The good, old ‘whore’

ROMA – Sure you get almost irritated at the mention of Tagetes minuta (lechuchutha), that invasive annoying plant.
It turns out the National University of Lesotho (NUL) is finding its use in detergents — to make a rival of pine gel!
Listen to the story of Thabiso Letseka and his work on Tagetes minuta guided by Dr Mosotho George.
Letseka has developed a pine gel-like product made from oil derived from lechuchutha, with a potential to replace the much-liked but expensive pine gel.
But a bit of history is in order.

The history of Tagetes minuta or lechuchutha in Lesotho is not a rosy one.
The legend goes that this plant was brought to Lesotho after 1914, before which time it was practically unknown.
It is known by many names in Lesotho, depending on which region of the country you live in.
They call it lechuchutha (a whore), monkhane and Jeremane (supposedly because it was brought by our forefathers who fought in Germany – (Jeremane) in the First World War.
The name lechuchutha is fitting.

The seeds of this plant are so good at sticking to human clothing and animals’ fur, the plant spreads itself all over the place pretty quick! “ke ke-ea-le-bafe.”
Add the fact that Basotho sparsely benefit from the plant, a weed that evades even the best of farmers, then you get why it is hated with a passion.
That is, until Letseka intervenes!
“It turns out the plant may be a blessing in disguise after all,” Letseka says.
“And the fact that it is so easy to grow makes it an ideal choice.”
So how did it catch his eye?

“I was once attached to a company called ChemCleaner, owned by Tšukulu Motsamai, a former NUL student who has formed his own detergents company in Leribe,” Letseka says.
In there, he noticed a problem.  Pine oils used to make pine gels are the most expensive components of the ingredients used.
The oils do not only have antimicrobial properties, they also give pine gels their gelatinous (mafatše thothomela) structure.
So what if the expensive pine oil is replaced with oil from locally available plants?
Would that not solve the problem of cost in the long run?

He collected three plants, algae (bolele), datura (letjoi) and lechuchutha and screened them.
They were screened for a number of volatile oils to see which of the three are as close in oil composition as pine oil.
“I used gas-chromatography mass-spectrophotometry to screen the volatiles,” Letseka said.

For instance, here is just a list of essential oils he identified in lechuchutha, don’t go away after reading them 🙂 limonene, ocimene, naphthalene, decahydro-2-methyl, 2-norpinalol,3,6,6-trimethyl, 2 butanone-4-95-methyl-2furanyl, cyclohexanone, (2-methylethynyl) trans and 3,7-epoxy-2-methylene-6-methyloct-en-1-al.
Don’t ask us what those things are! Or what they mean! Frankly speaking, we’ve got no clue!
But “one thing is for sure, the volatiles prove lechuchutha’s antimicrobial credentials,” Letseka says.

“We found that lechuchutha was the closest of the three plants to pine oil, so we selected it as a potential source of oil to replace pine oil in the production of gels,” he added.
“Of course datura was partly rejected for its toxicity.”
His next job was to extract the oils from lechuchutha.

Yes! Lechuchutha does have oil on its leaves, stems and seeds, but he concentrated on the leaves.
“So I used a process called steam distillation,” he mentioned a process that, despite is fancy name, is none other than “ho arubela” in Sesotho.
You see, Basotho used to put plants in hot water and then inhale the incoming steam — rich in “healing” volatiles.
“We use more or less the same old system that served Basotho so well for so long,” Letseka says.
“But in our case, the incoming steam, rich in volatiles, is condensed. The oily volatiles are then separated naturally from water,” following the famous phrase “oil and water don’t mix.”
“Ke metsi le oli”.

However, since there is much less oil compared to water, separation is not that easy.
So Letseka says he adds a chemical he calls diethyl ether.
“This I use to make a more efficient separation between oil and water.”
But don’t lose the bigger picture.

He is after lechuchutha oil, not diethyl ether.
So he has to remove diethyl ether from the oil.
After oil-water separation, he simply lets the highly volatile (e ea fofa) diethyl ether to evaporate leaving the oil behind (of course in industrial application, diethyl ether can be recycled).
The oil is used to make gel, not pine gel this time but lechuchutha gel.

This is made using a chemical he calls, Linear Alkyl Benzene Sulphonic Acid.
Used with lye (sodium hydroxide, to provide sodium ions), the chemical makes a perfect surfactant for detergents.
But to ensure he made the right material, he uses spectroflourophotometer (an instrument that measures light interactions with matter) to determine Critical Micelle Concentration.
“Despite the ongoing characterisation work, so far, I can conclude that my detergents are as good as pine oil based ones,” Letseka, the NUL chemicals maharishi says.

Own Correspondent