Neuroprotective effect of Lannea egregia Alkaloid-rich leaf extracts in streptozotocin-induced diabetic rats.

Background: Studies suggest that medicinal plant extracts can help reduce the neuron degeneration associated with diabetes. In this study, the neuroprotective effect of the alkaloid-rich extract from the leaves of Lannea egregia was assessed in rats with diabetes induced by streptozotocin (STZ). Methods: Lannea egregia alkaloid-rich analysis was carried out via a known procedure. The rats were randomly assigned into five treatment groups (n = 8): normal control, diabetic-induced rats (45 mg/kg STZ), and diabetic rats treated with low doses of Lannea egregia leaf alkaloid-rich extract (50 mg/kg b.w, LEL) and high (100 mg/kg b.w, LEH) (300 mg/kg and 150 mg/kg), and metformin (200 mg/kg). On 22nd day of the experiment, animals were sacrificed, and their blood and brains were collected for neuro-biomarker analysis. Results: Diabetic-induced rats that received metformin, LEL and LEH exhibited considerably reduced levels of dopamine, serotonin, norepinephrine, NO, MDA, and AChE, BChE activities when compared to untreated diabetic animals. Additionally, rats with diabetes that received treatment with metformin, LEL and LEH displayed a noticeable increase in ENTPDase, Na/K ATPase, GST, CAT, GPx, and SOD activities when compared to the untreated diabetic rats. Histological examination revealed improved brain architecture in the treated groups in contrast to those in diabetic-induced rats. Conclusion: The alkaloid-rich extracts of Lannea egregia might be effective in normalizing brain damage caused by complications of diabetes mellitus.

Curcumin and hydroxamate-derivative (PCI-34058) interfere with histone deacetylase I catalytic core Asp-His charge relay system: atomistic simulation studies.

Histone deacetylases (HDACs) are representative targets for the natural and synthetic chemicals used to transform cells to confer antitumor properties. In the current study, curcumin and hydroxamate-derivative PCI-34058-bound HDAC1 were subjected to atomistic simulation. The results support the view that fitting of curcumin and PCI-34058 within the HDAC1 pocket depends on extensive interactions between the aromatic moieties of the inhibitors and the extensive network of aromatic amino acid side chains lining the pocket of HDAC1. The interaction forces a local perturbation of the coiled structures connecting the pocket residues resulting in ligand-induced tightening of the pocket. In addition to the competitive occupancy of the histone-acetyl-lysine binding pocket by the inhibitors, interference with the in-pocket aspartate-histidine (ASP-HIS) charge relay system was also observed in inhibitor-bound HDAC1 systems. In conclusion, curcumin and PCI-34058-mediated ligand-dependent HDAC1 tunnel closure interferes negatively with the ASP-HIS charge relay system in HDAC1. Future design of HDAC inhibitors may benefit from optimizing competitive interaction with the ligand site and interference with the charge relay system.