29.09.2011
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Blood pressure regulator from salmon?

The first results obtained with NVD’s mass spectrometer will this week be presented at an international meeting in Gothenburg, Sweden.


Doctoral student Susan Skanderup Falkenberg at the National Food Institute, Technical University of Denmark (DTU Food), has visited the University of Faroe Islands for the purpose of analyzing some of her samples on NVD’s mass spectrometer. Susan is working on a project with the aim of isolating and characterizing bioactive compounds from parts of salmon that normally would be called waste. She has made aqueous extracts from salmon gills, skin and belly flap, and tested them for two biological activities: their antioxidant actions and their abilities to inhibit angiotensin-converting enzyme (abbreviated ACE).  ACE is an important regulator of blood pressure in humans as described below, and many medical drugs inhibit ACE (http://min.medicin.dk/Laegemiddelgrupper/Grupper/315358).


Susan found both antioxidant activities and ACE inhibitory activities in all the extracts, with the belly flap extract showing the highest activities. This extract was fractionated according to molecular size. Susan has now made an initial analysis of a few of these fractions by mass spectrometry at NVD. All fractions contain several compounds (Figure 1). Although much more work needs to be done, the preliminary conclusions is that the bioactive compounds are not made by the standard 20 amino acids, and that many of the compounds appear to be structurally related because they partly consists of the same subset of building stones (see Figure 2).

   
Susan’s work will this week be presented at the annual meeting of the West European Fish Technologists Association in Gothenburg, Sweden (www.wefta.org).

Bioprospecting and blood pressure
During the recent years, there has been an upsurge in the interest of bioprospecting, i.e., the process of finding, developing and exploiting new biological compounds, especially for health and medical purposes. The starting point for bioprospecting may in fact sometimes be materials that traditionally have been regarded as waste, or they have used for low-value purposes, like animal feed. If interesting bioactivities are found, attempts are made to isolate and identify the bioactive compounds. Thereafter the development of valuable new products can initiated. As examples for such bioactivities can be mentioned antibiotics and anti-bacterial agents, anticancer agents, immunostimulatory agents, agents that counteract inflammation, diabetes or oxidative damage. Hypertension is another lucrative area, with a global marked of US $39 billion in 2008. A major part of the hypertension drugs are targeting the angiotensin system. ACE has its name from one of its enzymatic activities, the conversion of angiotensin I to angiotensin II, which is an effective vasoconstrictor (making the diameter of blood vessels smaller), thereby increasing blood pressure. ACE also destroys bradykinin, a compound that increases the diameter of blood vessels and counteracts the angiotensin system. 

A future for bioprospecting in the Faroe Islands?
The Faroese fish industry generates vast amounts of waste every year, and there is clearly a potential to get higher value products from this waste. Furthermore, the Faroe Islands, Greenland and Denmark own enormous stretches of ocean that harbor organisms that have adapted to unhospitable environments: cold, depth, ice, waves constantly crushing against the rocks. Such organisms may contain new and valueable compounds.


One example of a product generated from marine waste, is shrimp alkaline phosphatase, purified from the thawing water during the industrial processing of artic shrimp. The enzyme is much used in molecular biotech industry and in experimental laboratories. Price? As a customer, you pay more than 1 million DKK per gram. Also many other organisms could contain compounds with interesting biological or medical activities. For example, at least two of the compounds used to prevent the rejection of transplanted organs were isolated from soil samples. Rapamycin (also known as sirolimus) is a bacterial product, first found in a soil sample from Eastern Island in the Pacific (price: 2 million DKK per gram), and cyclosporin A is a fungal product, first found in a soil sample from Hardangervidda, Norway (”cheap”, only 50000 DKK per gram). This does not mean that it will be easy to develop a new product. Long-term and dedicated efforts, patience and international collaborations will be needed. Risky projects, but if successful, the rewards can be high.

The main supervisor for Susan Skanderup Falkenberg is Dr. Henrik Heuch Nielsen (DTU Food), and co-supervisors are Drs. Hóraldur Joensen (NVD), Jan Stagsted (Århus University) and Flemming Jessen (DTU Food). The project is partly supported by Granskingarráðið.
The mass spectrometry facility of NVD is supported by a grant from Statoil.