Protective effects of boldine against free radical-induced erythrocyte lysis

Boldine, an aporphine alkaloid extracted from the leaves and bark of boldo (Peumus boldus Mol.), has been shown to exhibit strong free-radical scavenger and antioxidant properties. Here, we report the in vitro ability of boldine to protect intact red cells against the haemolytic damage induced by the free radical initiator 2, 2'-azobis-(2-amidinopropane) (AAPH). Boldine concentration-dependently prevented the AAPH-induced leakage of haemoglobin into the extracellular medium. Substantial and similar cyto-protective effects of boldine were observed whether the antioxidant was added 1 h prior to, or simultaneously with, the azo-compound. The delayed addition of boldine, by 1 h relative to AAPH, diminished but did not abolish its cytoprotective effect. However, negligible effects of boldine were observed after its addition to erythrocytes previously incubated with AAPH for 2 h. The data presented demonstrate that, in addition to its well-established antioxidant effects, boldine also displays time-dependently strong cytoprotective properties against chemically induced haemolytic damage.