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Molecular Mechanisms Underlying Cytotoxic Activity of Bioactive Pokeweed and Roseship Plant Extracts

Investigators
Goktepe, Ipek
Institutions
North Carolina A&T State University
Start date
2007
End date
2010
Objective
  1. Isolate the most active fractions from pokeweed and rose hip that show strong antiproliferative and apoptosis activity against breast, colon, and cervical cancer cells;
  2. Determine the molecular mechanism of action through which these bioactive compounds induce apoptosis;
  3. Characterize the bioactive compounds (in extract fractions) exhibiting the strongest cytotoxic/apoptosis activity;
  4. Conduct in vivo animal bioassays to evaluate efficacy isolated bioactive compounds responsible for cancer cell apoptosis.
More information
NON-TECHNICAL SUMMARY: In recent years, a significant emphasis has been placed on fighting cancer through the combination of chemotherapy (using cytotoxic agents) and naturally occurring chemopreventive agents. Plant extracts have been used as chemopreventive agents because their mechanistic actions on cancer cells are different from cytotoxic agents and some clinical work has found their combination to be effective. We recently investigated four plant extracts (pokeweed roots and leaves, rosehip fruits, king tuber mushrooms, and bitter kola nuts) in our lab for their antimicrobial and anticarcinogenic effects against select foodborne pathogens and cancer cell lines, respectively. Out of the four plants tested, two (pokeweed roots and rosehip fruits) showed potent antiproliferative activity against colon, breast, and cervical cancer cells in vitro. To further investigate the potential use of these two plant extracts in alternative and complementary medicine for the prevention and/or treatment of cancer, greater elucidation of their cytotoxic mechanisms and bioactivity is essential. This project involves a comprehensive approach for isolation of active compounds from pokeweed and rosehip to testing of their anticarcinogenic activity in animal models. As such the project is expected to provide a better understanding of the mechanisms of action of the tested plant extracts against cancer cells in vitro and in vivo models, and to confirm the safety of the isolated bioactive compounds.

APPROACH: The pokeweed roots and rosehip fruits will dried and powdered. The powdered materials will be individually soaked in water, 80% ethanol, n-hexane, 80% methanol, n-butanol, ethyl acetate, and chloroform to collect different fractions. The efficacy of each fraction will be tested on the growth of MCF7, HCT116, and HS792(C)M cells using the MTT assay. In order to determine the level of apoptosis in cancer cells, the potential role of caspase-3 proteases in the common pathways of plant extracts-induced apoptosis will be determined using a Caspase-Glo 3/7 reagent. Genomic DNA will be extracted from cancer cells; exposed (in separate trials) to pokeweed and rosehip fractions and will be either subjected to agarose gel electrophoresis, stained with ethidium bromide and DNA visualized by ultraviolet (UV) transillumination, or analyzed for quantitation of low-molecular-weight (LMW) DNA fragments. Bioactive compounds in rosehip and pokeweed fractions showing the strongest antiproliferative and apoptosis activity will be analytically separated. The compounds in fractions with strong activity will be separated using reverse phase silica gel column chromatography. Once the bioactive compounds responsible for cancer cell apoptosis are isolated and identified, their toxicity will be determined using mice inoculated with human cancer cells.

PROGRESS: 2007/01 TO 2007/12
OUTPUTS: Plant extracts have been used for the treatment of various diseases since ancient times. Even today, plant materials remain an important resource for preventing illnesses and diseases, including cancer. While many of these plants have been investigated for the development of novel drugs and alternative medicines, pokeweed (Phytolacca americana) has commended limited attractions for its potential anticancer properties. Pokeweed is a common perennial native plant found in northern and central North America, and it has been used by Native Americans to treat viral and bacterial infections for centuries. Recent studies conducted in our laboratories evaluated the anticarcinogenic activity of pokeweed root and leaf extracts on MCF-7 breast cancer cells, HCT 116 colon cancer cells, and HS792(C)M) cervical cancer cells. The results showed that both water and alcohol extracts of poke root exhibited strong inhibitory activity on cancer cell growth. On the other hand, pokeweed leaf extracts did not show significant antiproliferative activity against any cancer cells at the concentrations used. Another plant recently investigated in our lab for its anticarcinogenic effect is Rosa canina (rosehip). Alcohol extract of rosehip significantly reduced the proliferation of MCF7, HCT116, HS792(C) M cell lines at 125 ug/ml or above. Water extract from rosehip showed lower inhibitory effect against all cancer cells at concentrations tested. From the above findings, it is clear that pokeweed and rose hip extracts possess strong antiproliferative activity against breast, colon, and cervical cancer cell lines. To be utilized as effective chemopreventive agents, more research is necessary to understand the mechanisms of action by which these extracts act on cancer cells. The objectives of this research project are to:

  1. Isolate the most active fractions from pokeweed and rose hip that show strong antiproliferative and apoptosis activity against breast, colon, and cervical cancer cells,
  2. Determine the molecular mechanism of action through which these bioactive compounds induce apoptosis,
  3. Characterize the bioactive compounds (in extract fractions) exhibiting the strongest cytotoxic/apoptosis activity, and
  4. Conduct in vivo animal bioassays to evaluate efficacy of isolated bioactive compounds responsible for cancer cell apoptosis.
TARGET AUDIENCES: Scientists at academia, government agencies, and private sector; general public, especially people with cancer.

IMPACT: 2007/01 TO 2007/12
The project is expected to provide a better understanding of the mechanisms of action of rosehip and pokeweed plants' extracts against cancer cells in vitro and in vivo models, and to confirm the safety of the isolated bioactive compounds. The major impact of this project will be the experimental validation of the efficacy of "natural bioactive compounds" from pokeweed and rosehip for prevention/treatment of cancer. If proven safe and effective against cancer cell proliferation, the bioactive compounds isolated from rosehip and pokeweed could provide an alternative therapy/treatment for people dealing with cancer.
Funding Source
Nat'l. Inst. of Food and Agriculture
Project source
View this project
Project number
NCX-228-5-08-170-1
Accession number
211813
Categories
Sanitation and Quality Standards
Bacterial Pathogens
Commodities
Produce