No abstract

An immunomodulatory polysaccharide-rich substance (Noni-ppt) from the fruit juice of Morinda citrifolia has been found to possess both prophylactic and therapeutic potentials against the immunomodulator sensitive Sarcoma 180 tumour system. The antitumour activity of Noni-ppt produced a cure rate of 25%-45% in allogeneic mice and its activity was completely abolished by the concomitant administration of specific inhibitors of macrophages (2-chloroadenosine), T cells (cyclosporine) or natural killer (NK) cells (anti-asialo GM1 antibody). Noni-ppt showed synergistic or additive beneficial effects when combined with a broad spectrum of chemotherapeutic drugs, including cisplatin, adriamycin, mitomycin-C, bleomycin, etoposide, 5- fl uorouracil, vincristine or camptothecin. It was not beneficial when combined with paclitaxel, cytosine arabinoside, or immunosuppressive anticancer drugs such as cyclophosphamide, methotrexate or 6-thioguanine. Noni-ppt also demonstrated beneficial effects when combined with the Th1 cytokine, interferon gamma, but its activity was abolished when combined with Th2 cytokines, interleukin-4 or interleukin-10, thereby suggesting that Noni-ppt induces a Th1 dominant immune status in vivo. The combination of Noni-ppt with imexon, a synthetic immunomodulator, also demonstrated beneficial effects, but not when combined with the MVE-2 copolymer, a high molecular weight immunomodulator. It was also not effective when combined with interleukin-2 or interleukin-12.

The antitumour activity of Ganoderma lucidurn, called 'Ling-Zhi or holy mushroom' in Chinese traditional medicine, was investigated on intraperitoneally implanted Lewis lung carcinoma in syngeneic C57BL/6 mice. An aqueous extract of Ling-Zhi significantly increased the life span of tumour-implanted mice, when administered intraperitoneally alone or in combination with cytotoxic antitumour drugs (Adriamycin, fluorouracil, thioguanine, methotrexate, Cisplatin) or a synthetic immunomodulator (Imexon). The aqueous extract was not cytotoxic in cell cultures and the antitumour activity was abolished by pretreatment of mice with cyclosporine. The active principle(s) was found to be present predominantly in the ethanol precipitable fraction of the aqueous extract.

A defined pollen extract of selected plants has been reported to possess some pharmacological activities on chronic prostatis or benign prostatic hyperplasia. This paper describes the antitumour potential of the watersoluble fraction (Cernitin T60) of 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 mglmL, while it is significantly prolonged the life-span of mice carrying the tumour without any apparent side effects at 0.5 glkg. 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 a T-cell inhibitor (cyclosporin A). Cernitin T60 appears to be a potent immunostimulator of macrophages.