Irradiated Cerastes cerastes Venom as a Novel Tool for Immunotherapy

Immunotherapy is the most effective treatment for the snake bites. The antivenoms are commonly obtained by hyperimmunization of animals that suffer from venom toxicity. The present report describes gamma irradiation effects on Cerastes cerastes venom. Doses of 1 kGy and 2 kGy gamma radiations were used for venom detoxification. These treated venoms did not have any residual lethal effects until 10 LD₅₀. Immunological analysis of sera raised against native and irradiated venoms, showed that elicited antibodies to irradiated venoms were able to recognize native venom. Anti-2 kGy irradiated venom had more protective ability than anti-native venom, as tested in mice.     

Bioefficacy of Plumbago zeylanica (Plumbaginaceae) and Cestrum nocturnum (Solanaceae) plant extracts against Aedes aegypti (Diptera: Culicide) and nontarget fish Poecilia reticulata

In a search for natural products that could be used to control the vectors of tropical diseases, extracts of medicinal plants Plumbago zeylanica and Cestrum nocturnum have been tested for larvicidal activity against second, third, and fourth instar larvae of Aedes aegypti. The LC₅₀ values of all the extracts in different solvents of both the plants were less than 50 ppm (15.40–38.50 ppm) against all tested larval instars. Plant extracts also affected the life cycle of A. aegypti by inhibition of pupal development and adult emergence with increasing concentrations. The larvicidal stability of the extracts at five constant temperatures (19°C, 22°C, 25°C, 28°C, and 31°C) evaluated against fourth instar larvae revealed that toxicity of both plant extracts increases with increase in temperature. Toxicity studies carried out against fish species Poecilia reticulata, the most common nontarget organism in the habitats of A. aegypti, showed almost nil to meager toxicity at LC₅₀ and LC₉₀ doses of the plant extracts. The qualitative analysis of crude extracts of P. Zeylanica and C. nocturnum revealed the presence of bioactive phytochemicals with predominance of plumbagin in P. zeylanica and saponins in C. nocturnum. Partially purified plumbagin from P. zeylanica and saponins from C. nocturnum were obtained, and their presence was confirmed by thin-layer chromatography and biochemical tests. The bioassay experiment of partially purified secondary metabolites showed potent mosquito larvicidal activity against the fourth instar larval form. Therefore, this study explored the safer and effective potential of plant extracts against vector responsible for diseases of public health importance.     

Edematogenic Activity of Scorpion Venoms from the Buthidae Family and the Role of Platelet-Activating Factor and Nitric Oxide in Paw Edema Induced by <Emphasis Type="Italic">Tityus</Emphasis> Venoms

We compared the edematogenic activity of venoms of scorpions from the Buthidae family, Tityus bahiensis (Tbv), Tityus serrulatus (Tsv) and Rhopalurus rochai (Rrv). Three doses (20, 40 and 80 μg/kg sc) of each venom were administrated in hind paw of mice and edema was measured from 5 min to 24 h. Tbv and Tsv both induced edema of rapid onset (135% of increase at 15 min); Rrv induced only a mild edema (40% of increase). We then investigated the involvement of platelet-activating factor (PAF) and endogenous nitric oxide (NO) in Tbv and Tsv-induced paw edema. Pretreatment of mice with a PAF antagonist (WEB-2170) inhibited Tsv but not Tbv-induced edema. Pretreatment with a non selective inhibitor of NO-synthases (l-NAME) inhibited or increased the edema depending on the dose and the time the edema was measured. In conclusion, the venoms from Tityus are stronger inducers of edema than the venom from the Rhopalurus scorpion. The venoms of Tityus species are similar in potency and time-course edema development. PAF is involved in the edema induced only by Tsv.     

