Science Buddies: "Ask an Expert"

what are phytochemicals? how are phytochemicals screened?

Hi gudini

This has a good explanation of what a phytochemical is
http://www.wcrf-uk.org/nutritionist.las ... ochemicals

There are different approches to screening phytochemicals for potential drug activity.
One approach is to use background intomation that shows that a whole plant has the effect you are interested in, maybe it has been associated with a decreased risk of cancer. Then you need an assay to measure the effect in the lab using a simple system with a chemical reaction or cells that responds to the whole plant extract. So in my example it might be an assay that looks at if the extract can stop cancer cells from growing in a petri dish. Then you would use a method to try to separate the components of the whole plant extract and find which fraction has the activity and can stop the cancer cells growing. And lastly to identify the chemical that is in that fraction.

Another approach is to use a library of chemicals. This means a large number of thousands of different chemicals and test all of them to see if any has the activity you are looking for. This is often the way drugs companies do it. Because they can afford to buy the library of chemicals (which is very very expensive). And because they have the technology to make assays that can be done by robots so they can test thousands.

Hope this helps answer your questions,

Caroline

hey gudini

here is a website that contains phytochemicals
http://www.phytochemicals.info/

According to this site, Phytochemicals are non-nutritive plant chemicals that have protective or disease preventive properties. There are more than thousand known phytochemicals. It is well-known that plant produce these chemicals to protect itself but recent research demonstrate that they can protect humans against diseases. Some of the well-known phytochemicals are lycopene in tomatoes, isoflavones in soy and flavanoids in fruits. They are not essential nutrients and are not required by the human body for sustaining life.

another site that regards an experiment on phytochemical testing
http://www.ijpr-online.com/Docs/20032/IJPR122.htm
it is pretty interesting...you should read it