A Proline Derivative-Enriched Fraction from Sideroxylon obtusifolium Protects the Hippocampus from Intracerebroventricular Pilocarpine-Induced Injury Associated with Status Epilepticus in Mice

Abstract

The N-methyl-(2S,4R)-trans-4-hydroxy-l-proline-enriched fraction (NMP) from Sideroxylon obtusifolium was evaluated as a neuroprotective agent in the intracerebroventricular (icv) pilocarpine (Pilo) model. To this aim, male mice were subdivided into sham (SO, vehicle), Pilo (300 µg/1 µL icv, followed by the vehicle per os, po) and NMP-treated groups (Pilo 300 µg/1 µL icv, followed by 100 or 200 mg/kg po). The treatments started one day after the Pilo injection and continued for 15 days. The effects of NMP were assessed by characterizing the preservation of cognitive function in both the Y-maze and object recognition tests. The hippocampal cell viability was evaluated by Nissl staining. Additional markers of damage were studied—the glial fibrillary acidic protein (GFAP) and the ionized calcium-binding adaptor molecule 1 (Iba-1) expression using, respectively, immunofluorescence and western blot analyses. We also performed molecular docking experiments revealing that NMP binds to the γ-aminobutyric acid (GABA) transporter 1 (GAT1). GAT1 expression in the hippocampus was also characterized. Pilo induced cognitive deficits, cell damage, increased GFAP, Iba-1, and GAT1 expression in the hippocampus. These alterations were prevented, especially by the higher NMP dose. These data highlight NMP as a promising candidate for the protection of the hippocampus, as shown by the icv Pilo model.

A proline derivative-enriched methanol fraction from Sideroxylon obtusifolium leaves (MFSOL) stimulates human keratinocyte cells and exerts a healing effect in a burn wound model

“…1 H NMR was used to detect the presence of NMP just for the water fraction to yield 1.43 g of pure NMP (14.3%). This yield is in agreement with a previous finding by qNMR ( 13 ). The NMP spectrum extracted from the fraction corresponded to the pure isolated compound N -methyl-(2S,4R)- trans -4-hydroxy-L-proline (Supplementary Figures S1 and S2).…”

“…After lyophilization or rotary evaporation of the solvent, the fractions yielded 3.13, 3.03, 2.03, and 1.84 g, respectively. By 1 H NMR, the presence of NMP was investigated and fractions were adsorbed on 20 g of silica gel for flash chromatography and then eluted with 10% CH 2 Cl 2 /MeOH (5 fractions of 50 mL), followed by 20% CH 2 Cl 2 /MeOH (9 fractions of 50 mL and 6 fractions of 100 mL) ( 13 ).…”

N-Methyl-(2S, 4R)-trans-4-hydroxy-L-proline, the major bioactive compound from Sideroxylon obtusifolium, attenuates pilocarpine-induced injury in cultured astrocytes

“…These results are relevant in view of our recent report of the NMP anticonvulsant action in the intracerebroventricular pilocarpine model in mice (12). In that study, NMP was reported to decrease the pilocarpine-induced neuronal death and overexpression of GFAP and Iba-1 in hippocampal subfields.…”

“…Recently ( 11 , 12 ), we showed that the methanol fraction isolated from Sideroxylon obtusifolium leaves presents a high content of the anticonvulsant bioactive component N -methyl-(2S,4R)- trans -4-hydroxy-L-proline (NMP). This NMP fraction was shown to increase GFAP and Iba-1 expressions, biomarkers of astrocytes and microglia, in the hippocampus.…”

The N-Methyl-(2S, 4R)-trans-4-hydroxy-L-proline-Enriched Methanol Fraction from Sideroxylon obtusifolium Shows an Anticonvulsant Activity Associated with its Anti-inflammatory/Antioxidant Actions

“…Most bioactive small molecules, such as NMP, are known to interact with proteins or other macromolecule targets, which results in their final biological effects. Recently, we reported that one of the possible targets for the NMP molecule is the GABA transporter (GAT-1) [40]. These results point again to GABA neurotransmission involvement in the NMP action mechanism.…”