Evaluation of ovicidal and larvicidal effects of leave extracts of Hyptis suaveolens (L) POIT (Lamiaceae) against Anopheles gambiae (Diptera: Anophelidae) Complex (original) (raw)
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The female Anopheles gambiae s.l is the principal intermediate host/vector of Plasmodium-the causative organism of malaria fever in many tropical countries. After a preliminary acute toxicity screening of leaf extracts of Hyptis suaveolens using descending series of concentrations (1000 500, 100, 50 and 5 µg/m), two extracts (aqueous and ethanolic) were assayed against freshly laid eggs and larval instars of An. gambiae following the standard World Health Organisation ovicide and insecticide susceptibility bioassay methodology. The results indicate that both ethanolic and aqueous extracts of the test plant significantly (F = 30 23, df = 5, p < 0.01; F = 45.28, d = 5, ρ < 0 01 respectively) reduced the viability of the An. gambiae ova exposed to different doses of the extracts. In the ovicidal assay the lethal inhibition doses of egg hatching (IH50) was 31.52 and 48.01/µg/ml respect vely for the ethanolic and aqueous extracts. Also at a dose of 82 5 µg/ml the ethanolic extract completely inhibited An. gambiae hatching whereas the aqueous extract could inhibit only 70.42% egg hatching at the same dose. The results further indicate that both ethanolic and aqueous extracts also exhibited larval median lethal toxic (LC , l. f. i. t 50) values of 62.41 (range 61.22 – 67.04) and 80.02 (range 77.55 – 86.41) respectively thus making both extracts candidates for further fractionation and compound isolation s udies to characterize the active phytochemical constituents.
Journal of Medicinal Plants Research, 2017
Larvicidal effects of plant extracts against larvae of Anopheles gambiae were studied in the malaria entomology laboratory at Mendefera. The aim of the study was to evaluate ethanol and hot water extracts from leaves of seven different plants, viz., Azadirachta indica, Eucalyptus globulus, Tagetes minuta, Datura stramonium, Lantana camara, Ricinus communis and Jatropha curcas, as natural larvicides against third instar larvae of An. gambiae. Insecticidal susceptibility tests were carried out using WHO standard method and the mortality was observed after 24 and 48 h (h) of exposure. The experiment was conducted in complete randomized design in three replications. Data were collected on mortality of mosquito larvae in all the treatments and then subjected to statistical analysis using oneway ANOVA. Most of the tested extracts showed more than 50% mortality. J. curcas (100±0.00%) and R. communis (99.44±0.56) gave significantly higher larval mortalities at 1000 ppm concentration after 48 h of exposure. The experiment also showed that ethanol extracts gave higher larval mortality than hot water extracts and the efficiency of the extracts increased with an increase in the exposure period of the larvae.
Pharmacology online, 2007
Vector borne diseases are among the major causes of illness and death in many developing countries affecting substantial portion of the productive force. Medicinal plants with larvicidal properties have paramount importance for the local control of mosquito. This study was therefore focused on the phytochemical screening and laboratory investigation of the larvicidal properties of the aqueous extracts of 33 medicinal plants belonging to 27 families. The effects of aqueous extracts of 33 plants on laboratory reared Aedes agypti, Aedes africanus and Culex quinquefasciatus were evaluated using the standard WHO protocol. Portions of the same extracts were used for the identification of the major classes of secondary metabolites. Determination of the LD 50 of the most active plants extracts was also carried out on mice. Out of the tested 33 plant extracts, five plants, viz., Albizia gummifera (seeds), Balanites aegyptica (fruits), Hedera helix (leaves and fruits), Millettia ferruginea (seeds) and Warburgia ugandensis (leaves) exhibited promising larvicidal activities against Aedes agypti, Aedes africanus, and Culex quinquefasciatus, respectively. Acute toxicity studies of these plants on mice showed medium lethal dose (LD 50) values ranges from 150 mg per Kg to 450 mg per Kg when the aqueous extracts were administered intraperitonealy. Phytochemical investigation of the aqueous extracts used for the test revealed the presence of saponins, polyphenols, alkaloids and glycosides as major classes of compounds in most of the plants. The crude extracts of these plants demonstrating stronger larvicidal effect and safety on non-target organism stresses the need for extended laboratory and field evaluation, which could then be employed to play an important role in the control of the larvae of the vectors at their breeding site.
