APRT and Huntington disease: Further, various studies reported that natural CKs have a therapeutic potential in the treatment of age-related neurodegenerative diseases as Huntington’s disease (HD) [132] and Parkinson’s disease (PD) [133] with few side effects, and explained that kinetin can act as a phosphate donor after its conversion by adenosine phosphoribosyl transferase (APRT) into its triphosphate form, maintaining the N17 phosphorylation in HD model neurons and mutant huntingtin expression cells [132].