Effect of xanthones on lipid membranes

J.P. CEJAS,; A.S. ROSA; DISALVO, E. A; M.A. FRÍAS.

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias 2017; 2017

Xanthones are heterocyclic compounds with thedibenzo-γ-pyrone structure. In nature xanthones are a class of secondarymetabolites that produced commonly in several plant families. The fusedrings that form the xanthonic system and the eight possible types ofsubstitution provide an interesting framework from which different systems canbe designed. This statement is evidenced by a large number of natural xanthonesfound in the library of plants, fungi and lichens. In recent years,interest in their chemical and structural properties has increased due to manypharmacological uses that are assigned. Among the biological activitiesdescribed for these compounds, in vitro growth inhibitory activity in tumorcell lines appeared to be quite remarkable, since they are biologically activein a wide range of tumor cell lines.Recently a relationship was established betweengastric toxicity of non-steroidal anti-inflammatory drugs and their direct influenceon gastric phospholipid properties.The interest in this compound is related to itspossible integration to biological membrane in order to design lipid particlesfor drug delivery.This it is of interest to study the effect it may haveon membrane structure. For this reason, in this study, we investigated theinsertion of Xanthone (9H-xanthen-9-one)  and Hydroxy-xanthone(1-hydroxy-9H-xanthen-9-one) in lipid monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC),di-Oleoylphosphatidylcholine (DOPC),1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (etherPC),Phosphatidylethanolamine (16:0 DPPE) by measuring the changes in the dipolepotential, the area per lipid and compressibility properties. In addition, thechanges in packing and membrane polarity was assessed by measuring GeneralizedPolarization in gel and liquid crystalline states using Laurdan as afluorescent probe.The experimental results show that xanthone inserts inDPPC membrane interface orienting the CO group with the oxygen towards theaqueous media normal to membrane surface that explains the dipole potential.The aromaticring locates parallel to the first C atoms of the acyl chains apparently byinterqctiong with the non bound populations of the carbonyl groups of thephospholipid. This produces a modest area increase and a depolarization of theinterface. This was confirmed by molecular dynamics analysis.The presence of OHgroup attenuates the increase in the dipole potential demonstrated that it isessential the full insertion of the non polar moiety in the membrane phase toproduce the dipole potential increase.