Wednesday, January 25, 2017
African trees kill both malaria mosquitoes and the parasite.
A new study has shown that African trees kill both malaria mosquitoes and the parasite. Scientists from the University of Oslo, Faculty of Mathematics and Natural Sciences have examined the bark from two African trees and found substances that can kill both the mosquitoes that transmit malaria, and the parasite itself. Malaria is one of the world's most serious infectious diseases and affects more than 200 million people each year. Traditional healers in West Africa have for many years used extracts from the bark of two trees in the citrus family (Rutaceae) to treat malaria, which is a widespread disease in the region and kills hundreds of thousands of people worldwide every year. Researchers at the School of Pharmacy at the University of Oslo in Norway have now shown that bark from the trees contains substances that not only kill the malaria parasite, but also the mosquitoes that transmit the disease. The scientists found several interesting substances both in the so-called Olon tree (Zanthoxylum heitzii) that is found from Cameroon to Congo, and in a related tree from Mali. The most interesting and active compounds were found in the Olon tree, but also the bark of Zanthoxylum zanthoxyloides from Mali contains active substances. The scientists used extracts from the bark of the Olon tree and found that it contained at least one compound that kills the mosquitoes that transmit the malarial parasite,but the bark also contains another substance that kills the parasite itself. More than 30 species of the mosquito genus Anopheles kan infect humans with the malaria parasite,the scientists worked with both water-based and alcohol-based extracts from the bark of the two trees, and it turns out that the extracts with alcohol contains more of the active substances. The substance that kills the mosquito is called pellitorine and was found in the bark of both trees. The scientists also found that a mixture of four main substances from the bark of the Olon tree had a higher toxicity than pellitorine alone, even if the other ingredients were not toxic separately, this suggests that there is a synergistic effect between the ingredients. The scientists has now shown that the bark of the Olon tree from Congo contains at least two interesting compounds: Pellitorine that kills malaria mosquitoes, and dihydronitidin that kills the malaria parasite.