Research Projects

Anti-tumour Assay Research – Dr David Katerere

Anti-tumour Assay Research – Dr David Katerere

Dr David Katerere

PROMEC Unit, Medical Research Council, Cape Town

Title of the project

Biochemical and phytochemical evaluation of sutherlandia in anti-tumour assays

Highlights of the project

Prior to the work outlined below we had investigated the mutagenic and anti-mutagenic activity of sutherlandia extracts. In this cycle we built on those results and explored effects on cancer cell lines.

  • Anti-proliferative effects of aqueous and organic extracts of sutherlandia were investigated on human liver, colon and oesophageal cancer cell lines using 4 assays – MTT, LDH, ATP and BrdU. The results showed that in general the organic extract had superior activity to the aqueous extract against all the cell lines.
  • From the earlier studies on mutagenicity, it was shown that L-canavanine has pro-mutagenic activity. It was therefore deemed important to develop a method that can analyse for the presence of the compound in sutherlandia extracts. An LC-MS method has been developed for pharmacovigilence screening of different cultivars / varieties for L-canavanine levels. This will assist the manufacturers of sutherlandia herbal products.
  • The presence of imino sugars has been confirmed and these might explain the wide variety of biological activities associated with sutherlandia. We need to develop an analytical method for the analysis of imino sugars in sutherlandia products especially those that are being used in ongoing clinical trials. The absence of alkaloids has now been confirmed. A typical phytochemical extraction of alkaloids did not extract any such compounds.

Peer-reviewed publications

  • The Anti-proliferative effects of sutherlandia extracts on human liver, colon and oesophageal cancer cell lines (draft)
  • LC-MS method for the analysis of L-canavanine in sutherlandia varieties (early draft)
  • Poster presented at the MRC Research Day, Oct. 2008
  • Meela M, Katerere DR, Gamieldien K, & Gelderblom WCA. The Anti-proliferative effects of sutherlandia extracts on human liver, colon and oesophageal cancer cell lines
  • Oral presentation at the CANSA Conference, Aug 2008
  • Katerere DR, Gamieldien K, Sissing L, Meela M, Ntuli SB & Gelderblom WCA. “Cancer-bush” / Sutherlandia frutescens – anti-cancer drug of the future? Cancer Research in Action Conference. Emperors Palace, Johannesburg. 20 – 22 August 2008

How was this project of value in the struggle against cancer?

Having previously shown the anti-mutagenic properties of sutherlandia extracts (which would be important in the development of this herb into a chemoprevention agent), we have now shown that both water and organic extracts have anti-proliferative activity. The latter having potent activity against all three cancer cell lines. We are now trying to elucidate the components responsible for the activity.  This presents an important opportunity to discover new drugs; and medical history is replete with examples of anti-cancer drugs from natural products.

The development of an LC-MS method for the analysis of L-canavanine will provide a form of quality control for the raw materials that will be used in the manufacture of sutherlandia.

What are your future plans with this project?

We are proposing work on apoptosis, cell culture with an expanded battery of cell types to add to the information that we have already gathered. This will allow us to begin work on a 90 day oesophageal cancer rat model.

The most important anti-cancer drugs are from natural sources (vincristine, paclitaxel, combretastatin). These drugs offer far better risk – benefit ratio compared to the biologicals and are cheaper and can be used as enriched standardized phytomedicines. Therefore this sort of research should continue to be supported.

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