Long-term intake of an aqueous seed extract of Fraxinus excelsior L. attenuates the development of hypertension in spontaneously hypertensive rats

We have evaluated the effect of the long-term intake of different doses (20 mg/kg/day, 40 mg/kg/day and 60 mg/kg/day) of a Fraxinus excelsior L. seed extract named FraxiPure (TM) (FRP), on the development of hypertension of spontaneously hypertensive rats (SHR). Water was used as negative control and Captopril (50 mg/kg) was used as positive control. Systolic blood pressure was measured weekly in the rats, from the 6th to 24th week of life (6th to 20th week = treatment period; 20th to 24th week = follow-up period), by the tail cuff method: We also evaluated the effect of the different treatments on body weight, solid and liquid intake, along the experimental period. The development of hypertension was attenuated in the groups treated with Captopril or FRP, and the antihypertensive effect was more accentuated in the group treated with Captopril. It was paradoxically more accentuated in the groups treated with 20 mg/kg/day or 40 mg/kg/day of FRP than in the group treated with the highest dose of this extract. In addition, solid intake increased somewhat in the FRP groups, and the rats treated with this extract showed an increase in body weight gain. The arterial blood pressure increased in the treated SHR when the corresponding antihypertensive treatment was removed and the body weight of the FRP treated animals returned to control values along the follow-up period. Our results suggest that FRP may be used as a functional food ingredient with antihypertensive activity. Nevertheless, the possible orexigenic effect of FRP should be studied in the future.