In vitro total phenolics, flavonoids contents and antioxidant activity of essential oil, various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah

ObjectiveTo detect the in vitro total phenolics, flavonoids contents and antioxidant activity of essential oil, various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah.MethodsThe dry powder leaves of Tetrastigma were extracted with different organic solvent such as hexane, ethyl acetate, chloroform, butanol and aqueous methanol. The total phenolic and total flavonoids contents of the essential oil and various organic extracts such as hexane, ethyl acetate, chloroform, butanol and aqueous ethanol were determined by Folin - Ciocalteu method and the assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity using α, α-diphenyl- β-picrylhydrazyl (DPPH) method.ResultsThe total phenolic contents of the essential oil and different extracts as gallic acid equivalents were found to be highest in methanol extract (386.22 mg/g) followed by ethyl acetate (190.89 mg/g), chloroform (175.89 mg/g), hexane (173.44 mg/g), and butanol extract (131.72 mg/g) and the phenolic contents not detected in essential oil. The antioxidant capacity of the essential oil and different extracts as ascorbic acid standard was in the order of methanol extract > ethyl acetate extract >chloroform> butanol > hexane extract also the antioxidant activity was not detected in essential oil.ConclusionsThe findings show that the extent of antioxidant activity of the essential oil and all extracts are in accordance with the amount of phenolics present in that extract. Leaves of Tetrastigma being rich in phenolics may provide a good source of antioxidant.     

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

ObjectiveTo investigate the larvicidal and pupicidal activities of aqueous, ethyl acetate and methanol extracts of Catharanthus roseus (C. roseus) against malaria and filariasis vectors.MethodsThe 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 (LC₅₀ and LC₉₀) at which 50% and 90% of the treated larvae or pupae of the tested species were killed.ResultsThe 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 LC₅₀ 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 LC₅₀ 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 LC₅₀ 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.ConclusionsThe aqueous and methanol extracts of C. roseus leaves had an excellent potential to control the malarial vector An. stephensi and filariasis vector Cx. quinquefasciatus.     

Insecticidal, antimicrobial and antioxidant activities of bulb extracts of Allium sativum

ObjectiveTo evaluate the insecticidal, antimicrobial and antioxidant activities of bulb extracts of Allium sativum (A. sativum).MethodsDried bulbs of A. sativum were extracted with different solvents and evaluated for insecticidal, antimicrobial and antioxidant activities.MethodsAqueous and methanol extracts showed highest insecticidal activity (mortality rate of 81% and 64% respectively) against the larvae of Spodoptera litura (S. litura) at a concentration of 1 000 ppm. With regard to antimicrobial activity, aqueous extract exhibited antibacterial activity against gram positive (Bacillus subtilis, Staphylococcus aureu,) and gram negative (Escherichia coli and Klebsiella pneumonia) strains and antifungal activity against Candida albicans. While methanol extract showed antimicrobial activity against all the tested micro organisms except two (Staphylococcus aureus and Candida albicans), the extracts of hexane, chloroform and ethyl acetate did not show any anti microbial activity. Minimum inhibitory concentration of aqueous and methanol extracts against tested bacterial and fungal strains was 100–150 μg/mL. Antioxidant activity of the bulb extracts was evaluated in terms of inhibition of free radicals by 2, 2′-diphenly-1-picrylhydrazyl. Aqueous and methanol extracts exhibited strong antioxidant activity (80%–90% of the standard).ConclusionsAntioxidant and antimicrobial activity of A. sativum against the tested organisms therefore, provides scientific basis for its utilization in traditional and folk medicine. Also, our results demonstrated the insecticidal efficacy of A. sativum against S. litura, a polyphagous insect.     

Phytochemical analysis and in vitro antimicrobial activity of Illicium griffithii Hook. f. & Thoms extracts

