Studies On Synthesis, Characterization And Anti-aging Activity Of Metal Complex Of Soybean Isoflavone Aglycones

Soy isoflavones are a class of secondary metabolites in the growth process of soybeans or other legumes. They are extracted from plants and have similar structures with estrogen, so soy isoflavones are also called phytoestrogens.The fundmental structure of isoflavones is 3-benzene and pyrone structure, and its antioxidation is due to the group of 7-hydroxyl oxygen. Therefore, this researches focus on free isoflavones reacting with metal and their anti-aging activity so as to find out strong effective antisenility drugs.The main experimental method and content are summarized as follows:1) Soy isoflavones were extracted from soybean germ.The single factor experiments including the ethanol concentration, temperature, time, solid-liquid ratio and times, and L9(34) orthogonal experimentwere designed. The optimized extraction technology of soyisoflavones is: 80% ethanol concentration, solid-liquid ratio l:10, temperature 80℃, time 2.5h, twice extraction. Under this condition, the extraction yield of soybean isoflavones reaches maximum, 88.35%.2) Free isoflavones were obtained by the crude extract under acid hydrolysis condition. The conditions were 25% hydrochloric acid under temperature 90℃ for 4h.Water soluble protein and sugar were removed by distilled water and free isoflavones were purified with the ethyl acetate, acetone. The genistein and daidzein were isolated from soy isoflavones by preparative liquid chromatography and were determinedby ultraviolet spectrum, infrared spectrum method and HPLC respectively. The purity of daidzein and genistein respectively is 98.07% and 98.87%.3) Fe, Zn, and Cu metal complexes were synthesized by the metallic complexation reaction of genistein. And the metal complexes were analysed by UV, IR, elemental analysis, determination of metal content and TG. According to the data, the formula of metal complexes of genistein are deduced as Zn(C15H9O5)2 · 2H2 O, Fe(C15H9O5)2 · 2H2 O, Cu(C15H9O5)2·2H2O, respectively.4) In vitro, daidzein and genistein show antioxidant activity by the DPPH radical scavenging method, at concentration dependence. In vivo, subacute aging model was made bycontinue subcutaneous D-galactose injectionin mice after 40 days accompanying oral administration of the drugs for 3 weeks. High dose(100mg/kg) and low dose(50mg/kg)s of genisteinand its metal complexes can make GSH-Px activity, SOD activity and T-AOC content significantly raise, MDA content also obviously decreased in aging mice serum, brain and liver tissue. So, the genistein and its metal complexes have effects of antioxidation, and the complexes are stronger than genistein. In serum, the order of antioxidative activities is Cu>Fe>Zn. In the liver tissue, the order of antioxidative activities is Fe>C u>Zn. In the brain tissue, Zn metal complexes and Fe metal complexes have the same effect, and the C u metal complexes are relatively the worst.These results suggest that the metal complexes have organization selective. Genistein metal complexes can be used as a kind of good candidate of antisenility drugs.