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Flavonoids in Microheterogeneous Media, Relationship between Their Relative Location and Their Reactivity towards Singlet Oxygen.

Günther G, Berríos E, Pizarro N, Valdés K, Montero G, Arriagada F, Morales J - PLoS ONE (2015)

Bottom Line: In addition, these compounds do not produce changes in fluorescence anisotropy of DPH, discarding their location in deeper regions of the lipid bilayer.The determined chemical reactivity sequence is similar in all the studied media (kaempferol < quercetin < morin).Morin is approximately 10 times more reactive than quercetin and 20 to 30 times greater than kaempferol, depending on the medium.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.

ABSTRACT
In this work, the relationship between the molecular structure of three flavonoids (kaempferol, quercetin and morin), their relative location in microheterogeneous media (liposomes and erythrocyte membranes) and their reactivity against singlet oxygen was studied. The changes observed in membrane fluidity induced by the presence of these flavonoids and the influence of their lipophilicity/hydrophilicity on the antioxidant activity in lipid membranes were evaluated by means of fluorescent probes such as Laurdan and diphenylhexatriene (DPH). The small differences observed for the value of generalized polarization of Laurdan (GP) curves in function of the concentration of flavonoids, indicate that these three compounds promote similar alterations in liposomes and erythrocyte membranes. In addition, these compounds do not produce changes in fluorescence anisotropy of DPH, discarding their location in deeper regions of the lipid bilayer. The determined chemical reactivity sequence is similar in all the studied media (kaempferol < quercetin < morin). Morin is approximately 10 times more reactive than quercetin and 20 to 30 times greater than kaempferol, depending on the medium.

No MeSH data available.


Laurdan generalized polarization (GP) as a function of temperature.POPC / DPPC liposomes (o) and POPC / DPPC liposomes with addition of 9 x 10−5 M of morin (•).
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pone.0129749.g004: Laurdan generalized polarization (GP) as a function of temperature.POPC / DPPC liposomes (o) and POPC / DPPC liposomes with addition of 9 x 10−5 M of morin (•).

Mentions: Membranes formed by POPC are more fluid than those made of DPPC because an unsaturation in one of its hydrocarbon chains, mimicking better what would happen in a biological system (erythrocytes membrane). The results show that GP values are independent of the liposome size, so the curvature radius does not significantly affect nor membrane structure and probably neither its fluidity. The fluorescence study showed that in the temperature range below the phase transition (Tm) of POPC / DPPC liposomes the GP initial value is high (+0.5), and gradually decreases to a value of -0.1 at 48°C. This indicates a greater possibility of water access probably due to greater thermal agitation of the surfactant molecules (Fig 4). Below Tm, The addition of flavonoid (9.5x10-5 M) produces a large decrease in the GP value (+0.1); therefore its presence fluidizes the membrane, which indicates that the flavonoid shares the same location with Laurdan. For saturated phospholipids typical GP values around +0.5 − +0.6 have been reported for the pure gel phase, and for the pure crystal liquid state values range between -0.3 and -0.4.


Flavonoids in Microheterogeneous Media, Relationship between Their Relative Location and Their Reactivity towards Singlet Oxygen.

Günther G, Berríos E, Pizarro N, Valdés K, Montero G, Arriagada F, Morales J - PLoS ONE (2015)

Laurdan generalized polarization (GP) as a function of temperature.POPC / DPPC liposomes (o) and POPC / DPPC liposomes with addition of 9 x 10−5 M of morin (•).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476713&req=5

pone.0129749.g004: Laurdan generalized polarization (GP) as a function of temperature.POPC / DPPC liposomes (o) and POPC / DPPC liposomes with addition of 9 x 10−5 M of morin (•).
Mentions: Membranes formed by POPC are more fluid than those made of DPPC because an unsaturation in one of its hydrocarbon chains, mimicking better what would happen in a biological system (erythrocytes membrane). The results show that GP values are independent of the liposome size, so the curvature radius does not significantly affect nor membrane structure and probably neither its fluidity. The fluorescence study showed that in the temperature range below the phase transition (Tm) of POPC / DPPC liposomes the GP initial value is high (+0.5), and gradually decreases to a value of -0.1 at 48°C. This indicates a greater possibility of water access probably due to greater thermal agitation of the surfactant molecules (Fig 4). Below Tm, The addition of flavonoid (9.5x10-5 M) produces a large decrease in the GP value (+0.1); therefore its presence fluidizes the membrane, which indicates that the flavonoid shares the same location with Laurdan. For saturated phospholipids typical GP values around +0.5 − +0.6 have been reported for the pure gel phase, and for the pure crystal liquid state values range between -0.3 and -0.4.

Bottom Line: In addition, these compounds do not produce changes in fluorescence anisotropy of DPH, discarding their location in deeper regions of the lipid bilayer.The determined chemical reactivity sequence is similar in all the studied media (kaempferol < quercetin < morin).Morin is approximately 10 times more reactive than quercetin and 20 to 30 times greater than kaempferol, depending on the medium.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.

ABSTRACT
In this work, the relationship between the molecular structure of three flavonoids (kaempferol, quercetin and morin), their relative location in microheterogeneous media (liposomes and erythrocyte membranes) and their reactivity against singlet oxygen was studied. The changes observed in membrane fluidity induced by the presence of these flavonoids and the influence of their lipophilicity/hydrophilicity on the antioxidant activity in lipid membranes were evaluated by means of fluorescent probes such as Laurdan and diphenylhexatriene (DPH). The small differences observed for the value of generalized polarization of Laurdan (GP) curves in function of the concentration of flavonoids, indicate that these three compounds promote similar alterations in liposomes and erythrocyte membranes. In addition, these compounds do not produce changes in fluorescence anisotropy of DPH, discarding their location in deeper regions of the lipid bilayer. The determined chemical reactivity sequence is similar in all the studied media (kaempferol < quercetin < morin). Morin is approximately 10 times more reactive than quercetin and 20 to 30 times greater than kaempferol, depending on the medium.

No MeSH data available.