Investigation of the free radical scavenging ability of <scp>l</scp>-tryptophan and its derivatives using experimental methods and quantum chemical calculations
Dinh Quy Huong, Pham Dinh Tu Tai, Nguyen Quang Trung, Nguyen Minh Thong, Nguyễn Minh Tâm, Nguyen Hai Phong, Pham Cam Nam
Abstract
assay, indicating less effective scavenging. Theoretical calculations, performed by analyzing frontier molecular orbitals and molecular electrostatic potential, revealed that electron-donating regions were primarily distributed across the aromatic rings and heteroatoms. At the same time, electron-accepting zones were only located at nitrogen heteroatoms. The hydrogen atoms within the hydroxyl and amine groups of LP and HLP molecules were preferential positions for nucleophilic attacks. Furthermore, thermodynamic and kinetic analyses suggested that hydrogen atom transfer was the predominant mechanism governing the reaction of LP and HLP with free radicals. The presence of the OH group in the HLP molecule significantly enhanced its free radical scavenging ability compared to LP.