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Permanent URI for this communityhttps://hdl.handle.net/20.500.12503/29916
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Browsing Abstracts by Author "Acharya, Suchismita"
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Item SMALL MOLECULE SA-2 USEFUL FOR TREATING ALZHEIMER'S DISEASE(2020) Weston, Courtney; Mahapatra, Vasu; Stankowska, Dorota; Acharya, Suchismita; Amankwa, Charles E.Purpose: Alzheimer's disease (AD) is a neurodegenerative disorder affecting mainly the aged population. Oxidative stress is known to play important role in the pathogenesis of AD and is increased in the brain with aging. Reactive oxygen species (ROS) are released in excess which leads to neuronal atrophy and long-term tissue damage. Low levels of nitric oxide (NO) is beneficial for neurogenesis and has antioxidant activity. Our goal is to synthesize novel hybrid molecules with dual antioxidant-nitric oxide donating activity against oxidative stress-induced hippocampal neuronal HT-22 cell deaths. Method: The compounds (SA-2, SA-9 and SIN-1) were synthesized and encapsulated into nanoparticles (NP). Structure of the compounds and size of nanoparticles were confirmed using 1HNMR and DLS. Mouse HT-22 cells were seeded in 96 well plates, tert-butyl hydrogen peroxide (TBHP,10µM- 5mM) was added and incubated at 2, 4, 6 and 12 hours. MTT assay (Promega) was performed to determine the effective concentration (EC50) of TBHP. For cell viability study cells were treated with/without TBHP and compounds (SA-2, SA-2 NP, SA-9, SIN-1, 1µM, 10 µM and 100 µM). After 6 hours, MTT assay was performed to assess cell proliferation. Results: We found the EC50 of TBHP is 80µM (6h). Compound SA-2 (100µM) and SA-2 NP (0.1%, equivalent to 25µM of free SA-2) provided significant protection to TBHP induced HT-22 cell death. Conclusion: SA-2 NP is highly effective than free SA-2. Further assessments are ongoing.Item Synthesis and Bioactivity of Nitric Oxide Donor and Antioxidant Drug Hybrid(2020) Nguyen, Ngoc; Weston, Courtney; Acharya, Suchismita; Khowaja, SanoberPurpose: In ischemic stroke or peripheral artery disease, there is a blockage of the arteries that results in increased free radicals and cell death. Our goal was to synthesize a hybrid compound SA-9-01 and assess the NO releasing and reactive oxygen species (ROS) scavenging ability using chemical assays. We hypothesize that the hybrid compound will prevent cell death by improving blood circulation and neutralizing ROS. Methods: SA-9-01 was synthesized using a synthetic procedure similar to a previously designed analog SA-2 and structure was verified by 1HNMR. The NO releasing activity was determined using the Griess assay by measuring the total nitrite formation. The xanthine oxidase assay was used to measure the ROS scavenging activity. Results: Compound SA-9 (25 mM) released NO at concentrations between 1.35-1.40 µM at t=90 mins sufficient to provide therapeutic activity, while a known NO donor SIN-1 released between 2-15 µM at same concentration and time point. From the xanthine oxidase assay, the scavenging ratio for SA-9-01 (250 µM) was about 20-25% at t=100 mins and comparable to previously described compound SA-2 and Baicalein (the positive control). Conclusion: Compound SA-9-01 was synthesized successfully with the correct chemical structure and was found to be a tautomer of the first batch SA-9. The Griess assay demonstrated that SA-9 releases physiological level of NO. SA-9-01 also demonstrated ROS scavenging activity. The testing of SA-9-01 in cells is under progress.Item Synthesis and Bioactivity Study of Novel Hybrid Antioxidant(2020) Weston, Courtney; Khowaja, Sanober; Acharya, Suchismita; Nguyen, NgocPurpose: Antioxidant enzymes are the first line defense for preventing oxidative stress (OS) by scavenging free radicals, and different enzymes scavenge different reactive oxygen species (ROS). We focused on two major antioxidants: superoxide dismutase (SOD), which removes superoxide; and glutathione peroxidase (GPx), which removes hydrogen peroxide radicals. The purpose was to synthesize a hybrid compound with multiple antioxidant activities and to test the total ROS scavenging ability using a chemical assay. The goal is to use this class of compound as a method of preventing and treating ophthalmologic diseases related to oxidative damage. Methods: Synthesis of a hybrid antioxidant MN-1-26 was carried out using an amide coupling reaction between 4-amino Tempol (a SOD mimetic) and NHBoc methionine followed by purification using liquid chromatography. Structure confirmation was done using proton NMR. The ROS scavenging chemical assay was conducted following a literature protocol where pyrogallol was used as the ROS generator. Changes in UV absorbance were measured at different time points to compare MN-1-26 (250µm) with SA-2 (a known SOD mimetic) and Baicalein (a polyphenolic antioxidant) as positive controls. Result: Compound MN-1-26 has the correct chemical structure, determined by proton NMR, with the highest superoxide scavenging ratio (28%) at 90 minutes compared to SOD mimetic SA-2 (22%), and Baicalein (24%). Conclusion: The hybrid antioxidant demonstrated superior ROS scavenging activity over individual antioxidants. Further cellular studies of MN-1-26 are under progress, with the goal of reducing OS and cell death in vitro.Item Synthesis and in vitro study of dual acting hybrid compound for treating Glaucoma(2020) Stankowska, Dorota; Acharya, Suchismita; Ellis, Dorette; Weston, Courtney; Li, Linya; Gondi, SudershanPurpose: Glaucoma presents with high intraocular pressure (IOP) due to decreased aqueous humor outflow and impaired trabecular meshwork (TM). Increased IOP affects the optic nerve head leading to degeneration of retinal ganglion cells (RGC's). Currently many therapies aim to reduce IOP, however they do not address the damage done to the RGCs. Our goal is to find a multifunctional molecule that can lower IOP while also being neuroprotective. For this project, we planned to synthesize a series of compounds and evaluate their cellular activity in primary human TM cells. Methods: Compounds SA-2, PLGA encapsulated SA-2 nanoparticles (NP) and SA-24 were synthesized. Proton NMR and dynamic light scattering methods were used to determine structure and particle size. Greiss assay was used to assess total nitrite and reactive oxygen species (ROS) scavenging assay was performed following the manufacturer's protocol. Next, primary hTM-80 cells were seeded in 96 well plates to confluency, and exposed to tert-butyl hydrogen peroxide (TBHP, 300uM) for 15 min. followed by treatment with the compounds. The cell proliferation was measured using MTT assays (Promega). The experiments were done in quadruplicates. Results: SA-2, SA-2NP and SA-24 were equally effective in scavenging ROS at 250 µM and SA-2 provided highest amount of NO. Compound SA-2 (200uM) and SA-2NP (1%) significantly protect TBHP induced decreased cell proliferation. Conclusion: Compound SA-2 has both NO releasing and ROS scavenging activity. As expected, SA-2NP has slow release profile and better proliferative activity.