Clitoria ternatea Mediated Synthesis of Graphene Quantum Dots for the Treatment of Alzheimer’s Disease

Abstract

The main purpose of the present study was to synthesize graphene quantum dots (GQDs)from the flowers of Clitoria ternatea with the help of one-pot microwave-assisted green synthesis for the treatment of Alzheimer's disease. Further, the synthesized graphene quantum dots show a particle size of 10 nm ±1.3, a PDI of 0.354 ± 1.8, and a ζ potential of −46 ± 0.4, indicating the good stability of the quantum dots. With the help of scanning electron microscopy (SEM) and transfer electron microscopy (TEM) examination, the surface microscopic behavior of the synthesized quantum dots was determined. The presence of functional groups in the quantum dots was determined by Fouriertransform infrared spectroscopy (FTIR) study, the chemical state information on the sample was determined with the help of X-ray photoelectron spectroscopy (XPS), and the surface area of the dots was determined with the help of a surface area analyzer. With the help of a radial arm maze and water morris maze assay, the learning and memory capacity of the quantum dots was assessed, and the results show that the ctGQDs significantly decreased the transfer latency to reach the baited arm in 10.37 ± 1.65 s or to the hidden platform in 18.42 ± 0.99 s in 7 days. The synthesized quantum dots show more inhibition of the acetyl cholinesterase enzyme, i.e., 86.32 ± 1.52%, as compared to that of pure donepezil, i.e., 72.46 ± 2.21%. ctGQDs considerably increased the level of glutathione and protein and decreased the level of lipid peroxide and nitric oxide. The histopathological image of ctGQDs shows more preservation of small pyramidal cell and treats the disorganization of the cells. These results suggest that the quantum dots significantly crossed the blood−brain barrier since they were small in size and were effective in reducing Alzheimer-like symptoms in rodents, and thus, it can be concluded that Clitoria ternatea flowers can be used as an adjuvant in the treatment of Alzheimer's.

Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death

“…In accordance with the previously reported ROS-and NO-scavenging activity of GQD [24,27,56,57], we used EPR, chemical radical scavenging assays, and cytofluorometry to confirm their ability to neutralize • OH, O2 •− , and NO in cell-free conditions, as well as in SNP-treated SH-SY5Y cells. Somewhat surprisingly, the cytotoxicity of SNP in our experiments was mostly independent of NO, which was only marginally involved in the protection from SNP-induced cells death.…”

“…In conclusion, our study demonstrates that • OH/NO quenching and Akt/mTOR-dependent autophagy induction independently cooperate in GQD-mediated protection of SH-SY5Y neuronal cells from SNP-induced apoptotic death. While these findings remain to be confirmed in primary neurons and in vivo, the unique capacity of GQD to act both as antioxidants and inducers of prosurvival autophagy, coupled with low toxicity and the ability to cross blood-brain barrier [27,77] qualifies them as potential candidates for the treatment of oxidative/nitrosative stress-associated neurodegenerative and neuroinflammatory disorders.…”

“…The ability of GQD to enter various cell types, including neurons, is well documented [19][20][21][22][23]. While photoactivated GQD generate ROS [21,[24][25][26], in the absence of photoexcitation they act as antioxidants and protect cells by scavenging • OH, O2 •− [24,25], and NO [27]. GQD [21,28,29] and SNP [30][31][32] also induce macroautophagy (hereafter autophagy), a process in which damaged organelles and protein aggregates are sequestered within double-membrane autophagosomes, which subsequently fuse with lysosomes where autophagic cargo is degraded [33].…”

Nano-Theranostics Approaches and Mitochondrial Targeted Drug Delivery: Alzheimer ’s Disease Therapeutic Interventions

“…It was observed that these carbon dots showed more percentage of inhibitions than conventional acetylcholinesterase (AChE) inhibitors due to their small size which confers them to the unique ability to cross BBB easily. These NPs prevented the aggregation of Aβ peptides [97]. In another experiment, selenium quantum dots (SeQDs) had been prepared which have high BBB activity and a high cellular uptake rate.…”

Graphene Quantum Dots by Eco-Friendly Green Synthesis for Electrochemical Sensing: Recent Advances and Future Perspectives

“…For the synthesis of quantum dots, plants have proved to be excellent precursors, thanks to their high carbon content. For this reason, the alcoholic extract of a climbing plant ( Clitoria ternatea ) was used by Tak et al [ 67 ]. The Clitoria ternatea flower extract was mixed with HPLC water and subsequently heated to 900 W in a microwave oven for 5–10 min, then the resulting residue was distributed in absolute ethanol to form a GQD dispersion.…”