Although the laboratory testing showed that certain lots of the mixture contained indomethacin, warfarin, and DES, the amount of DES present may not have accounted for all of the estrogenic effect of PC-SPES. There is some evidence that the mixture acts differently from DES at the molecular level.[7,21] In addition, its anticancer effects on both AI prostate cancer and AD prostate cancer may point to a mechanism other than estrogen-like activity.[19,22,23] The in vitro activity of PC-SPES against cancer cells other than prostate also gives rise to the speculation that its estrogen-like qualities might not account for all of the mixture's anticancer activity.[24,25]
Considerable research has been conducted on the anticancer properties of the eight individual botanicals in PC-SPES.
Baikal skullcap (Scutellaria baicalensis)-Chinese name huang qin-contains baicalin and wogonin, two active flavones. Baicalin converts to baicalein, which is another active flavone. In vitro, baicalin and baicalein inhibit cell growth of AD LNCaP and JCA-1 AI human prostate cancer cell lines [24,25], as well as inducing apoptosis in human LNCaP cells. Baicalin also shows antimutagenic and antioxidant activity in vitro as well as free radical scavenging ability.[27,28,29,30,31,32]
Licorice (Glycyrrhiza glabra or Glycyrrhiza uralensis)-Chinese name gan cao-contains the very active flavonoid licochalcone A, which has demonstrated in vitro estrogenic activity. This botanical shows a broad range of anticancer activity in vitro. It enhances the cytotoxicity of commonly used anticancer drugs and induces apoptosis in MCF-7 human breast cancer and HL-60 promyelocytic leukemia cell lines.[33,34,35,36]
Reishi mushroom (Ganoderma lucidum [Curtis: fr.] Karst.)-Chinese name ling zhi- has been shown to aid in the recovery of leukocyte counts in irradiated mice in a dose-dependent manner. It contains the polysaccharide G009, which has demonstrated antioxidant behavior against HL-60 cells in vitro and dose-dependent inhibition of lipid peroxidation in rat brain cells in vitro.[37,38,39,40,41]
Isatis (Isatis indigotica)-Chinese name da qing ve-contains active agents in each part of the plant. TCM has different names for the medicinals coming from the leaf, stem, and root and uses these plant products for different purposes. Indirubin, an active ingredient, and its analogs have demonstrated inhibition of cyclin-dependent kinases in human mammarycarcinoma cell line MCF-7 in vitro.
Ginseng (Panax ginseng or Panax pseudoginseng var. notoginseng)- Chinese name tianqi-contains ginsenosides and saponins. Of the 30 ginsenosides that have been isolated from Panax ginseng, only the 20(S)-protopanaxadiol type R3 has inhibited cell growth and suppressed PSA expression, androgenreceptor and 5-alpha-reductase activity, and PCNA production in vitro.[43,44,45]
Chrysanthemum flowers (Dendranthema morifolium)-Chinese name ju hua-contain triterpene diols and triols. Arnidiol exhibited cytotoxicity in vitro against 58 of the 60 human cancer cell lines developed by the National Cancer Institute (NCI) Developmental Therapeutics Program.