| Black ginseng(BG)is a type of processed ginseng.Ginsenosides as major bioactive constituents in ginseng can undergo oxidative decomposition during heat treatment and can produce low-polarity ginsenosides which have higher activity.Therefore,BG and its ginsenosides have attracted more and more researcher′s attention in recent years.In this paper,BG was processed at different temperatures and different relative humidity,and the possible transformation of ginsenosides during the process was analyzed.At the same time,the free radical scavenging ability and the cytotoxicity efficiency against Hep G2 cell of the black ginseng gnsenoside extract(BGE)were studied.It further provided theoretical and technical support for black ginseng and its ginsenosides as functional food or disease prevention ingredients.In this study,the effects of temperature,humidity and treatment time on the ginsenoside content and ginsenoside composition were investigated.At the same time,the changes of moisture content,chromatic aberration,polysaccharide content and total saponin content during the formation of BG were measured.The changes of 10 ginsenosides during the preparation of BG were analyzed by high performance liquid chromatography(HPLC)and mass spectrometry(MS).Our findings demonstrated that the highest total ginsenoside content was 7.48%after 12 days treatment at temperature 80°C and RH 75%.After treatment,the less polar ginsenosides content increased and the polar ginsenosides content decreased.Among them,less polar ginsenosides Rg3 and CK were accumulated increasingly from 0.88 mg/g and 0.84 mg/g to 7.30 mg/g and 15.08 mg/g,respectively.In addition,the possible transformations of 10 ginsenosides during processing were speculated,and it was found that in this study,the transformation of protopanaxadiol-type gisenoside mainly occurred.The scavenging abilities of 1,1-diphenyl-2-trinitrophenylhydrazine(DPPH),2,2-diazo-bis-3-ethylbenzothiazoline-6-sulfonic acid(ABTS~+),hydroxyl radical(·OH)and the reducing power were measured to evaluate the antioxidant capacity in vitro of BGE.The results showed that the IC50 of BGE for DPPH,ABTS~+and·OH scavenging ability were 0.43 mg/m L,1.14 mg/m L and 5.92 mg/m L,respectively,while the IC50 of WGE on DPPH,ABTS~+and·OH scavenging abilities were 3.21 mg/m L,2.52 mg/m L and 8.07mg/m L.As well as the total reducing ability of BGE was also significantly better than WGE,which indicated that the processed black ginseng may have stronger antioxidant activity.In order to evaluate the potential antitumor activity of ginsenoside extracts,Hep G2cells was incubated with WGE and BGE for 12,24,and 48 h to determine cell viability using the CCK-8 method.And it was found that the effect of inhibiting the viability of Hep G2 cells in the BGE group was more significant than WGE group.The apoptosis induced by WGE and BGE was analyzed by flow cytometry after staining with Annexin V-FITC and PI.With the stimulation concentration of BGE increasing from 50μg/m L to300μg/m L,the percentage of apoptotic cells increased from 17%to 69%,which was significantly higher than the effect of WGE stimulation 8%to 31%.To further discuss the inhibition mechanisms of BGE on cell apoptosis,the expression of apoptosis-related proteins in Hep G2 cells were analyzed by western blotting analysis.In this study,the protein expressions of caspase-3,caspase-9,caspase-6,p53 and PARP in Hep G2 cells were significantly increased with the treatment of BGE,especially the caspase-3 and caspase-9.Therefore,the cytotoxicity effect of BGE on Hep G2 cells may be due to the mitochondrial apoptosis pathway induced by up-regulated caspase family proteins.These results provided theoretical and technical support for black ginseng and its ginsenosides as anticancer active ingredients,and further proved the prospect of BG or BGE as functional food or disease prevention ingredients. |
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