Saturday, 24 January 2015

We have a lovely bunch of coconuts in the lab!

I was delighted to see the natural product experimental planning taking shape this week. Last year, lemons proved the most popular source of potential ant-bacterials, but this year coconuts are topping the bill! It has prompted me to use coconuts as the backdrop to help with your experimental planning. The first thing I noticed was an overwhelming rush of enthusiasm to make the plant extracts. However, how many of you weighed the item? Did you measure the volume of the coconut (or kiwi fruit etc)? If you did, how did you do it? How did you extract the "milk"? What was the volume? How did you store it?

These were the questions that I asked several groups and the reason for asking is simple. Whenever you embark on an experiment, you must plan to record all of your observations. Before you extract the coconut milk, weigh the coconut. You should then compare (for example) 3 coconuts. Are they the same weight? What is the average weight? The same applies to the volume (think ancient Greeks taking baths!). Ask yourself why these measurements are important.

Now we come to the fluid inside the coconut: the so called coconut milk. Milk is usually defined as the fluid from a mother's breast or from the udder of a cow. It is a mixture rich in proteins and fats. So what is in coconut milk? You should consider the coconut carefully. Define its structure, consider the biological origin of its distinctive structures and then think about the source and composition of the "milk". You should then plan how you make various extracts, with reference to the chemical composition of the various parts of the "nut".

The search for lauric acid (above) was a topic of discussion with two groups. This is one of the therapeutic molecules found in coconut milk. If I tell you that chemistry is full of alternative names for the same thing (trivial and systematic), you may be surprised to find that lauric acid, which is claimed to be of therapeutic value, is very similar to the detergent we use to denature proteins, sodium dodecyl sulphate. So how can two very similar molecules have such different properties! 

What I want you all to do is to measure everything you possibly can before you commit to any destruction of the plant or fruit. Take photos and annotate the structures. Research what is known about your choice of plant and then consider whether you are likely to find water soluble or lipid soluble antibacterials....and how you might plan for both! But don't lose that enthusiasm!!!

No comments:

Post a Comment