Process optimization and character evaluation of Bletilla striata polysaccharide (BSP) and chitosan (CS) composite hemostatic sponge (BSP-CS).

Bletilla striata polysaccharide (BSP) and chitosan (CS) were chemically cross-linked using oxalyl chloride to prepare a composite hemostatic sponge (BSP-CS), and the process parameters were optimized using the Box-Behnken design (BBD) with response surface methodology. To optimize the performance of the hemostatic sponge, we adjusted the ratio of independent variables, the amount of oxalyl chloride added, and the freeze-dried volume. A series of evaluations were conducted on the hemostatic applicability of BSP-CS. The characterization results revealed that BSP-CS had a stable bacteriostatic effect on Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa within 72 h, and the bacteriostatic rate was above 30%. The CCK-8 cytotoxicity test demonstrated that BSP-CS had a certain effect on promoting cell proliferation of L929 cells. In the mouse tail-cutting experiment, the hemostasis time of BSP-CS was 463.0±38.16 s, shortened by 91.3 s on average compared with 554.3±34.67 s of the gauze group. The blood loss of the BSP-CS group was 28.47±3.74 mg, which was 34.7% lower than that of the control gauze group (43.6±3.83 mg). In the in vitro coagulation experiment, the in vitro coagulation index of the BSP-CS group was 97.29%±1.8%, which was reduced to 8.6% of the control group. The CT value of the BSP-CS group was 240±15 s, which was 155 s lower than that of the gauze group (355±31.22 s). All characterization results indicate that BSP-CS is an excellent hemostatic material.

Polyphosphoric acid-promoted one-pot synthesis and neuroprotective effects of flavanones against NMDA-induced injury in PC12 cells.

We report herein an efficient polyphosphoric acid (PPA) promoted one-pot protocol for the synthesis of flavanone derivatives from 2-hydroxyacetophenones and benzaldehydes. A variety of flavanones were produced in moderate to excellent yields and evaluated for their neuroprotective effects against N-methyl-d-aspartate (NMDA)-induced excitotoxicity in PC12 cells. Derivatives bearing electron-donating groups exhibited better neuroprotective activity. Compound 3m demonstrated the best protective potency and reversed the intracellular calcium (Ca2+) influx caused by NMDA, suggesting that flavanones protected the PC12 cells against NMDA-induced neurotoxicity via inhibition of Ca2+ overload.

Bioassay-guided isolation of a Mycobacterium tuberculosis bioflim inhibitor from Arisaema sinii Krause.

Mycobacterium tuberculosis biofilms harbour drug-tolerant bacteria. Identification of drugs that inhibit biofilm formation could enable the dramatic shortening of tuberculosis treatments using standard antibiotics. Arisaema sinii Krause is used to treat pulmonary and lymphatic tuberculosis by Dong People of China. Current study was aimed to purify the active components against M. tuberculosis biofilms from Arisaema sinii extract by using bioassay-guided isolation. (E)-2-(methyl (phenyl) amino) ethyl 2-(2-hydroxyundecanamido)-7, 11-dimethyl-3-oxotetradec-4-enoate, compound 1, was identified as the active component. It could inhibit mycobacterial biofilm formation, disperse the preformed biofilms, and disrupt the mature biofilms at concentration of 4, 8, and 32 µg/ml, respectively. At the dose of 32 µg/ml, it could potentiate the bactericidal activity of isoniazid against M. tuberculosis in mature biofilms. The results of this study indicate that compound 1 might be a novel lead compound against mycobacterial biofilm formation.