Mosquito larvicidal activity of some common spices and vegetable waste on Culex quinquefasciatus and Anopheles stephensi

Objective:To investigate the larvicidal activities of crude and chlor of orm:methanol(1:1 v/ v) extracts of some common spices(Cuminum cyminum,Allium sativum,Zingiber offinale, Curcuma longa) and vegetable waste(Solanum tuberosum germinated tuber) against Anopheles stephensi and Culex quinquefasciatus mosquito larvae.Methods:Larval mortality of above mosquito species were observed after 24,48 and 72 h of exposure to five concentrations of aqueous extract(0.1%,0.2%,0.3%,0.4%and 0.5%) and four concentrations(25,50,75 ppm) of chlor of orm:methanol(1:1 v/v) extract.The lethal concentration of individual spices or vegetable waste was determined by log-probit analysis(at 95%confidence level) and effect of crude and chlor of orm:methanol(1:1 v/v) extracts were recorded on non target organisms.Results: Relative mortality rate of both larval mosquito species were recorded in the following sequences: Cuminum cyminum】 Allium sativum】Zingiber offinale,Curcuma longa 】 Solanum tuberosum germinated tuber for crude extract,and efficacy of chlor of orm:methanol(1:1 v/v) extract were as follows:Curcuma longa 】 Zingiber offinale 】 Solanum tuberosum germinated tuber 】 Cuminum cyminum】 Allium sativum.Conclusions:Crude and chlor of orm:methanol(1:1 v/v) extract of Cuminum cyminum,Allium sativum,Zingiber offinale,Curcuma longa and Solanum tuberosum germinated tuber can be recommended effectively in mosquito control programmes at very low concentrations.No mortality and other abnormalities were noticed on non target organisms and further studies are needed to investigate the chemical structure of active principal which are responsible for larvicidal activity.

Mosquito larvicidal effect of orthophosporic acid and lactic acid individually or their combined form on Aedes aegypti

Objective:To observe the effect of two common organic acids on the larvae of Aedes aegypti (Ae.aegypti)(L),the natural vector of dengue fever/dengue hemorrhage fever,chikugunya and allergic skin reaction especially in children.Methods:Two common organic acids(lactic acid and orthophosporic acid of gradually increasing concentration) were used against laboratory reared third instars larvae of Ae.aegypti in order to observe the rate of mortality after 8.16 and 24 h of post exposure respectively in laboratory.Results:Larval mortality rates recorded were in the following sequences:orthophosphoric acid and lactic acid at 1:1 combination 】orthophosphoric acid】lactic acid.Conclusions:These two organic acids may be used perfectly in combination (1:1) along with other conventional vector control methods to reduce the Ae.aegypti population, especially in those areas where surveillance and supervisory mechanism are poor or insufficient.

Isolation and identification of bioactive antibacterial components in leaf extracts of Vangueria spinosa(Rubiaceae)

Objective:The column chromatographic fraction of ethyl acetate(EA1,EA2,EA3,EA4 and EA5) leaf extracts of Vangueria spinosa(V.spinosa) were screened for antibacterial activity and phytochemical analysis.Methods:EA3 fraction was isolated and identified by column chromatography,thin layer chromatography,spectral data analysis and phytochemical screening were used for analysis.Results:EA3 fraction was significantly active at 4 to 64 mg/L against Staphylococcus aureus,Escherichia coli,Klebsiella pneumoniae and Pseudomonas aeruginosa with minimum inhibitory concentration of 1.5625 to 3.1250 mg/mL.The active fraction(EA3) revealed the presence of flavonoid with retention factor value(R_f) of 0.39.The active antibacterial agent in the most potent fraction(EA3) was isolated and identified as flavonoid(-)-epicatechin-3-O-β-glucopyranoside by thin layer chromatography(TLC) and phytochemical screening.EA1 and EA2 show inhibitory activity at 4 to 64 mg/L against Staphylococcus aureus only where as fraction EA4 and EA5 do not shows any inhibitory activity within that range of concentration against any bacteria.Conclusions:The results support the ethnomedicinal use of leaf of V.spinosa for the treatment of bacterial diseases.

Mosquito larvicidal activity of Rauvolfia serpentina L.seeds against Culex quinquefasciatus Say

Objective:To establish the larvicidal activities,if any of solvent extracts of Rauvolfia serpentina (R.serpentina) L.seeds against Culex quinquefasciatus(Cx.quinquefasciatus) Say.1823 as target species.Methods:Seeds of R.serpentina were extracted with five solvents graded according to the polarity[viz.petroleum ether.benzene,ethyl acetate,acetone and absolute alcohol] continuing one after another with the same seeds.Results:Mortality rate with petroleum ether extract was significantly higher than other extracts.The mortality rates of late 3rd instar larvae wore 50.33±5.51.10.00±1.00.0.00±0.00.21.33±1.53 and 0.00±0.00 in 100 ppm concentration of petroleum ether,benzene,ethyl acetate,acetone and absolute alcohol respectively,after 24 h of exposure period.Conclusions:Results of this study show that petroleum ether extract of R. serpentina seed may be considered as a potent source of mosquito larvicidal agent.

