Phytochemical extractions from the leaves of <i>Ravenala madagascariensis</i> from Sundarban area and its effect on southern house mosquito (<i>Culex quienquefasciatus</i> Say 1823) larvae

Abstract

Vector control is a major issue mainly in this time when resistance to chemical insecticides leads to a greater problem. For an alternative measure novel botanical sources can be used as a good insecticide with less toxic hazards to the environment and public health. The present study estimated larvicidal activities of the crude and solvent extracts of Ravenala madagasariensis against the filarial vector Culex quinquefasciatus under laboratory conditions. Crude extracts of R. madagasariensis mature leaves were examined for larvicidal activity against all the larval instars (1 st to 4 th ) of Cx. quinquefasciatus. Solvent extraction was carried out using three different solvents viz. petroleum ether, chloroform: methanol (1:1 v/v) and absolute alcohol. Dose dependent mortality assays were performed using the bioactive fractions of the solvent extracts. Further, determinations of LC 50 and LC 90 values were accomplished through log-probit analyses and regression analyses. The larvicidal activity of R. madagasariensis leaves were statistically justified through ANOVA analyses. Effects of the bio-active portions were examined on a non-target water fauna. After 72 h of exposure 78.67% mortality of 1 st instars larvae was recorded at 0.5% concentration of crude extract. 150 ppm concentration of solvent extract showed 100% mortality against 1 st instars larvae after 72 h of exposure. 200 ppm concentration was responsible for 100% mortality of 2 nd instars larvae in 72 h. 250 ppm concentration showed significant mortality against 3 rd and 4 th instars larvae.Chironomus circumdatus larvae, non target organism, exhibited no significant mortality. This experimental study was an initiative to ascertain R. madagasariensis as a novel resource of target specific larvicide against Cx. quinquefasciatus larvae.

Some Determinant Factors of Malaria Prevalence in Nigeria

“…Owoeye et al (2016), Hamza et al (2014) further reported that A. gambiae and A. arabiensis are the main species that transmit malaria. Bhattacharya et al (2014b), Ndiok et al (2016) also reported that Culex quinquefasciatus transmits lymphatic filariasis. Adebajo et al (2014) reported that Aedes aegypti transmits chikungunya, yellow and dengue fevers.…”

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“…TLC of chloroform: methanol extract indicated the existence of steroidal compounds and bioassay reveals a significant death rate in that fraction (p<0.05). Chloroform: methanol extract from some other plants is also reported to exhibit mosquito larvicidal potential [35,44,45] and comparisons show that the LC 50 value of the chloroform: methanol extract fraction of V. spinosa leaves against Cx. quinquefasciatus larvae are quite acceptable.…”

Larvicidal Efficacy of <i>Cleistanthus patulus</i> Muell. Arg. (Euphorbiaceae) Leaf Extract against Filarial Vector <i>Culex quinquefasciatus</i> (Say 1823)

“…Larval control is easier than control of adults due to their low mobility and confinement to water bodies. (Bhattacharya et al, 2014b) and Solanum nigrum berry (Rawanietal, 2013) showed potent larvicidal property against Cx. quinquefasciatus.…”