Transformation of ginsenosides by moderate heat-moisture treatment and their cytotoxicity toward HepG2 cells

Abstract

In the current study, the effects of heat-moisture treatment on the ginsenoside contents and ginsenoside compositions such as Rg₃, CK and Rb₁ etc. were investigated at different temperatures, relative humidities (RHs) and treatment times. Our findings demonstrated that the highest total ginsenoside content was 7.48% after 12 days treatment at temperature 80 °C and RH 75%. Correspondingly, 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, during heat-moisture treatment. Compared to the ginsenoside extracts of untreated ginseng (UGE), the ginsenoside extracts of heat-moisture treated ginseng (HMGE) exerted better scavenging activities of 1,1-Diphenyl-2-picryl-hydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cation (ABTS⁺), and hydroxyl (OH) radicals, as well as higher cytotoxicity efficiency against HepG2. In addition, HMGE promoted cell apoptosis by up-regulating the related protein expression, especially the caspase-3, caspase-9, and poly (ADP-ribose) polymerase (PARP). Therefore, the cytotoxicity of HMGE against HepG2 cells may be due to the mitochondrial apoptosis pathway induced by up-regulated caspase. These results strongly proved the promising prospect of HMGE as functional food or ingredient in nourishing or disease chemoprevention.

Keywords: Cell apoptosis; Chemical changes; Ginseng; Heat-moisture treatment; Saponin.