A systematically chemical investigation of Citrus changshan-huyou Y.B. Chang resulted in the isolation and structure determination of twelve known natural products, including limonoid ( 1 ), nootkatone ( 2 ), scoparone ( 3 ), β-sitosterol ( 4 ), 3,5,6,7,8,3',4'-heptamethoxyflavone ( 5 ), nobiletin (