H. Al Zuhair et al., Pumpkin-seed oil modulates the effect of felodipine and captopril in spontaneously hypertensive rats, PHARMAC RES, 41(5), 2000, pp. 555-563
Natural products like pumpkin-seed oil (PSO) may modify the potency of the
calcium antagonist felodipine (FEL) or angiotensin-converting enzyme inhibi
tor (ACE-inhibitor), captopril (CPT) in modulating the biochemical derangem
ent in blood, heart and kidney as well as blood pressure and heart rate of
spontaneously hypertensive rats (SHR) were investigated. SHR were treated o
rally with FEL at a dose of 0.45 mg kg(-1) body wt, or CPT at a dose of 9 m
g kg(-1) body wt. once daily for 4 weeks. PSO was administered at a dose of
40 mg kg(-1) body wt. alone or with FEL or CPT in the previous respective
dose regimen for the same period to SHR. This study showed that hypertensio
n induced increments the content of malondialdehyde (MDA) by 55% and 38% as
well as the activity of glutathione peroxidase (GSH-Px) by 26% and 23% in
heart and kidney, respectively, accompanied by reductions in the activity o
f myocardial superoxide dismutase (SOD) from 3.40 +/- 0.17 to 2.42 +/- 0.19
U mg protein(-1) and contents of glutathione (GSH) and protein thiols (PrS
Hs) in different tissues of SHR as compared to normotensive rats. Treatment
of SHR with FEL or CPT monotherapy or combined with PSO produced improveme
nt in the measured free radical scavengers in the heart and kidney. Our res
ults also showed that pretreatment of SHR with PSO for 4 weeks then i.v. ad
ministration of FEL or CPT produced a significant beneficial hypotensive ac
tion. The results were explained in the light of the antioxidant properties
of PSO. Therefore, it is concluded that concomitant administration of FEL
or CPT with natural antioxidants can yield a beneficial therapeutic effect
and retard the progression of hypertension. (C) 2000 Academic Press.