Abstract:

Collagen hydrolysates prepared from the whole swine femur, femoral shaft and femoral head were tested for their
antihypertensive effects in spontaneous hypertension rats (SHRs). SHRs were fed adaptively for 7 days and then randomly
divided into 11 groups of 8 each: negative group was treated with distilled water; each hydrolysate had 3 dose groups (lowdose
group, middle-dose group and high-dose group), which were treated with 20.0, 40.0 mg/kg and 60.0 mg/kg.ig collagen
hydrolysates respectively; and positive group was treated with 10.0 mg/kg.ig captopril. The rats’ systolic pressure was
measured every 2 hours. The results indicated that hydrolysates from the whole swine femur and femoral shaft and the low
dose group of femoral head hydrolysate had no significant antihypertensive effect; the middle-dose and high-dose groups of
femoral head significantly lowered the blood pressure in SHRs. Spectrophotometry were used to detect the ACE inhibition
rate of the different hydrolysates. The hydrolysates of whole femur and femoral head had values of IC50 against ACE of 3.546 mg/mL
and 2.045 mg/mL, respectively. Thus these three hydrolysates have potent ACE inhibitory activity in vitro, but only a certain
concentration of femoral head hydrolysates can effectively reduce the systolic pressure in SHRs.

Key words: swine femur, antihypertensive peptide, angiotensin-converting enzyme (ACE), spontaneous hypertension rats (SHR)