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    Antitumor activity of chitosan from mayfly with comparison to commercially available low, medium and high molecular weight chitosans
    (Springer, 2018) Tan, Gamze; Kaya, Murat; Tevlek, Atakan; Sargın, İdris; Baran, Talat
    Insects' cuticles have a potential to be evaluated as a chitin source. Especially adults of aquatic insects like mayflies (order Ephemeroptera) swarm in enormous numbers in artificially lit areas while mating in spring and then die by leaving huge amounts of dead insects' bodies. Here in this study, mayfly corpses were harvested and used for production of low MW chitosan. Dried mayfly bodies had 10.21% chitin content; mayfly chitin was converted into chitosan with efficiency rate of 78.43% (deacetylation degree, 84.3%; MW, 3.69 kDa). Cytotoxicity and anti-proliferative activity of mayfly and commercially available shrimp chitosans (low, medium, and high MW) were determined on L929 fibroblast and three different cancer types including HeLa, A549, and WiDr. Apoptosis and necrosis stimulating potential of mayfly and commercial chitosans were also evaluated on A549 and WiDr cells using acridine orange and propidium iodide dual staining to observe morphological changes in nuclei and thus to reveal the predominant cell death mechanism. The effects of chitosans have varied depending on cell types, concentration, and chitosan derivatives. Mayfly and low MW chitosans had a cytotoxic effect at a concentration of 500 mu g mL(-1) on non-cancer cells. At concentrations below this value (250 mu g mL(-1)), mayfly and commercial chitosans except high MW one exhibited strong inhibitory activity on cancer cells especially A549 and WiDr cells. Mayfly chitosan induced early and late apoptosis in A549 cells, but late apoptosis and necrosis in WiDr cells. This study suggests that dead bodies of mayflies can be used for production of low MW chitosan with anti-proliferative activity.
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    Comparison of garlic and onion extract-derived gold nanoparticles: Characterization and anticancer activity
    (Editions de Sante, 2023) Tan, Gamze; Tevlek, Atakan; Aydın, Halil Murat
    The present study aims to probe the antioxidative and anticancer activities of gold nanoparticles (AuNPs) reduced by Allium cepa L. (onion-O) and Allium sativum L. (garlic-G) extracts. Versatile analyzes were employed to evaluate the morphological and hydrodynamic properties of the particles, as well as to determine their bioactive components and radical scavenging activities. The biological effects of particles such as toxicity, proliferation, motility, and cell-death mechanism were tested in vitro on fibroblast (L929) and different cancer cell lines. The size range of the spherical particles prepared in three groups for each plant extract was found to vary between 5-10 nm and 7–18 nm for garlic and onion respectively, depending on the extract amount. The particles were also found to be well-dispersed and colloidally stable in aqueous media. Gallic acid was the common phenolic compound in the extracts. The radical scavenging properties of the particles increased depending on the extract amount, and the effect was greater in those synthesized with onion extract. When comparing different types of AuNPs, garlic-reduced AuNPs (GAuNPs) had a more stable effect on cancer cells than onion-reduced AuNPs (OAuNPs). Fluorescence staining showed that nanoparticles caused relatively similar necrotic responses in WiDr cells. However, OAuNPs triggered apoptosis to a greater extent in MCF-7 cells than GAuNPs. Both types of particles inhibited cell migration in both healthy and cancerous cells. In sum, both AuNPs exhibited cytotoxicity through their ability to modulate proliferation, apoptosis, and motility. ©