Interaction of oridonin with human serum albumin by isothermal titration calorimetry and spectroscopic techniques

Study on the interaction of paeoniflorin with human serum albumin (HSA) by spectroscopic and molecular docking techniques

“…Fluorescence quenching is usually classified into two types: dynamic quenching and static quenching. It can be distinguished by their different dependence on temperature and excited-state lifetime [ 23 , 29 ]. For the dynamic quenching, higher temperatures will result in faster diffusion and larger amounts of collisional quenching.…”

“…To further detect the binding site of paeoniflorin with HSA, the competitive binding experiment was carried out. Warfarin and ibuprofen especially bound to site I and site II, respectively, were chosen as the site markers [ 23 , 44 ]. According to the Fig.…”

“…In this work, the absorption wavelength of paeoniflorin was overlapped with the absorption wavelength of HSA. Thus, the fluorescence intensities of all HSA solutions were corrected for the inner-filter effect of fluorescence according to the following equation [ 23 , 24 ]: where F corr and F obs are the fluorescence intensity corrected and observed at the emission wavelength, respectively. A ex and A em are the absorbance of HSA at the excitation and emission wavelengths, respectively.…”

An emissive dual-sensitized bimetallic Eu2III-bioprobe: design strategy, biological interactions, and nucleolus staining studies

“…The protein binding interactions of the Eu 2 III bioprobe 1 were studied using the emission spectral titration method, where the concentration of bovine serum albumin (BSA) was kept constant in Tris-HCl–NaCl (5 mM) buffer at 298 K. The Eu 2 dimeric complex was added, and after each addition, the luminescent response ( λ ex : 295 nm) corresponding to the tryptophan (Trp) residue present in BSA was monitored, and the quenching of emission was recorded. The quenching constant ( K BSA ) of the Eu 2 III bioprobe 1 was calculated based on the slope of an I 0 / I vs. [Q] plot using the Stern–Volmer equation: 43 I 0 / I = 1 + k q τ 0 [Q] = 1 + K BSA [Q]where I 0 and I are the emission intensities of the Trp residue in the absence and presence of quencher, respectively, [Q] is the concentration of quencher, K q represents the quenching rate constant, and τ 0 is the average lifetime in the absence of the quencher. The static equilibrium binding constant is calculated based on the modified Stern–Volmer equation: 44 Log [( I 0 − I )/ I ] = log K + n log [Q]where n is the number of binding sites and K is the binding constant of the desired complex with BSA.…”

Oridonin: A Review of Its Pharmacology, Pharmacokinetics and Toxicity

“…In the aspect of anti-breast cancer, oridonin could synergistically enhance the anti-tumor effect of doxorubicin on aggressive breast cancer by promoting apoptosis and anti-angiogenesis ( Li et al, 2019 ). Besides, this compound could inhibit angiogenesis and EMT related to VEGF-A ( Li C. Y. et al, 2018 ), block Notch signaling pathway to inhibit the growth and metastasis of breast cancer ( Xia et al, 2017 ), and induce autophagy to promote apoptosis ( Li and Yang, 2015 ). In addition to its above anti-tumor effects, there is growing evidences that oridonin exhibits other anti-tumor activities such as colorectal cancer ( Bu H. et al, 2019 ), pancreatic cancer ( Liu D. et al, 2020 ), gallbladder cancer ( Chen, et al, 2019 ), prostate cancer ( Lu et al, 2017 ) and so on.…”