Pharmaceutical Sciences and Natural Products - Research Publications

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Author: search.filters.author.Joshi, GHas files: Yes

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    Knoevenagel/tandem knoevenagel and michael adducts of cyclohexane-1,3-dione and aryl aldehydes: Synthesis, DFT studies, xanthine oxidase inhibitory potential, and molecular modeling
    (American Chemical Society, 2019) Arora, S; Joshi, G; Kalra, S; Wani, A.A; Bharatam, P.V; Kumar, Pradeep; Kumar, Raj
    Xanthine oxidase (XO) plays a crucial role in the formation of uric acid by oxidative hydroxylation of purines. Herein, we report the design and synthesis of Knoevenagel/tandem Knoevenagel and Michael adducts of cyclohexane-1,3-dione and aryl aldehydes as nonpurine XO inhibitors derived from naturally occurring scaffolds. Density functional theory calculations highlighted the reaction pathways and reasoned the formation of tandem Knoevenagel and Michael adducts. The synthetics were assessed for their XO inhibitory potential, and among them, four compounds (1b, 1g, 2b, and 3a) were found to possess best IC 50 values in the range of 3.66-4.98 μM. Interestingly, Knoevenagel adducts exhibited a competitive-type inhibition, whereas tandem Knoevenagel and Michael adducts produced a noncompetitive mode of inhibition. The compounds were capable of reducing the H 2 O 2 levels induced by XO, both in normal and cancer cells with no significant cytotoxicity. Molecular modeling studies highlighted the role of interactions of compounds with residual amino acids of the XO active site and also corroborated with the observed structure-activity relationship. © 2019 American Chemical Society.
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    Pd-Catalyzed Four-Component Sequential Reaction Delivers a Modular Fluorophore Platform for Cell Imaging
    (American Chemical Society, 2019) Ansari, A.J; Joshi, G; Sharma, P; Maurya, A.K; Metre, R.K; Agnihotri, V.K; Chandaluri, C.G; Kumar, Raj; Singh, S; Sawant, D.M.
    A Pd-catalyzed cascade reaction of four versatile privileged synthons is described. The sequential reaction involves the formation of five new chemical bonds by concatenating three distinct chemical steps. One of the derivatives exhibited absorption in the visible region, fluorescence with a high quantum yield, and excellent photostability. Its application is explored in live cell imaging, which exhibited cytoplasmic and mitochondrial specific staining with no toxicity. © 2019 American Chemical Society.
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    Nano-Co-Delivery of Berberine and Anticancer Drug Using PLGA Nanoparticles: Exploration of Better Anticancer Activity and In Vivo Kinetics
    (Springer, 2019) Khan, I; Joshi, G; Nakhate, K.T; Ajazuddin, Kumar Raj; Gupta, U.
    Purpose: Combinatorial approach can be beneficial for cancer treatment with better patient recovery. Co-delivery of natural and synthetic anticancer drug not only valuable to achieve better anticancer effectivity but also to ascertain toxicity. This study was aimed to co-deliver berberine (natural origin) and doxorubicin (synthetic origin) utilizing conjugation/encapsulation strategy through poly (lactic-co-glycolic acid) (PLGA) nanoparticles. Methods: Doxorubicin was efficiently conjugated to PLGA via carbodiimide chemistry and the PLGA-doxorubicin conjugate (PDC) was used for encapsulation of berberine (PDBNP). Results: Significant anti-proliferative against MDA-MB-231 and T47D breast cancer cell lines were observed with IC50 of 1.94 ± 0.22 and 1.02 ± 0.36 μM, which was significantly better than both the bio-actives (p < 0.05). The ROS study revealed that the PDBNP portrayed the slight increase in the reactive oxygen species (ROS) pattern in MDA-MB-231 cell line in a dose-dependent manner, while in T47D cells, no significant change in ROS was seen. PDBNP exhibits significant alteration (depolarization) in mitochondrial membrane permeability and arrest of cell cycle progression at sub G1 phase while the Annexin V/PI assay followed by confocal microscopy resulted into cell death mode to be because of necrosis against MDA-MB-231 cells. In vivo studies in Sprague Dawley rats revealed almost 14-fold increase in half life and a significant increase in plasma drug concentration. Conclusion: The overall approach of PLGA based co-delivery of doxorubicin and berberine witnessed synergetic effect and reduced toxicity as evidenced by preliminary toxicity studies. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
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    Relay tricyclic Pd (ii)/Ag (i) catalysis: design of a four-component reaction driven by nitrene-transfer on isocyanide yields inhibitors of EGFR.
    (Royal Society of Chemistry, 2018) Sawant, D.M.; Sharma, S; Pathare, R.S; Joshi, G; Kalra, S; Sukanya, S; Maurya, A.K.; Metre, R.K; Agnihotri, V.K.; Khan, S.; Kumar, Raj; Pardasania, R. T.
    Synthesis of pyrazolo[1,5-c]quinazolines from four easily available precursors is presented through a one-pot tricyclic Pd(II)/Ag(I) relay catalysis. The bimetallic relay cascade forges five new chemical bonds by concatenating six discrete chemical steps. The relay catalysis enables four-component assembly of pyrazolo[1,5-c]quinazolines that selectively inhibit EGFR, exhibit apoptosis through the ROS-induced mitochondrial-mediated pathway, and arrest the cell cycle at the G1 phase.
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    Unanticipated Cleavage of 2-Nitrophenyl-Substituted N-Formyl Pyrazolines under Bechamp Conditions: Unveiling the Synthesis of 2-Aryl Quinolines and Their Mechanistic Exploration via DFT Studies.
    (ACS Publications, 2018) Joshi, G; Wani, A.A.; Sharma, S; Bhutani, P; Bharatam, P.V.; Paul, A.T.; Kumar, R.
    We herein report for the first time an unusual decomposition of 2-nitrophenyl-substituted N-formyl pyrazolines under Bechamp reduction condition employed to yield 2-aryl quinolines exclusively instead of pyrazolo[1,5-c]quinazolines. The reaction investigation suggests acid-mediated cleavage of 1 followed by a retro-Michael addition, and a subsequent in situ intramolecular reductive cyclization through a modified Friedlander mechanism afforded 2-aryl quinolines (2) in good yields. The proposed mechanistic pathways were supported via experimental evidence and density functional theory studies. B3LYP/6-31+G(d) analysis indicated the involvement of trans-2-hydroxyaminochalcone as a key intermediate and its isomerization and cyclization, leading to unusual product formation.