripening. It was observed from the chemometric analysis that gallic acid, chlorogenic acid, benzene-1,2,4-triol, and d-malic acid are responsible for high α-amylase inhibitory activity. Gallic acid and chlorogenic acid are positively correlated with high α-glucosidase inhibitory activity. Inhibition of the two enzymes by gallic acid, benzene-1,2,4-triol, chlorogenic acid, and α-amylase by d-malic acid supported the findings. The present experiment reports the importance of both primary and secondary metabolites for the bioactivity of plant extracts.

26 citations

Journal ArticleDOI
TL;DR: Potential toxicity caused by arsenate (AsV) among four rice cultivars tested that varied with respect to accumulation of total arsenic, arsenite (AsIII) and their differential translocation rate which had deleterious impact on growth and metabolism is examined.
Abstract: Arsenic (As) accumulation in rice is a principal route of As exposure for rice based population. We have tested physiochemical and molecular parameters together to identify low As accumulating rice cultivars with normal growth and vigor. The present study examined potential toxicity caused by arsenate (AsV) among four rice cultivars tested that varied with respect to accumulation of total arsenic, arsenite (AsIII) and their differential translocation rate which had deleterious impact on growth and metabolism. Intracellular homeostasis of rice cultivars viz., TN-1, IR-64, IR-20 and Tulaipanji was hampered by 21 days long As(V) treatment due to generation of reactive oxygen species (ROS) and inadequate activity of catalase (CAT; EC 1.11.1.6). Upregulation of oxidative stress markers viz., H2O2, proline and MDA along with alteration in enzymatic antioxidants profile were conspicuously pronounced in cv. Tulaipanji while cv. TN-1 was least affected under As(V) challenged environment. In addition to that genomic template stability and band sharing indices were qualitatively measured by DNA profiling of all tested cultivars treated with 25 μM, 50 μM, and 75 μM As(V). In rice cv. Tulaipanji genetic polymorphism was significantly detected with the application of random amplified polymorphic DNA (RAPD) tool and characterized as susceptible cultivar of As compared to cvs. TN-1, IR-64 and IR-20 that is in correlation with data obtained from cluster analysis. Hence, identified As tolerant cultivars viz., TN-1, IR64 and IR-20 especially TN-1 could be used in As contaminated agricultural field after appropriate field trial. This study could help to gather information regarding cultivar-specific tolerance strategy to avoid pollutant induced toxicity.

24 citations


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Reference EntryDOI
15 Jul 2005
TL;DR: The scope of work of each of the FDA's major components is described, and the role of statisticians at FDA is addressed.
Abstract: The Food and Drug Administration (FDA) is a regulatory agency of the United States federal government This article describes the scope of work of each of the FDA's major components, and addresses the role of statisticians at FDA Keywords: drug regulation; clinical trials; medical devices; safety; bioassay

579 citations

Journal ArticleDOI
TL;DR: It is concluded that the retarded starch digestion in vitro by polyphenols results from inhibition of key digestive enzymes, including α-amylase and α-glucosidase, as well as from interactions betweenpolyphenols and starch.
Abstract: Polyphenols, as one group of secondary metabolite, are widely distributed in plants and have been reported to show various bioactivities in recent year. Starch digestion not only is related with food industrial applications such as brewing but also plays an important role in postprandial blood glucose level, and therefore insulin resistance. Many studies have shown that dietary phenolic extracts and pure polyphenols can retard starch digestion in vitro, and the retarding effect depends on the phenolic composition and molecular structure. Besides, dietary polyphenols have also been reported to alleviate elevation of blood glucose level after meal, indicating the inhibition of starch digestion in vivo. This review aims to analyze how dietary polyphenols affect starch digestion both in vitro and in vivo. We can conclude that the retarded starch digestion in vitro by polyphenols results from inhibition of key digestive enzymes, including α-amylase and α-glucosidase, as well as from interactions between polyphenols and starch. The alleviation of postprandial hyperglycemia by polyphenols might be caused by both the inhibited starch digestion in vivo and the influenced glucose transport. Therefore, phenolic extracts or pure polyphenols may be alternatives for preventing and treating type II diabetes disease.

210 citations

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate that both fluorescent and unlabeled live cells in a Petri dish observed with a microscope can be automatically recognized by computer vision and picked up by a computer-controlled micropipette.
Abstract: Fluorescence-activated cell sorting (FACS) applying flow cytometry to separate cells on a molecular basis is a widespread method. We demonstrate that both fluorescent and unlabeled live cells in a Petri dish observed with a microscope can be automatically recognized by computer vision and picked up by a computer-controlled micropipette. This method can be routinely applied as a FACS down to the single cell level with a very high selectivity. Sorting resolution, i.e., the minimum distance between two cells from which one could be selectively removed was 50–70 micrometers. Survival rate with a low number of 3T3 mouse fibroblasts and NE-4C neuroectodermal mouse stem cells was 66±12% and 88±16%, respectively. Purity of sorted cultures and rate of survival using NE-4C/NE-GFP-4C co-cultures were 95±2% and 62±7%, respectively. Hydrodynamic simulations confirmed the experimental sorting efficiency and a cell damage risk similar to that of normal FACS.

93 citations

Journal ArticleDOI
TL;DR: The ethnopharmacological, phytochemical, and pharmacological studies of Phyllanthus over the past few decades are discussed, including the researches of their remarkable antiviral, antioxidant, antidiabetic, and anticancer activities.
Abstract: The plants of the genus Phyllanthus (Euphorbiaceae) have been used as traditional medicinal materials for a long time in China, India, Brazil, and the Southeast Asian countries. They can be used for the treatment of digestive disease, jaundice, and renal calculus. This review discusses the ethnopharmacological, phytochemical, and pharmacological studies of Phyllanthus over the past few decades. More than 510 compounds have been isolated, the majority of which are lignins, triterpenoids, flavonoids, and tannins. The researches of their remarkable antiviral, antioxidant, antidiabetic, and anticancer activities have become hot topics. More pharmacological screenings and phytochemical investigations are required to support the traditional uses and develop leading compounds.

91 citations