Cytotoxic Activities of 9,10-seco-Cycloartane-Type Triterpenoids from the Chinese Liverwort Lepidozia reptans.

Ten new triterpenoids, including nine 9,10-seco-cycloartanes (1-9) and one 9,19-cyclolanostane (10), as well as one sesquiterpenoid (11) and four known compounds (12-15), were extracted and purified from the whole plant of the Chinese liverwort Lepidozia reptans. Multiple techniques (NMR, HRESIMS, IR, and X-ray crystallographic analysis) were applied to determine the structures of the isolated compounds. Bioassay determinations showed that compound 7, which contains an α,ß-unsaturated carbonyl moiety in its structure, inhibited the growth of a panel of cancer cell lines with IC50 values ranging from 4.2 ± 0.2 to 5.7 ± 0.5 µM. Further investigation revealed that compound 7 induces PC-3 cell death via mitochondrial-related apoptosis.

Rapid and sensitive detection of Mycobacterium tuberculosis based on strand displacement amplification and magnetic beads.

Tuberculosis is one of the main infectious diseases threatening public health, and the development of simple, rapid, and cost-saving methods for tuberculosis diagnosis is of profound importance for tuberculosis prevention and treatment. The bacterium Mycobacterium tuberculosis (MTB) is the pathogen that causes tuberculosis, and assaying for MTB is the only criterion for tuberculosis diagnosis. A new enzyme-free method based on strand displacement amplification and magnetic beads was developed for simple, rapid, and cost-saving MTB detection. Under optimum conditions, a good linear relationship could be observed between fluorescence and MTB specific DNA concentration ranging from 0.05 to 150 nM with a correlation coefficient of 0.993 (n = 8) and a detection limit of 47 pM (3σ/K). The present method also distinguished a one base mismatch from MTB specific DNA, showing great promise for MTB genome single base polymorphism analysis. MTB specific DNA content in polymerase chain reaction samples was successfully detected using the new method, and recoveries were 97.8-100.8%, indicating that the present method had high accuracy and shows good potential for the early diagnosis of tuberculosis.

New Off-On Sensor for Captopril Sensing Based on Photoluminescent MoO x Quantum Dots.

Molybdenum oxide nanomaterials have recently attracted widespread attention for their unique optical properties and catalytic performance. However, until now, there is little literature on the application of photoluminescent molybdenum oxide nanomaterials in biological and pharmaceutical sensing. Herein, photoluminescent molybdenum oxide quantum dots (MoO x QDs) were synthesized via a facile method, and then, the synthesized MoO x QDs were further applied as a new type of photoluminescent probe to design a new off-on sensor for captopril (Cap) determination on the basis of the fact that the quenched photoluminescence of MoO x QDs by Cu2+ was restored with Cap through specific interaction between the thiol group of Cap and Cu2+. Under optimal conditions, the restored photoluminescence intensity showed a good linear relationship with the content of Cap, ranging from 1.0 to 150.0 µM, with a limit of detection of 0.51 µM (3σ/k). Additionally, the content of Cap in pharmaceutical samples was successfully detected with the newly developed off-on sensor, and the recoveries were 99.4-101.7%, which suggest that the present off-on sensor has a high accuracy.

Highly Photoluminescent Molybdenum Oxide Quantum Dots: One-Pot Synthesis and Application in 2,4,6-Trinitrotoluene Determination.

As a well-studied transition-metal semiconductor material, MoOx has a wider band gap than molybdenum disulfide (MoS2), and its property varies dramatically for the existence of several different allotropes and suboxide phases of molybdenum oxides (MoOx, x < 3). In this manuscript, a one-pot method possessing the advantages of one pot, easily prepared, rapid, and environmentally friendly, has been developed for facile synthesis of highly photoluminescent MoOx quantum dots (MoOx QDs), in which commercial molybdenum disulfide (MoS2) powder and hydrogen peroxide (H2O2) are employed as the precursor and oxidant, respectively. The obtained MoOx QDs can be further utilized as an efficient photoluminescent probe, and a new turn-off sensor is developed for 2,4,6-trinitrotoluene (TNT) determination based on the fact that the photoluminescence of MoOx QDs can be quenched by the Meisenheimer complexes formed in the strong alkali solution through the inner filter effect (IFE). Under the optimal conditions, the decreased photoluminescence of MoOx QDs shows a good linear relationship to the concentration of TNT ranging from 0.5 to 240.0 µM, and the limit of detection was 0.12 µM (3σ/k). With the present turn-off sensor, TNT in river water samples can be rapidly and selectively detected without tedious sample pretreatment processes.