Browsing by Author "Sweta Misra"

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Resolution, absolute configuration and antifilarial activity of coumarinyl amino alcohols
(Elsevier Ltd, 2017) Priyanka; Sweta Misra; Shailja Misra-Bhattacharya; Ray J. Butcher; Diksha Katiyar
The resolution of racemic coumarinyl amino alcohols 5–10 was achieved by using the inexpensive and readily accessible chiral resolving agent N-carbethoxy-L-proline (S)-11. Direct esterification of rac-5–10 with (S)-11 furnished diastereomeric esters, which were easily separated by column chromatography. The obtained diastereomers yielded the desired enantiopure coumarinyl amino alcohols (S)-(+)-5–10 and (R)-(−)-5–10 in good yields with high enantiomeric excess on saponification. The absolute configurations were determined by X-ray crystal analysis and/or by comparison of the specific rotations. Furthermore, in in vitro antifilarial motility inhibition assays, enantiopure coumarins (S)-(+)-9, (R)-(−)-9 and (S)-(+)-10, (R)-(−)-10 were found to be less efficient in affecting the viability of macrofilariae of Brugia malayi than their racemic forms 9 and 10, respectively, indicating the synergistic effect of the enantiomers in evoking antifilarial action. © 2017 Elsevier Ltd
Synthesis and biological evaluation of 4-oxycoumarin derivatives as a new class of antifilarial agents
(Elsevier Masson SAS, 2015) Sweta Misra; Lav Kumar Singh; Priyanka; Jyoti Gupta; Shailja Misra-Bhattacharya; Diksha Katiyar
Abstract A series of 4-oxycoumarin derivatives was synthesized, characterized and evaluated in vitro and in vivo for antifilarial activity against the human lymphatic filarial parasite, Brugia malayi. A majority of the compounds studied showed potent in vitro activity with low IC50 values in the micro molar (μM) range (0.014-1.73 and 0.0056-0.43) against adult worms and microfilariae, respectively. Compounds 8 and 9 were identified to be the most promising antifilarial candidate molecules exhibiting activity in the nanomolar (nM) range. The IC50 values for compound 8 were 14 nM and 5.6 nM while for compound 9 were 94 nM and 13 nM, respectively, for adult worm and microfilaria. These two compounds also displayed promising adulticidal activity (74.9 ± 4.8% and 69.4 ± 2.8%, respectively) in the primary rodent (jird) screen. This study also serves as a starting point for investigating structure-activity relationship with different amino substituents. © 2015 Published by Elsevier Masson SAS.
Synthesis, Structure Elucidation, Homology Modeling and Antifilarial Activity of 7-Benzamidocoumarin Derivatives
(Wiley-Blackwell, 2019) Priyanka; Neelabh; Neha Tiwari; Rajesh K. Sharma; Poonam Gupta; Sweta Misra; Shailja Misra-Bhattacharya; Ray J. Butcher; Karuna Singh; Diksha Katiyar
A series of 7-benzamidocoumarin derivatives 10–25 starting from 7-amino coumarins 7 and 8 has been synthesized, characterized and evaluated in vitro for antifilarial activity against the human lymphatic filarial parasite, Brugia malayi. Compounds 13 and 20–23 showed permanent paralysis of the worm with 90–95% inhibition of motility of adult worms at 10 μM. All the synthesized compounds were docked on the modeled receptor of Onchocerca volvulus chitinase OvCHT1. Compound 13 with binding energy of −7.95 Kcal/mol showing three hydrogen bonds with the active site of the enzyme emerged as the best inhibitor. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim