Progress in pharmacological actions of ginsenoside compound K, an active metabolite of protopanaxadiol type saponins

Ginsenoside compound K (CK), 20-O-β-(D-glucopyranosyl)-20(S)- protopanaxadiol, is a major form of protopanaxadiol type saponins absorbed by the human body after oral administration, and a real component that mediates pharmacologic actions. Recently, new progress has been made in studies on pharmacological actions: (1) CK can activate caspase 8, which plays a key role in CK-stimulated apoptosis via activation of caspase 3 directly or indirectly through mitochondria pathway and can regulate the metastasis and invasiveness of tumor cells by downregulating metalloproteinase 9 gene expression; (2) CK can reduce expression levels of NO synthase and cyclooxygenase-2 and inhibit secretion of some pro-inflammatory cytokines like interleukin 4 (IL-4), IL-6 or tumor necrosis factor-a, which are responsible for its anti-inflammatory, anti-allergic, and neuro-protective activities; (3) CK can enhance the insulin secretion by blocking the ATP sensitive K⁺ channel, improve insulin sensitivity, and shift glucose metabolisim from hepatic glucose production to hepatic glucose utilization in the liver, suggesting that CK be a therapeutic reagent for type 2 diabetic patients; (4) CK can prevent the ultraviolet radiation induced skin damage by up-regulating nucleotide excision repair gene expression.