Plasma Protein Binding of Herbal-Flavonoids to Human Serum Albumin and Their Anti-proliferative Activities

Abstract Herbal-flavonoids (HF) as polyphenolic secondary metabolites are taken in the daily diet to join in many metabolic processes in the human organism. Anti-proliferative activities and human serum albumin (HSA) binding capacities of herbal-flavonoids namely 7,5’-dimethoxyisoetin (HF1), homoorientin-6’’-4-O-methyl-myo-inositol (HF2), (2R, 3R)-(+)-dihydrokaempferol-7,4’-dimethylether (HF3), eriodictyol-7,4’-dimethylether (HF4) and flavonoids isoorientin (HF5) and genkwanin (HF6) were investigated. Anti-proliferative activities were determined by the xCELLigence system by treatment with human prostate (PC3) and cervical cancer (HeLa) cells. The binding capacities were studied by two-dimensional (2D-FL) and three-dimensional (3D-FL) fluorescence spectroscopy. HeLa and PC3 cell lines were treated with flavonoids at 10, 50 and 100 μg/mL concentrations over a 48 hour period. Stable anti-proliferative efficacy plots were obtained for tested flavonoids. From the flavonoids, HF3 and HF4 showed the strongest anti-proliferative effect against PC3 and HeLa cell line. HF1 and HF2 exhibited the strongest binding capacity to the HSA corresponding to Kb values of 3.81 x 104 M-1 and 6.00 x 104 M-1, respectively. The studies revealed that the flavonoids form the basis of in vivo preclinical studies as important nutraceuticals of the daily diet, as well as modelled in medical and pharmacological applications.

摘要：植物类黄酮（Herbal-flavonoids, HF）作为多酚类次生代谢产物，可通过日常饮食摄入并参与人体机体的诸多代谢过程。本研究针对六种植物类黄酮——7,5’-二甲氧基异非瑟素（HF1）、同荭草素-6''-4-O-甲基-肌醇（HF2）、(2R,3R)-(+)-二氢山奈酚-7,4’-二甲醚（HF3）、圣草酚-7,4’-二甲醚（HF4）、异牡荆素（HF5）与芫花素（HF6）——的抗增殖活性及与人血清白蛋白（human serum albumin, HSA）的结合能力展开了探究。抗增殖活性采用xCELLigence系统，通过处理人前列腺癌（PC3）细胞与宫颈癌（HeLa）细胞进行测定；结合能力则通过二维（2D-FL）与三维（3D-FL）荧光光谱法开展研究。实验以10、50、100 μg/mL三个浓度的类黄酮处理HeLa与PC3细胞系，孵育时长为48小时。受试类黄酮均获得了稳定的抗增殖活性曲线，其中HF3与HF4对PC3及HeLa细胞系表现出最强的抗增殖效果；HF1与HF2与人血清白蛋白的结合能力最强，对应的结合常数Kb分别为3.81×10⁴ M⁻¹与6.00×10⁴ M⁻¹。本研究结果显示，此类植物类黄酮作为日常饮食中的重要膳食营养保健成分，可为体内临床前研究奠定基础，同时也可作为医学与药理学应用的研究模型。