Comparison of vespid venoms collected by electrostimulation and by venom sac extraction

Venoms of three vespid species, yellow jacket, bald-faced hornet, and yellow hornet, obtained by either electrostimulation or venom sac extraction were compared with regard to their enzymatic activity, antigenicity, and allergenicity. Phospholipase A, phospholipase B, and hyaluronidase enzymatic activities were present in all six preparations. The activity of venom sac extracts lay in the range found in different batches of venoms obtained by electrostimulation for each species. Analysis of sera from vespid-sensitive patients in the radioallergosorbent test (RAST) with discs coupled with either venom sac extracts or venoms obtained by electrostimulation showed a good correlation of the results within all three species (r = 0.95). In RAST inhibition the potency of venom sac extracts and venom obtained by electrostimulation was similar for each species. Analysis of rabbit antisera to the six preparations revealed similar patterns in immunoelectrophoresis and identity reactions between the major antigens within each species. Tissue protein contamination was detected in all venom sac extracts but not in venoms obtained by electrostimulation.     

Cross‐reactive carbohydrate determinants strongly affect the results of the basophil activation test in hymenoptera‐venom allergy

Background In hymenoptera‐venom allergy, sera of up to 60% of patients show in vitro reactivity to honeybee venom (HBV) and yellow jacket venom (YJV). This phenomenon is mainly caused by specific IgE (sIgE) against cross‐reactive carbohydrate determinants (CCD). Whether or not these antibodies can induce clinical symptoms is a longstanding debate. Objective The aim of this study was to investigate the biological activity of CCD‐sIgE and the suitability of the basophil activation test (BAT) in hymenoptera venom‐allergic patients having CCD‐sIgE. Methods The biological activity of CCD‐sIgE was analysed by application of native and CCD‐depleted YJV and HBV in BAT with the blood of 62 hymenoptera venom‐allergic patients and 16 non‐allergic controls. According to results of intracutaneous skin tests (IC) with YJV and HBV and the existence of CCD‐sIgE, patients were classified into six subgroups. Results In patients with mono‐positive IC and CCD‐sIgE, and thus double‐positive sIgE, BAT with native venoms was also double positive in up to 67% of the patients. In contrast, BAT with CCD‐depleted venoms was positive only with the IC‐positive venom. However, activation of basophils with the IC‐negative venom was significantly lower compared with the IC‐positive one. In IC mono‐positive patients without CCD‐sIgE, BAT was mono‐positive with the IC‐positive venom in the native and in the CCD‐depleted form. CCD‐positive patients with double‐positive IC were a heterogeneous group, with the majority of CCD‐positive patients also being double positive with the native forms of both venoms but mono‐positive with the CCD‐depleted ones. Conclusions In vitro BAT clearly demonstrates biological activity of CCD‐sIgE. However, because most of the patients showed a mono‐positive IC and activation of basophils with the IC‐negative venom was significantly lower compared with the IC‐positive one, the present data suggest that CCD‐sIgE is clinically irrelevant in these patients. Cite this as: M. Mertens, S. Amler, B. M. Moerschbacher and R. Brehler, Clinical & Experimental Allergy, 2010 (40) 1333–1345.     

Enzymes of bee venom, sac and whole body.

By using the Api-Zym System 55 enzymes were determined to be present in bee venom, venom sac, sacless whole body extract and whole body commercial extracts. Acid phosphatase activity was high in bee venom and sacless whole body extracts. Arylamidase activities were elevated in sacless whole body extracts and very low or undetectable in venoms. Conversely, glycyl-prolin arylamidase activity was high in venoms and very low in the other extracts.     

