Evaluation of Two Different Solvents for Azolla pinnata Extracts on Chemical Compositions and Larvicidal Activity against Aedes albopictus (Diptera: Culicidae)

Abstract

Limited success for Aedes control program has impelled the necessities for new insecticide search. Hence, alternative plant compounds may be competent to overcome the pesticide resistance problem and to lead a chemical-free environment. Following go-green conceptions, larvicidal effects of the Azolla pinnata extracts using methanol and acetone solvent against Aedes albopictus late 3rd instar larvae were evaluated. The A. pinnata fresh plant from Kuala Krai, Kelantan, Malaysia (5° 31′ N 102° 12′ E) was used for crude extraction with Soxhlet apparatus using methanol and acetone solvents. Next, larvicidal test following WHO guidelines was tested against late 3rd instar to early 4th instar larvae of Ae. albopictus mosquitoes. Meanwhile, the chemical composition of extracts and their structures have been identified using GCMS-QP2010 Ultra (Shimadzu) fitted with Rtx-5MS capillary column (30 m × 0.25 mm inner diameter, ×0.25 μm film thickness; maximum temperature, 370°C), coupled to QP2010 Ultra (Shimadzu) MS. Results of methanol solvent showed the highest larvicidal activity against late 3rd instar to early 4th instar Ae. albopictus larvae with LC50 and LC95 values of 867 ppm and 1293 ppm at 24 hours, respectively, and 647 ppm and 972 ppm at 48 hours, respectively. Meanwhile, acetone solvent compounds were recorded with LC50 and LC95 values of 1072 ppm and 1302 ppm at 24 hours, respectively, and 904 ppm and 1126 ppm at 48 hours, respectively. Finally, the chemical composition of A. pinnata plant extracts has been characterized for 35 active compounds from methanol solvent and 37 active compounds with acetone solvent. In conclusion, A. pinnata plant bioactive molecules are efficient and could be developed as an eco-friendly, “go-green” approach for mosquitoes' larvicidal control programs. Thus, our study suggests that future research can be conducted on A. pinnata bioactive ingredients against Ae. albopictus larvae in small-scale field trials as botanical insecticide for environmentally friendly approach.

Chemical composition and larvicidal activity againstAedesmosquitoes of flower extracts fromClitoria Ternatea

“…The percentage composition of the crude extract constituents was expressed as the percentage by peak area. The identification and characterization of chemical compounds in various crude extracts were based on the GC retention time [2,4].…”

“…Currently only physical and chemical methods were commonly used to control mosquito borne diseases. Physical approaches such as mosquito bed nets, mosquito window nets at homes, electrical mosquito rackets are only temperamental solutions [2]. Besides that the use of chemical methods such as temephos and pyrethroids are more prominent with some resistant challenges [2].…”

“…Physical approaches such as mosquito bed nets, mosquito window nets at homes, electrical mosquito rackets are only temperamental solutions [2]. Besides that the use of chemical methods such as temephos and pyrethroids are more prominent with some resistant challenges [2]. Chemical insecticides enhanced biological activity by synthetic chemicals resulting from active or inactive based compounds and explanatory effects of structurally related compounds that counter resistance development which characterizes most single-component bioactive compounds on current mosquitocide classes [2][3][4][5].…”

“…Besides that the use of chemical methods such as temephos and pyrethroids are more prominent with some resistant challenges [2]. Chemical insecticides enhanced biological activity by synthetic chemicals resulting from active or inactive based compounds and explanatory effects of structurally related compounds that counter resistance development which characterizes most single-component bioactive compounds on current mosquitocide classes [2][3][4][5]. Additionally, Ravi et al [4] supported the conceptions of botany control mechanisms for a simple and sustainable method compared to conventional insecticides.…”

“…Nothing like current synthetic or chemical insecticides, advantages of plant based insecticides are composed by natural blends of multiple chemical compounds which may act synergistically on both physiological and behavioral processes of mosquitoes [2][3][4][5][6]. Hence, alternative use of bio-insecticides would provide a more accurate solution against Dengue vectors, Ae.…”