Abstract
A screening process has been developed to evaluate four dietary supplements for their potential to affect coagulation through the extrinsic pathway in human tissue. An established analytical method was used to determine prothrombin time (PT) using a clinical laboratory fibrometer.1,2 Dong quai, Korean ginseng, cat's claw, and ginger were studied. Extracts of plant material were made by mixing the native material in synthetic plasma at room temperature for 1.0 hour. Plasma was simulated by preparation of 6% bovine albumen, phosphate buffered at pH 7.3, with the ionic strength controlled using common physiologic salts. Concentrations of the extract were prepared by varying the amount of material extracted with a given volume of synthetic plasma. Initially, a volume study was conducted to determine the extent to which an aliquot of human plasma could be diluted before changing the PT. Ten microliters of the appropriate extract were added to an aliquot of pooled human plasma collected from male volunteers between the ages of 18-57 years and the PT measured. Evaluation of the data (n = 6) using an unpaired t-test and assuming equal variances at a= 0.05 suggests that Korean ginseng and ginger do not alter prothrombin times, using this model. Conversely, dong quai and cat's claw extracts significantly increased PT when compared to the blank, p = 6.9 X10 “5 and 5.022 X10−12 at herb extract ratios of 309.5 mg/ml and 249.2 mg/ml, respectively. Dong quai and cat's claw extracts combined with human plasma yielded mean prothrombin times that were 109.1% ±2.57 and 163.0% ±4.15 of their respective blanks. This study shows that the in vitro model may be useful to predict changes in PT in patients consuming dietary supplements and in identifying potential interactions with dietary supplements and anticoagulant therapy.