PLoS ONE, 2013
Pyrethroid insecticides induce an excito-repellent effect that reduces contact between humans and mosquitoes. Insecticide use is expected to lower the risk of pathogen transmission, particularly when impregnated on long-lasting treated bednets. When applied at low doses, pyrethroids have a toxic effect, however the development of pyrethroid resistance in several mosquito species may jeopardize these beneficial effects. The need to find additional compounds, either to kill diseasecarrying mosquitoes or to prevent mosquito contact with humans, therefore arises. In laboratory conditions, the effects (i.e., repellent, irritant and toxic) of 20 plant extracts, mainly essential oils, were assessed on adults of Anopheles gambiae, a primary vector of malaria. Their effects were compared to those of DEET and permethrin, used as positive controls. Most plant extracts had irritant, repellent and/or toxic effects on An. gambiae adults. The most promising extracts, i.e. those combining the three types of effects, were from Cymbopogon winterianus, Cinnamomum zeylanicum and Thymus vulgaris. The irritant, repellent and toxic effects occurred apparently independently of each other, and the behavioural response of adult An. gambiae was significantly influenced by the concentration of the plant extracts. Mechanisms underlying repellency might, therefore, differ from those underlying irritancy and toxicity. The utility of the efficient plant extracts for vector control as an alternative to pyrethroids may thus be envisaged.
Asian Journal of Research in Zoology
This study evaluated the larvicidal potential of the ethanolic and aqueous leaf extracts of Hyptis suaveolens Poit on the 4th larval instar of laboratory-reared Anopheles spp at varying concentrations of 0.1ml, 0.2ml, 0.3ml, 0.4ml and 0.5ml for specified periods of 24hrs, 48hrs and 72hrs. Qualitative phytochemical screening of the leaf extracts identified bioactive components like alkaloid, saponin, phenol, anthraquinone and flavonoid. The LC50 and LC90 values obtained indicate that the ethanolic leaf extracts of Hyptis suaveolens Poit had the greatest toxicity on the test organisms within 24hrs of exposure at median LC50 value of 0.485ml compared to the LC50 value of 0.625ml by its aqueous extract. The relative median potency estimates indicate that within 24 hrs, the ethanolic Hyptis suaveolens Poit was 0.161 times more potent on the test organism than aqueous Hyptis suaveolens Poit. The result of this research, therefore, underscores the efficacy of Hyptis suaveolens Poit as an e...
Journal of Science and Technology, 2011
Laboratory experiments were conducted to evaluate the larvicidal activity of ethanol extracts from leaves of three plants: castor bean (Ricinus communis), vinca (Vinca rosea) and lantana (Lantana camara) under 5 concentrations as 250-3000 ppm against the 3 rd instar larvae of the main mosquito vector of malaria in Sudan Anopheles arabiensis. The different larval mortality percentages were recorded after 24 hours. The larvicidal effect of each plant extract was compared with the standard larvicide Temephos (Abate ®). The three tested plant extracts in their different concentrations have shown larvicidal effects on An. arabiensis larvae. Statistical analysis showed no significant differences between the higher concentration of each of the three plant ethanol extracts and the standard larvicide Temephos and that all concentrations recorded 100 % mortality of the tested larvae. The results indicated that, castor extract had the greatest larvicidal effect against An. arabiensis larvae with the lowest LC 50 (282.7060 ppm) followed by vinca and lantana extracts respectively. This study suggests that, the leaf extracts of the three plant species should be considered as promising larvicides against An. arabiensis larvae.
Efficacy of Some Plant Extracts on Anopheles gambiae Mosquito Larvae
Academic Journal of …, 2009
Abtract: The efficacy of both the ethanolic and aqueous extracts of the fruits of Physalis angulata L. (Solanaceae); Xylopia aethiopica (Dunal) A. Rich (Annonaceae) and seeds of Piper guineense Schum and Thonn (Piperaceae); Jatropha curcas Linn. (Euphorbiaceae) were tested on the second instar larvae of Anopheles gambiae (L) at varying concentrations. With percentage mortality, P. guineense (83.33%) in ethanol was the most effective followed by its aqueous form (71.67%), P. angulata (36.94%) in ethanol, X. aethiopica (34.44%) in ethanol, J. curcas (33.06%) in ethanol, aqueous extracts of both P. angulata and X. aethiopica at 29.44% while the least active was J. curcas (20.56%) in water. On the basis of 24hrs LC values, P. guineense 50 (0.028 mg ml ) ethanolic extract acted most followed by its aqueous form (0.09 mg ml ), ethanolic extract of P. angulata (2.5 mg ml ), ethanolic form of J. curcas (3.25 mg ml ), X. aethiopica (3.57 mg ml ) ethanolic 1 1 1
BMC Veterinary Research, 2013