ObjectiveTo evaluate the antimicrobial activity of hexane, ethyl acetate and methanol extracts of seeds and fruits of Illicium griffithii (I. griffithii)(Family: Schisandraceae).MethodsThe antimicrobial activity of the organic extracts were determined using disc diffusion assay against Gram-positive bacterial strains (three reference cultures and three clinical isolates), Gram-negative bacterial strains (nine reference cultures and six clinical isolates), and six fungi. The primary phytochemical and chemical compositions were analyzed using qualitative chemical analysis and gas chromatography-mass spectrometry respectively.ResultsEthyl acetate extract of fruits was effective against most of the tested reference cultures such as Staphylococcus aureus, Yersinia enterocolitica, Vibrio parahaemolyticus, Bacillus subtilis, Salmonella paratyphi, Enterococcus feacalis, Xanthomonas oryzae and Pseudomonas aerugenosa, whereas methanol extract showed activity only against Staphylococcus aureus, Bacillus subtilis and Xanthomonas oryzae. The hexane and ethyl acetate extracts of fruits were more effective against most of the clinical isolates, whereas methanol extract was effective only against Klebsiella pneumoniae ESBL. The extracts of fruits and seeds did not show any significant antifungal activity against tested fungi. The presence of phenols, tannins, flavonoids, triterpenoids, steroids, alkaloids, saponis and carbohydrates in the different extracts was established. Gas chromatography-mass spectrometry studies on hexane and ethyl acetate extract of fruits resulted in the identification of 31 and 39 compounds respectively.ConclusionsPotent antibacterial phytochemicals are present in ethyl acetate extract of I. griffithii fruits. Further studies are needed to investigate activities of I. griffithii against multidrug resistant bacteria.     

Comparative study of total phenolics,flavonoids contents and evaluation of antioxidant and antimicrobial activities of different polarities fruits crude extracts of Datura metel L.

ObjectiveTo determine the total phenolics and flavonoids and to evaluate antioxidant and antimicrobial activities of different extracts from fruits of Datura metel (D. metel).MethodsDifferent crude extracts from the fruits of D. metel were subjected to determination of total phenolics, flavonoids, antioxidant and antimicrobial activities by established methods.ResutlsThe total phenolics results showed that ethyl acetate extract was the most efficient (60.26%) compared to hexane, chloroform, butanol and methanol extracts which had phenolic contents of 50.08, 35.50, 52.54 and 26.49%, respectively. Almost similar results were obtained from the fruits crude extracts for total flavonoids and results found that methanol crude extract was the highest (1.71%) compared to other crude extracts. The antioxidant activity results showed that methanol extract acted the highest activity compared to other extracts and in the order of methanol>ethyl acetate>hexane>chloroform>butanol extract. All extracts were displayed moderate antibacterial potential against the tested bacteria such as Staphylococcus aureus, Escherichia coli and Pseudomonus aeruginosa in the range of 0%–10%.ConclusionsThe results of this present study clearly showed that the crude extracts of D. metel demenstrated antimicrobial and antioxidant activities and it may act as potential antioxidant sources for human biological system.     

Antibacterial activity of medicinal plant Cyclea peltata (Lam) Hooks & Thoms

ObjectiveTo investigate the antibacterial activity of Padathaali (Cyclea peltata) against three gram positive and eight gram negative bacterial strains.MethodsThe fresh whole plants were collected from Kerala, India. The dry crude nonpolar and polar extract of whole plant of C. peltata i. e. Petroleum ether, hexane, chloroform, ethyl acetate, acetone, methanol and aqueous extracts of five concentrations (1, 2, 5, 10 mg/ml) were used to investigate the antibacterial activity. NCCL standards were strictly followed to perform antibacterial disc susceptibility test using disc diffusion method.ResultsAll the extracts showed varying degree of inhibitory potential against all the tested bacteria. Methanol extract of plant had higher inhibitory action against Staphylococcus aureus, Streptococcus haemolyticus, Klebsiella pneumonia and Proteus vulgaris. Acetone extract of plant showed maximum inhibitory action against Klebsiella pneumonia and Streptococcus haemolyticus.ConclusionsThe present investigation showed the effectiveness of crude extract of this plant against tested bacterial strains. This study further suggests the use of whole plant extract in treating disease caused by tested microbial organisms.     

Investigation of the volatile oils,lipid constituents and biological activity of Ballota andreuzziana,Teucrium zanonii and Verbena tenuisecta in Libya

