Larvicidal and repellent activity of medicinal plant extracts from Eastern Ghats of South India against malaria and filariasis vectors

Objective:To evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminum）,Lantana camma（L.camara）,Nelumbo nucifera （N.nucifera） Phyllanlhus amarus（P.amarus）.Piper nigrum（P.nigrum） and Trachyspermum ammi（T.ammi） against Anopheles stephensi（An.stephensi） and Culex quinquefasciatus（Cx. quinquefasciatus）.Methods:The larvicidal activity of medicinal plant extracts were tested against earl) fourth-instar larvae of malaria and filariasis vectors.The mortality was observed 24 h and 48 h after treatment,data were subjected to probit analysis to determine the lethal concentrations(LC50 and LC90) to kill 50 and 90 per cent of the treated larvae of the tested species. The repellent efficacy was determined against two mosquito species at five concentrations（31.25. 62.50.125.00.250.00,and 500.00 ppm） under the laboratory conditions.Results:All plant extracts showed moderate effects after 24 h and 48 h of exposure;however,the highest activity was observed after 24 h in the leaf methanol extract ol N.nucifera.seed ethyl acetate and methanol extract of P.nigrum against the larvae of An.Stephensi(LC50 = 34.76.24.54 and 30.20 ppm) and against Cx.quinquefasciatus(LC50= 37.49.43.94 and 57.39 ppm),respectively.The toxic effect of leaf methanol extract of C.siamea,seed methanol extract of C.cyminum,leaf ethyl acetate extract of N.nucifera.leaf ethyl acetate and methanol extract of P.amarus and seed methanol extract of T.ammi were showed 100%mortality against An.stephensi and Cx.quinquefasciatus alter 48 h exposer.The maximum repellent activity was observed at 500 ppm in methanol extracts of N. nucifera.ethyl acetate and methanol extract of P.nigrum and methanol extract of T.ammi and the mean complete protection time ranged from 30 to 150 min with the different extracts tested. Conclusions:These results suggest that the leaf and seed extracts of C.siamea.N.nucifera.P. amarus.P.nigrum and T.ammi have the potential to be used as an ideal ecofriendly approach for the control of the An.stephensi and Cx.quinquefasciatus.

Acaricidal activity of synthesized titanium dioxide nanoparticles using Calotropis gigantea against Rhipicephalus microplus and Haemaphysalis bispinosa

Objective:To assess the acaricidal activity of titanium dioxide nanoparticles(TiO_2 NPs)synthesized from flower aqueous extract of Calotropis gigantea(C.gigantea)against the larvae of Rhipicephalus(Boophilus)microplus[R.(B.)microplus]and the adult of Haemaphrysalis bispinosa(H.bispinosa).Methods:The lyophilized C.gigantea flower aqueous extract of 50 mg was added with 100 mL of TiO(OH_2)(10 mM)and magnetically stirred for 6 h.Synthesized TiO_2 NPs were characterized by X-ray diffraction(XRD).Fourier transform infrared spectroscopy(FTIR),Scanning electron microscopy(SEM),and Energy dispersive X-ray spectroscopy(EDX).The synthesised TiO_2 NPs were tested against the larvae of R(B.)microplus and adult of H.bispinosa were exposed to filter paper impregnated method.Results:XRD confirmed the crystalline nature of the nanoparticles with the mean size of 10.52 nm.The functional groups for synthesized TiO_2NPs were 1405.19,and 1053.45 cm^(-1)for-NH_2 bending,primary amines and amides and 1053.84and 1078.45 cm^(-1)for C-O.SEM micrographs of the synthesized TiO_2 NPs showed the aggregated and spherical in shape.The maximum efficacy was observed in the aqueous flower extract of C.gigantea and synthesized TiO_2 NPs against R.(B.)microplus(LC_(50)=24.63 and 5.43 mg/L and r^2=0.960 and 0.988)and against H.bispinosa(LC_(50)=35.22 and 9.15 mg/L and r^2=0.969 and 0.969).respectively.Conclusions:The synthesized TiO_2 NPs were highly stable and had significant acaricidal activity against the larvae of R.(B.)microplus and adult of H.bispinosa.This study provides the first report of synthesized TiO_2 NPs and possessed excellent anti-parasitic activity.

Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus and Culex gelidus

Objective:To investigate the larvicidal activity of synthesized silver nanoparticles（Ag NPs） utilizing aqueous bark extract of Ficus racemosa（F.racemosa） was tested against fourth instar larvae of filariasis vector,Culex quinquefasciatus（Cx.quinquefasciatus） and japanese encephalitis vectors,Culex gelidus（Cx.gelidus）.Methods:The synthesized Ag NPs was characterized by UV-vis spectrum,X-ray diffraction（XRD）,Scanning electron microscopy（SEM） and Fourier transform infrared（FTIR）.The larvicidal activities were assessed for 24 h against the larvae of Cx.quinquefasciatus and Cx.gelidus with varying concentrations of aqueous bark extract off.racemosa and synthesized Ag NPs.LC50 and r2 values were calculated.Results:The maximum efficacy was observed in crude aqueous extract of F.racemosa against the larvae of Cx.quinquefasciatus and Cx.gelidus(LC50=67.72 and 63.70 mg/L;r2=0.995 and 0.985) and the synthesized Ag NPs(LC50=12.00 and 11.21 mg/L;r2=0.997 and 0.990).respectively.Synthesized Ag NPs showed the XRD peaks at 2θvalues of 27.61,29.60,35.48,43.48 and 79.68 were identified as （210）,（121）,（220）,（200） and（311） reflections,respectively.The FTIR spectra of Ag NPs exhibited prominent peaks at 3 425,2 878,1 627 and 1 382 in the region 500-3 000 cm-1.The peaks correspond to the presence of a stretching vibration of（NH） C=O group.SEM analysis showed shape in cylindrical,uniform and rod with the average size of 250.60 nm.Conclusions:The biosynthesis of silver nanoparticles using bark aqueous extract of F.racemosa and its larvicidal activity against the larvae of disease spreading vectors.The maximum larvicidal efficacy was observed in the synthesized Ag NPs.

Efficacy of larvicidal and pupicidal activity of Catharanthus roseus aqueous and solvent extracts against Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera: Culicidae)

Objective: To investigate the larvicidal and pupicidal activities of aqueous, ethyl acetate and methanol extracts of Catharanthus roseus ( C. roseus ) against malaria and filariasis vectors. Methods: The larvicidal and pupicidal activities of C. roseus leaf extracts were tested against the fourth instar larvae and pupae of Anopheles stephensi ( An. stephensi ) and Culex quinquefasciatus ( Cx. quinquefasciatus ). The mortality was observed after 24 and 48 h post the treatment. The data were subjected to probit analysis to determine the lethal concentrations (LC 50 and LC 90 ) at which 50% and 90% of the treated larvae or pupae of the tested species were killed. Results: The larval and pupal mortality were observed after 24 and 48 h of exposure of aqueous, ethyl acetate and methanol extracts of C. roseus ; no mortality was observed in the control group. The LC 50 values against the fourth-instar larvae of An. stephensi were 68.62 and 72.04 mg/mL for the aqueous extract, 82.47 mg/mL for the ethyl acetate extract, and 78.80 and 86.64 mg/mL for the methanol extract, while the aqueous, ethyl acetate and methanol extracts had LC 50 values of 85.21, 76.84 and 94.20 mg/mL against the fourth-instar larvae of Cx. quinquefasciatus . The aqueous, ethyl acetate and methanol extracts had LC 50 values of 118.08, 182.47 and 143.80 mg/mL against the pupae of An. stephensi and 146.20, 226.84 and 156.62 mg/mL against the pupae of Cx. quinquefasciatus , respectively. Conclusions: The aqueous and methanol extracts of C. roseus leaves had an excellent potential to control the malarial vector An. stephensi and filariasis vector Cx. quinquefasciatus .

Adult emergence inhibition and adulticidal activities of medicinal plant extracts against Anopheles stephensi Liston

Objective:To determine the adult emergence inhibition（EI） and adulticidal activities of hexane,chloroform,ethyl acetate,and acetone leaves extracts of Anisomeles malabarica（A. malabarica）,Euphorbia hirta（E,hirta）,Ocimum basilicum（0.basilicum）,Ricinus communis（R. communis）,Solanum trilobatum（S.trilobatum）,Tridax procumbens（T.procumbens） and seeds of Gloriosa superba（G.superba） against Anopheles stephensi（An,stephensi）.Methods:The EI and adulticidal trials were carried out according to World Health Organization（WHO） procedures with slight modifications.The extracts were diluted in dimethyl sulphoxide in order to prepare a serial dilution of test dosages（15.625,31.25,62.5,125,250,500 and 1 000μg/mL）.Five duplicate trials were carried out for every sample concentration,and for each trial a negative control was included and the mortality was determined after 24 h of exposure.Results:The highest EI activity was found in ethyl acetate extracts of A malabarica,chloroform extracts of O.basilicum, S.trilobatum,acetone of extract of R.communis,T.procumbens,and seed extract of G.superba with EI50 values 143.12,119.82.157.87,139.39,111.19,and 134.85μg/mL,and the effective adulticidal activity was observed in chloroform,acetone extracts of G.superba,T.procumbens,R. communis,S.trilobatum and ethyl acetate extract of 0.basilicum with LD50 values 120.17,108.77, 127.22,163.11,118.27,and 93.02μg/mL,respectively.Chi-square value was significant at P【0.05 level.Conclusions:These results should encourage further efforts to investigate the compounds that might possess good EI and adulticidal properties when isolated in pure form.