Background: Helminthiasis is a major limitation to the livestock industry in Africa. Haemonchus contortus is the singular most important helminth responsible for major economic losses in small ruminants. The high cost of anthelmintics to small farmers, resistance to available anthelmintics and residue problems in meat and milk consumed by humans further complicates matters. The use of plants and plant extracts as a possible source of new anthelmintics has received more interest in the last decade. Our aim was not to confirm the traditional use, but rather to determine activity of extracts. Based on our past experience acetone was used as extractant. Because it is cheaper and more reproducible to evaluate the activity of plant extracts, than doing animal studies, the activity of acetone leaf extracts of thirteen plant species used traditionally in ethnoveterinary medicine in South Africa were determined using the egg hatch assay and the larval development test. Cytotoxicity of these extracts was also evaluated using the MTT cellular assay. Results: Extracts of three plant species i.e. Heteromorpha trifoliata, Maesa lanceolata and Leucosidea sericea had EC 50 values of 0.62 mg/ml, 0.72 mg/ml and 1.08 mg/ml respectively for the egg hatch assay. Clausena anisata; (1.08 mg/ml) and Clerodendrum glabrum; (1.48 mg/ml) extracts were also active. In the larval development assay the H. trifoliata extract was the most effective with an EC 50 of 0.64 mg/ml followed by L. sericea (1.27 mg/ml). The activities in the larval development test were generally lower in most plant species than the egg hatch assay. Based on the cytotoxicity results C. anisata was the least toxic with an LC 50 of 0.17 mg/ml, while Cyathea dregei was the most toxic plant with an LC 50 of 0.003 mg/ml. The C. anisata extract had the best selectivity index with a value of 0.10 and 0.08 for the two assays, followed by H. trifoliata and L. sericea with values of 0.07, 0.07 and 0.05, 0.04. The C. dregei extract had the worst selectivity index with a value of 0.00019 for both assays. Conclusion: The result of this study indicates which species should be further investigated in depth for isolation of compounds.
Malaria Journal, 2022
BackgroundThe use of synthetic insecticides against mosquitoes may lead to resistance development and potential health hazards in humans and the environment. Consequently, a paradigm needs to shift towards the alternative use of botanical insecticides that could strengthen an insecticide resistance management programme. This study aimed to assess the insecticidal effects aqueous, hexane, and methanol crude leaf extracts of Calpurnia aurea, Momordica foetida, and Zehneria scabra on an insectary colony of Anopheles stephensi larvae and adults.MethodsFresh leaves of C. aurea, M. foetida and Z. scabra were collected and dried, then separately ground to powder. Powdered leaves of test plants were extracted using sonication with aqueous, hexane, and methanol solvents. The extracts were concentrated, and a stock solution was prepared. For comparison, Temephos (Abate®) and control solutions (a mixture of water and emulsifier) were used as the positive and negative controls, respectively. Different test concentrations for the larvae and the adults were prepared and tested according to WHO (2005) and CDC (2010) guidelines to determine lethal concentration (LC) values. Mortality was observed after 24 h exposure. The statistical analyses were performed using Statistical Package for the Social Sciences (SPSS) software (Kruskal-Wallis test) and R software (a generalized linear model was used to determine LC50 and LC90 values of the extracts).ResultsThe lowest LC50 values were observed in aqueous extracts of M. foetida followed by Z. scabra extract and C. aurea leaves at 34.61, 35.85, and 38.69 ppm, respectively, against the larvae. Larval mortality was not observed from the hexane extracts and negative control, while the standard larvicide (temephos) achieved 100% mortality. Further, the adulticidal efficacy was greatest for aqueous extract of Z. scabra with LC50 = 176.20 ppm followed by aqueous extract of C. aurea (LC50 = 297.75 ppm).ConclusionThe results suggest that the leaf extracts of the three test plants have the potential of being used for the control of vector An. stephensi larvae and adult instead of synthetic mosquitocides. Further studies need to be conducted to identify the active ingredients and their mode of action.
The ethanolic and aqueous extracts of the fruits of Tetrapleura tetraptera (Fabiaceae) and seeds of Delonix regia (Bojer ex Hook.) Raf (Fabiaceae) and Raphia vinifera L. (Arecaceae) were tested on the second instar larvae of Anopheles gambiae (L) at varying concentrations. With percentage mortality, T. tetraptera (59.17%) in ethanol was the most effective followed by D. regia (42.78%) in ethanol, T. tetraptera (31.67%) in water, D. regia (20.56%) aqueous extract and R. vinifera (19.44%) in ethanol, while the aqueous extract of R. vinifera (16.39%) was the least active. On the basis of 24hrs LC values, T. tetraptera (0.08g/ml) ethanolic 50 extract was the most toxic followed by the ethanolic extract of D. regia (1.4mg/ml), aqueous extract of T. tetraptera (5.37%), ethanolic form of R. vinifera (10%), D. regia (11.5%) aqueous extract while the aqueous forms of R. vinifera (12.5%) was the least active. For all the plants used, there were significant difference among the ethanolic extracts and the aqueous forms. This could also make mosquito control in rural area become easier than before and will also be less toxic to other non-target species.