ObjectiveTo determine the chemical composition of essential oils and lipid constituents of Ballota andreuzziana (B. andreuzziana), Teucrium zanonii (T. zanonii) and Verbena tenuisecta (V. tenuisecta) growing in Libya, and to test the antibacterial activity of different extracts of Teucrium zanonii.MethodsThe volatile oils of all plants were extracted by hydrodistillation method and analyzed by GC/MS method. The lipid constituents of plants were obtained by extraction with petroleum ether and fractionated into fatty alcohols, fatty acids and unsapoinfiable matters. Antibacterial activity of T. zanonii extracts and antioxidant activity of different extracts of T. zanonii were also studied.ResultsThe volate oil of B. andreuzziana was found to consists of 20 compounds in which caryophyllin is the main one (63.1%), the volatile oil of T. zanonii consists of 74 compounds in which germacrene-D was the main compound, while the volatile oil of V. tenuisecta consists of 13 compounds with 1-octen-3-ol as a major constituent (52.87%). The study of antimicrobial activity of different extracts of V. tenuisecta showed that, both methanol and butanol extracts exhibited the highest activity against Mycobactirium phlei (M. phlei) and Candida albicans (C. albicans) respectively, while petroleum ether, fatty alcohols and unsaponifiable fractions had no antimicrobial activity against all the tested microorganisms. Investigation of the antioxidant activity of different extracts of T. zanonii using DPPH method proved that, the ethyl acetate and butanol fractions showed the highest activity where the inhibition percentage (I%) are 93.6 and 92.1 respectively.ConclusionsThis is the first report about the volatile oils of these plants where T. zanonii have the highest content and the highest number of the identified compounds. The study of antioxidant T. zanonii extracts proved that, the ethyl acetate, butanol and aqueous extracts have the highest antioxidant activity. Methanol and butanol extracts of V. tenuisecta exhibited the highest activity against M. phlei and C. albicans respectively.     

Antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis

ObjectiveTo explore antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis (A. officinalis).MethodsIn the present study the leaf extracts of A. officinalis were examined for its antibacterial potential using five different solvents against some reference strains of human pathogenic bacteria for the crude extract. Maximum activity was observed for ethyl acetate and hence different concentrations like 15 μL, 25 μL, and 50 μL of ethyl extracts was checked for its antibacterial activity. Partial purification of crude extract was carried by column chromatography and fractions were analyzed using gas chromatography-mass spectrometry (GC-MS) to identify compounds.ResultsThe crude ethyl acetate extracts of A. officinalis showed remarkable antibacterial activity with zones of inhibition of 13 mm against Eschericia coli (E. coli) and 11 mm against Staphylococcus aureus (S. aureus). Fraction 13 (ethyl acetate÷methanol= 8÷2) as the most potent one against with the minimal inhibitory concentration of 30 mm against E. coli and 25 mm against S. aureus. The GCMS resultsof active column fraction (F13) revealed that the active principals were a mixture of hydroxy-4 methoxybenzoic acid, diethyl phthalate, oleic acid.ConclusionsThe leaf extracts with proven antibacterial effects can clearly be directed towards cancer treatment as to inhibiting cancer cell growth. The limited number of test organisms owes to a constraint of resource. So, the effect of strong bursts of leaf extracts on human pathogenic bacteria should further be tested on a wide range of test organisms.     

Antibacterial and antibiofilm activities of polysaccharides,essential oil,and fatty oil extracted from Laurus nobilis growing in Lebanon

ObjectiveTo evaluate the antibacterial activity of the extracts of Laurus nobilis against three Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212 and Staphylococcus epidermidis CIP 444) and two Gram-negative bacteria (Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 27853). Also, the antibiofilm activity has been investigated against the biofilm produced by Staphylococcus epidermidis CIP 444.MaterialsThe polysaccharides, essential oil, and fatty oils extracted from the plant were used in broth microdilution methods to study the minimal inhibitory concentration, and then the minimal bactericidal concentration was determined.ResultsThe results showed that alginate, fucoidan, fatty oils and essential oil have good antibacterial activities against the 5 bacterial strains, and a negligible biofilm eradication activity of fucoidan, laminaran, fatty oil, and essential oil was observed, but a promising biofilm eradication activity was obtained with alginate, which showed a reduced biofilm mass even at low concentration.ConclusionsThe extracts obtained have promising antibacterial capacities which need further investigation for them to be incorporated in medical or nutritional applications.     

Monitoring in vitro efficacy of Holarrhena antidysenterica against multidrug resistant enteropathogenic bacteria

