Effect of steroidal saponins of Anemarrhenae rhizoma on superoxide generation in human neutrophils

Effect of six steroidal saponins isolated from Anemarrhenae rhizoma on supe roxide generation in human neutrophils was investigated. The steroidal sapo nins examined were anemarrhenasaponin-I (An-I), anemarrhenasaponin-Ia (An-I a), timosaponin B-I (TBI), timosaponin B-II (TB-II), timosaponin B-III (TB- III) and timosaponin A-III (TA-III). An-I, An-Ia, and TB-III suppressed the superoxide generations induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) and arachidonic acid (AA) in a concentration-dependent manner, but e nhanced that induced by phorbol 12-myristate 13-acetate (PMA), While TB-II also suppressed and enhanced the superoxide generations induced by fMLP and PMA, respectively, the compound significantly enhanced the AA-induced supe roxide generation. TB-I enhanced the fMLP-induced superoxide generation in a low concentration range (peak at 40 mu M), gave no effect on the PMA-indu ced superoxide generation and weakly enhanced the AA-induced superoxide gen eration. TA-III enhanced the fMLP-induced superoxide generation more than t wice as much as that by TB-I in the same concentration range. However, TA-I II enhanced the PMA-induced superoxide generation and most significantly su ppressed the AA-induced superoxide generation. (C) 1999 Academic Press.