Effects of plant phenolics and grape extracts from Greek varieties of Vitis vinifera on Mitomycin C and topoisomerase I-induced nicking of DNA

In recent years, a number of reports have shown the anticancer activity of grape extracts and wine against various types of cancer such as breast, lung and gastric cancer. This property is mainly attributed to the plant polyphenols identified in grapes. The aim of the present study was to investigate the mechanisms by which grape extracts and plant polyphenols found in them exert their chemopreventive and antitumour activities. Thus, aqueous and methanolic extracts from two Greek varieties of Vitis vinifera, fractions enriched in polyphenols of these extracts and polyphenolics (caffeic acid, ferulic acid, gallic acid, protocatechuic acid and rutin) found in grapes were screened using two in vitro assays: i) the topoisomerase I relaxation assay and ii) the mitomycin C-induced DNA strand breakage. The grape extracts, the polyphenol-rich fractions and some of the polyphenolics (caffeic acid and protocatechuic acid) were potent inhibitors of topoisomerase I, indicating that the inhibition of this enzyme may be one of the mechanisms accounting for the anticancer activity of these compounds. Moreover, the grape extracts inhibited the mitomycin C-induced DNA strand breakage suggesting that they could prevent ROS-mediated DNA damage. On the other hand, the polyphenol-rich fractions and the plant polyphenols enhanced the mitomycin C-induced DNA strand breakage indicating prooxidant activity. Thus, it is of interest that whole grape extracts act as chemopreventive agents by inhibiting topo I and mitomycin C-induced DNA damage, while polyphenol enriched fractions and plant polyphenolics exert prooxidant activity leading to enhancement of DNA damage which may account for the cytotoxic and apoptosis-inducing properties of plant polyphenols against cancer cells.     

Enhancement of natural killer cell activity in vitro against human tumor cells by some plants from Jordan

The effect of different concentrations (0, 0.01, 0.1, and 0.5 mg/ml) of plant aqueous extracts on the anti-tumor activity of natural killer (NK) cells isolated from human blood was examined. Plant extracts induced significant enhancement of (26.6-67.7%) of NK cell activity against K562 tumor cells. This increase in NK cell cytotoxicity was found to be due to the enhancement of NK cell production of interferon-gamma (87-337%), and on tumor necrosis factor-alpha (60-200%). Furthermore, the release of both granzyme A and N-acetyl-beta-D-glucosaminidase was increased significantly when compared with controls. Activation of granzyme A and N-acetyl-beta-D-glucosaminidase was clearly observed ranging from 24.2-106.4% to 26.8-110.7%, respectively. Lastly, in the absence of IL-2, plant extracts caused a significant increase in NK-cell-induced cytotoxicity (256%) against K562 tumor cells, and in the presence of IL-2 stimulated cells plant extracts caused an increase in NK cell-cytotoxicity (112%).     

Evaluation of anti-inflammatory,anti-nociceptive,and anti-arthritic activities of Indian Apis dorsata bee venom in experimental animals: biochemical,histological, and radiological assessment

Abstract

Traditionally venoms are used from thousands of years to treat pain, inflammation, and arthritis. In Ayurveda “Suchika Voron” and “Shodhona” were practiced against pain.

In the present study, venom composition of the Indian honeybee Apis florea (AF), Apis dorsata (AD), and Apis cerana indica (AC) were analyzed using electrophoresis (SDS-PAGE). This venom analysis was used to shed light upon the correlation in structure and the venom composition among the three species in Indian fields.

Among the three species, Indian Apis dorsata bee venom (ADBV) is evaluated for an anti-inflammatory, anti-nociceptive activity, and antiarthritic activity in different animal models. The effect of ADBV is revealed for its anti-arthritic activity in the FCA- and CIA-induced arthritis model in male Wistar rats. The immunosuppressant action of ADBV was studied by hemagglutination antibody titer. It has been found that ADBV possesses anti-inflammatory and antinociceptive activities. In FCA- and CIA-induced arthritis, ADBV able to decrease rheumatoid factor, pain perception parameters, C-reactive protein, erythrocytes sedimentation rate, urinary hydroxyproline, serum transaminase level, and serum nitric oxide level when compared with diseased control arthritic rats. IL-6, TNF-α level was found to be decrease by ADBV treatment in collagen induced arthritis model. Thus this study confirmed the scientific validation behind utilization of venom in Indian Apis dorsata bees in arthritis and inflammatory diseases which has been not reported till date.     