ObjectiveTo assess antibacterial activities of leaf and bark extracts of Holarrhena antidysenterica (H. antidysenterica), used by an Indian aborigine for ailments of human gastrointestinal tract, against eight extended spectrum β-lactamase producing multidrug resistant enteropathogens.MethodsAntibacterial activities of eight solvent-extracts of the plant were monitored by the agar-well diffusion method on lawns of all bacteria. Further, minimum inhibitory concentrations and minimum bactericidal concentrations of the best three solvent extracts were determined by the micro-broth dilution method. Preliminary phytochemical analysis of the active leaf and bark extracts were carried out.ResultsIt was found that Enterobacter aerogenes was resistant to 14 of 16 antibiotics, likewise, Escherichia coli to 13, Klebsiella sp. to 14, Salmonella paratyphi to 7, Salmonella typhi to 15, Shigella dysenteriae and Shigella sonnei to 14, Vibrio cholerae to 4 of 16 antibiotics. It was found that plant-extracts with petroleum ether and n-hexane had the least antibacterial activity. Extracts of leaves with chloroform, methanol, and water registered moderate antibacterial activity, whereas bark-extracts with ethyl acetate, acetone, and ethanol had a comparatively higher antibacterial activity on all these strains. Maximum sizes of zone of inhibition due to leaf extracts with ethyl acetate, acetone, and ethanol, and on the other hand, bark extracts with ethyl acetate, acetone and methanol were recorded against these bacteria; minimum inhibitory concentration and minimum bactericidal concentration values of specifically these extracts were determined. Phytochemical analysis of the methanolic bark extract of H. antidysenterica confirmed the presence of alkaloids, terpenoids, reducing sugars, tannins, and flavonoids.ConclusionData analysis revealed that leaves and bark of H. antidysenterica could serve as complementary/supplementary drugs along with suitable antibiotics to control the marauding multidrug resistant enteropathogens.     

Evaluation of the lemongrass plant (Cymbopogon citratus) extracted in different solvents for antioxidant and antibacterial activity against human pathogens

ObjectiveTo test antibacterial and antioxidant activity of the lemongrass plant Cymbopogon citratus (C. citratus) leaves extracted serially by the solvents (chloroform, methanol and water).MethodsThe plant leaves extracts were used for antibacterial activity on Bacillus subtilis, Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Nocardia sp., Serratia sp., and Enterobacter aeruginosa microorganisms by the Kirby Bauer agar disc diffusion method. This study was carried out on lemongrass plant leaf extracts in different concentration of all solvents. The leaf extracts from different solvents were tested for their scavenging activity against the stable free radical DPPH in quantization using a spectrophotometric assay. Oxidative damage was induced in vitro by treating blood DNA and analyzing the effects of the leaf extracts.ResultsThe results showed that C. citratus extracts exhibited maximum zones of inhibition in chloroform, methanol and water extracts. It was Observed that the C. citratus extracts exhibited maximum zone of inhibition against Bacillus subtilis, Pseudomonas aeruginosa and Proteus vulgaris. Analyzed data in the present work suggested that antibacterial activity of C. citratus plant leaf extracts showed good results for Gram-positive and Gram-negative organisms. DPPH scavenging activity was highly elicited by the extract of C. citratus. Chloroform, methanol and water extracts of C. citratus leaves effectively decreased the extent of DNA damage.ConclusionsThe present study suggested that the lemongrass plant extracts could offer various health benefits.     

Effect of henna and roselle extracts on pathogenic bacteria

ObjectiveTo investigate the antibacterial effects of water and ethanolic extracts of henna leaves and roselle calyxes against pathogenic bacteria isolated from domestic wastewater.MethodsThe antimicrobial activity was determined in the extracts using agar disc diffusion method. The antibacterial activities of extracts (2.5%, 5.0% and 10.0% w/v) of both henna and roselle were tested against one Gram-positive Bacillius subtilis; two Gram-negative Escherichia coli, Pseudomonas aeruginosa human pathogenic bacteria.ResultsEthanolic extracts had more antimicrobial activity than water extracts. Ethanolic extract of roselle had the highest antibacterial activity against all tested organisms, followed with ethanolic extract of henna. Pseudomonas aeruginosa was the most sensitive bacteria to plant extracts.ConclusionThe results of this study suggested that roselle contains more phyto-chemicals with antimicrobial activity than henna on the bacteria strains under study, and these phyto-chemicals were more effective when extracted by ethanol rather than water.     

Antimicrobial activity and composition of the volatiles of Cinnamomum tamala Nees. and Murraya koenigii (L.) Spreng. from Uttarakhand (India)

ObjectiveTo examine the composition of Cinnamomum tamala and Murraya koenigii essential oils and their antimicrobial activities against nine microbial strains.MethodsEssential oils were obtained by hydrodistillation from the leaves of two spice trees and were analyzed by GC and GC/MS. The oils were also tested for their antimicrobial activity using broth micro dilution method.ResultsCinnamaldehyde (37.85%) and cis-linalool oxide (29.99%) were the main components characterized in the oil of C. tamala, whereas α-pinene (39.93%), sabinene (13.31%) and trans-caryophyllene (9.02%) detected as the major constituents in M. koenigii oil. C. tamala oil exhibited significant antifungal activity and satisfactory antibacterial activity, while lesser antimicrobial activity was observed in M. koenigii oil.ConclusionsThe present study suggested that C. tamala oil was more effective against bacterial and fungal strains as compared with M. koenghii oil.     

