title: Screening, identification, and potential interaction of active compounds from Eucommia ulmodies leaves binding with bovine serum albumin.
abstract: The aqueous extract of  Eucommia ulmoides  leaves has been commonly known as Du-zhong tea as a functional health food for the treatment of hypertension, hypercholesterolemia, and fatty liver. This study developed a centrifugal ultrafiltration-high-performance liquid chromatography (HPLC) method for screening and identification of bioactive compounds in  E. ulmoides  leaves binding with bovine serum albumin (BSA). Six active compounds were screened, isolated, and elucidated by their ultraviolet (UV), electrospray ionization-mass spectrometry (ESI-MS), and nuclear magnetic resonance (NMR) data as geniposidic acid (1), caffeic acid (2), chlorogenic acid (3), quercetin-3-O-sambubioside (4), rutin (5), and isoquercitrin (6). The interaction between active compounds and BSA was investigated in the absence and presence of other compounds by quenching the intrinsic BSA fluorescence. The results indicated that the structures significantly affected the binding process. The values of binding constants for compounds 2-6 were in the range of 10(5)-10(6) mol L(-1), while geniposidic acid (1) hardly quenching the BSA intrinsic fluorescence. However, the quenching process of geniposidic acid was easily affected in the presence of other active compounds. The formation of the geniposidic acid-phenylpropanoid (flavonoid) complex could increase the binding affinity of geniposidic acid with BSA; however, the increased steric hindrance of the complex may make phenylpropanoid or flavonoid dissociate from BSA and then decrease their affinities.
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, People's Republic of China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Zhang
authors.forename: Mijun
authors.initials: M
authors.lastname: Peng
authors.forename: Liangliang
authors.initials: L
authors.lastname: Liu
authors.forename: Shuyun
authors.initials: S
authors.lastname: Shi
authors.forename: Sheng
authors.initials: S
authors.lastname: Peng
mesh_terms: D002109:Caffeic Acids / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D002498:Centrifugation; D002726:Chlorogenic Acid / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D031283:Eucommiaceae / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D057888:Iridoid Glucosides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry* / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry*; D012431:Rutin; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D014462:Ultrafiltration
chemical_list: D002109:Caffeic Acids; D005419:Flavonoids; D057888:Iridoid Glucosides; D010936:Plant Extracts; D012710:Serum Albumin, Bovine; C058966:geniposidic acid; D002726:Chlorogenic Acid; D012431:Rutin; C040048:caffeic acid