Antitumour Potential of Pollen Extract on Lewis Lung Carcinoma Implanted Intraperitoneally in Syngeneic Mice

A defined pollen extract of selected plants has been reported to possess some pharmacological activities on chronic prostatitis or benign prostatic hyperplasia. This paper describes the antitumour potential of the water-soluble fraction (Cernitin T60) of the pollen extract against Lewis lung carcinoma implanted intraperitoneally in syngeneic mice. Cernitin T60 was not cytotoxic in cell cultures at concentrations up to 2.5 mg/mL, while it is significantly prolonged the life-span of mice carrying the tumour without any apparent side effects at 0.5 g/kg. In addition, Cernitin T60 demonstrated beneficial therapeutic effects in an additive fashion on the life-span of mice when it was combined with standard cytotoxic antitumour drugs such as adriamycin, cisplatin, vincristine, methotrexate, fluorouracil, or thioguanine. The antitumour potential of Cernitin T60 was completely abolished by treatment with inhibitors of macrophage functions (2-chloroadenosine or carrageenan), but not with the T-cell inhibitor (cyclosporin A). Cernitin T60 appears to be a potent immunostimulator of macrophages.