Search

Many Chinese herbs are well known for their neuroprotective and anti-oxidant properties. Extracts of Salvia miltiorrhiza and Anemarrhenae asphodeloides, tanshinone IIA (tanIIA), salvianolic acid B (Sal B) and sarsasapogenin (ML-1), were selected to study their dissociation potential towards Aβ42 peptide fibrils and neuroprotective effect on cells. Moreover, derivatives of sarsasapogenin (ML-2, ML-3 and ML-4) have been prepared by the addition of modified carbamate moiety. TanIIA and Sal B have shown to possess a strong ability to dissociate Aβ42 fibrils. The dissociation potential of ML-1 increased upon the introduction of carbamate moiety with N-heterocycles. In silico data revealed that derivatives ML-4 and Sal B interact with Aβ42 regions responsible for fibril stabilization through hydrogen bonds. Contrary, tanIIA binds close to a central hydrophobic region, which may lead to destabilization of fibrils. Sarsasapogenin derivative ML-2 decreased nitride oxide production, and derivative ML-4 enhanced the growth of neurites. The reported data highlight the possibility of using active compounds to design novel treatment agents for Alzheimer's disease.

The complex pathogenesis of Alzheimer’s disease (AD) has become a major obstacle in its treatment. An effective approach is to develop multifunctional agents that simultaneously target multiple pathological processes. Here, a series of diosgenin-indole compounds were designed, synthesized and evaluated for their neuroprotective effects against H2O2 (hydrogen peroxide), 6-OHDA (6-hydroxydopamine) and Aβ (beta amyloid) damages. Preliminary structure-activities relationship revealed that the introduction of indole fragment and electron-donating group at C-5 on ring indole could be beneficial for neuroprotective activities. Results indicated that compound 5b was the most promising candidate against cellular damage induced by H2O2 (52.9 ± 1.9%), 6-OHDA (38.4 ± 2.4%) and Aβ1-42 (54.4 ± 2.7%). Molecular docking study suggested the affinity for 5b bound to Aβ1-42 was −40.59 kcal/mol, which revealed the strong binding affinity of 5b to Aβ1-42. The predicted values of brain/blood partition coefficient (−0.733) and polar surface area (85.118 A2) indicated the favorable abilities of BBB permeation and absorption of 5b. In addition, 5b significantly decreased ROS (reactive oxygen species) production induced by H2O2. In the following in vivo experiment, 5b obviously attenuated memory and learning impairments of Aβ-injected mice. In summary, compound 5b could be considered as a promising dual-functional neuroprotective agent against AD.

A novel series of multitargeted molecules were designed and synthesized by combining the pharmacological role of cholinesterase inhibitor and antioxidant of steroid as potential ligands for the treatment of Vascular Dementia (VD). The oxygen-glucose deprivation (OGD) model was used to evaluate these molecules, among which the most potent compound ML5 showed the highest activity. Firstly, ML5 showed appropriate inhibition of cholinesterases (ChEs) at orally 15 mg/kg in vivo. The further test revealed that ML5 promoted the nuclear translocation of Nrf2. Furthermore, ML5 has significant neuroprotective effect in vivo model of bilateral common carotid artery occlusion (BCCAO), significantly increasing the expression of Nrf2 protein in the cerebral cortex. In the molecular docking research, we predicted the ML5 combined with hAChE and Keap1. Finally, compound ML5 displayed normal oral absorption and it was nontoxic at 500 mg/kg, po, dose. We can draw the conclusion that ML5 could be considered as a new potential compound for VD treatment.

In order to produce an effective and multi-targeted clinical drug that could prevent progressive neurodegeneration, a series of diosgenin carbamate derivatives were designed, synthesized and tested for their anti-inflammatory, antioxidant and anti-Aβ activities. The results demonstrated that compound M15 was the most promising derivative against inflammatory (NO inhibition 22.7 ± 2.2%,10 μM) and cellular damage induced by H2O2 (SH-SY5Y cell protection = 75.3 ± 3.4%, 10 μM) or Aβ (astrocytes protection = 70.2 ± 6.5%, 10 μM). Molecular docking studies revealed the strong binding affinity of M15 to the active site of nNOS, Aβ42 and pro-inflammatory proteins. Western blot demonstrated that M15 decreased IL-1β, IL-6 and TNF-α level, which may contribute to its anti-inflammatory effects. In addition, M15 maintained mitochondrial function as well as cell viability through reducing H2O2-induced ROS production. The results indicated that oral administration of M15 attenuated memory deficits and played a neuroprotective effect on subcutaneous (s.c.) D-gal aging mice. In summary, M15 could be considered as a potential multifunctional neuroprotective agent due to the effects of anti-inflammatory, antioxidant and anti-Aβ activities.