Fast repair of TMP radical anions by phenylpropanoid glycosides (PPGs) andtheir analogs

Repair effect on TMP radical anions by phenylpropanoid glycosides (PPGs) an d their analogs, isolated from Chinese folk medicinal herbs, were studied u sing a pulse radiolysis technique. The radical anion of TMP was formed by t he reaction of hydrated electron with TMP. On pulse irradiation of a nitrog en saturated TMP aqueous solution containing 0.2 mol/l t-BuOH and one of th e PPGs or their analogs, the transient absorption spectrum of the radical a nion of TMP decayed with the formation of that of the radical anion of PPGs or their analogs within several decades of microseconds after electron pul se irradiation. The results indicated that TMP radical anions can be repair ed by PPGs or their analogs. The rate constants of the repair reactions wer e deduced to be 1.64-2.75 x 10(9) M-1 s(-1). A deeper understanding of this new repair mechanism will undoubtedly help researchers design strategies t o prevent and/or intervene more effectively in free radical related disease s. (C) 2000 Elsevier Science Ltd. All rights reserved.