Antitumor studies of a traditional Hawaiian medicinal plant, Morinda citrifolia (noni), in vitro and in vivo

The fruit juice of Morinda citrifolia (noni) contains a polysaccharide-rich substance (noni-ppt) with antitumor activity in the Lewis lung (LLC) peritoneal carcinomatosis model. Therapeutic administration of noni-ppt significantly enhanced the duration of survival of syngeneic LLC tumor bearing mice. It did not exert significant cytotoxic effects in an adapted culture of LLC cells, LLC1, but could activate peritoneal exudate cells (PEC) to impart profound toxicity when co-cultured with the tumor cells. This suggested the possibility that noni-ppt may suppress tumor growth through activation of the host immune system. Concomitant treatment with the immunosupressive agent, 2-chloroadenosine (macrophage inhibitor) or cyclosporine (T-cell inhibitor) diminished its activity, thereby substantiating an immunomodulatory mechanism. Noni-ppt was capable of stimulating the release of several mediators from murine effector cells, including tumor necrosis factor-;Therapeutic administration of noni-ppt demonstrated significant suppression of S.180 ascites growth in allogenic animals, without being substantially cytotoxic to these cells in vitro. However, noni-ppt could elicit PEC to exert significant cytotoxic effects against the tumor cells when co-cultured. Preliminary studies also indicated that noni-ppt may have beneficial prophylactic activity against S.180 ascites growth.;Improved survival time and curative effects occurred when noni-ppt was combined with sub-optimal doses of the standard chemotherapeutic agents, adriamycin, cisplatin, 5-fluorouracil, and vincristine in the LLC peritoneal carcinomatosis model, suggesting important clinical applications of noni-ppt as a supplemental agent in cancer treatment.