Recently, we found that
4-hydroxyderricin, one of the major
chalcones in Angelica keiskei extract (an
ethyl acetate extract from the yellow liquid of stems), suppressed increases in systolic blood pressure and reduced both serum
very low-density lipoprotein levels and liver
triglyceride content in
stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, we have isolated
laserpitin, a characteristic
coumarin, from the A. keiskei extract and examined the effect of dietary
laserpitin on blood pressure and lipid metabolism in SHRSP. Six-week-old male SHRSP were fed diets containing 0.1%
laserpitin for 7 weeks with free access to the diet and water. Bodyweight gain was reduced by dietary
laserpitin after 4 weeks through to 7 weeks without any significant change in daily food intake. Serum total
cholesterol,
phospholipid and
apolipoprotein (
apo) E levels were significantly increased, which was due to significant increases in
cholesterol,
phospholipid and
apoE contents in the low- and
high-density lipoprotein (
LDL and HDL, respectively) fractions. These results suggest that dietary
laserpitin increases serum
apoE-HDL levels. In the liver, significant decreases in relative liver weight and
triglyceride content were found
after treatment with
laserpitin for 7 weeks. An investigation of hepatic
mRNA expression of
proteins involved in lipid metabolism indicated that a significant decrease in hepatic
triglyceride lipase may be responsible for the increase in serum HDL levels and also indicated that a marked decrease in
adipocyte determination and differentiation factor 1 may be responsible, at least in part, for the decrease in hepatic
triglyceride content. In conclusion, dietary
laserpitin produces increases in serum HDL levels, especially
apoE-HDL, and decreases in the hepatic
triglyceride content in SHRSP.