Larvicides are products that kill mosquito larvae. Essential oils and plant extracts are emerging natural sources of larvicides, insecticides and insect antifeedant (Duke, 1990). The essential oils from the leaves and stem barks of three Nigerian medicinal plants; Anthocleista vogelii, Morus mesozygia and Sterculia tragacantha were obtained by hydrodistillation and characterized using GC and GC-MS analyses; thereafter the constituents were identified by comparing their mass spectra with NIST 1998 library data of the GC-MS system as well as by comparison of their retention indices (RI) with relevant literature data (Adams, 2007). The oils were tested for their ability to kill mosquito larva using 3rd instar stage of female Culex mosquito and the LC50 values were calculated using Probit analysis (Finey, 1971). The yields of the essential oils varied from 0.46–0.73% (w/w). The characterised constituents ranged from 90.3– 96.9% representing the total identified compounds in the entire oils. A. vogelii leaves was dominated by 1,8-cineole (24.4%) and viridiflorol (24.2%) while the stem bark had in abundance 2-pentylfuran (13.4%) and 1-octen-3-ol (9.3%); the leaves of M. mesozygia leaves was dominated by (E)-β-ionone (12.4%) and β-elemene (11.7%) and the stem-bark had in abundance 2-dodecanone (77.0%) and hexahydrofarnesylacetone (13.0%), on other hand, the major constituents in the leaf essential oil S. tragacantha was β-bisabolol (13.1%) and (E)-geranylacetone (11.3%); hexahydrofarnesylacetone (32.5%) and 1,8-cineole (14.7%) were the most abundant in the stem-bark of S. tragacantha oil. The general profile of the six essential oils indicates they are rich in apocarotenes. The oils also displayed different levels of toxicity to the larva of Culex mosquito, the LC50 values varied in the range 83.52 – 1131.97 μg/mL indicating high toxicity to low toxicity. The studied essential oils are dominated by compounds that have displayed biological activities and the mosquito larvicidal assay provides evidence that the oils could be good mosquito larvicidal agents useful to combat the spread of filariasis.
Volatile constituents and larvicidal activity of the essential oils from three Nigerian medicinal plants
FLAMINI, GUIDO
2015-01-01
Abstract
Larvicides are products that kill mosquito larvae. Essential oils and plant extracts are emerging natural sources of larvicides, insecticides and insect antifeedant (Duke, 1990). The essential oils from the leaves and stem barks of three Nigerian medicinal plants; Anthocleista vogelii, Morus mesozygia and Sterculia tragacantha were obtained by hydrodistillation and characterized using GC and GC-MS analyses; thereafter the constituents were identified by comparing their mass spectra with NIST 1998 library data of the GC-MS system as well as by comparison of their retention indices (RI) with relevant literature data (Adams, 2007). The oils were tested for their ability to kill mosquito larva using 3rd instar stage of female Culex mosquito and the LC50 values were calculated using Probit analysis (Finey, 1971). The yields of the essential oils varied from 0.46–0.73% (w/w). The characterised constituents ranged from 90.3– 96.9% representing the total identified compounds in the entire oils. A. vogelii leaves was dominated by 1,8-cineole (24.4%) and viridiflorol (24.2%) while the stem bark had in abundance 2-pentylfuran (13.4%) and 1-octen-3-ol (9.3%); the leaves of M. mesozygia leaves was dominated by (E)-β-ionone (12.4%) and β-elemene (11.7%) and the stem-bark had in abundance 2-dodecanone (77.0%) and hexahydrofarnesylacetone (13.0%), on other hand, the major constituents in the leaf essential oil S. tragacantha was β-bisabolol (13.1%) and (E)-geranylacetone (11.3%); hexahydrofarnesylacetone (32.5%) and 1,8-cineole (14.7%) were the most abundant in the stem-bark of S. tragacantha oil. The general profile of the six essential oils indicates they are rich in apocarotenes. The oils also displayed different levels of toxicity to the larva of Culex mosquito, the LC50 values varied in the range 83.52 – 1131.97 μg/mL indicating high toxicity to low toxicity. The studied essential oils are dominated by compounds that have displayed biological activities and the mosquito larvicidal assay provides evidence that the oils could be good mosquito larvicidal agents useful to combat the spread of filariasis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
