Asep Kadarohman

Biolarvicidal of Vetiver Oil and Ethanol Extract of Vetiver Root Distillation Waste (Vetiveria zizanoides) Effectiveness toward Aedes aegypti, Culex sp., and Anopheles sundaicus

Abstract This study investigated biolarvicidal of vetiver oil and ethanol extract of vetiver root distillation waste (Vetiveria zizanoides) effectiveness toward the Larvae of Aedes aegypti, Culex sp., and Anopheles sundaicus. Phytochemical screening and chemical compounds analysis by GC-MS were also performed. Terpenoids, flavonoids, and saponins had been found in ethanol extract of vetiver root distilling waste and terpenoids, steroids, flavonoids and saponins had also been discovered in vetiver oil. GC-MS analysis upon ethanol extract of vetiver root distilling waste indicated 11 components; with naphthalene (22.42 %), linoleic acid (14.47 %), palmitic acid (8.09 %), and valerenol (6.66 %) as the main components. There were 33 components of vetiver oil; with cyclo-isolongifolene (10.90 %), valerenol (10.52 %), viridiflorol (8.17 %), and ziorene (4.66%) as the main components. Larvicidal effect on 3rd and 4th instar larvae of the mosquito species, which were Aedes aegypti, Culex sp., and Anopheles sundaicus, had also been investigated in a concentration dependent manner for 24 hours. Various concentration of ethanol extract of vetiver root distilling waste were 500, 1000, 2000, 3000, and 4000 ppm and the samples of vetiver oil were 1, 10, 50, 100, 200, and 500 ppm. The mortality percentages of Aedes aegypti, Culex sp., and Anopheles sundaicus larva in 1000 ppm concentration of ethanol extract of vetiver root distilling waste were 56, 50, and 100 % with LC50 1373.6, 7095.4, and 482.7. LT50 in 4000 ppm concentration of Aedes aegypti, Culex sp., and Anopheles sundaicus were 353.3, 1351.6, and 168.4 minutes. The mortality percentages of Aedes aegypti, Culex sp., and Anopheles sundaicus larvaes in 100 ppm concentration of vetiver oil were 100, 100, and 32 % with LC50 2.885, 0.245, and 87.931 ppm. The results showed that significant activity of distillation waste of vetiver root had been found on Anopheles sundaicus and on Culex sp. of vetiver oil.

Profile of students’ comprehension of 3D molecule representation and its interconversion on chirality

This study aims at describing (1) students’ level comprehension; (2) factors causing difficulties to 3D comprehend molecule representation and its interconversion on chirality. Data was collected using multiple-choice test consisting of eight questions. The participants were required to give answers along with their reasoning. The test was developed based on the indicators of concept comprehension. The study was conducted to 161 college students enrolled in stereochemistry topic in the odd semester (2014/2015) from two LPTK (teacher training institutes) in Bandar Lampung and Gorontalo, and one public university in Bandung. The result indicates that college students’ level of comprehension towards 3D molecule representations and its inter-conversion was 5% on high level, 22 % on the moderate level, and 73 % on the low level. The dominant factors identified as the cause of difficulties to comprehend 3D molecule representation and its interconversion were (i) the lack of spatial awareness, (ii) violation of ...