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Author

Arun Balakrishnan

Other affiliations: University of Leicester
Bio: Arun Balakrishnan is an academic researcher from Anna University. The author has contributed to research in topics: Apoptosis & Enteropathogenic Escherichia coli. The author has an hindex of 20, co-authored 50 publications receiving 1248 citations. Previous affiliations of Arun Balakrishnan include University of Leicester.


Papers
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TL;DR: The crude methanolic extract and the isolated pure compound are capable of carrying out a natural anti-inflammatory activity at sites where chronic inflammation is present by switching off the pro-inflammatory cytokines and mediators, which initiate the process.

163 citations

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TL;DR: Egoflavin, a pigment from an endophytic fungus growing on the leaves of an Indian medicinal plant Mimosops elengi (bakul), is isolated and showed good anti-inflammatory and anticancer activities.
Abstract: Biodiversity is a major resource for identification of new molecules with specific therapeutic activities. To identify such an active resource, high throughput screening (HTS) of the extracts prepared from such diversity are examined on specific functional assays. Based on such HTS studies and bioactivity-based fractionation, we have isolated ergoflavin, a pigment from an endophytic fungus, growing on the leaves of an Indian medicinal plant Mimosops elengi (bakul). We report here the isolation, structure elucidation, and biological properties of this compound, which showed good anti- inflammatory and anticancer activities. Introduction. - Natural products from medicinal plants and microorganisms are the most consistent and productive source for thefirst-in-classdrugs (1). Recently, a great deal of interest has been generated by discovery of remarkable pharmacological agents from endophytic fungi (2). In our ongoing pharmacological screening program on biodiversity of endophytic fungi present in Indian landscape, we have discovered a remarkable anti-inflammatory and anticancer activity in extracts/fractions of an endophytic fungus of the ascomycetes family growing on an Indian plant named Mimosops elengi. The primary purpose for such broad-based screening of endophytic fungi was to identify novel inhibitors of pro-inflammatory cytokines involved in various immunological pathways. The therapeutic areas for which the screening was carried out included inflammation, diabetes, and cancer targets. Our anticancer screen is designed to identify compounds active against multiple cancers (renal cell carcinoma, pancreatic tumours, non-small cell lung carcinoma, and colon cancers). Cytotoxicity-based screening for identification of compounds with anticancer properties has been previously shown to be successful in discovery of many clinically used anticancer natural products (3), for example, the cell-based screening of cytotoxic compounds by the National Institute of Health, USA (4). To discover natural products with anti-inflammatory and anticancer properties, the fermented broths of a number of endophytic fungi were tested. Amongst the different strains of fungi, the one coded as PM0651480 was isolated from the leaves of the plant Mimosops elengi (Sapotaceae). The extract prepared from this fungal culture showed good anti-inflammatory and anticancer activity, and we describe here the isolation of the active compound ergoflavin from this endophyte culture. Ergoflavin was originally

109 citations

Journal ArticleDOI
TL;DR: Investigation of methanolic extracts of Aegles marmelos and Syzygium cumini on a battery of targets glucose transporter, peroxisome proliferator activator receptor gamma and phosphatidylinositol 3' kinase involved in glucose transport found them to activate glucose transport in a PI3 kinase-dependent fashion.

92 citations

Journal ArticleDOI
TL;DR: The results indicate that 7′-hydroxy-3′,4′,5,9,9′-pentamethoxy-3,4-methylene dioxy lignan was capable of inhibiting telomerase activity and also could inhibit bcl2 and activate caspase 3 and caspasing 8 whose significance in the induction of apoptosis is well known.
Abstract: Conventional solvent fractionation and bioactivity based target assays were used to identify a new anti-cancer molecule from Phyllanthus urinaria, a herbal medicinal plant used in South India. At each step of the purification process the different fractions that were isolated were tested for specific anti-proliferative activity by assays measuring the inhibition of [3H]thymidine incorporation, and trypan blue drug exclusion. The ethyl acetate fraction that contained the bioactivity was further purified and resolved by HPLC on a preparative column. The purity of each of the fractions and their bioactivity were checked. Fraction 3 demonstrated a single spot on TLC and showed maximum anti-proliferative activity. This fraction was further purified and the structure was defined as 7′-hydroxy-3′,4′,5,9,9′-pentamethoxy-3,4-methylene dioxy lignan using NMR and mass spectrometry analysis. The pure compound and the crude ethyl acetate fraction which showed anti-proliferative activities were examined for ability to target specific markers of apoptosis like bcl2, c-myc and caspases and for effects on telomerase. Four specific cancer cell lines HEp2, EL-1 monocytes, HeLa and MCP7 were used in this study. The results indicate that 7′-hydroxy-3′,4′,5,9,9′-pentamethoxy-3,4-methylene dioxy lignan was capable of inhibiting telomerase activity and also could inhibit bcl2 and activate caspase 3 and caspase 8 whose significance in the induction of apoptosis is well known. We believe that this compound could serve as a valuable chemotherapeutic drug after further evaluations. British Journal of Cancer (2002) 87, 98–105. doi:10.1038/sj.bjc.6600422 www.bjcancer.com © 2002 Cancer Research UK

85 citations

Journal ArticleDOI
TL;DR: Three different series of pyrazolo[3,4-b]pyridines and their structural analogues are synthesized using novel synthetic strategy involving one-pot condensation of 5, 6-dihydro-4H-pyran-3-carbaldehyde/2-formyl-3, 4,6-tri-O-methyl-D-glucal/chromone-3

80 citations


Cited by
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01 Jan 1999
TL;DR: Caspases, a family of cysteine-dependent aspartate-directed proteases, are prominent among the death proteases as discussed by the authors, and they play critical roles in initiation and execution of this process.
Abstract: ■ Abstract Apoptosis is a genetically programmed, morphologically distinct form of cell death that can be triggered by a variety of physiological and pathological stimuli. Studies performed over the past 10 years have demonstrated that proteases play critical roles in initiation and execution of this process. The caspases, a family of cysteine-dependent aspartate-directed proteases, are prominent among the death proteases. Caspases are synthesized as relatively inactive zymogens that become activated by scaffold-mediated transactivation or by cleavage via upstream proteases in an intracellular cascade. Regulation of caspase activation and activity occurs at several different levels: ( a) Zymogen gene transcription is regulated; ( b) antiapoptotic members of the Bcl-2 family and other cellular polypeptides block proximity-induced activation of certain procaspases; and ( c) certain cellular inhibitor of apoptosis proteins (cIAPs) can bind to and inhibit active caspases. Once activated, caspases cleave a variety of intracellular polypeptides, including major structural elements of the cytoplasm and nucleus, components of the DNA repair machinery, and a number of protein kinases. Collectively, these scissions disrupt survival pathways and disassemble important architectural components of the cell, contributing to the stereotypic morphological and biochemical changes that characterize apoptotic cell death.

2,685 citations

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TL;DR: A comprehensive review highlights recent advances in understanding of the intestinal pathotypes of E. coli, which carry an enormous potential to cause disease and continue to present challenges to human health.
Abstract: Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.

1,097 citations

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882 citations

Journal ArticleDOI
TL;DR: This is a review of anticancer agents isolated from endophytic fungi from 1990–2010, based on the assessment of the authors of the paper of the cytotoxicity of each compound against specific cancer cell lines.

458 citations