The protective effect of standardized extract of centella asiatica ECa 233 on hemin-induced lipoprotein oxidation

Abstract

Oxidation reaction of low density lipoprotein (LDL) plays a pivotal role in atherogenesis. Hemin (protoporphyrin IX- Fe²⁺) is oxidative mediator found in plasma of thalassemia patient. Centella asiatica is a medicinal plant shown to be antioxidant. The aim of this study was to determine the effect of standardized extract of Centella asiatica ECa233 and asiatic acid on hemin-induced LDL oxidation (he-oxLDL). LDL was pre-incubated with either ECa233 or asiatic acid for 30 minutes and α-tocopherol as a positive control, and then oxidation was initiated by incubation with hemin at 37˚C for 24 hours. The degree of LDL oxidation was determined by measurement of thiobarbituric acid reactive substances (TBARs), α-tocopherol and the relative electrophoretic mobility (REM). TBARs levels and REM values were increased in he-oxLDL. The results showed that ECa233 and asiatic acid (20-80 µg/ml) can inhibit TBARs formation at 6 hr 70% while at 24 hr they can inhibit only 15-20%. However, ECa233 and asiatic acid cannot decrease REM value, indicating that both compounds cannot protect protein oxidation. In conclusion, ECa233 and asiatic acid could protect lipid peroxidation in LDL induced by hemin significantly at 6 hr but this effect was not prolonged to 24 hr.