Isolation and identification of antibacterial components in seed extracts of Argemone mexicana L.(Papaveraceae)

Objective:The column chromatographic fractions of chloroform(CH1,CH2,CH3) seed extracts of Argemone mexicana(A.mexicana) were screened for antibacterial activity and phytochemical analysis.Methods:CH3 fraction was isolated and identified by column chromatography,thin layer chromatography,spectral data analysis and phytochemical screening were used for analysis. Results:CH3 fraction was significantly active at 4 to 64 mg/mL against Staphylococcus aureus, Escherichia coli,Klebsiella pneumoniae and Pseudomonas aeruginosa with minimum inhibitory concentration of 1.5625 to 3.125 mg/mL.The active fraction(CH3) revealed presence of alkaloid with retention factor value of 0.44.The active antibacterial agent in the most potent fraction (CH3) was isolated and identified as N-demethyloxysanguinarine by thin layer chromatography (TLC) and phytochemical screening.The CH1 and CH2 fractions did not show inhibitory activity. Conclusions:The results support the ethnomedicinal use of seeds of A.mexicana for treatment of bacterial diseases.

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.

Larvicidal activity of Dregea volubilis and Bombax malabaricum leaf extracts against the filarial vector Culex quinquefasciatus

Objective:To analyze the larvicidal activity of two plant leaf powder and leaf-extracts, Dregea volubilis and Bombax malabaricum against Culex quinquefasciatus.Methods:The larvicidal bioassay was done for powdered leaves of Dregea volubilis and Bombax malabaricum individually and their methanol extracts against first-,second-,third- and fourth-instar larval forms of Culex quinquefasciatus.Mortality rate was recorded after 24,48 and 72 h of postexposure. LC50 and LG90 values were calculated at different time intervals for third instar larvae. Results:All the graded concentration（0.1%,0.2%,0.3%,0.4%,0.5%） of powdered leaves showed significant（P 【0.05） larval mortality.The mortality rate was higher in 50 ppm doses of methanolic extracts of both the plants against Culex quinquefaciatus.The corresponding 【C50 values were 56.97 ppm and 48.85 ppm,respectively after 24 h of exposure.There is no mortality of non-target organism such as Chironomous circumdatus,Oreochromis niloticus niloticus and Diplonichus annulatum within 72 h of post exposure to 0.1%,0.2%,0.3%crude powdered leaves and methanolic extracts of both the two individual plants under the laboratory condition.The results of preliminary qualitative phytochemical analysis of both the plants revealed the presence of many bioactive principles such as steroids,tannins,flavonoids,triterpenoids,saponins,etc. that may be responsible for their bio-control potentiality.Conclusions:The results have shown potential and eco-friendly use of both plant extracts against larva of Culex quinquefasciatus for the first time.

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.

Concurrent dengue and malaria in an area in Kolkata

Objective:To establish the nature and extent of dual dengue and malaria infections in an endemic area through a longitudinal study.Methods:A prospective study was conducted from August 2005 to December 2010 to document the nature and extent of concurrent dengue and malaria infections in an area in central Kolkata,endemic both for dengue and malaria.Results: Of 2 971 suspected cases of dengue fever,in 605(20.36%) persons dengue infection was detected, of whom 46(7.60%,46/605) patients(40 and 6 suffered from secondary and primary dengue fever respectively) were simultaneously suffering from malaria(28 and 18 were infected with Plasmodium vivax(P.vivax) and Plasmodium falciparum(P.falciparum) respectively,such dual infections of dengue and malaria were detected in all the years of the study period,except 2007,indicating intense transmission of both dengue and malaria in the study area,and the phenomenon was not an isolated one,the rate of concomitant infections ranged from 25%in 2009 to 4.9%in 2005.Out of total population surveyed,1.54%(46/2 971) had concurrent dengue and malaria infection.Conclusions:These findings added a new dimension in diagnosis,treatment, epidemiology and control of dengue and malaria.The possible risk of concurrent dengue and malaria infectioas should always be kept in mind in endemic areas for early diagnosis employing modern technology and prompt and effective treatment to avoid serious complications.

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.

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.

Studies on seasonal fluctuation of different indices related to filarial vector,Culex quinquefasciatus around foothills of Susunia of West Bengal,India

Objective:To collect information on the seasonal activity of filarial vector around foothills of Susunia of West Bengal,India.Methods:Indoor-resting mosquitoes were collected from the human habitations of 16 villages.Collected mosquitoes were identified and examined for different parameters following standard methods recommended by World Health Organization and pioneer workers.Results:Overall man hour density,infection rate,infectivity rate,human blood index and daily mortality rate of the vector were assessed as 10.54%,6.31%,1.38%,77.33%and 13.00%, respectively,which were 12.17%,8.63%,2.26%,100.00%and 17.00%,respectively in the summer season.Average load of microfilaria,1st stage,2nd stage and 3rd stage larvae of Wuchereria bancrofti in infected vectors were 10.02.7.50,5.56 and 4.68,respectively,which were 11.58,9.90. 6.27 and 5.44,respectively in summer.Among the searched shelters 63.37%,8.16%and 2.08% were found to be invaded by any vector,infected vector and infective vector,respectively,which were 68.75%,12.76%and 3.91%,respectively in summer.Conclusions:Different indices related to the vector were much higher in summer,which indicates that,summer is the most favorable season for transmission of lymphatic filariasis in the study area.Available data will help to formulate an effective vector control measure.

Effect of common salt on laboratory reared immature stages of Aedes aegypti(L)

Objective:To observe the effect of common salt(NaCl) on immature stages of laboratory reared Aedes aegypti(L).Methods:A laboratory colony of Aedes aegypti mosquitoes of Rajahmundry strain was established in the laboratory of National Institute for Communicable Disease(NICD), Rajahmundry unit at(26±2)℃with relative humidity of(70±10)%.1.00%,1.25%and 1.50% solutions of common salt(NaCl) were selected to observe the susceptibility status of immature stages of Aedes aegypti in laboratory.Results:Fifty percent larvae of Aedes aegypti died within 19,31 and 48 hours when exposed to 1.50%,1.25%and 1.00%common salt solution, respectively.Ninety percent of the larvae died within 29,57 and 108 hours when exposed to the same salt solutions,respectively.Very high pupal mortality was observed varying from 81.8% to 40.0%.Formation of pupae was found inversely proportional in the presence of concentration of common salt in breeding water.Conclusions:With easy availability,less toxicity and long lasting nature,common salt may be applied in unused containers,especially in junkyards where surveillance mechanism is poor along with other conventional vector control methods in order to control breeding of Aedes aegypti,the vector of dengue/ dengue hemorrhagic fever and chikungunya.

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.