Comparative studies of the anti-leishmanial activity of three <Emphasis Type="Italic">Crotalus durissus</Emphasis> ssp. venoms

In this study, we compared the anti-leishmanial activity of three crotalic venoms (Crotalus durissus terrificus–Cdt, Crotalus durissus cascavella–Cdca, and Crotalus durissus collilineatus–Cdcol). Different concentrations of each venom incubated with Leishmania (Leishmania) amazonensis promastigotes were used. Cdt venom exhibited a higher anti-leishmanial activity (Inhibitory concentration-IC50-value of 4.70 ± 1.72 μg/ml) in comparison with that of Cdca venom (IC50 value of 9.41 ± 1.21 μg/ml), while Cdcol venom increased parasite numbers in 50% at a concentration of 44.30 ± 2.18 μg/ml. In addition, this venom showed a low anti-leishmanial activity in higher concentrations (IC50 value of 281.00 ± 9.50 μg/ml). The main fractions of Cdca venom were isolated and assayed under similar conditions used for assessing crude venom. The most active fractions were gyroxin and crotamine that had IC50 values of 3.80 ± 0.52 μg/ml and 19.95 ± 4.21 μg/ml, respectively. Convulxin also inhibited parasite growth rate, although this effect was not dose-dependent. Crotoxin was the least effective fraction with an IC50 value of 99.80 ± 2.21 μg/ml. None of the protein fractions presented cytotoxic effects against J774 cells in culture. In vivo assays using BALB/c mice revealed that crotoxin and crotamine were the main toxic fractions. In conclusion, C. durissus cascavella venom has three main fractions with anti-leishmanial activity. These results open new possibilities to find proteins that might be used as possible agents against cutaneous leishmaniasis.     

Insect Allergy

One hundred and seventeen persons all stung by yellow jacket (YJ) and/or bee were examined by means of skin prick test with venom of these insects, skin prick test with 10 inhalant allergens and analyses of total IgE. Specific IgE and IgG against honey bee and YJ venom. Eighty-seven persons had had a systemic reaction. Positive correlations ( P < 0.05) were found between results of skin prick tests and specific IgE against venoms and, for YJ, between the severity of symptoms after sting and the size of skin prick test with the venom. That some of the more severe symptoms could have been caused by non-immunological mechanisms could explain why a significant correlation was present only between the results of the prick test and specific IgE and not between these tests and the clinical symptoms. Specific IgE values against YJ and honey bee venom showed convariation, although no correlation could be demonstrated between the clinical symptoms after stings from these insects, or between skin prick test results using the two different extracts. The severity of the sting reactions was not correlated to age, atopic disposition, amount of total IgE, number of stings during life, or positive skin prick test to inhalant allergens. It is concluded that in insect allergy, specific IgE analysis and skin prick tests are supplementary.     

Effects of venom immunotherapy on serum level of CCL5/RANTES in patients with Hymenoptera venom allergy

Abstract

Hymenoptera venoms are known to cause life-threatening IgE-mediated anaphylactic reactions in allergic individuals. Venom immunotherapy is a recommended treatment of insect allergy with still the mechanism not being completely understood. We decided to assess the serum CCL5/RANTES level in patients who experienced severe anaphylactic reaction to Hymenoptera venom and to find out changes in the course of immunotherapy. Twenty patients (9 men, 11 women, mean age: 31.91?±?7.63 years) with history of anaphylactic reaction after insect sting were included into the study. Diagnosis was made according to sIgE and skin tests. All of them were enrolled into rush venom immunotherapy with bee or wasp venom extracts (Pharmalgen, ALK-Abello, Horsholm, Denmark). Serum levels of CCL5/RANTES were measured using a commercially available ELISA kit (R&D Systems, Minneapolis, MN). CCL5/RANTES serum concentration are higher in insect venom allergic patients than in healthy controls (887.5?±?322.77 versus 387.27?±?85.11?pg/ml). Serum concentration of CCL5/RANTES in insect venom allergic patient was significantly reduced in the course of allergen immunotherapy already after 6 days of vaccination (887.5?±?322.77 versus 567.32?±?92.16?pg/ml). CCL5/RANTES serum doesn’t correlate with specific IgE. Chemokine CCL5/RANTES participates in allergic inflammation induced by Hymenoptera venom allergens. Specific immunotherapy reduces chemokine CCL5/RANTES serum level already after initial days of venom immunotherapy.     

