Skripsi

EVALUASI AKTIVITAS LARVISIDA DAN REPELEN SERTA MEKANISME INHIBISI ASETILKOLINESTERASE DARI EKSTRAK METANOL BAWANG MERAH (ALLIUM CEPA) TERHADAP AEDES AEGYPTI.

Latar Belakang Umbi bawang merah (Allium cepa) memiliki kandungan bahan aktif yang berpotensi menjadi larvisida dan repelen alami untuk mengendalikan vektor nyamuk DBD, yaitu Aedes aegypti. Penelitian ini bertujuan untuk mengevaluasi aktivitas larvisida dan repelen ekstrak umbi bawang serta mekanismenya terhadap Ae. aegypti. Metode Larva instar 3—4 Ae. aegypti diberikan ekstrak dengan konsentrasi berbeda dan diamati sampai 72 jam. Tingkat mortalitas larva serta nilai LC50 dan LC90 ekstrak pada 24 jam diukur untuk melihat aktivitas larvisida ekstrak. Tingkat hambatan hinggap ekstrak diuji menggunakan Y-tube olfactometer selama 120 menit menggunakan nyamuk betina dewasa Ae. aegypti yang telah dipuasakan dan umpan bayi tikus Wistar yang diberikan konsentrasi ekstrak yang berbeda. Absorbansi AChE larva yang mati dan nyamuk betina yang terpapar ekstrak diuji untuk mengetahui tingkat inhibisi AChE ekstrak. Data dianalisis menggunakan uji Kolmogorov-Smirnov, one way ANOVA, Post-Hoc Tukey, Probit, dan T-berpasangan. Hasil Terdapat perbedaan bermakna pada mortalitas larva (p < 0.05) setelah terpapar ekstrak. Nilai LC50 dan LC90 pada 24 jam adalah 29.697 dan 228.672 ppm. Ekstrak umbi bawang merah menyebabkan paralisis dan kerusakan morfologi pada larva, serta menghambat hinggapnya nyamuk betina sebesar 100% selama 120 menit. Absorbansi AChE larva dan nyamuk pada menit ke-0 dan ke-10 yang terpapar ekstrak mengalami perbedaan bermakna (p < 0.05). Inhibisi aktivitas AChE terlihat pada larva yang mati setelah dibandingkan dengan aktivitas AChE kelompok kontrol. Kesimpulan Ekstrak umbi bawang merah memiliki aktivitas larvisida dan repelen kontak terhadap Ae. aegypti. Ekstrak umbi bawang merah dapat membunuh larva dengan merusak morfologi dan menginhibisi aktivitas AChE larva, serta menghambat hinggapnya nyamuk dengan mempengaruhi indera penciumannya.
Kata Kunci: Aedes aegypti, Allium cepa, Asetilkolinesterase, Y-tube olfactometer


Introduction The red onion bulb (Allium cepa) contains active ingredients which are potential to become natural larvicides and repellents for controlling the dengue fever mosquito vector, Aedes aegypti. This study aims to evaluate the larvicidal and repellent activities of the red onion bulb extract and its mechanism against Ae. aegypti. Method 3rd—4th instar Ae. aegypti larvae were given extracts with different concentrations and observed until 72 hours. The larval mortality rate also the LC50 dan LC90 values at 24 hours were measured to assess the larvicidal activity of the extract. The landing inhibition of the extract was tested using a Y-tube olfactometer for 120 minutes with adult female Ae. aegypti mosquitoes that had been starved and Wistar rat pups as bait, which were given different concentrations of the extract. The absorbance of AChE in dead larvae and female mosquitoes exposed to the extra was tested to determine the AChE inhibition level of the extract. Data were analyzed using the Kolmogorov-Smirnov, one-way ANOVA, Post-Hoc Tukey, Probit, and paired T-test. Results A significant difference in larval mortality was found (p < 0.05) after exposure to the extract. The LC50 and LC90 values at 24 hours were 29.697 and 228.672 ppm, respectively. The red onion bulb extract caused paralysis and morphological damage to the larvae, and inhibited the landing of female mosquitoes by 100% for 120 minutes. The absorbance of AChE in larvae and mosquitoes at 0 and 10 minutes post-extract exposure showed significant difference (p < 0.05). AChE activity inhibition was observed in dead larvae, compared to the AChE activity in the control group. Conclusion The red onion bulb extract has larvicidal and contact repellency activity against Ae. aegypti. The extract can kill larvae by damaging its morphology and inhibiting its AChE activity, also inhibit mosquitoes from landing by affecting their sense of smell.
Keywords: Acethylcolinesterase, Aedes aegypti, Allium cepa, Y-tube olfactometer