Synthesis, pharmacological evaluation and mechanistic study of scutellarin methyl ester -4′-dipeptide conjugates for the treatment of hypoxic-ischemic encephalopathy (HIE) in rat pups

• Published in: Bioorganic chemistry 2020-08, Vol.101, p.103980, Article 103980
• Main Authors: Li, Tao, Wu, Dirong, Yang, Yang, Xiao, Tao, Han, Yilin, Li, Jing, Liu, Ting, Li, Li, Dai, Zeqin, Li, Yongjun, Fu, Xiaozhong
• Format: Article
• Language: English
• Subjects: Animals; Apigenin - chemical synthesis; Apigenin - pharmacology; Apigenin - therapeutic use; Brain Diseases - drug therapy; Dipeptide conjugates; Erigeron - chemistry; Glucuronates - chemical synthesis; Glucuronates - pharmacology; Glucuronates - therapeutic use; Humans; Hypoxia-Ischemia, Brain - drug therapy; Hypoxic-ischemic encephalopathy; Medicine, Chinese Traditional - methods; Molecular Docking Simulation - methods; Molecular Structure; Oligopeptide transporter 1; Pathomorphological damage; Rats; Scutellarin; Structure-Activity Relationship
• ISSN: 0045-2068; 1090-2120
• DOI: 10.1016/j.bioorg.2020.103980

[Display omitted] •Scutellarin methyl ester-4′-dipeptide conjugates were synthesized and evaluated as potential protective agents against HIE.•5k exhibit the highest Papp A to B, lowest ER value in Caco-2 cells, and the highest uptake value in hPepT1-MDCK cells.•5k exhibit more potent protective activity against oxidative damage by improving the relevant detection indicators.•5k has significantly therapeutic effect on HIE rat pups by reducing infarct area and APP/ BACE-1 expression.•Favorable pharmacokinetic profiles of 5k were also confirmed in our studies. A series of novel scutellarin methyl ester-4′-dipeptide conjugates exhibiting active transport characteristics and protection against pathological damage caused by hypoxic-ischemic encephalopathy (HIE) were successfully designed and synthesized. The physiochemical properties of the obtained compounds, as well as the Caco-2 cell-based permeability and uptake into hPepT1-MDCK cells were evaluated using various analytical methods. Scutellarin methyl ester-4′-Val-homo-Leu dipeptide (5k) was determined as the optimal candidate with a high apparent permeability coefficient (Papp A to B) of 1.95 ± 0.24 × 10−6 cm/s, low ER (Papp BL to AP/Papp AP to BL) of 0.52 in Caco-2 cells, and high uptake of 25.47 μmol/mg/min in hPepT1-MDCK cells. Comprehensive mechanistic studies demonstrated that pre-treatment of PC12 cells with 5k resulted in more potent anti-oxidative activity, which was manifested by a significant decrease in the malondialdehyde (MDA) and reactive oxygen species (ROS) levels, attenuation of the H2O2-induced apoptotic cell accumulation in the sub-G1 peak, and improvement in the expression of the relevant apoptotic proteins (Bcl-2, Bax, and cleave-caspase-3). Moreover, evaluation of in vivo neuroprotective characteristics in hypoxic-ischemic rat pups revealed that 5k significantly reduced infarction and alleviated the related pathomorphological damage. The compound was also shown to ameliorate the neurological deficit at 48 h as well as to decrease the brain tissue loss at 4 weeks. Conjugate 5k was demonstrated to reduce the amyloid precursor protein (APP) and β-site APP-converting enzyme-1 (BACE-1) expression. Pharmacokinetic characterization of 5k indicated favorable druggability and pharmacokinetic properties. The conducted docking studies revealed optimal binding of 5k to PepT1. Hydrogen bonding as well as cation-π interactions with the corresponding amino acid residues in the target active site wer