CALCIUM-CHANNEL BLOCKADE AND ANTI-FREE-RADICAL ACTIONS OF PANAXADIOL SAPONINS RB-1, RB-2, RB-3, R(C), AND R(D)

AIM: To identify the calcium channel blockade and anti-free-radical ac tions of panaxadiol saponins Rb-1, Rb-2, Rb-3, R(c), and R(d). METHODS : On ventricular myocardiocytes of Wistar rats, single channel activit ies of L, T, and B type Ca2+ channels were recorded with the cell-atta ched configuration of patch-clamp technic, and free radical contents w ere measured with electron spin resenance method. RESULTS: Rb-1, Rb-2, Rb-3, and R(c) 200 mu mol . L(-1) shortened the open times, prolonged the close times, and reduced the open-state probabilities of calcium channels and 30 mu mol . L(-1) antagonized the increase of free radica l content induced by xanthine 0.42 mmol . L(-1)-xanthine oxidase 5.3 n mol . L(-1), but R(d) in the same dose behaved none of the effects. CO NCLUSION: Rb-1, Rb-2, Rb-3, and R(c) had both the calcium channel bloc kade and anti-free-radical actions.