THE EFFECT OF MECLOFENOXATE WITH GINKGO-BILOBA EXTRACT OR ZINC ON LIPID PEROXIDE, SOME FREE-RADICAL SCAVENGERS AND THE CARDIOVASCULAR-SYSTEM OF AGED RATS

Aged rats are highly prone to many physiological changes such as blood pressure and heart rate. These changes could be due to modification i n membrane phospholipid composition of their blood vessels. Lipid pero xide in vivo has been identified as a basic deteriorative reaction in cellular mechanisms of aging in human. The effect of a nootropic drug, meclofenoxate (MF) or its combination with extract of ginkgo biloba ( EGb-761) or zinc (Zn) on malondialdehyde (MDA) product as an index of endogenous lipid peroxidation; phospholipid; glutathione (GSH) and pro tein thiols (PrSHs) contents as well as superoxide dismutase (SOD) act ivity in blood, brain, heart and liver of 24-month-old male rats was i nvestigated. Aged rats were treated with MF once daily at oral doses o f 100 mg kg-(1) body wt. alone or with either EGb at a dose of 150 mg kg(-1) body wt. or Zn at 10.5 mg kg(-1) body wt, for 4 weeks. This stu dy showed that aging caused a higher increment in MDA level of brain a nd heart than liver and plasma accompanied with reduction in brain and heart phospholipid contents as well as alteration of the antioxidant systems as compared to 4-month-old rats. Treatment of aged rats with M F alone or combined with either EGb or Zn caused improvement in the me asured free radical scavengers especially in brain and heart tissues. Our results also showed that both EGb and Zn induced a significant pot ential effect of MF action on blood pressure and heart rate. The resul ts were explained in the light of the antioxidant properties of EGb an d Zn. Thus it is concluded that EGb and Zn have a beneficial role with MF in diminishing cumulative oxidative changes in aging. (C) 1998 The Italian Pharmacological Society.