(20S)-Protopanaxadiol (20-Epiprotopanaxadiol) (20-Epiprotopanaxadiol), an apoptosis inducer, is an aglycon metabolic derivative of the protopanaxadiol-type ginseng saponin.

(20S)-Protopanaxadiol对Int-407细胞的生长抑制50%浓度(LC50)为23μg/ml，而在Caco-2细胞中，(20S)-Protopanaxadiol的LC50确定为24μg/ml。(20S)-Protopanaxadiol在Int-407细胞系中产生大量的sub-G1（凋亡）细胞（Int-407细胞系是来自大约2个月胚胎的非恶性人类胚胎细胞系，而Caco-2是人类结肠腺癌细胞系）。这一反应归因于各个人参皂苷糖基化的差异，从而影响亲疏水平衡[2]。(20S)-Protopanaxadiol的孵育还显著降低U251-MG和U87-MG细胞的存活率，这种效果呈剂量和时间依赖性。(20S)-Protopanaxadiol的细胞毒作用伴随着细胞粘附蛋白表达的降低，包括N-钙黏着蛋白和整合素β1，进而导致焦点粘附激酶的磷酸化减少。此外，(20S)-Protopanaxadiol孵育减少了cyclin D1的表达，并随后诱导细胞周期在G1阶段停滞[3]。

在应用(20S)-Protopanaxadiol和PPT处理后，可在高架十字迷宫（EPM）测试中显著增加开放臂区的逗留时间及进入次数。(20S)-Protopanaxadiol处理能有效抑制固定应激引起的皮质醇及白细胞介素(IL)-6水平，其通过酶联免疫吸附测定法（enzyme-linked immunosorbent assay）进行测定。(20S)-Protopanaxadiol和PPT可能分别通过γ-氨基丁酸A（GABAA）受体和5-羟色胺受体展现抗焦虑效果，而(20S)-Protopanaxadiol对于抗炎作用的潜力可能超过PPT[1]。

Int-407 and Caco-2 cells are seeded at a concentration of 1×106 cells/mL in 24-well plates in separate experiments. Test ginsenosides (PPD, PPT, Rh2) are added to wells to the LC50 concentration determined previously from the MTT assays. The ginsenoside concentrations used for Int-407 cells are 23, 26, and 53 μg/mL, respectively, for PPD, PPT, and Rh2. In a similar experiment using Caco-2 cells, 24 μg/mL for both PPD and PPT and 55 μg/mL for Rh2 is used. Untreated cells represented the control. Cells are incubated at 37℃ in a 5% CO2 humidified incubator for 24, 48, and 72 h. Cell-free supernatant are obtained by centrifugation(400 g) for 10 min, and the lactate dehydrogenase (LDH) assay is conducted as previously reported.(Only for Reference)