Sains Malaysiana 48(9)(2019): 1919–1926 http://dx.doi.org/10.17576/jsm-2019-4809-13 Evaluation of in vitro Bioactivity of Melaleuca cajuputi Powell Essential Oil against Aedes aegypti (L.) and Aedes albopictus (Skuse) (Penilaian Bioaktiviti in vitro Minyak Pati Melaleuca cajuputi Powell terhadap Aedes aegypti (L.) dan Aedes albopictus (Skuse) AZLINDA ABU BAKAR*, HAMDAN AHMAD, SALLEHUDIN SULAIMAN, BAHARUDIN OMAR & RASADAH MAT ALI ABSTRACT The aim of this study was to evaluate the in vitro activity of Melaleuca cajuputi essential oil leaf extract against Aedes aegypti and Aedes albopictus. The essential oil of the M. cajuputi was obtained via steam hydro-distillation and analyzed by GC-MS for the chemical constituents. GC-MS analysis showed that the essential oil of M. cajuputi contained 13 compounds with two major chemical constituents, 2-propenoic acid (29.55%) and caryophyllene (20.04%). Adulticidal and larvicidal bioassay was evaluated following WHO guidelines. Larvicidal bioassays were conducted with the 10, 50, 80, 100, and 120 mg/L M. cajuputi essential oil against late 3 rd instar of Ae. aegypti and Ae. albopictus which give LC 50 120.99 mg/L and 222.58 mg/L, respectively. Adult mortality was observed after 24 h with the LC 50 of 0.029 mg/cm 2 for Ae. aegypti and 0.028 mg/cm 2 for Ae. albopictus. In adulticidal bioassay, M. cajuputi essential oils showed effective results at 0.04 mg/cm 2 concentrations, with values for KT 50 of 77.71 min for Ae. aegypti and 69.49 min for Ae. albopictus. M. cajuputi essential oils exhibited moderate toxicity effects against the larva and adults of Aedes species and may be used as an alternative to chemical insecticide. Keywords: Adulticidal; Aedes; essential oil; larvicidal; Melaleuca cajuputi ABSTRAK Tujuan kajian ini adalah untuk menilai aktiviti ekstrak daun minyak pati Melaleuca cajuputi secara in vitro terhadap larva Aedes aegypti dan Aedes albopictus. Minyak pati M. cajuputi diperoleh secara stim penyulingan-hidro dan dianalisis menggunakan GC-MS untuk menentukan komponen bahan kimia. Analisis GC-MS menunjukkan kandungan komponen kimia minyak pati M. cajuputi terdiri daripada 13 sebatian dengan dua unsur kimia utama iaitu asid 2-propenoik (29.55%) dan karioflena (20.04%). Bioasai nyamuk dewasa dan larva dijalankan mengikut garis panduan WHO. Bioasai larva telah dijalankan dengan minyak pati M. cajuputi berkepekatan 10, 50, 80, 100, dan 120 mg/L terhadap instar 3 Ae. aegypti dan Ae. albopictus yang memberikan nilai LC 50 masing-masing, ialah 120.99 mg/L dan 222.58 mg/L. Kadar mortaliti nyamuk dewasa diperhatikan selepas 24 jam dan nilai LC 50 yang diperoleh bagi Ae. aegypti dan Ae. albopictus masing- masing, ialah 0.029 mg/cm 2 dan 0.028 mg/cm 2 . Melalui ujian bioasai adultisid yang dijalankan, minyak pati M. cajuputi menunjukkan hasil yang efektif pada kepekatan 0.04 mg/cm 2 dengan nilai KT 50 ialah 77.71 min bagi Ae. aegypti dan 69.49 min bagi Ae. albopictus. Minyak pati M. cajuputi menunjukkan kesan ketoksikan sederhana terhadap larva dan dewasa spesies Aedes dan dapat digunakan sebagai insektisid alternatif terhadap insektisid bahan kimia. Kata kunci: Adultisidal; Aedes; bioaktiviti; larvisidal; Melaleuca cajuputi; minyak pati INTRODUCTION The Ae. aegypti mosquito has emerged as one of the most dangerous vectors, as it is able to transmit Yellow fever, dengue, chikungunya, and Zika. Dengue is a serious arboviral disease of the Africa, America, and Asia. The spread of dengue fever and Yellow fever in many parts of the world can be directly attributed to the proliferation and adaptation of these mosquitoes to breeding and living close to human populations and settlings. The secondary vector, Ae. albopictus, which was originally confned to Asia and known as Asian Tiger mosquito, has also contributed to the spread of the dengue fever, chikungunya, and Yellow fever as well. Yellow fever, which has a 400-year history, occurs only in tropical areas of Africa and the Americas. In Malaysia, dengue fever (DF) and dengue hemorrhagic fever (DHF) are the most common vector-borne diseases throughout the year across the nation, with occasional cases of chikungunya in some areas. However, both DF and DHF disease have a signifcant impact in shaping the socio- economic development and the formation of a government and local authorities’ policy (Packierisamy 2015). Dengue fever in Malaysia was frst reported by Skae (1902). By the early 1970s, DHF had spread all of Malaysia and has since caused a signifcant health burden to the population. Until now, the most effective way to control vector- borne diseases has been relying on chemical insecticides. Chemical insecticides are shown to be effective in controlling the spread of the diseases during the outbreak