Assessment of immunogenic characteristics of Hemiscorpius lepturus venom and its cross-reactivity with venoms from Androctonus crassicauda and Mesobuthus eupeus

Abstract

Hemiscorpius lepturus (H. lepturus), one of the most venomous scorpions in tropical and sub-tropical areas, belongs to the Hemiscorpiidae family. Studies of antibodies in sera against the protein component of the venom from this organism can be of great use for the development of engineered variants of proteins for eventual use in the diagnosis/treatment of, and prevention of reactions to, stings. In the present in vitro study, the proteins of H. lepturus venom, which could specifically activate the production of immunoglobulin G (IgG) in victims accidently exposed to the venom from this scorpion, were evaluated and their cross-reactivity with venoms from two other important scorpion species including Androctonus crassicauda and Mesobuthus eupeus assessed. H. lepturus venom was analyzed with respect to its protein composition and its antigenic properties against antibodies found in sera collected from victims exposed to the venom of this scorpion within a previous 2-month period. The cross-reactivity of the H. lepturus venom with those from A. crassicauda and M. eupeus was assessed using ELISA and immunoblotting. Electrophoretic analysis of the venom of H. lepturus revealed several protein bands with weights of 8–116 KDa. The most frequent IgG-reactive bands in the test sera had weights of 34, 50, and 116?kDa. A weak cross-reactivity H. lepturus of venom with venoms from A. crassicauda and M. eupeus was detected. The results of immunoblotting and ELISA experiments revealed that H. lepturus venom activated the host immune response, leading to the production of a high titer of antibodies. Clearly, a determination of the major immunogenic components of H. lepturus venom could be valuable for future studies and ultimately of great importance for the potential production of recombinant or hypo-venom variants of these proteins.     

Aqueous extracts of Syzygium brazzavillense can inhibit the infection with coxsackievirus B4 in vitro

Traditional practitioners commonly use plant crude extracts to treat various diseases in patients with symptoms that can be seen during enterovirus infections. In this study, the antienteroviral activity of medicinal plants from the Republic of Congo has been evaluated in vitro. Through an ethnopharmacological approach, seven plants grouped into six families were identified. Aqueous and organic extracts of various organs from these plants were prepared. The organic extracts at subcytotoxic concentrations did not inhibit the cytopathic effect (CPE) induced by coxsackievirus (CV)B1-5, CVA6, poliovirus type 1, and enterovirus 71. The aqueous extract of Syzygium brazzavillense, but not those of other plants, inhibited the CPE induced by CVB3 and CVB4 at 30 µg/mL (CC₅₀; 2800 µg/mL, IC₅₀; 0.8 µg/mL) and by CVB2 and poliovirus type 1 at higher concentrations. When aqueous extract of this plant was mixed with CVB4, the replication of the virus was inhibited. In conclusion, aqueous extracts of Syzygium brazzavillense can inhibit the infection with CVB4 and other enteroviruses in vitro. The present ethnopharmacological investigation helped to identify a plant with potential properties useful to combat enterovirus infections.     

Larvicidal activity of medicinal plant extracts and lignan identified in Phryma leptostachya var. asiatica roots against housefly (Musca domestica L.)

