| dc.description.abstract | This study was designed to investigate the effects of different processing
methods on the antioxidant and anti-cancer properties of soymilk crude phenolic
extract (CPE) using the human prostate cancer cell line DU 145 as a model
system. Four grinding methods and two ultra-high temperature (UHT)
processing methods were investigated. Briefly, the four grinding methods
included grinding with tap water (Method 1), okara-washed water (Method 2),
soaked water (Method 3), as well as both okara-washed water and soaked
water (Method 4); the two UHT processing conditions included one-phase UHT
(143 °c, 60 s) and two-phase UHT (120 °C, 80 s + 140 °C, 4 s) methods. The
antioxidant capability of CPE was measured by oxygen radical absorbance
capacity (ORAC) and/or ferric reducing antioxidant power (FRAP) and 2,
2-diphenyl-1-picrylhydrazyl free radical scavenging activity (DPPH) assays. The
DU 145 human prostate cancer cell line was sub-cultured in the presence of
CPE at various concentrations (0, 1, 2, 4, 8 mg/ml) for 48 h and the percentage
of cell viability was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl
tetrazolium bromide (MTT) assay and/or flow cytometric analysis with
carboxyfluorescein succinimidyl ester (CFSE) staining. An induction of apoptosis was detected by flow cytometric analysis with annexin V/ propidium
iodide (Pl) double staining, morphological change observation with acridine
orange/ethidium bromide (AO/EB) double staining, and Western blot assay of
apoptotic proteins.
The results showed that grinding Method 4 and the two-phase UHT method
exhibited greater total phenolic content and antioxidant capability than the other
three grinding methods and one-phase UHT, respectively. In addition, soymilk
CPE inhibited cell proliferation in a dose-dependent manner and upon
purification. The anti-proliferation effects observed in soymilk CPE were
associated with the apoptosis induction in DU 145 cell line as evidenced by
morphological changes and the expression of apoptotic proteins. These results
suggest that the soymilk CPE plays an important role in anti-proliferation, and
apoptotic properties of soy in DU 145 cells. Furthermore, these health-promoting
properties were affected by processing conditions, such as grinding and thermal
conditions. The results of this study benefit the soy product industry to select
appropriate processing conditions to retain more health-promotion
phytochemicals during soy food's processing. | en_US |
