EXTRACTION OF ANTHRAQUINONE DERIVATIVES FROM RHUBARB RHIZOMES AND THEIR ANTIBACTERIAL TESTS

Photometry was employed to study the optimum extraction conditions of anthraquinone derivatives from rhizomes of Rheum officinale Baill in this study.The influences of extraction solvents(chloroform,benzene,ethanol,methanol,and glycerol),acid,and extraction time on the extraction yield were discussed.The results indicate that,to the Rhubarb rhizomes powder with the average particle size 0.18 mm,the conditions of the extraction solvent composed by chloroform,glycerol,and sulfuric acid(20%)in the ratio of 4:1:1(v:v),the weight of dried Rhubarb to the solvent volume in the ratio of 1:12 ew:vT,extraction time of 110 min,the anthraquinone derivatives extraction could achieve the best yield.And the antibacterial tests showed the raw extraction products had the MIC(minimal inhibitory concentration)of 20μg=mL and 30μg=mL to Staphylococcus aureus and Escherichia coli,respectively.

Inhibition of human cytochrome CYP1B1 by anthraquinone compounds,chrysophanol and physcion

The in vitro inhibitory effects of chrysophanol and physcion on CYP1B1 were explored,utilizing ethoxyresorufin as the substrate.The inhibition kinetics of CYP1B1 by these compounds were assessed with escalating doses of ethoxyresorufin.Both chrysophanol(IC_(50)(0.47±0.01)μmol·L^(-1))and physcion(IC_(50)(0.35±0.02)μmol·L^(-1))significantly reduce the catalytic efficiency of CYP1B1.The V_(max)and K_(m)values are determined to be(51.9912±10.0547)pmol·μg^(-1)(protein)·min^(-1) and(0.9663±0.2987)nmol·L^(-1)for chrysophanol,and(45.4227±1.9978)pmol·μg^(-1)(protein)·min^(-1) and(0.4367±0.0386)nmol·L^(-1)for physcion,respectively.Kinetic analysis reveals that chrysophanol and physcion exert mixed inhibitory effects on CYP1B1.This mixed inhibition is primarily characterized by the compounds’ability to competitively bind to the active sites of CYP1B1,as well as potentially through non-competitive mechanisms,thereby reducing the enzyme’s catalytic efficiency.Molecular docking studies are conducted to elucidate the interaction between anthraquinone derivatives and CYP1B1,indicating that these compounds may inhibit CYP1B1 activity by binding to their active sites.The demonstrated capacity of chrysophanol and physcion to inhibit CYP1B1 enzymatic function unveils a potential anticancer mechanism,advancing our comprehension of how the structure of anthraquinone derivatives correlates with CYP1B1 inhibition and paving the way for developing innovative cancer treatments.