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Student Develops Natural Mosquito Repellant with Native Taiwan Plant Extract

Student Develops Natural Mosquito Repellant with Native Taiwan Plant Extract

Jen-Yu Chang, a fourth year student from the NPUST Department of Wood Science and Design was interested in finding a new way to combat mosquitoes in a manner that is more natural and closer to home. She took her idea to Professor Hong-Lin Lee of the NPUST Graduate Institute of Bioresources, and working together, they developed a natural mosquito repellant ointment based on a plant variety native to Taiwan and commonly found in Pingtung, the “Clausena excavata Burm. f.”

The newly developed repellant was put head to head repellant made from Cajeput Oil, a product that is currently on the market and which often contains additives. The results showed that the effectiveness of new natural product was superior to that Cajeput oil based alternative. Jen-Yu Chang entered her research results at the 2018 National College and University Student Practical Project Competition and Achievement Exhibition in the “Biotechnology, Medicine and Agriculture” category and was selected as the winner in the runoffs.

NPUST President Chang-Hsien Tai made some context to the research, stating that “the Department of Wood Science and Design course design actually includes physics, chemistry and biology. In addition to using principles of physics to create furniture and design spaces, there are practical plant chemistry courses which emphasize concepts of circular economies. It is about helping students give back to society. Jen-Yu Chang product was able to stand out in a national competition, and it will also be able help reduce dengue. It is an outstanding performance, worth commending.”

Clausena excavata Burm. f. is a plant native to Taiwan and is mostly found on central and southern parts of the island, most abundantly on the Hengchun Peninsula in Pingtung. The plant is often used by Taiwan’s aboriginals, and its rich scent is able to keep mosquitos at bay. Jen-Yu Chang shared her motivations, stating that in Taiwan “most essential oil products on the market are imported. My original idea was to use local plants to create a Made in Taiwan product. Adding the scent of Clausena excavata Burm. f. has a good repellant effect on mosquitos, so this set the stage for the research. Its my aim to develop a better formula and work towards getting it mass produced”.

Under the direction of Hong-Lin Lee water distillation methods were used on the Clausena to extract its essential oils, then bees wax, sweet almond oil and other richly scented repellants including lemongrass, lemon tart, mint and cajeput were added to create a mosquito repellant with natural ingredients. Experiments proved its effectiveness.

When comparing the new concoction with the Cajeput Oil at 5% concentration, the effectiveness of the new product lasted 7 minutes longer, totaling 20 minutes. At a 10% concentration, the effectiveness was more than twice as long, lasting 37 minutes. When the Clausena repellent was used at a concentration of 30%, it had an effectiveness that exceeded 2 hours.

In order to confirm the mosquito repellent properties, gas chromatography mass spectrometry was used to conduct an analysis. The essential oils of the Clausena excavata Burm. f. were shown to have a high concentration of Safrole (55.39%), the fumes of which are toxic to insects. Additionally, it contained β- Caryophyllene (2.83%) and Terpinolene (15.50%), both of which are quite effective in warding off Aedes aegypti and Aedes albopictus mosquitos.

For modern health conscious consumers, natural ingredients are increasingly sought after and chemicals are avoided whenever possible. This current research devoted to developing a totally natural mosquito repellent using essential oils from Clausena excavata Burm. f should be able to give consumers peace of mind while adding new value to this native plant species of Taiwan. 

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