Control of human filarial vector,Culex quinquefasciatus Say 1823(Diptera:Culicidae)through bioactive fraction of Cayratia trifolia leaf

Objective:To investigate the mosquito larvicidal activity of Cayratia trifolia(L.)Domin(Vitaceae:Vitales)(C.trifolia)which is distributed in many parts of India with medicinal properties as vector control is facing threat due to the emergence of resistance to synthetic insecticides.Methods:Young and mature leaves of C.trifolia were investigated for larvicidal activity against3rd instars larvae of Culex quinquefasciatus in different seasons throughout the year.The active fractions were extracted using six different solvents in a non-polar to polar fashion viz petroleumether,benzene,chloroform:methanol(1:1 v/v),acetone,absolute alcohol and distilled water.Dose dependent mortality was recorded against each solvent extract.Determination of LD_(50)and LD_(90)were executed through log-probit analysis using the most bioactive fraction.The fluctuations in mortality were statistically co-related through ANOVA analyses concerning different seasons and types of leaves as random variables.Justification of larvicidal activity was established through student's t-test.Costing effects were evaluated on the non-target water fauna under laboratory conditions.Thin layer chromatographic techniques were performed for phytochemical analysis and categorization of chemical personality of the active fractions using the most effective solvent extract following standard methods.Results:Significant variations in mortality rate were noted with respect to the type of leaves(mature and senescence),concentration of leaf extract and between seasons.The water extract among all the solvent extracts was found to induce cent percent mortality at 50 mg/L in test mosquito species within 24 h with a LD_(50)and LD_(90)value of 10.70 mg/L and 27.64 mg/L respectively.No significant mortality was recorded in non-target water population.Chromatographic analyses of the water extract revealed the presence of steroids,triterpene glycosides,essential oil,phenolics and diterpenes as secondary phytochemicals.Conclusions:Water extract of C.trifolia leaf promised as a cost effective and potent larvicidal agent against Culex quinquefasciatus.

Lymphatic filariasis in the foothill areas around Susunia of West Bengal in India

Objective:To investigate the filarial epidemiology in 16 foothill villages around Susunia hill,Bankura district, West Bengal,India.Indices studied were microfilaria rate,mean microfilarial density,filarial disease rate and endemicity rate.Other indices related to transmission were incrimination of vector species,man-hour density of the vector,vector infection and infectivity rates,human blood index of the vector etc.Methods:Examination of 20μL night blood samples by finger prick and clinical examination for filarial diseases of 3 737 people(2 241 male and 1 496 female) was done randomly covering nearly 22%population of the study area.Aspects related to vectors were dealt by regular collection and dissection of mosquitoes.Results:Overall microfilaria rate,mean microfilarial density,disease rate and endemicity rate were 6.10%,10.86%,20.20%and 25.58%,respectively. Causative parasite was identified as Wuchereria bancrofii and Culex quinquefasciatus was incriminated as the vector therein.Vector infection rate,infectivity rate and human blood index were assessed to be 6. 31%,1.38%and 77.33%,respectively.Conclusion:Present study is highly endemic for bancroftian filariasis. More than one fourth of the population under study were filarial victims indicating an overall alarming situation and immediate measure should be taken to rectify the situation.

Efficacy of Limonia acidissima L.(Rutaceae) leaf extract on larval miniatures of Culex quinquefasciatus Say 1823

Objective:To investigate the role of leaf extract of Limonia acidissima L.(Rutaceae) as a biocontrol agent against the larval form of Culex quinquefasciatus,and characterization of bioactive component responsible for larvicidal activity.Methods:Larval mortality of mosquito species was observed after 24,48 and 72 hours of exposure to different concentrations of aqueous extract,solvent extract and subsequently bioaclive compound.The bioaclive compound was subjected to IR and GC-MS analysis.Results:Mortality rale al 3%concentration of crude extract were highest(90%) amongsl all concentrations tested and subsequently highest(95%) mortality was achieved in chloroform:methanol extract at 100 ppm concentrations.IR and GC-MS analysis of bioaclive compound revealed the presence of steroid compound which may act as larvicide. Conclusions:The chloroform:methanol extract of mature leaves of Limonia acidissima was found to exhibit considerable mosquito larvicidal activity against Culex quinquefasciatus.