Assessment of in vitro antimicrobial potency and free radical scavenging capacity of the essential oil and ethanol extract of Calycotome villosa subsp. intermedia growing in Algeria

ObjectiveTo assess the antimicrobial and antioxidant activity of the essential oil and ethanol extract of the aerial parts of Calycotome villosa subsp. intermedia growing in the West Northern region of Algeria.MethodsChemical composition of essential oils obtained by hydrodistillation from areal parts of Calycotome villosa subsp. intermedia was investigated using gas chromatography (retention indices) and gas chromatography-mass spectrometry while the antimicrobial activities were determinate by paper disc diffusion method and minimum inhibitory concentration assays tested against four bacterial strains and one yeast and antioxidant activity was evaluated as a free radical scavenging capacity (RSC).ResultsEssential oils were dominated by non-terpenic compounds and fatty acids. However, the phenylpropanoids, monoterpenes and sesquiterpenes components were only present in small percentages. The most important antibacterial activity of essential oil was expressed on Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae and Salmonella typhimurium. Antioxidant activity was evaluated as a RSC. RSC was assessed by measuring the scavenging activity of essential oil and ethanol extract on 1,1-diphenyl-2-picrylhydrazil (DPPH). Investigated ethanol extract reduced the DPPH radical formation (IC₅₀=68 μg/mL).ConclusionResults in this experiment indicate that the essential oil and the ethanol extract display antibacterial activity against two Gram-positive bacteria and activity to a lesser extent against two Gram-negative species. They may be a new potential source of components, which are likely to have impact on human health.     

Antibacterial activity of GUAVA, Psidium guajava Linnaeus, leaf extracts on diarrhea-causing enteric bacteria isolated from Seabob shrimp, Xiphopenaeus kroyeri (Heller)

Guava leaf tea of Psidium guajava Linnaeus is commonly used as a medicine against gastroenteritis and child diarrhea by those who cannot afford or do not have access to antibiotics. This study screened the antimicrobial effect of essential oils and methanol, hexane, ethyl acetate extracts from guava leaves. The extracts were tested against diarrhea-causing bacteria: Staphylococcus aureus, Salmonella spp. and Escherichia coli. Strains that were screened included isolates from seabob shrimp, Xiphopenaeus kroyeri (Heller) and laboratory-type strains. Of the bacteria tested, Staphylococcus aureus strains were most inhibited by the extracts. The methanol extract showed greatest bacterial inhibition. No statistically significant differences were observed between the tested extract concentrations and their effect. The essential oil extract showed inhibitory activity against S. aureus and Salmonella spp. The strains isolated from the shrimp showed some resistance to commercially available antibiotics. These data support the use of guava leaf-made medicines in diarrhea cases where access to commercial antibiotics is restricted. In conclusion, guava leaf extracts and essential oil are very active against S. aureus, thus making up important potential sources of new antimicrobial compounds.     

Antimicrobial activity of mangrove plant (Lumnitzera littorea)

ObjectiveTo investigate the antimicrobial activities of n-hexane, ethyl acetate and methanol extracts of the leaves of Lumnitzera littorea (L. littorea) against six human pathogenic microbes.MethodsThe antimicrobial activity was evaluated using disc diffusion and microdilution methods.ResultsThe antimicrobial activities of the crude extracts were increased with increasing the concentration. It is clear that n-hexane extract was the most effective extract. Additionally, Gram positive Bacillus cereus (B. cereus) appear to be the most sensitive strain while Pseudomonas aeruginosa (P. aeruginosa) and the yeast strains (Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans)) appear to be resistance to the tested concentrations since no inhibition zone was observed. The inhibition of microbial growth at concentration as low as 0.04 mg/mL indicated the potent antimicrobial activity of L. littorea extracts.ConclusionsThe obtained results are considered sufficient for further study to isolate the compounds responsible for the activity and suggesting the possibility of finding potent antibacterial agents from L. littorea extracts.     

