Synthesis,Characterization And Bioactivity Of Four Luteolin Metal Complexes Based On The Theory Of Coordination Chemistry Of Traditional Chinese Medicine

According to the theory of coordination chemistry of traditional Chinese medicine,the active ingredients in traditional Chinese medicine may be organic or trace elements,and it may be the metal complexes formed during the boiling process of traditional Chinese medicine.However,the existing two related research methods have failed to solve the problems of which organic components in Chinese medicine can form complexes with which metal ions,what structure the newly formed complex is,and what role it plays in the treatment of diseases by Chinese medicine.Luteolin is used as a flavonoid compound,and its combination with trace metal elements can often improve its biological activity,for example,anti-tumor,anti-inflammatory,anti-allergic,anti-fibrosis,anti-oxidation and so on.However,a large number of reported methods for preparing complexes are basically carried out in alkaline alcohol solutions?methanol or anhydrous ethanol?,which differ greatly from traditional Chinese medicine extraction techniques.Currently,metal complexes are isolated from traditional Chinese medicines.Research has rarely been reported.In this dissertation,firstly,by optimizing the reaction conditions,the ability of luteolin to form complexes with common metal trace elements in five traditional Chinese medicines was studied.Secondly,four kinds of luteolin metal complexes were studied.The structure was characterized and the effects of free radical scavenging and DNA fragmentation were studied.Finally,the samples of methanol extract and 20%formic acid-methanol dissolved in two aqueous extracts of traditional Chinese medicine were analyzed by high performance liquid chromatography.The main research contents and research results of the paper are as follows:?1?Preparation of luteolin metal complexes.Luteolin and five essential metal elements(Mg²⁺,Ca²⁺,Fe³⁺,Cu²⁺and Zn²⁺)were reacted under the traditional Chinese medicine extraction process.The content of ligands before and after the reaction was quantified by high performance liquid chromatography and analyzed.The optimal reaction conditions for the synthesis reaction?reaction temperature,reaction time,reaction solvent amount,and material amount ratio?.At the same time,the ability of luteolin to form complexes with five metal ions was studied.The experimental results show that the optimum conditions for the formation of complexes with luteolin and metal ions are as follows:reaction temperature 90°C,reaction time 2 h,reaction solvent volume 20 mL,and molar ratio of ligand to metal ion 1:1.Under water decoction conditions,Cu²⁺forms the complex with luteolin most easily,followed by Fe³⁺,while the complexing ability of Mg²⁺,Ca²⁺and luteolin is poor,and Zn²⁺does not form complexes.?2?Structural characterization of four kinds of luteolin metal complexes.The structures of four metal luteolin complexes were characterized by UV-Vis spectrophotometer,¹H-NMR,IR spectrometer and ESI-TOF-MS/MS.The results showed that Mg²⁺and Ca²⁺were coordinated with luteolin by 4-C=O,while Fe³⁺and Cu²⁺were coordinated by 4-C=O and5-OH in a 1:2 ratio.?3?Study on bioactivity of luteolin metal complexes.First,the free radical scavenging activities of luteolin,metal salts,and luteolin metal complexes were studied.The experimental results show that at low concentrations,the metal complexes have stronger free radical scavenging than luteolin.Secondly,the pyrolytic activity of luteolin,metal salt,and luteolin metal complex on plasmid pBR 322 DNA was studied.The experimental results showed that luteolin-iron and luteolin-copper had the effect of cleaving the disrupted plasmid pBR 322 DNA,while luteolin and metal salts alone had no activity,indicating that luteolin passed through Fe³⁺and Cu²⁺.Formation of complexes produces new biological activity.?4?The possibility of the existence of luteolin-metal complexes in decoction of traditional Chinese medicine.Taking honeysuckle and Huangshan Gongju as the research object,the samples after methanol and 20%formic acid-methanol were dissolved in two aqueous extracts of traditional Chinese medicine were analyzed by HPLC,and the metal complexes were explored by comparing the changes in the number of peaks and peak areas.Whether it exists in Chinese medicine decoction.The experimental results show that the complex formed by luteolin and metal trace elements does exist in the decoction of traditional Chinese medicine.