Bio-Physical Chemistry and Nano-Science Group
The Chemistry Department at Tougaloo College pursues research studies which encompass three main themes of contemporary interest:
Studies on the antioxidative properties of plant flavonoids in preventing glycation of proteins and DNA
Flavonoids are polyhydroxy phenolic compounds which are ubiquitously present in fruits and vegetables like apples, grapes, onions, oranges etc. and are gradually emerging as potent therapeutic drugs effective against a wide range of free radical mediated diseases e.g. atherosclerosis, ischemia, diabetes, neuronal degeneration, cardiovascular disorders, cancer. Flavonoids usually contain one or more aromatic hydroxyl groups, which actively scavenge free radicals and are responsible for the antioxidant activity. We are studying the structural variations of protein and DNA which occur by glycation / glycosylation in presence of sugars, as a model of diabetes mellitus. We use spectroscopic, chromatographic and related biophysical techniques in order to prove that plant flavonoids are potent antioxidants to prevent this oxidative glycation in DNA / proteins.
DNA Templates for Fluorescent Silver Clusters
We are involved in the development of novel nonmaterial’s, which are very useful in bio imaging. Silver nanoclusters are a new class of fluorescent labels in biology. I am studying the properties of different sequences of DNA encapsulated, brightly fluorescing photo-activated silver nanoclusters that have much brighter and more robust emission than organic dye molecules. These highly bright, robust nanomaterials should enable direct labeling of proteins to image live cells, study protein-protein interactions, and potentially help to observe individual proteins as they fold to their native conformations. We observed that the secondary and tertiary structure of DNA play an important role in deciphering the emission characteristics of the silver clusters. At neutral or slightly acidic pH cytosine rich DNA folds in unusual non-Watson Crick manner called i-motif, which is found to be important in controlling the size of the silver cluster.
Spectroscopic studies on the binding of therapeutically active plant flavonoids with physiological targets
We have fruitfully exploited the exquisitely sensitive intrinsic fluorescence emission properties of plant flavonoids which possess potential anti-oxidant, anti-cancer, anti-AIDS and other important therapeutic properties with high potency and low systematic toxicity, to explore their interactions with physiologically relevant targets viz proteins, DNA, biomembranes and encapsulation in nano-cavities of cyclodextrin based drug delivery vehicles. We found that the flavonoid molecules bind with two distinct sites in human serum albumin, while in membranes they are localized at the interfacial regions. Flavonoids are found to intercalate in DNA. Such works would lead to new avenues for examining ‘structure-activity’ relationships and ‘screening’ of flavonoid derivatives with desired therapeutic properties and also provide insights toward future goals for developing effective drug delivery strategies.
Awards from Dr. Sengupta’s laboratory:
1. Undergraduate student Jasmine Taylor received award for poster presentation at Mississippi Academy of Sciences, USM, 2012. 2nd place.
2. Tougaloo College Mississippi College Research Symposium, 2012. Undergraduate students Laura Blackmon (currently pursuing Ph.D at UMC) received 2nd prize in poster presentation. Jasmine Taylor won 3rd prize in the same.
3. Dr. Sengupta received the American Association for the Advancement of Science (AAAS) Women's International Research Collaborations (WIRC) for Minority Serving Institutions (MSIs), the Travel award in 2012 from NSF.
List of Publications