Study On The Interaction Of Indirubin And Indigo With DPPC Liposomes

The interaction between drug molecules and biofilms is a prerequisite for the drug’s pharmacodynamic effects.Studying the interaction between drug molecules and biofilms is of great significance for elucidating the active mechanism of drugs.Liposomes can spontaneously assemble into a closed and curved bilayer structure,which has a bilayer structure similar to the cell membrane of the basic unit of the organism.It is currently a common model for studying the interaction between drug molecules and biofilm.Indigo naturalis is a commonly used traditional Chinese medicine.Its main active ingredients are indirubin and indigo,both of which are isomers of each other.Modern pharmacological studies have shown that indigo naturalis has good antibacterial and antitumor effects.Among them,indirubin has a significant inhibitory effect on chronic myelogenous leukemia,and has the characteristics of little toxic and side effects,no obvious bone marrow suppression and significant clinical efficacy.For indigo,although its content is much higher than indirubin,but there are few reports on its biological activity,currently mainly used for dyeing textiles.In order to clarify the huge difference in the biological activity of indirubin and its isomer indigo,this subject uses the liposome formed by DPPC as a simplified biofilm model membrane,and uses spectroscopic and thermodynamic techniques to analyze indigo.The effects of indirubin and indigo on the microstructure of DPPC liposome membranes,and the differences in the role of indirubin and indigo and phospholipids in cell membranes are described.By comparing the interaction levels between indirubin and indigo and liposome-simulated biofilm,the possible reasons for the difference in biological activity between the two are proposedIn this paper,differential scanning calorimetry,synchrotron radiation X-ray diffraction and Fourier transform infrared spectroscopy were used to study the interaction between indirubin and indigo and DPPC liposome membrane from different angles.Through the above technical means,the role of indirubin and indigo in DPPC liposomes and their effects on the phase of DPPC liposome membranes were obtained,and the effects of the molecular structure differences of the two on biofilms were analyzed.The study found that the addition of indirubin and indigo can cause changes in the main phase transition temperature of DPPC liposomes.When the drug concentration is less than 6 mol%,the addition of indirubin enhances the DPPC liposome membrane fluidity.Then indigo shows the opposite inhibitory effect.The interlayer repeat distance of the phospholipid bilayer is composed of the thickness of the phospholipid bilayer and the thickness of the water layer Since the thickness of the water layer is related to the phase state of the liposome,the DPPC liposomes are always in the layered gel phase under the experimental conditions,so the thickness value of the water layer will not change significantly,and the change of the interlayer repeat distance can be approximately represents the change in the thickness of the phospholipid bilayer.When the drug concentration is higher than 6 mol%,indirubin increases the repetition distance between DPPC liposome layers more than indigo,which causes the hydrocarbon chain of DPPC molecules to become more perpendicular to the membrane surface.The distribution position of the drug in the lipid bilayer directly affects the phase behavior of the liposome.When the drug concentration is less than 6 mol%,the addition of indigo can increase the area of the low-wave array more than indirubin,indicating that at this concentration compared with indigo,indirubin and DPPC liposome have a weaker effect on the head area.Comparing the above experimental results,it can be concluded that the interference effect of indirubin on the DPPC lipid bilayer is significantly stronger than that of indigo,and this interference effect has a significant correlation with drug concentration.When the concentration is less than 6 mol%,the disturbance of indirubin on the membrane is mainly reflected in increasing the fluidity of the membrane;when the concentration is more than 6 mol%,the disturbance of indirubin on the membrane is mainly reflected in increasing the lipid bilayer thickness.The interference of indirubin on the lipid bilayer may cause changes in the permeability of cell membranes to amino acids,sugars,nucleosides,and inorganic ions.These series of changes will also cause the substance and energy of chronic myeloid leukemia cells metabolism changes.In addition to disturbing the lipid bilayer,the distribution positions of indirubin and indigo in the lipid bilayer may also be another major factor causing the difference in their efficacy.Indigo is mainly distributed in the head region of the lipid bilayer,while indirubin can diffuse into the hydrophobic region of the membrane,indicating that the permeability of indirubin is significantly stronger than indigoIn summary,this article uses differential scanning calorimetry,synchrotron radiation X-ray diffraction and fourier transform infrared spectroscopy to study the effects of indirubin and its isomers indigo and DPPC liposomes.Some relevant conclusions have been drawn,which provides a theoretical research basis for further exploring the mechanism of action between the two and biofilms.