Medicinal plant extracts from 27 plant species in 20 families were tested for their larvicidal activity against housefly, Musca domestica (L.). Responses varied with plant material and concentration. Among plant species tested, Phryma leptostachya var. asiatica showed 100% larvicidal activity against M. domestica at 10 mg/g concentration. Larvicidal activities of Atractylodes japonica, Saussurea lappa, Asiasarum sieboldi, and Gleditsia japonica var. koraiensis were 89.3%, 85.3%, 93.3%, and 96.6% at 10 mg/g concentration, respectively. Extracts of Prunus persica, Curcuma longa, and Paeonia moutan produced moderate activity. Larvicidal activity of other plant extracts was less than 50%. Among test plant species, P. leptostachya var. asiatica showed the most potent larvicidal activity. The active constituent of P. leptostachya var. asiatica roots was identified as the leptostachyol acetate by spectroscopic analysis. The LC₅₀ values of leptostachyol acetate against M. domestica larvae were 0.039 mg/g. Naturally occurring medicinal plant extracts and P. leptostachya var. asiatica root-derived compounds merit further study as potential housefly larval control agents or lead compounds.     

Natural rubber latex and hymenoptera venoms share ImmunoglobinE-epitopes accounting for cross-reactive carbohydrate determinants

BACKGROUND: Epidemiological data on the prevalence and risk factors of latex sensitization have suggested a significant association between latex sensitization and the presence of one or more positive skin prick test responses to aeroallergens, food allergens and to one or more insect venoms. Xylose and core 3-fucose are typical complex glycans in plants and are foreign to mammals. Plant N-glycans and insect N-glycans may cross-react in humans. OBJECTIVE: The aim of our study was to investigate whether there are cross-reactive IgE-binding structures in natural rubber latex (NRL) and hymenoptera venoms and to examine their nature. METHODS: Hundred and twenty-five consecutive patients with insect venom allergy were screened for coincidental latex-specific IgE. IgE-binding components in the venoms from Apis mellifera and/or vespula species and in NRL extracts were characterized by IgE-immunoblotting to the natural allergen sources and determination of specific IgE to recombinant allergens. Cross-reactive components were investigated by inhibition experiments. The involvement of carbohydrates in the constitution of cross-reactive IgE-epitopes was further examined by specific IgE-binding to cross-reactive carbohydrate determinants (CCD) in bromelain and horseradish peroxidase as well as by periodate treatment. RESULTS: NRL glove extracts inhibited patients' serum IgE-binding to venom allergens. Vice versa, the IgE-binding to latex glove extracts could be inhibited by pre-incubation with the insect venoms. Specific IgE-binding to recombinant latex allergens was absent, whereas the cross-reactive IgE-epitopes were sensitive to periodate treatment and specific IgE to CCD (MMXF and MUXF type) could be detected. CONCLUSION: Insect venoms and NRL share IgE-binding CCD that may be responsible for positive serological test results to NRL in patients with insect venom allergy. This copositivity occurs frequently (13.6%) among venom-allergic individuals and did not elicit clinical symptoms upon contact to latex in the patients examined. In contrast, true cosensitization to insect venoms and NRL allergens can occur and may not be missed.     

In vitro leishmanicidal activity of Tityus discrepans scorpion venom

Leishmania parasites are sensitive to peptides with antimicrobial and ion-channel inhibitory activity. Because scorpion venoms are rich sources of such peptides, the leishmanicidal effect of Tityus discrepans venom was investigated. A negative correlation between cell growth and venom concentration was observed for venom-treated cultures of Leishmania (L.) mexicana mexicana promastigotes; 50% growth inhibition was obtained at 0.4 μg/ml. Light microscopy showed rounded, highly vacuolated L. (L.) m. mexicana cells with impaired flagellar motion after 15 min of incubation at 35 μg/ml. Ultrastructural studies confirmed an intense cytoplasm vacuolation and also enlargement of the flagellar pocket. Survival rates for New World Leishmania promastigotes (75% venom effective concentration, μg/ml) obtained after acute (1 h) venom toxicity tests were: L. (L.) m. mexicana (2.3), Leishmania (V.) braziliensis (11.3), and Leishmania (L.) chagasi (56.2). Heat (90°C) treatment of venom and fraction TdII abolished most of their leishmanicidal effect. Acute toxicity assays performed with Sephadex G-50 fractions indicated that leishmanicidal activity is associated with the venom lowest molecular mass components (2.8–7.4 kDa), as determined by MALDI-TOF mass spectrometry.     

