Abstract
Five ginsenosides $(A_1,\;A_2,\;B_1,\;B_2,\;C)$ and a yellow pigment were isolated from American ginseng stems and leaves. Ginsenoside $A_2,\;B_1,\;B_2$ and C were proven to be identical with Korean ginseng root ginsenoside $Rg_1,$ Rd, Re and $Rb_2,$ respectively. The yellow pigment proved identical with panasenoside isolated from Korean ginseng leaves. Ginsenoside $A_1$, which was also present in American ginseng roots, was not identical to any of the known root (ginsenoside $R_{0}-Rg_{2}$) and leaf (ginsenoside $F_{1}-F_{3}$) Korean ginseng saponins. A gas-liquid chromatographic method was developed to analyze ginsenosides and sapogenins in rabbit plasma and urine samples. Panasenoside and stigmasterol were found to be the best internal standards for ginsenosides and sapogenihs, respectively. Ginsenoside C had a significantly longer half-life, higher plasma protein binding, lower metabolic and renal clearance than ginsenoside $A_1,\;A_2\;and\;B_2$. Ginsenosides were not found in rabbit plasma and urine samples after oral administration. Ginsenoside C had a higher toxicity than ginsenoside $A_2$ after intraperitoneal administration to mice. Toxicity was not observed after oral administration of the ginsenosides.