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 dosedependent 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 weekold mixed male/female, 10 animals per group, 2501000 mcg. daily doses for 14 days), and mouse Lewis Lung Carcinoma (C57, 6 wk old mixed male/female, 10 animals per group, 2501000 mcg. Daily doses for 14 days) models. Inhibition (5477% 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 angiogen¬esis inhibitor that has immunostimulatory activity in vitro and anti-tumor activity in vivo and that PGM should be studied further as an antineoplastic agent.
Background
Every aspect of tumor growth requires vascular growth. In 1971 Folkman hypothesized that controlling angiogenesis could be a feasible anti-tumor strategy. Recently the description of angiostatin and endostatin has resulted in increased interest in angiogenesis inhibitors as anti-tumor agents.
Because of an anecdotal report of complete remission in a case of human ovar¬ian carcinoma after consumption of 'an extract of the ubiquitous plant Convolvulus arvensis, we tested extract of this plant for anti-angiogenesis and immune stimulating effects.
Convolvulus arvensis is well known to contain toxic alkaloids. Therefore, in this study we examined a high molecular weight water extract of the plant that does not contain appreciable concentrations of alkaloids, which are depleted in the manufacturing process. The extract is primarily comprised of proteoglycan molecules and is herein referred to as PGM.
Summaries of Animal & Human Studies
See following pages for summaries and results of several significant animal and human studies conducted by the above researchers
Researchers' Conclusion
Research has been presented demonstrating that an extract of the plant Convolvulus arvensis has potent angiogenesis inhibiting and immune-stimulating qualities. This extract also demon¬strated anti-tumor effects in two mouse tumor models. The exact details regarding the anti-angiogenesis mechanism of bindweed extract are not completely understood. This extract should be studied further to elucidate its anti tumor effects and mechanisms of action. .
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