Browsing by Author "Ratnakar Tiwari"

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Fresh water cyanobacteria Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 as an anticancer drug resource
(Public Library of Science, 2015) Akanksha Srivastava; Ratnakar Tiwari; Vikas Srivastava; Tej Bali Singh; Ravi Kumar Asthana
An increasing number of cancer patients worldwide, especially in third world countries, have raised concern to explore natural drug resources, such as the less explored fresh water filamentous cyanobacteria. Six strains of cyanobacteria (Phormidium sp. CCC727, Geitlerinema sp. CCC728, Arthrospira sp. CCC729, Phormidium sp. CCC731, Phormidium sp. CCC730, and Leptolyngbya sp. CCC732) were isolated (paddy fields and ponds in the Banaras Hindu University, campus) and five strains screened for anticancer potential using human colon adenocarcinoma (HT29) and human kidney adenocarcinoma (A498) cancer cell lines. Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 were the most potent as determined by examination of morphological features and by inhibition of growth by graded concentrations of crude extracts and thin-layer chromatography (TLC) eluates. Cell cycle analysis and multiplex assays using cancer biomarkers also confirmed Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 as cancer drug resources. Apoptotic studies in the cells of A498 (cancer) and MCF-10A (normal human epithelial) exposed to crude extracts and TLC fractions revealed no significant impact on MCF-10A cells emphasizing its importance in the development of anticancer drug. Identification of biomolecules from these extracts are in progress. © 2015 Srivastava et al.
Green synthesis of gold nanoparticles from Dunaliella salina, its characterization and in vitro anticancer activity on breast cancer cell line
(Editions de Sante, 2019) Ankit Kumar Singh; Ratnakar Tiwari; Vikas Kumar Singh; Prabhakar Singh; Sk Riyazat Khadim; Urmilesh Singh; Laxmi; Vikas Srivastava; S.H. Hasan; R.K. Asthana
An ecofriendly and efficient method (photoinduced) has been used for green synthesis of stable gold nanoparticles (AuNPs) using aqueous extract as a reducing and stabilizing agent, derived from halotolerant microalga Dunaliella salina. Synthesis of AuNPs was confirmed by UV–Vis spectroscopy showing sharp SPR band at 560 nm after 30 min exposure of sunlight. The synthesis was optimized further as exposure(75min) to sunlight, aqueous extract of Dunaliella (AED) inoculum dose(30%) and HAuCl 4 .xH 2 O (1 mM). The presence of nearly spherical shape of AuNPs with average size of 22.4 nm and crystalline nature were confirmed by TEM, SAED and XRD analysis. The XPS analysis of AuNPs showed presence of two individual peaks at 85.17 and 88.94eV that attributed to Au 4f7/2 and Au 4f5/2 respectively. Phycochemical analysis of AED demonstrated presence of phenolics, flavonoids, tannin and proteins. AED when subjected to SDS-PAGE showed protein bands of 92 and 66 KDa. AuNPs were tested for anticancer activity on MCF7 (cancer) and MCF 10A (normal) cell lines, keeping commercial drug cisplatin as positive control. AuNPs selectively killed cancer cells and were not detrimental to the normal cell line whereas cisplatin killed normal cells also at 48 h exposure, therefore, such AuNPs may be used as an anticancer agent. © 2019 Elsevier B.V.
Photo-induced biosynthesis of silver nanoparticles from aqueous extract of Dunaliella salina and their anticancer potential
(Elsevier B.V., 2017) Ankit Kumar Singh; Ratnakar Tiwari; Vijay Kumar; Prabhakar Singh; S.K. Riyazat Khadim; Anupam Tiwari; Vikas Srivastava; S.H. Hasan; R.K. Asthana
The synthesis of silver nanoparticles (AgNPs) via green route, using biological entities is an area of interest, because one of the potential applications in the nanomedicine. In the present study, we have developed photo-induced, ecofriendly, low cost method for biosynthesis of the stable silver nanoparticles using aqueous extract of Dunaliella salina (AED) which act as both reducing as well as stabilizing agent. Biosynthesis of the AgNPs was optimized as: sunlight exposure (30 min), AED (5% (v/v)) and AgNO3 (4 mM). Biosynthesis of AgNPs was monitored by using UV–Vis spectroscopy which exhibited sharp SPR band at 430 nm after 30 min of bright sunlight exposure. SEM and TEM analyses confirmed the presence of spherical AgNPs with average size of 15.26 nm. Crystalline nature of AgNPs was confirmed by SAED and XRD analyses where Braggs reflection pattern at (111), (200), (220) and (311) corresponded to face centered cubic crystal lattice of metallic silver. FTIR analysis revealed the involvement of various functional groups present in AED. AFM analysis confirmed the average surface roughness of synthesized AgNPs as 8.48 nm. AgNPs were also screened for anticancer potential using assay of calcein AM/PI, Annexin/PI and cancer biomarkers against cancer cell line (MCF-7), while normal cell line (MCF-10A) were kept as control. Interestingly, anticancer potential was comparable to the known anticancer drug (Cisplatin), and was not detrimental to the normal cell line. Therefore, such green synthesized AgNPs may be explored as anticancer agent. © 2016 Elsevier B.V.