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Investigation of Breadfruit (Artocarpus altilis) for use in the control of the yellow fever mosquito Aedes aegypti

University of British Columbia

Insect borne diseases such as malaria, yellow fever and Dengue fever are among the most economically devastating diseases present on our planet. Traditional knowledge from the Pacific islands suggests using the male inflorescences of breadfruit (Artocarpus altilis) as a mosquito repellent. The cultivation of breadfruit as a source of starch to bolster food sustainability in developing nations has grown in the past ten years. Thus, the use of male inflorescences as a novel source of mosquito repellents or insecticides presents a valuable secondary product from breadfruit that could be made alongside its primary role as a food source. In order to investigate the potential for biogenic amines such as serotonin and melatonin sourced from plants such as breadfruit, an in depth investigation of the toxicity and its associated underlying mechanism must be elucidated. In Chapter 2, breadfruit male inflorescences were processed using two different extraction methods. The first was a methanol extraction method and the second was a cold-pentane extraction method. These extracts were tested in a larvicidal bioassay with Aedes aegypti larvae. Methanol extracts showed significantly greater toxicity than the pentane extracts and all future work in subsequent chapters was done on methanol extracts. In Chapter 3, methanol extracts of multiple varieties of breadfruit including two Artocarpus altilis and Artocarpus mariannensis hybrids: ulu afa and Lipet, Artocarpus camansi and a mixed Artocarpus sample were chemically characterized. It was determined that all varieties of extract tested contained serotonin. As well, a wide variety of compounds were putatively identified in the extracts with the majority being fatty acids, phenols, and terpenes previously associated with biological activity towards insects. In Chapter 4, toxicity values for each variety of Artocarpus were assessed with the mixed Artocarpus sample being the highest in insecticidal activity. Haemolymph serotonin wasn shown to significantly decrease after breadfruit extract exposure, even though the serotonin gene pathway transcripts were largely unaffected, suggesting that this change is not transcriptionally regulated.

Text

2015-08-26

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/54641

Biology

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/2.5/ca/