Complexation of Ginkgo biloba extract with phosphatidylcholine improves cardioprotective activity and increases the plasma antioxidant capacity in the rat

The aim of this work was to compare in the rat the cardioprotective efficac y and the total plasma antioxidant activity of a standardised Ginkgo biloba L. extract (GB) as such (300 mg/kg/day) or complexed with phosphatidylchol ine (GB-PC; 1:2 w/w), after a 5 days oral administration. At the end of the treatment, the total plasma antioxidant defence was determined by the TRAP and FRAP assays, and the hearts from all groups of animals subjected to mo derate ischemia (flow reduction to 1 ml/min for 20 min) and reperfusion (15 ml/min for 30 min). The recovery of left ventricular developed pressure (LV DP) at the end of reperfusion was 35-40% of the preischemic values in both control and vehicle rats, 50.2% in the GB group and 72.5% in the GB-PC pre- treated animals. Creatine kinase (CK) outflow in the perfusate from the hea rts of GB and GB-PC treated animals were restrained to a different extent v s. controls (by 71%. GB-PC; by 22% GB); the rate of prostacyclin (6-keto-PG F(1 alpha)) release was far greater in GB-PC than in GB hearts. In parallel , the GB extract significantly increased the total antioxidant plasma capac ity (by 24.5%, TRAP; 27.9% FRAP) only when complexed with phospholipids. Th is indicates an increased bioavailability of phenolic antioxidants when sui tably embedded within a lipophilic carrier. The results of this study demon strate that complexation of Ginkgo biloba with phospholipids induces in the rat, even after a short treatment a greater resistance of the heart to isc hemia/reperfusion damage in respect to the native extract, due to an increa sed plasma antioxidant activity.