Comparison of the effect of L-carnitin loaded β-Cyclodextrin functionalized N-doped carbon dots on Artemia salina synthesized using Rhododendron luteum and Rhododendron ponticum

In this study, two different Rhododendron species (Rhododendron luteum ve Rhododendron ponticum), colloquially known as Rhododendron, collected from Turnalık plateau in Ordu province, were used. N-doped carbon dots functionalized with L-carnitine-loaded β-Cyclodextrin were synthesized by the hydrothermal method, with plants used as carbon sources. Characterization of the synthesized carbon dots (LCAR/β-CD@Rh.l/N-CD and LCAR/β-CD@Rh.p/N-CD) was examined by SEM, TEM, UV-VIS, EDX and Elemental Analysis. The synthesized carbon dots show a monodisperse distribution in a spherical structure with dimensions of approximately 3-5 nm. C, O, N and H elements and O-H, C-H, C–O–C, C-O, N-H, C-N and C-C groups were detected in the structure of CDs. The acute toxicity of the synthesized carbon dots was determined on A. salina larvae, which are zooplankton. This aim, Artemia larvae were exposed to carbon dots at concentrations ranging from 5 to 100 mL and at time intervals of 12, 24, 48, 72 and 96 h. By probit analysis, LC50 values were calculated as 12.858 for LCAR/β-CD@Rh.l/N-CD and 21.058 for LCAR/β-CD@Rh.p/N-CD, respectively. Antimicrobial and antioxidant activities (SOD, CAT), oxidative stress markers (ROS, MDA) and DPPH radical scavenging activities were investigated at sublethal concentrations determined as a result of acute toxicity. SOD, CAT and MDA activities varied depending on the exposure time in larvae exposed to carbon dots. ROS formation in larvae was observed with fluorescence microscopy. In the DPPH radical scavenging assay, it was determined that the Rh.l extract indicated DPPH radical scavenging activity close to the standard substance (BHT). It was determined that carbon dots and L-carnitine synthesized with extracts obtained from the Rhododendron plant had antimicrobial effects on microorganisms. In fluorescence microscopy and scanning electron micrographs of larvae treated with carbon dot, various structural defects such as abdominal shortening, abdominal fragmentation, and limb loss were detected in Artemia larvae.