Unraveling fluorescent mechanism of biomass-sourced carbon dots based on three major components: Cellulose, lignin, and protein.

The complexity of biomass components leads to significant variations in the performance of biomass-based carbon dots (CDs). To shed light on this matter, this study presents a comparative analysis of the fluorescence properties of CDs using pure cellulose, lignin, and protein as models. Three CDs showed different fluorescent properties, resulting from the structure difference and carbonization behavior in the hydrothermal. The relatively gentle thermal degradation of proteins allows the macromolecular structure of amino acids to be preserved. This preservation results in a more regular lattice structure, a larger sp2 domain size, and N-doping, which contribute to the highest quantum yield (QY) of 8.7% of the CDs. In contrast, cellulose undergoes more severe thermal degradation with large amounts of small molecules generated, resulting in the CDs with fewer surface defects, more irregular lattice structures, and lower QY. These results provide a guideline for the design of carbon dots from different biomass.

Diketopiperazine and enterotoxin analogues from the mangrove derived-soil Streptomyces sp. SCSIO 41400 and their biological evaluation.

A new diketopiperazine, cyclo-(d-8-acetoxyl-Pro-l-Leu) (1), together with eight known compounds (2-9) including three enterotoxins (2-4), four diketopiperazines (5-8) and maltol (9), were isolated from the mangrove derived-soil Streptomyces sp. SCSIO 41400. The planar structures of all compounds were determined from analysis of NMR spectra, MS, optical rotation and comparing with literature data. The absolute configuration of compound 1 was assigned by electronic circular dichroism (ECD). The isolated compounds (1-9) were tested for their acetyl cholinesterase (AChE) and pancreatic lipase (PL) enzyme inhibitory activities. Among them, the new diketopiperazine (1) displayed preferable PL enzyme inhibitory activity with IC50 value of 27.3 µg/mL, while compounds 2, 5 and 6 showed weak PL enzyme inhibitory activity. Further molecular docking simulation exhibited that compound 1 could be well bind with the catalytic pocket of the PL. Besides, compound 9 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with MIC value of 12.5 µg/mL, which was comparable to that of the positive control ampicillin with MIC value of 3.125 µg/mL.

[Effects of beta-asarone on expression of FOS and GAD65 in cortex of epileptic rat induced by penicillin].

OBJECTIVE: To study effects of beta-asarone on expression of FOS and GAD65 in cortex of epileptic rat induced by penicillin. METHODS: The epileptic animal models were induced by penicillin. The rats were randomly divided into beta-asarone of high (100 mg/kg), medium (50 mg/kg), low (25 mg/kg) dose group, positive control group (Phenytoin sodium), negative control group (matrix). The medicine was administered orally. The effects of beta-asarone on expression of FOS and GAD65 in cortex of epileptic rat were detected by immuohistochemistry method. RESULTS: beta-asarone could raise expression of FOS and reduce expression of GAD65 obviously. There were significant differences between negative control group and beta-asarone group. And it showed significant dose-effect relationship. CONCLUSION: Up-regulation of FOS may be a effective link of anti-epileptic effect of beta-asarone; reduced expression of GAD65 may be a follow-up impact of beta-asarone treatment.

[Effects of beta-asarone on morphology and cell viability in PC12 cells and cultured rat cortical neurons].

OBJECTIVE: To observe the effects of beta-asarone on the morphology and cell viability in PC12 cells and cultured neonate rat cortical neurons. METHODS: The cultured neonate rat cortical neurocytes were stained immunocytochemically with NSE, GFAP antibodies, respectively; Morphological changes were observed under phase contrast microscope after PC12 cells and cultured rat cortical neurons with beta-asarone of different concentrationfor 24h in vitro, and the cell viability of PC12 and cortical neurons were examined by MTT assay. RESULTS: Most of the cultured neonate rat cortical neurocytes were positively stained with NSE antibody, and positively with GFAP in a less degree; Treatment of PC12 cells with concentrations of 7.5, 15, 30, 60 microg/ml beta-asarone for 24 h could facilitate the proliferation in PC12 cells, 120, 240, 480 microg/ml beta-asarone could inhibit the proliferation inversely, and with the concentration of beta-asarone increasing, the inhibition was enhanced; Treatment of cultured neonate rat cortical neurons with concentrations of 7.5, 15, 30, 60,120 nicrog/ml beta-asarone for 24 h, there were no visible effects on morphology and cell viability, 240 microg/ml beta-asarone could facilitate the proliferation obviously, but 480 microg/ml beta-asarone induced injury on neurons. CONCLUSION: beta-asarone maybe has anti-tumor and protective effects on cultured neurons.