TY - JOUR

T1 - Synergy between plant phenols and carotenoids in stabilizing lipid-bilayer membranes of giant unilamellar vesicles against oxidative destruction

AU - Zhou, Yi-Ming

AU - Liu, Xiao-Chen

AU - Li, Yu-Qian

AU - Wang, Peng

AU - Han, Rui-Min

AU - Zhang, Jian-Ping

AU - Skibsted, Leif H.

PY - 2020

Y1 - 2020

N2 - We have investigated the synergism between plant phenols and carotenoids in protecting the phosphatidylcholine (PC) membranes of giant unilamellar vesicles (GUVs) from oxidative destruction, for which chlorophyll-a (Chl-a) was used as a lipophilic photosensitizer. The effect was examined for seven different combinations of β-carotene (β-CAR) and plant phenols. The light-induced change in GUV morphology was monitored via conventional optical microscopy, and quantified by a dimensionless image-entropy parameter, ΔE. The ΔE-t time evolution profiles exhibiting successive lag phase, budding phase and ending phase could be accounted for by a Boltzmann model function. The length of the lag phase (LP in s) for the combination of syringic acid and β-CAR was more than seven fold longer than for β-CAR alone, and those for other different combinations followed the order: salicylic acid < vanillic acid < syringic acid > rutin > caffeic acid > quercetin > catechin, indicating that moderately reducing phenols appeared to be the most efficient membrane co-stabilizers. The same order held for the residual contents of β-CAR in membranes after light-induced oxidative degradation as determined by resonance Raman spectroscopy. The dependence of LP on the reducing power of phenols coincided with the Marcus theory plot for the rate of electron transfer from phenols to the radical cation β-CAR+ as a primary oxidative product, suggesting that the plant phenol regeneration of β-CAR plays an important role in stabilizing the GUV membranes, as further supported by the involvement of CAR+ and the distinct shortening of its lifetime as shown by transient absorption spectroscopy.

AB - We have investigated the synergism between plant phenols and carotenoids in protecting the phosphatidylcholine (PC) membranes of giant unilamellar vesicles (GUVs) from oxidative destruction, for which chlorophyll-a (Chl-a) was used as a lipophilic photosensitizer. The effect was examined for seven different combinations of β-carotene (β-CAR) and plant phenols. The light-induced change in GUV morphology was monitored via conventional optical microscopy, and quantified by a dimensionless image-entropy parameter, ΔE. The ΔE-t time evolution profiles exhibiting successive lag phase, budding phase and ending phase could be accounted for by a Boltzmann model function. The length of the lag phase (LP in s) for the combination of syringic acid and β-CAR was more than seven fold longer than for β-CAR alone, and those for other different combinations followed the order: salicylic acid < vanillic acid < syringic acid > rutin > caffeic acid > quercetin > catechin, indicating that moderately reducing phenols appeared to be the most efficient membrane co-stabilizers. The same order held for the residual contents of β-CAR in membranes after light-induced oxidative degradation as determined by resonance Raman spectroscopy. The dependence of LP on the reducing power of phenols coincided with the Marcus theory plot for the rate of electron transfer from phenols to the radical cation β-CAR+ as a primary oxidative product, suggesting that the plant phenol regeneration of β-CAR plays an important role in stabilizing the GUV membranes, as further supported by the involvement of CAR+ and the distinct shortening of its lifetime as shown by transient absorption spectroscopy.

U2 - 10.1039/c9sm01415b

DO - 10.1039/c9sm01415b

M3 - Journal article

C2 - 31970380

AN - SCOPUS:85080136722

VL - 16

SP - 1792

EP - 1800

JO - Journal of Materials Chemistry

JF - Journal of Materials Chemistry

SN - 1744-683X

IS - 7

ER -