Soundar Divakar

Bio: Soundar Divakar is an academic researcher from Central Food Technological Research Institute. The author has contributed to research in topics: Lipase & Triacylglycerol lipase. The author has an hindex of 23, co-authored 104 publications receiving 2099 citations.

Isolation and identification of a radical scavenging antioxidant – punicalagin from pith and carpellary membrane of pomegranate fruit

Abstract: Pith and carpellary membrane (CM) constitute 13% of pomegranate fruit composition. Pith acts as an anchoring tissue while CM acts as a protective membrane; both play significant roles in determining the health and disease status of pomegranate arils but remain unexplored for their nutraceutical properties. Activity-guided repeated fractionation of the methanol extract on a silica gel column, followed by preparative HPLC, yielded a compound which exhibited strong radical scavenging activity with EC50 values of 16.7 plus or minum 2.3 and 54.2 plus or minus 4.6 against DPPH free radical and superoxide radicals, respectively. It also showed a very strong lipid peroxidation inhibitory activity in a liposome model system with an EC50 value of 54.2 plus or minus 0.9. However, it showed negligible metal chelating activity. Based on UV, IR, 2D-NMR, GC-Mass and MALDI-Mass studies, the compound was identified as punicalagin. The antioxidant activity of punicalagin and the methanol extract can be ascribed mainly to radical scavenging ability.

Isolation of a free radical-scavenging antioxidant from water spinach (Ipomoea aquatica Forsk)

Abstract: Ipomoea aquatica Forsk, a green leafy vegetable that is a rich source of vitamins and amino acids with many health benefits, has been explored for the isolation and identification of its bioactive compounds. Activity-guided repeated fractionation of a methanol extract on a silica gel column followed by an XAD column yielded a compound that exhibited antioxidant activity with an EC50 value of 83 ± 1.02 µgml−1 reaction mixture. It also showed very strong lipid peroxidation-inhibitory activity in a liposome model system with an EC50 value of 72.2 ± 0.9 µgml−1. However, it showed negligible metal-chelating activity. Based on UV, 2D nuclear magnetic resonance and gas chromatography/mass spectrometry studies, the compound was tentatively identified to be 7-O-β-D-glucopyranosyl-dihydroquercetin-3-O-α- D-glucopyranoside. This is the first report on the antioxidant properties of I aquatica leaf extracts.  2005 Society of Chemical Industry

Curcumin: The Indian solid gold

Abstract: Turmeric, derived from the plant Curcuma longa, is a gold-colored spice commonly used in the Indian subcontinent, not only for health care but also for the preservation of food and as a yellow dye for textiles. Curcumin, which gives the yellow color to turmeric, was first isolated almost two centuries ago, and its structure as diferuloylmethane was determined in 1910. Since the time of Ayurveda (1900 Bc) numerous therapeutic activities have been assigned to turmeric for a wide variety of diseases and conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, wounds, sprains, and liver disorders. Extensive research within the last half century has proven that most of these activities, once associated with turmeric, are due to curcumin. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Curcumin exhibits activities similar to recently discovered tumor necrosis factor blockers (e.g., HUMIRA, REMICADE, and ENBREL), a vascular endothelial cell growth factor blocker (e.g., AVASTIN), human epidermal growth factor receptor blockers (e.g., ERBITUX, ERLOTINIB, and GEFTINIB), and a HER2 blocker (e.g., HERCEPTIN). Considering the recent scientific bandwagon that multitargeted therapy is better than monotargeted therapy for most diseases, curcumin can be considered an ideal "Spice for Life".

Biomimetic Reactions Catalyzed by Cyclodextrins and Their Derivatives.

Abstract: Cyclodextrins are extremely attractive components of artificial enzymes and other biomimetic materials. They are readily available, they bind hydrophobic substrates into their cavities in water solution, and they have two rims of hydroxyl groups (Figure 1) that can either react with substrates themselves or be used to attach other catalytic and functional groups. Of course, they have disadvantages. For one, unless they are extensively modified their complexes with substrates can be rather flexible and, perhaps, with unpredictable preferred geometry. They are also unstable to strong acid. Thus for some purposes such synthetic cavity species as calixerenes1 or synthetic macrocycles2-4 may have advantages. However, one of the chief advantages of cyclodextrins is highly attractivesthey are readily available, so it is possible to avoid the synthesis of a binding group and go directly to studies of what can be achieved with their use. Afterward, the lessons learned may be applied to other systems with advantage. This review will cover all the literature on reactions in which cyclodextrins bind substrates and then either catalyze their reactions or mimic a step in an enzymatic catalytic sequence. However, it will not describe work in which cyclodextrins simply change the course of a reaction without playing an obvious catalytic role involving substrate binding. For example, there are systems in which the main function of the cyclodextrin seems to be to complex a metal ion and keep it in solution.5-11 There are other studies in which binding into a cyclodextrin simply alters the selectivity of attack by an external reagent in some way12-24 or causes solubilization to facilitate phase transfer catalysis.12,25,26 Presumably such other areas are described elsewhere in this volume. While much work on artificial enzymes using cyclodextrins has been done in the author’s laboratory, and will be described, every effort is made to describe all the relevant work in the field. Several reviews of this subject already exist and should be consulted for further information.2,27-70 The readily Ronald Breslow, born in 1931 in Rahway, NJ, completed his B.A. in chemistry in1952, his M.A. in medical science in 1953, and his Ph.D. in chemistry in 1955 with R. B. Woodward, all at Harvard University. After a postdoctoral year with Alexander Todd in Cambridge, he came to Columbia University where he is now University Professor and Professor of Chemistry. His work on enzyme models, on novel conjugated aromatic and antiaromatic molecules, on electrochemical and hydrophobic methods in mechanistic chemistry, and on anticancer cytodifferentiating agents has been recognized by a number of awards, including the U.S. National Medal of Science. In 1996, he served as President of the American Chemical Society.