Abdullah Fauziah, Subramanian Partiban, Ibrahim Halijah, Abdul Malek Sri Nurestri, Lee Guan Serm, Hong Sok Lai
Institute of Biological Sciences, Universiti Malaya, 50603 Kuala Lumpur, Malaysia Centre for Research in Biotechnology for Agriculture (CEBAR), University of Malaya, 50603 Kuala Lumpur, Malaysia
Institute of Biological Sciences, Universiti Malaya, 50603 Kuala Lumpur, Malaysia Department of Biomedical Sciences, Faculty of Biomedicine and Health, Asia Metropolitan University, 43200 Selangor, Malaysia.
J Insect Sci. 2015 Feb 16;15(1):175. doi: 10.1093/jisesa/ieu175. Print 2015.
Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices.
采用双选生物测定法评估高良姜（当地称为“lengkuas”）精油和甲醇提取物对两种白蚁，即截头堆砂白蚁（沃斯曼）和弯颚散白蚁（霍尔姆格伦）（等翅目：鼻白蚁科）的拒食特性。将一张用高良姜精油处理的直径4厘米的纸盘和另一张用甲醇或己烷处理作为对照的纸盘放入装有10只白蚁的培养皿中。截头堆砂白蚁对2000 ppm精油处理的纸盘平均消耗量（毫克）为3.30±0.24毫克，弯颚散白蚁为3.32±0.24毫克。高良姜精油在拒食效果上显示出显著差异，2000 ppm的高良姜精油被认为是产生最大拒食效果的最佳浓度。使用气相色谱 - 质谱法测定精油成分。精油的主要成分是1,8 - 桉叶素（61.9%）。使用500 ppm的1,8 - 桉叶素进行拒食生物测定表明，两种白蚁对纸的消耗量均显著减少。因此，高良姜精油中引起拒食活性的生物活性剂被鉴定为1,8 - 桉叶素。驱避活性表明，250 ppm的1,8 - 桉叶素对截头堆砂白蚁产生了50.00±4.47%的驱避率，而对于弯颚散白蚁，则需要750 ppm的1,8 - 桉叶素才能产生类似的驱避活性（56.67±3.33%）。在接触毒性研究中，弯颚散白蚁比截头堆砂白蚁更敏感，弯颚散白蚁的致死剂量（LD50）为945毫克/千克，而截头堆砂白蚁的LD50值为1102毫克/千克。因此，1,8 - 桉叶素可被开发为可持续农业实践中防治白蚁的替代方法。
