Identification of Inhibitors against Botulinum Neurotoxins: 8-Hydroxyquinolines Hold Promise

A pH-Sensitive Lignin-Based Material for Sustained Release of 8-Hydroxyquinoline

The fabrication of pH-sensitive lignin-based materials has received considerable attention in various fields, such as biomass refining, pharmaceuticals, and detecting techniques. However, the pH-sensitive mechanism of these materials is usually depending on the hydroxyl or carboxyl content in the lignin structure, which hinders the further development of these smart materials. Here, a pH-sensitive lignin-based polymer with a novel pH-sensitive mechanism was constructed by establishing ester bonds between lignin and the active molecular 8-hydroxyquinoline (8HQ). The structure of the produced pH-sensitive lignin-based polymer was comprehensively characterized. The substituted degree of 8HQ was tested up to 46.6% sensitivity, and the sustained release performance of 8HQ was confirmed by the dialysis method, the sensitivity of which was found to be 60 times slower compared with the physical mixed sample. Moreover, the obtained pH-sensitive lignin-based polymer showed an excellent pH sensitivity, and the released amount of 8HQ under an alkaline condition (pH = 8) was obviously higher than that under an acidic condition (pH = 3 and 5). This work provides a new paradigm for the high-value utilization of lignin and a theory guidance for the fabrication of novel pH-sensitive lignin-based polymers.

Designing, synthesis and evaluation of derived analogues of selected small molecule non-peptidic inhibitors against serotype BoNT/ F

Botulinum neurotoxins are lethal Biowarfare categorized in group A of selected agents, by CDC USA. The unavailability of counter-measures against these neurotoxins has been a matter of extensive research. The 8-hydroxyquinoline (8-HQ) scaffold is established privileged compound and its potential as drug candidate against BoNTs is recently being explored. We have reported 8-HQ compounds NSC1014 and NSC1011 as potential small molecule inhibitors against BoNT/F. In the present study, analogues of NSC84087 and NSC1014 were designed, synthesized and studied for their inhibitory role against BoNT/F intoxication through in silico study, in vitro and in-vivo assays. ∼25 in-house synthesized small molecule inhibitors were evaluated against rBoNT/F light chain through fluorescence thermal shift (FTS) assay and then further assessed through endopeptidase assay. The binding affinity analysis was done through surface plasmon resonance (SPR) based Proteon™ XPR 36 system. Finally, the in-vivo efficacy of these compounds was evaluated in mice model. Analogues C87.9, C87.10 and C87.12 of compound NSC84087 and C14.10, C14.11 and C14.13 of NSC1014 showed promising results through FTS assay and endopeptidase assay. SPR based protein-small molecule interaction studies showed KD values in sub-micromolar range signifying high affinity interaction. The IC₅₀ of C14.10 was found to be the lowest of 3.016 ± 0.798 μM as determined through endopeptidase assay. Finally, efficacy of selected molecules was evaluated in mice, C14.10 and C14.13 protected 40% animals against 4X LD₅₀ and extended survival time up to 200% at 10X LD₅₀. The present study thus proposes the emergence of NSC84087 and NSC1014 analogues as lead compound against BoNT/F.