2.2. Experimental design
S. platensis powder was purchased from Gih Hwa Enterprises
Co., Ltd., Taipei, Taiwan. The hot-water extract of S. platensis was
prepared based on a method described before [16]. Ten grams of
S. platensis powder was added to 250 ml of deionized water and
boiled for 3 h. The suspension was filtered through a nylon mesh.
The filtrate was concentrated under reduced pressure. The harvest
weight of the hot-water extract obtained from 10 g of S. platensis
dry powder was 2.55 g. Carbohydrate and protein contents in the
extract were 15.8% as glucose and 35.6% as bovine serum albumin
(BSA), respectively, measured by the phenolesulfuric acid method
[17] and Bio-Rad Protein assay based on the Bradford method [18].
The hot-water extract was prepared with sterile saline to make
solutions of 3, 5 and 10 mg ml1, which were served as the test
solutions.