Studies on antagonism effect of Semen raphani on Panax ginseng from saponin composition and hypothalamic-pituitary-adrenal axis regulation effect

Semen raphani (S. raphani) and Panax ginseng (P. ginseng) is one of eighteen counters in Traditional Chinese Medicine (TCM). This study was aimed to investigate the antagonistic effect of S. raphani on P. ginseng. Three extractions were obtained with single P.ginseng extraction (GW), mixture of P.ginseng and S. raphani extraction (GWSW) and co-extraction of P.ginseng and S. raphani (GSW). Saponin were detected and fingerprinted after LC-Q-TOF-MS identification. The effect of three extractions on HPA regulation was evaluated through the indicators of plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in mouse. Results showed that saponin contents in three extractions were 1.236 +/- 0.048 mg/mL, 1.220 +/- 0.034 mg/mL and 0.966 +/- 0.05 mg/mL for GW, GWSW, GSW separately. Twenty-seven saponin monomers were identified in both GW and GWSW while only twenty-four saponin monomers were identified in GSW with saponin monomers decreased on different levels. GW could change levels of CORT and ACTH in quiet and stressed mice (P < 0.05) compared to saline group while GSW and GWSW could not. These results suggested that S. raphani could inhibit saponin dissolution of P.ginseng which could directly result in the reduced saponin content. More importantly, it was found in this study that S. raphani could weaken the effect of P.ginseng in vivo no matter they were extracted together or not. This study explained the antagonistic effect of S. raphani on P.ginseng and strengthened the usage in TCM that P.ginseng should not taken together with S. raphani. (C) 2018 Published by Elsevier B.V.