Evaluation of antibacterial activity of selected medicinal plant extracts from south India against human pathogens

ObjectiveThe present study was to evaluate the antibacterial properties of 21 crude extracts from leaf and flower of Aristolochia indica (A. indica), Cassia angustifolia (C. angustifolia), leaf of Catharanthus roseus (C. roseus), Diospyros melanoxylon (D. melanoxylon), Dolichos biflorus (D. biflorus), Gymnema sylvestre (G. sylvestre) and Justicia procumbens (J. procumbens).MethodsThe ethyl acetate, acetone and methanol extract of medicinal plants were evaluated against Gram-positive Bacillus cereus (B. cereus) and Gram-negative bacteria Aeromonas hydrophila (A. hydrophila), Enterobacter aerogenes (E. aerogenes), Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) by using well diffusion assay and minimum inhibitory concentration (MIC).ResultsThe crude plant extracts demonstrated broad spectrum activity against all bacteria. The highest inhibitory zone was observed in leaf methanol extract of A. indica against E. aerogenes (25 mm), and E. coli (20 mm), flower methanol extract of C. angustifolia against B. cereus (22 mm) and leaf acetone extract of G. sylvestre against B. cereus (22mm). The MIC values of leaf methanol extract of A. indica against K. pneumonia (22.6μg/ml), and flower extract showed against E. coli (MIC: 24.2μg/ml), leaf ethyl acetate extract of C. angustifolia against K. pneumoniae (MIC: 28.4μg/ml). Acetone ethyl acetate and methanol extracts of D. melanoxylon and D. biflorus showed the lowest MIC activity value of >30 μg/ml against all tested pathogens.ConclusionThe antibacterial activity could be confirmed in most species used in traditional medicine in South India. Nevertheless, traditional knowledge might provide some leads to elucidate potential candidates for future development of new antibiotic agents.     

In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

ObjectiveTo investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens.MethodsWater and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC).ResultsMethanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9–22.6 mm, MIC: 200–3200 μg/mL, MBC: 200–6400 μg/mL) against all the pathogenic enteric bacteria (Vibrio cholerae, Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001).ConclusionsFor the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.     

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

ObjectiveTo evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna (A. concinna), Cassia siamea (C. siamea), Coriandrum sativum (C. sativum),Cuminum cyminum (C. cyminum), Lantana camara (L. camara), Nelumbo nucifera (N. nucifera) Phyllanthus amarus (P. amarus), Piper nigrum (P. nigrum) and Trachyspermum ammi (T. ammi) against Anopheles stephensi (An. stephensi) and Culex quinquefasciatus (Cx. quinquefasciatus).MethodsThe larvicidal activity of medicinal plant extracts were tested against early 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.ResultsAll 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 of 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 after 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.ConclusionsThese 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.     

Evaluation of larvicidal activity of medicinal plant extracts against three mosquito vectors

ObjectiveTo evaluate the mosquito larvicidal activity of plant extracts.MethodsThe hexane, chloroform, ethyl acetate, acetone, and methanol leaf, flower and seed extracts of Abrus precatorius (A. precatorius), Croton bonplandianum (C. bonplandianum), Cynodon dactylon (C. dactylon), Musa paradisiaca (M. paradisiaca) and Syzygium aromaticum (S. aromaticum) were tested against fourth instar larvae of Anopheles vagus (An. vagus), Armigeres subalbatus (Ar. subalbatus) and Culex vishnui (Cx. vishnui).ResultsThe highest larval mortality was found in seed ethyl acetate extracts of A. precatorius and leaf extracts of C. bonplandianum, flower chloroform and methanol extracts of M. paradisiaca, and flower bud hexane extract of S. aromaticum against An. vagus with LC₅₀ values of 19.31, 39.96, 35.18, 79.90 and 85.90 μg/mL; leaf ethyl acetate and methanol extracts of C. dactylon, flower methanol extract of M. paradisiaca, flower bud methanol extract of S. aromaticum against Ar. subalbatus with LC₅₀ values of 21.67, 32.62, 48.90 and 78.28 μg/mL, and seed methanol of A. precatorius, flower methanol extract of M. paradisiaca, flower bud hexane extract of S. aromaticum against Cx. vishnui with LC₅₀ values of 136.84, 103.36 and 149.56 μg/mL, respectively.ConclusionsThese results suggest that the effective plant crude extracts have the potential to be used as an ideal ecofriendly approach for the control of disease vectors. This study provides the first report on the larvicidal activity of crude solvent extracts of different mosquitoes.