Mexican health authorities say the best way to avoid either dengue or chikungunya is to avoid being bitten by mosquitoes. Now, just as both viruses are being widely reported in our country, along comes a new repellent.
Developed by researchers at the Academic Department of Zoology at the Autonomous University of Baja California Sur (UABCS), the repellent’s formula is derived from the nim tree and can be prepared simply and cheaply at home.
The nim (or neem) is a fast-growing tree that can reach a height of 15–20 metres (49–66 ft), it is native to India and the Indian subcontinent, but nowadays it can be found in any tropical and semi-tropical region throughout the world. Its fruits and seeds are the source of nim oil. Nim trees have been cultivated and grown in Mexico for several years now.
Research leader Ramón Cepeda Palacios and his team carried out a double-blind test – giving six volunteers the real repellent or a placebo – in a mosquito-infested area. The test found that 80% of bites sustained by the volunteers were on those who had not used a lotion made from the tree.
Cepeda Palacios said the research was intended to devise a treatment to neutralize the disease-carrying bite of infected mosquitoes. Currently there exist around 100 supposed remedies, consisting of ingredients as diverse as cloves, garlic and tobacco.
Researchers at the university took advantage of a locally growing resource – the abundant nim tree – whose flowers and fruit they used to make a lotion.
Cepeda Palacios said the tree flowers in June when mosquitoes are at their most numerous. Its fruit matures in August and September, which coincides with the rainy season. Again this is ideal timing, as more mosquito bites and higher reproduction of female adult insects are recorded during this period.
But the principal ingredients of the repellent can also be obtained from the seeds alone.
“To prepare 250 milliliters of lotion all that is needed are 20 grams of nim tree seeds [about 100], 250 milliliters of 70% alcohol solution and a wide-mouthed bottle measuring 350 milliliters,” said Cepeda Palacios. “Grind or crush the seeds using a mortar and pestle or blender, then put them in the bottle along with the alcohol and shake the mixture every three hours for a day to macerate.
“Leave this to stand for another half-day before separating the seeds and liquid, pouring the latter into an atomizer [used for sprays such as perfume], or simply another clean bottle. This lotion can then be used from the next day onwards.”
Cepeda Palacios added that the lotion should be applied every three to four hours, particularly on the legs, arms and neck. “One 250-milliliter bottle should be enough to last a small family one week,” he said.
The lotion will last up to 10 months after preparation if kept in the bottle.
Products from the nim tree have been used for medicinal purposes in India for many centuries.
– Source: mexiconewsdaily.com