Synthesis And In Vitro Antioxidant Capacities Assay Of Xanthonic Derivatives

Xanthones(9H-xanthen-9-ones) are heterocyclic compounds with the dibenzo-γ-pyrone framework.Naturally-occurring xanthones which are separated from Gentianaceae,Sankoh, Gamboge Branch,Polygalaceae and Liliaceae are yellow or white phenolic compounds. Early pharmacological studies have shown that xanthones have a very wide range of pharmacological activities,including diuretic,anti-microbial,anti-virus,strong heart, antidepressants,anti-tuberculosis,and anti-cancer activity.Research on xanthonic derivatives research began to carry out since 1960s,Synthesis and modified of natural products is an important supplement to natural products as well as research and development of new chemical entities.The study of structure-activity relationship of xanthonic derivatives will xontribute to clarify there diverse pharmacological effects and mechanisms of the action mode.In this dissertation,twenty-two xanthonic derivatives were designed and synthesized, which include the simple oxygen substituted xanthone,and halogen substituted xanthene ketones,ketones xanthene alkaloids,as well as isopentenyl substituted xanthene ketones the four types of xanthene derivatives by means of GSS reaction,Mannich reaction,Friedei -Crafts reaction.MS,NMR were used to determine their structures.DPPH free radical scavenging method has been adapted to evaluate in vitro antioxidant activity of the synthetic xanthene derivatives.Detection by UV absorption detection microplate reader value,calculated in various derivatives on the clearance rate of DPPH·.And Trolox as a control to TEAC(Trolox equivalent antioxidant capacity) value of the reference,the evaluation of xanthene derivatives antioxidant activity.The results showed that compounds 7,9,14,15,16,17,18,21,have the weak antioxidant capacity,followed by the TEAC value 1.19,15.68,3.34,0.93,0.56,0.66, 0.36,0.29μg / mL.In this paper twenty-two xanthonic derivatives were designed and synthesized.And seventeen compounds are new compounds.Eight compounds showed the weak antioxidant capacities.Isopentenyl substituent had few contributions to the antioxidant capacity. 1,3-dihydroxy-2-(pyrrolidin-1-ylmethyl)-9H-xanthen-9-one showed the best antioxidant capacity in the synthetical xanthonic derivatives.