[Spectroscopic studies on binding of beta-elemene to human serum albumin]

Beta-Elemene is an antitumor drug which is isolated from the traditional Chinese medicinal herb Curcumae Phaeocaulis Rhizoma, it is the main component of elemene which is extracted from the plant and delivered via blood circulation after intravenous injection. The antitumor effect of beta-elemene in vitro and in vivo was definite, and beta-elemene could improve the patient immunity and no sever side effect, drug resistance or bone marrow suppression were found during the clinical studies. And human serum albumin (HSA) is a primary extracellular protein which has a high concentration distribution in blood plasma and has many characteristic physiological functions. Therefore, the binding of beta-elemene to protein may be very important for absorption, distribution, metabolism and elimination. Therefore, the study on the interaction of beta-elemene with drug-carrying protein is very important. In this work, molecular binding of beta-elemene to human serum albumin (HSA) was investigated by using spectrofluorometer. the binding constants suggested that a strong interaction and the formation of a complex between beta-elemene and HSA. This clearly implies that beta-elemene can be stored and removed by the proteins in the body. Furthermore, the fluorescence quenching results showed that the HSA fluorescence was quenched by beta-elemene through static quenching mechanism. Thermodynamic parameters showed that hydrophobic interactions play a role in the binding of beta-elemene to HSA. The negative deltaH(0) and positive deltaS(0) in case of beta-elemene therefore showed that electrostatic attraction play a role in the binding of beta-elemene to HSA.