Antioxidant Action of Tetrandrine: An Alkaloid from the Roots of Radix stephania tetrandra,S Moore

The antioxidant action of the alkaloid tetrandrine(TD), was investigated using systems generating biologically relevant reactive oxygen species. TD appeared to scavenge OH^• produced in a mixture of EDTA-Fe³⁺/ascorbate and H₂O₂ and suppressed the peroxidation of phospholipid liposomes in the presence of iron(III) and ascorbate. TD was a good scavenger toward trichloromethyl peroxyl with a rate constant of 6·5±0·3×10⁷ M ^-1 s^-1 generated by pulse radiolysis. TD did not promote DNA damage in the bleomycin-Fe³⁺ system and a concentration up to 500 μM produced a weak inhibition of DNA damage by bleomycin-Fe³⁺ in the presence of ascorbic acid. The present data suggest that TD possess antioxidant properties. © 1997 SCI.