A Structure-Function Relationship Exists for Ginsenosides in Reducing Cell Proliferation and Inducing Apoptosis in THP-1 Cells

Ginsenosides of 20(S)-protopanaxadiol and 20(S)-protopanaxatriol classification including the aglycones, PD, PI and ginsenosides Rh2, Rhl were shown to posses characteristic effects on proliferation of THP-l human leukaemia cells. A similar result was not apparent for ginsenoside Rg3 or dexamathasone. The concentration to inhibit $50\%$ of cells $(LC_{50})$ for PD, Rh2, PI and Rhl were 13 ${\mu}g/mL,\;15{\mu}g/mL,\;19{\mu}g/mL\;and\;210\;{\mu}g/mL$ respectively. Cell cycle analysis showed apoptosis with PD and PI treatment of THP-1 cells resulting in a build up of sub-G1 cells after 24, 48 and 72 hours of treatment. Rh2, and dexamathasone treatments also increased apoptotic cells after 24 hours, where as Rhl did not. After 48 and 72 hours Rh2, Rhl and dexamathasone similarly increased apoptosis, but these effects were significantly (P<0.05) lower than observed for both PD and PI treatments. Furthermore, treatments that produced the largest build up of apoptotic cells were also found to have the largest release of lactate dehydrogenase (LDH). It can be concluded from these studies that the presence of sugars to PD and PI aglycone structure reduces the potency to induce apoptosis, and alternately alter membrane integrity. These cytotoxic effects to THP-l cells were different from dexamethasone.