Inhibition of human platelet aggregation and secretion by ant venom and a compound isolated from venom

Venom from the tropical ant,Pseudomyrmex. triplarinus, has activity against rheumatoid arthritis. Since platelets are involved in inflammatory responses, they were employed to study the effects of venom on prostaglandin-dependent human platelet aggregation and secretion. The assay is very sensitive and uses microliter volumes, which makes it useful as a screen during isolation and characterization of venom components. Whole venom inhibited arachidonic acid- and U46619-induced platelet aggregation with IC₅₀s of 45 and 39 g/ml, respectively. This suggested that venom prevented the action of prostaglandins. Pure venom was fractionated by gel filtration and at least three materials with antiplatelet activity were detected. The smallest component (factor F) was most active and was purified by additional molecular filtration and characterized by UV absorbance, thin-layer chromatography, nuclear magnetic resonance spectra, and activity to platelets. Factor F was identified as adenosine, which is known to stimulate platelet adenylate cyclase and has not been previously reported to be a component of insect venom.     

Allergens in Hymenoptera venom XV: The immunologic basis of vespid venom cross-reactivity

RAST-inhibition studies were performed by use of whole venom sac extracts to inhibit binding to purified venom allergens from various vespid wasps. Immunodiffusion studies were also performed with rabbit antisera raised against purified venom proteins. Immunologic cross-reactivity was demonstrated among the hyaluronidases, phospholipases, and antigen 5 s from both subgenera of yellow jackets, white-faced hornets, and paper wasps. The paper wasp hyaluronidase and antigen 5 were less related to those of the other three species than those of yellow jackets and hornets. It appears that immunologic cross-reactivity is the major mechanism of multiple allergic sensitivity to vespid venoms. Therapy with only the primary venom should be sufficient to protect against reactions from cross-reacting venoms.     

Larvicidal activity of <Emphasis Type="Italic">Saraca indica,Nyctanthes arbor-tristis</Emphasis>, and <Emphasis Type="Italic">Clitoria ternatea</Emphasis> extracts against three mosquito vector species

Screening of natural products for mosquito larvicidal activity against three major mosquito vectors Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi resulted in the identification of three potential plant extracts viz., Saraca indica/asoca, Nyctanthes arbor-tristis, and Clitoria ternatea for mosquito larval control. In the case of S. indica/asoca, the petroleum ether extract of the leaves and the chloroform extract of the bark were effective against the larvae of C. quinquefasciatus with respective LC₅₀ values 228.9 and 291.5 ppm. The LC₅₀ values of chloroform extract of N. arbor-tristis leaves were 303.2, 518.2, and 420.2 ppm against A. aegypti, A. stephensi, and C. quinquefasciatus, respectively. The methanol and chloroform extracts of flowers of N. arbor-tristis showed larvicidal activity against larvae of A. stephensi with the respective LC₅₀ values of 244.4 and 747.7 ppm. Among the methanol extracts of C. ternatea leaves, roots, flowers, and seeds, the seed extract was effective against the larvae of all the three species with LC₅₀ values 65.2, 154.5, and 54.4 ppm, respectively, for A. stephensi, A. aegypti, and C. quinquefasciatus. Among the three plant species studied for mosquito larvicidal activity, C. ternatea was showing the most promising mosquito larvicidal activity. The phytochemical analysis of the promising methanolic extract of the seed extract was positive for carbohydrates, saponins, terpenoids, tannins, and proteins. In conclusion, bioassay-guided fractionation of effective extracts may result in identification of a useful molecule for the control of mosquito vectors.