A chemical with anti-cancer agents

ROMA – A Master’s student in chemistry at the National University of Lesotho (NUL), Mvove Mpopo, has uncovered a chemical that has the potential to fight cancer in a local plant. Do not run away (yet) on hearing the fancy name of this chemical.

The name is, wait for it…3-((2)-heptadec-14enyl) benzene-1-ol. That’s the name! He found it in a local plant called Karroo Kunibush or “mokhoamphiri”.

More important, he found that this complex chemical in this plant has been found to have cancer-fighting properties. Here is the story of the young man supervised by Dr Mohale Mabaleha and Dr Manoharan Pillai. Plants are amazing living things.

In fact, when one famous inventor, Thomas Edison, was praised for his good inventions, he fought back with a short lesson, “until a man duplicates a blade of grass, nature will always laugh at his so-called ‘scientific inventions’”.

He was right. A mere blade of grass is more complex than anything any human being has ever done.

“Other than chemicals that form the structure of plants, such as cellulose, plants have chemicals whose job is partly to protect themselves from diseases,” Mpopo said.

“We call some of those chemicals phytochemicals. We are after those because they can help us against diseases…too.”

In fact, in this plant alone, Mpopo said he has identified a whopping 43 classes of such chemicals.

“Among the classes are the flavonoids, alkaloids, terpenoids, quinolines and their derivatives, phenols, the list goes on and on.”

Never mind the fancy names. But one of the most interesting chemicals he uncovered was 3-((2)-heptadec-14enyl) benzene-1-ol. Getting to find such a chemical is like searching for a needle in a forest.

It is not for the faint-hearted. This is how he pulled it off. First he took a plant, Karroo Kunibush, which in science, is known as Searsia Burchellii. Then he pulled out a group of unknown chemicals from this plant.

“We put the plant in chloroform to dissolve this army of chemicals out of it,” he said.

The chemical mixture is then passed through a process he called Thin Layer Chromatography (TLC). This process is meant to find the best solvent system that can separate the unknown chemicals from the plant. Remember we want to isolate and identify them.

“In the end, we found that a combination of Chloroform and Hexane in a ratio of 9 to 1 by volume was the best combination of solvents to make the best separation.”

Then he ran another process, now to make the separation. This one is called Column Chromatography (CC). It was run using the 9 to 1 solvent system identified above.

Then, these unknown chemicals were separated. That’s good, but they were not pure. He wanted to get them to be as pure as possible. To ensure purity, he said he kept running between TLC and CC until he could confirm that the chemicals were as pure as possible.

He then went for yet another process, a much more complex one. It is called Nuclear Magnetic Resonance (NMR). He calls this a 1 and 2 D NMR. Well the NMR would help identify what some of these strange chemicals were.

He picked one purified but unknown chemical and ran with it. However, getting to that point, where a compound was identified with certainty, was the closest thing to a true definition of Rocket Science.
Pay attention to how they do it.

“We identified quaternary carbons on this chemical,” he said.

Well, these are those carbon atoms not attached to hydrogens but to four distinct carbon groups.

“We then used Heteronuclear Single Quantum Coherence (HSQC) to identify carbons attached to hydrogens.”

He said they then followed up with a Heteronuclear Multiple Bond Correlation (HMBC) technique to identify which carbons were two to three bonds away from hydrogens. He then followed up with CO-related SpectroscopY (COSY) to find which hydrogens were neighbours to which hydrogens.

He then appealed to Carbon-13 method to find which carbons were “sitting” in which spaces. Then he used Proton NMR to find which hydrogens were sitting where. This was followed by Distortionless Enhancement by Polarisation Transfer (DEPT 135) to find CHs, CH3s and CH2s.

As if that was not enough already, he followed up with DEPT 90 to identify only the CHs. With this information, he was able to identify the chemical and draw its structure as shown in the picture. Yes, he figured out that the chemical was 3-((2)-heptadec-14enyl) benzene-1-ol! Once the chemical was identified, investigations were made to find what was already known about it.

“It was found to have anti-cancer properties,” he concluded.

Own Correspondent