Perbandingan kandungan senyawa rotenoid dan aktivitas insektisida ekstrak Tephrosia vogelii terhadap hama kubis Crocidolomia pavonana

Abstract

Fish-poison bean, Tephrosia vogelii (Fabaceae), is a potential source of botanical insecticides. Fish-poison bean leaves contain insecticidal rotenoid compounds including rotenone, deguelin, and tephrosin. Fifteen samples of fish-poison bean leaves collected from 8 locations in West Java ware extracted with acetone by maceration method. Yield of the extracts ranged from 7.10% to 13.75%. The result of qualitative analysis using thin layer chromatography with n-hexane:CH2Cl2:MeOH (55:44:1) as eluent showed 3 wellseparated spots. High performance liquid chromatography and liquid chromatographymass spectrometer analyses identified rotenone (retention time 15.9 min) and two other compounds that have retention time in the proximity of rotenone’s retention time, i.e. deguelin (17.5 min) and one unidentified compound (13.6 min). Rotenone content in 15 extracts of fish-poison bean leaves ranged from 0.0475% to 0.3844%, in which the highest rotenone content was found in extract of purple-flowered fish-poison bean leaves from Panglejar area, Cikalong Wetan District, Bandung. The highest deguelin area was found in white-flowered fish-poison bean leaf sample from Cigombong District, Bogor. When analyzed separately, the variation in rotenone and deguelin contents could not explaine the variation in insecticidal activity of the tested fish-poison bean extracts. This suggests that the variation in rotenoid contents as a whole contribute to the variation in insecticidal activity.