Bioactivity of Medicinal Bolivian Andean plants. Effects on cell proliferation and related processes.

Colon cancer is common in both developed and developing countries, and is responsible for at least 600,000 deaths globally every year. It is therefore the second most common cause of cancer-related mortality. Extensive studies are being conducted worldwide to find more effective drugs that can be used in cancer treatment. In these studies, phytochemicals have proven to be good sources for drug discovery. In Bolivia, there is a long tradition of using plants for medicinal purposes. The objective of the present thesis was to study the effects of extracts and compounds from medicinal plants in Bolivia on the growth of colon cancer (Caco-2) cells. Firstly, a survey of many plant extracts and some isolated compounds for their antiproliferative activity was performed. Sixty-six extracts from thirty-two medicinal plants and 15 extracts from 8 food plants were evaluated for antiproliferative activity in Caco-2 cells. Extracts from 7 plant species showed antiproliferative activity but in most of the preparations tested no cytotoxic activity was observed at the concentrations used. Secondly, some assays including DNA replication, DNA degradation, oligonucleosomal formation, and caspase-3 activity were performed to understand the mechanism by which the compounds isolated affect cell proliferation and cell death. Curcuphenol, isolated from Baccharis genistelloides and Myrmekioderma styx, and damsin and coronopilin, isolated from Ambrosia arborescens, were found to inhibit cell proliferation and to induce cell death in colon cancer cells. Further studies are needed to find new anti-cancer compounds in medicinal plants in Bolivia.