Structure modification of luteolin and the influence of its derivatives on biological activities

Lingyang Kong ^* Lianqing He Li Chenliang Lengleng Ma Junbai Ma Meitong Pan Shan Jiang Weili Liu Jiao Xu Wei Ma

• Heilongjiang University of Chinese Medicine, Harbin, China

This research aims to synthesize luteolin derivatives from hemp seeds by means of chemical synthesis, improve the synthesis process, simplify the procedure, and increase the yield to obtain new luteolin derivatives. Additionally, anti-inflammatory and antioxidant activities of hemp seed extracts and newly synthesized substances are tested to screen out substances with high anti-inflammatory and antioxidant activities. Using luteolin as the raw material, acetyl, propionyl, and butyryl groups are introduced into the molecular structure of luteolin. A one-pot synthesis method is employed to modify the hydroxyl groups at positions 5, 7, 3', and 4' to obtain six new luteolin acyl derivatives. The molar ratio of reaction conditions is 1:4. Pyridine (20 ml) is used as the solvent, and the reaction is carried out at 25°C and 110°C. Finally, the products are separated and purified by column chromatography and recrystallization, and six new luteolin acyl derivatives were synthesized: namely, 7,3',4'-tri-O-acetylated luteolin (A), 7,3',4'-tri-O-propionylated luteolin (B), 7,3',4'-tri-O-butyrylated luteolin (C), 5,7,3',4'-tetra-O-acetylated luteolin (D), 5,7,3',4'-tetra-O-propionylated luteolin (E), and 5,7,3',4'-tetra-O-butyrylated luteolin (F). By establishing a psoriasis like mouse model, the anti-inflammatory and antioxidant indicators of magnolol and its acyl derivatives were evaluated. Finally, six new acyl derivatives of luteolin were synthesized through structural modification, which improved their solubility and bioavailability. In the psoriasis model, it has been demonstrated that the acyl derivatives of solid wood rhinoceros have anti-inflammatory and antioxidant activities, and have shown a relieving effect on psoriasis.