Abstract

This study was focused on the effect of plant metabolites (phloretin, capsaicin, digitonin, diosgenin and betulin) on the model lipid membranes. The methods of assessing the permeability of lipid bilayers based on measuring the leakage of a fluorescent marker (calcein) from liposomes and differential scanning microcalorimetry of vesicle suspension were used. It was found that the release rate of calcein from 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine (POPC) liposomes with test compounds added to the suspension at a ratio with lipid 1 : 50 decreased in the order capsaicin > phloretin >> betulin ≈ diosgenin ≈ digitonin. In the case of cholesterol- and ergosterol-containing POPC liposomes, the activity decreased as diosgenin ≈ digitonin > betulin > capsaicin > phloretin. It was demonstrated that phloretin and capsaicin significantly reduce the melting temperature (T_m) and to increase the half-width of the main peak on the endotherm (T_1/2) of dipalmitoylphosphocholine (DPPC), distearoylphosphocholine (DSPC) and diarachidoylphosphocholine (DAPC). These results show that the incorporation of these small molecules between the polar “heads” of phosphocholine. It was found that the increase in the length of saturated chains of membrane-forming lipids (from 16 to 20 hydrocarbon units), the absolute values of ΔT_m and ΔT_1/2 decreased in the presence of phloretin and increased with capsaicin. This may be the result of differences in the localization of phloretin and capsaicin in the membrane. Steroid saponins exhibited a weak effect on the thermotropic behavior of phosphocholines. The absolute values of ΔT_m and ΔT_1/2 decreased in the order DPPC, DSPC, and DAPC and increased in the order betulin, diosgenin, and digitonin. Steroid saponins are characterized by a more pronounced effect on the thermotropic behavior of the sterol–phospholipid mixture. The findings are consistent with the assumption of a high affinity of the tested saponins for sterol-containing membranes.

中文翻译：

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植物代谢产物对不同厚度模型脂质膜的紊乱作用

摘要

这项研究的重点是植物代谢产物（金盏花素，辣椒素，洋地黄皂苷，薯os皂甙元和白桦蛋白）对模型脂质膜的影响。使用了基于测量脂质体的荧光标记物（钙黄绿素）渗漏和囊泡悬浮液的差示扫描量热法评估脂质双层的渗透性的方法。发现钙黄绿素从1-棕榈酰基-2-油基-sn的释放速率-甘油-3-磷酸胆碱（POPC）脂质体与测试化合物以脂质1:50的比例添加到悬浮液中，其顺序依次为辣椒素>视紫红质>>山毛蛋白≈薯os皂苷元≈洋地黄皂苷。对于含胆固醇和麦角固醇的POPC脂质体，其活性降低，如薯gen皂苷元≈洋地黄皂苷>山毛蛋白>辣椒素>毛ore素。结果表明，伞菌素和辣椒素显着降低了解链温度（T _m）并增加了吸热峰主峰的半峰宽（T _1/2）二棕榈酰磷酸胆碱（DPPC），二硬脂酰磷酸胆碱（DSPC）和二花生四烯酰基磷酸胆碱（DAPC）。这些结果表明，这些小分子在磷酸胆碱的极性“头部”之间结合。结果发现，在膜形成脂质的饱和链的长度的增加（从16至20烃单元），Δ的绝对值Ť_米和Δ Ť _1/2在根皮素的存在而减小，随辣椒素增加。这可能是膜上视绿蛋白和辣椒素位置不同的结果。类固醇皂苷对磷胆碱的热致行为表现出较弱的影响。ΔT _m和ΔT _1/2的绝对值依次降低DPPC，DSPC和DAPC的顺序，并增加白蛋白，薯os皂素和洋地黄皂苷的顺序。类固醇皂苷的特征是对固醇-磷脂混合物的热致行为有更明显的影响。该发现与被测皂苷对含固醇膜的高亲和力的假设是一致的。