Anticancer effect and neurotoxicity of S-(+)-deoxytylophorinidine, a new phenanthroindolizidine alkaloid that interacts with nucleic acids

Phenanthroindolizidine alkaloids are a family of plant-derived compounds with significant antineoplastic activity as well as other effects like antiamebicidal, antiviral, and anti-inflammatory activities. The specific biomolecular targets of these compounds have not yet been clearly identified. S-(+)-Deoxytylophorinidine (CAT) is a new phenanthroindolizidine alkaloid, originally extracted from the roots of Tylophora atrofolliculata and Tylophora ovata. Potent anticancer activity was observed in vitro and in vivo. Neurotoxicity of CAT was also studied and it was far less serious than that of vinblastine. Interactions between this compound and DNA had been studied in detail in our laboratory previously, and we further studied its interactions with RNA.

Immunostimulatory activities of a low molecular weight antitumoral polysaccharide isolated from Agaricus blazei Murill (LMPAB) in Sarcoma 180 ascitic tumor-bearing mice

LMPAB is a linear beta-(1-3)-glucan we isolated from polysaccharide extract of Agaricus blazei Murill (AbM). Effects of LMPAB on splenic natural killer (NK) cell activity, splenocyte proliferation, index of spleen and thymus, IFN-gamma expression in spleen and the concentration of IL-12, IL-18 and TNF-alpha in serum of S180 ascitic tumor-bearing mice were detected. The results showed that intraperitoneal injection of LMPAB (100 mg x kg(-1) x d(-1)) significantly increased the thymus index. LMPAB augmented splenic NK cell activity in a dose-dependent manner (50-200 mg x kg(-1) x d(-1)). The concanavalin A (3 microg/ ml) stimulated splenocyte proliferation was significantly enhanced by LMPAB at dosages of 50, 100 or 200 mg x kg(-1) x d(-1). Further studies showed that LMPAB (50, 100 or 200 mg x kg(-1) x d(-1), 14d) significantly increased the production of IL-12, TNF-alpha, IL-18 and the expression IFN-gamma as determined by ELISA and immunohistochemistry, respectively. These results clearly indicate that the anti-tumor effects of LMPAB are closely associated with up-regulation of activity of NK cells, expression of IFN-gamma in spleen and the systemic level of IL-12, IL-18 and TNF-alpha in tumor-bearing mice.