Abstract:

Purple potato homogenate was filtrated through multiple layers of gauze, and both the filtrate and residue were harvested. After a period of time of sedimentation, the filtrate was separated into two layers, namely water-soluble upper layer and starch-rich lower layer. The effects of purple potato homogenate, its filtration residue and the water soluble and starch-rich factions of its filtrate on blood pressure of spontaneously hypertensive rats (SHR) was investigated by using 12-week-old male SHR and Wistar rats as the trial animals with different gavage administration doses (0.1, 1 g/kg bw and 5 g/kg bw). The results showed that none of the above four materials had an obvious effect on the blood pressure of normal Wister rats in the given dose range. Except the starch-rich fraction, all the others had a significant effect on decreasing blood pressure of SHR. The water-soluble fraction was the most effective antihyperglycemic factor with 20.83 mmHg drop at 1 hour after administration at 0.1 g/kg bw, 23.50 mmHg at 2 hours after administration at 1 g/kg bw, 24.48 mmHg at 4 hours after administration at 5 g/kg bw. These drops were followed by a slow rebound up to the pre-administration level at 8 hours. From these results, it can be concluded that all the byproducts of purple potato starch extraction have a notable antihyperglycemic effect.

Key words: purple potato, hypertension, spontaneously hypertensive rats (SHR), starch