Traditional preparations of kava (Piper methysticum) inhibit the growth of human colon cancer cells in vitro.
BACKGROUND
Epidemiological studies indicate there is low incidence of colon cancer in the South Pacific islands, including Fiji, West Samoa, and Vanuatu. Cancer incidence has been shown to be inversely associated with kava (Piper methysticum G. Forst.) ingestion. Hypothesis/Purpose: Kava prepared traditionally will inhibit the growth of human cancer cells. This investigation entails preparation and analysis of kava extracts and study of the growth inhibitory activity of the extracts, alone and combined with hibiscus.


METHODS
We will prepare kava as in Micronesia - as a water extract, high in particulate content, alone or combined with sea hibiscus (Hibiscus tiliaceus L.) - and examine the components and growth inhibitory activity.


METHODS
We obtained ground kava prepared in the traditional way from lateral roots and sea hibiscus mucilage and sap from different sources in Micronesia, and prepared water extracts (unfiltered, as well as filtered, since in traditional use the kava beverage contains a high particulate content) and partitions. We used the MTT assay to determine the growth inhibitory activity of the preparations on colon and breast cancer cells and nonmalignant intestinal epithelial cells. LC-MS analysis was used to examine the components of the kava and sea hibiscus extracts and partitions.


RESULTS
Traditional preparations of kava inhibit the growth of breast and colon cancer cells. Among the kava preparations, the order of decreasing activity was Fiji(2), Fiji(1), Hawaii; the unfiltered preparations from Fiji were more active than the filtered. Phytochemical analysis indicated that filtering reduced most kavalactone and chalcone content. For example, for Fiji(2), the ratio of dihydromethysticin in filtered/unfiltered kava was 0.01. Thus, for the extracts from Fiji, growth inhibitory activity correlates with the content of these compounds. Unfiltered and filtered kava from Fiji(1) were more active on malignant than nonmalignant intestinal epithelial cells. Since kava is prepared in Micronesia by squeezing the extract through sea hibiscus bark, we assayed the growth inhibitory activity of combinations of kava and sea hibiscus sap and found that sea hibiscus enhanced the growth inhibitory effect of kava.


CONCLUSIONS
Our results show that traditional kava, alone or combined with sea hibiscus, displays activity against human cancer cells and indicate it will be worthwhile to develop and further analyze these preparations to prevent and treat colon and other cancers. Our findings suggest it is important to examine the activity of plants in the form that people consume them.
The Institute of Economic Botany, The New York Botanical Garden, Bronx, NY 10458, USA; Lehman College, The City University of New York, Bronx, NY 10468, USA; Columbia University College of Physicians and Surgeons, New York, NY 10032, USA. Electronic address: lseinbond@gmail.com.
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LS
Einbond
Lehman College, The City University of New York, Bronx, NY 10468, USA; The CUNY Graduate Center, Biology, Biochemistry and Chemistry Ph.D. Programs, The City University of New York, New York, NY 10016, USA.
A
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Negrin
Lehman College, The City University of New York, Bronx, NY 10468, USA; The CUNY Graduate Center, Biology, Biochemistry and Chemistry Ph.D. Programs, The City University of New York, New York, NY 10016, USA.
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DM
Kulakowski
Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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Wu
Lehman College, The City University of New York, Bronx, NY 10468, USA.
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Antonetti
Lehman College, The City University of New York, Bronx, NY 10468, USA.
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Jalees
The Institute of Economic Botany, The New York Botanical Garden, Bronx, NY 10458, USA.
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Law
Naturex, Avignon, BP 81218 - 84911 Avignon cedex 9 - France.
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Roller
Lehman College, The City University of New York, Bronx, NY 10468, USA; The CUNY Graduate Center, Biology, Biochemistry and Chemistry Ph.D. Programs, The City University of New York, New York, NY 10016, USA.
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Redenti
Lehman College, The City University of New York, Bronx, NY 10468, USA; The CUNY Graduate Center, Biology, Biochemistry and Chemistry Ph.D. Programs, The City University of New York, New York, NY 10016, USA.
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EJ
Kennelly
The Institute of Economic Botany, The New York Botanical Garden, Bronx, NY 10458, USA; The CUNY Graduate Center, Biology, Biochemistry and Chemistry Ph.D. Programs, The City University of New York, New York, NY 10016, USA.
M J
MJ
Balick
D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000453:epidemiology; D005367:Fiji / Q000453:epidemiology; D031584:Hibiscus / Q000737:chemistry*; D006801:Humans; D020901:Kava / Q000737:chemistry*; D013058:Mass Spectrometry; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D011753:Pyrones / Q000494:pharmacology*; D018947:Samoa / Q000453:epidemiology; D014407:Tumor Cells, Cultured / Q000187:drug effects*; D009514:Vanuatu / Q000453:epidemiology
D010936:Plant Extracts; D010937:Plant Growth Regulators; D011753:Pyrones
Chalcone; Hibiscus tiliaceus; Kavalactone; Malvaceae; Piper methysticum; Piperaceae