Green synthesis of fluorescent carbon dots from carrot juice for in vitro cellular imaging carbon dots;carrot;fluorescent;biocompatibility;bioimaging; We report the use of carrot, a new and inexpensive biomaterial source, for preparing high quality carbon dots (CDs) instead of semi-conductive quantum dots for bioimaging application. The as-derived CDs possessing down and up-conversion photoluminescence features were obtained from carrot juice by commonly used hydrothermal treatment. The corresponding physiochemical and optical properties were investigated by electron microscopy, fluorescent spectrometry, and other spectroscopic methods. The surfaces of obtained CDs were highly covered with hydroxyl groups and nitrogen groups without further modification. The quantum yield of as-obtained CDs was as high as 5.16%. The cell viability of HaCaT cells against a purified CD aqueous solution was higher than 85% even at higher concentration ($700{\mu}g\;mL^{-1}$) after 24 h incubation. Finally, CD cultured cells exhibited distinguished blue, green, and red colors, respectively, during in vitro imaging when excited by three wavelength lasers under a confocal microscope. Offering excellent optical properties, biocompatibility, low cytotoxicity, and good cellular imaging capability, the carrot juice derived CDs are a promising candidate for biomedical applications.

Globally, gastric ulcer is a vital health hazard for a human. Rabdosia inflexa (RI) has been used in traditional medicine for inflammatory diseases. The present study aimed to investigate the protective effect and related molecular mechanism of RI using lipopolysaccharide (LPS)-induced inflammation in RAW 246.7 cells and HCl/EtOH-induced gastric ulcer in mice. We applied 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), nitric oxide (NO), reactive oxygen species (ROS), histopathology, malondialdehyde (MDA), quantitative real-time polymerase chain reaction (qPCR), immunohistochemistry (IHC), and Western blot analyses to evaluate the protective role of RI. Study revealed that RI effectively attenuated LPS-promoted NO and ROS production in RAW 246.7 cells. In addition, RI mitigated gastric oxidative stress by inhibiting lipid peroxidation, elevating NO, and decreasing gastric inflammation. RI significantly halted elevated gene expression of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthetase (iNOS), and cyclooxygenase-2 (COX-2) in gastric tissue. Likewise, RI markedly attenuated the mitogen-activated protein kinases (MAPKs) phosphorylation, COX-2 expression, phosphorylation and degradation of inhibitor kappa B (IκBα) and activation of nuclear factor kappa B (NF-κB). Thus, experimental findings suggested that the anti-inflammatory and gastroprotective activities of RI might contribute to regulating pro-inflammatory cytokines and MAPK/NF-κB signaling pathways.