ANTI-ANGIOGENIC, ANTI-TUMOR AND IMMUNOSTIMULATORY EFFECTS OF A NON-TOXIC PLANT EXTRACT (PGM)
Authors: Riordan NH, Meng X, Riordan HD.
ABSTRACT: Recruitment of new blood vessels plays a crucial role in tumor survival and growth. Several agents that act as angiogenesis inhibitors are currently being investigated as anti-tumor agents. Proteoglycan extract (PGM) was tested for anti-angiogenic, immunostimulatory, and anti-neoplastic activity.
PGM is a non-toxic extract of the ubiquitous plant, Convolvulus arvensis. In the chicken egg chorioallantoic membrane assay PGM inhibited new blood vessel growth in a dose-dependent manner. Results were 18, 55, and 73% inhibition at concentrations of 50, 100, and 200 mcg, respectively. PGM significantly inhibited tumor growth in the mouse fibrosarcoma (S-180 Kun Ming 3-4 wk old mixed male/female, 10 animals per group, 250-1000 mcg daily doses for 14 days), and mouse Lewis lung carcinoma (C57, 6 wk old mixed male/female, 10 animals per group, 250-1000 mcg daily doses for 14 days) models. Inhibition (54-77% inhibition by weight compared to controls, up to 96.8% by cellular composition) occurred regardless of route of administration: intravenous; intraperitoneal; subcutaneous; and oral.
PGM induced lymphocyte growth in a dose dependent manner. The ability of PGM-treated phagocytes to phagocytose yeast cells was 85% greater than controls.
We conclude that PGM is a potent angiogenesis inhibitor that has immunostimulatory activity in vitro and anti-tumor activity in vivo and that PGM should be studied further as an anti-neoplastic agent.