Interaction of bioactive components caffeoylquinic Acid derivatives in Chinese medicines with bovine serum albumin.
Five caffeoylquinic acid derivatives (CQAs), including methyl 3,4-di-O-caffeoylquinate (3,4-diCQM), methyl 3,5-di-O-caffeoylquinate (3,5-diCQM), 3,4-di-O-caffeoylquinic acid (3,4-diCQA), 3,5-di-O-caffeoylquinic acid (3,5-diCQA) and chlorogenic acid (CA), were isolated from Lonicera fulvotomentosa HSU et S. C. CHENG to be used as model compounds. The binding of these bioactive components to bovine serum albumin (BSA) was investigated by fluorescence quenching method. The results showed that there were binding affinities for CQAs with BSA, and the binding constants ranked in the following order: 3,4-diCQM>3,5-diCQM<3,4-diCQA>3,5-diCQA>CA, under the physiological conditions, which suggested that the numbers and the substituted positions of caffeoyl group as well as the esterification of carboxyl group in the molecular structures appeared to contribute moderate effects to the interaction processes. Furthermore, the Stern-Volmer curves demonstrated that CQAs caused the fluorescence quenching through a static quenching procedure. Thermodynamic analysis indicated that both hydrophobic and electrostatic interactions played major roles in stabilizing the complex. The binding distance for each binding reaction was also calculated by the Föster theory.
Tang
Dan
D
Key Laboratory of Modern Chinese Medicines, Ministry of Education, China Pharmaceutical University, No. 24, Tongjia Lane, Nanjing 210009, PR China.
Li
Hui-Jun
HJ
Li
Ping
P
Wen
Xiao-Dong
XD
Qian
Zheng-Ming
ZM
D001665:Binding Sites; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D007202:Indicators and Reagents; D031239:Lonicera / Q000737:chemistry; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
D004365:Drugs, Chinese Herbal; D007202:Indicators and Reagents; D012996:Solutions; C472707:caffeoylquinic acid; D011801:Quinic Acid; D012710:Serum Albumin, Bovine