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1.
Aliquots of powdered dried leaves of Tephrosia vogelii (Leguminosae – Papilionoideae) were extracted with hexane, acetone and ethanol. The extracts were tested for their potential to protect stored legume seeds from damage by the bruchids Acanthoscelides obtectus, Callosobruchus maculatus and Callosobruchus chinensis (Coleoptera – Bruchidae). While the acetone and ethanol extracts were ineffective except for a significant but low effect on A. obtectus, the hexane extract had a relatively high efficacy, providing similar control of all three bruchid species. This effect was manifested in slowly‐reduced adult survival within 7 days and in reduced numbers of eggs laid and of F1 progeny produced, resulting in seed damage averaging 7.1% compared to 99.8% in the untreated controls after one generation. These findings are discussed in the context of previously identified constituents of T. vogelii, the rotenoids rotenone, tephrosin and deguelin.  相似文献   

2.
Six different solvents namely: methanol, ethanol, water, acetone, pet-ether or n-hexane was used to extract the essential oils from cashew kernel. The extracted oils were evaluated on Sitophilus zeamais (Motschulsky 1855) for mortality, oviposition and adult emergence effects. The long-term storage and water absorption capacity of the treated maize grains was also investigated. Results showed that the steam distillate was most lethal on S. zeamais. The least potent extracts on S. zeamais were those extracted with methanol and ethanol. The extracts drastically reduced oviposition in S. zeamais. Maize grains treated with steam distillate extract had the lowest water absorption capacity, while the highest water absorption capacity was obtained in grains treated with ethanol and methanol. Extracts of steam distillate, n-hexane, petroleum ether and acetone completely prevented infestation and subsequence damage of the treated maize grains for a period of three months. In the grains treated with the methanol and ethanol extracts, damage of 28.61% and 6.24%, respectively were obtained. The results obtained reveal that extracts of cashew kernel are effective in controlling S. zeamais and could serve as an alternative to synthetic insecticides.  相似文献   

3.
Hippocratea excelsa andHippocratea celastroides have therapeutic and insecticide applications in Mexican traditional medicine. The toxicity ofH. excelsa root cortex has been previously demonstrated against the stored grain pest Sitophilus zeamais. To identify the active compounds, several extracts (petroleum ether, CH2Cl2, acetone, methanol, and water) and compounds were obtained from the roots, and tested (1% w/w) with a force-feeding assay againstS. zeamais. AllH. excelsa extracts showed high antifeedant activity, and elicited moderate mortality. The triterpenoid pristimerin and a mixture of sesquiterpene evoninoate alkaloids, isolated from the hexane and methanol extracts, respectively, strongly reduced the insect feeding capacity. Other triterpenoids (friedelin, β-sitosterol, canophyllol) isolated from the hexane extract, and the alditol galactitol obtained from the water extract, were innocuous or its activity was not statistically significant. The organic extracts fromH. celastroides only showed moderate antifeedant activity, while the water extract was innocuous. Galactitol was also obtained from this extract.  相似文献   

4.
Most management practices of Sitophilus zeamais Motschulsky, a field-to-post-harvest insect pest of cereals, have focused on post harvest control methods. This experiment was designed to investigate the potential of cropping system and modification of time of harvest to control S. zeamais. Intercropping and harvest time modification had significant (P < 0.05) effect on the number of S. zeamais emerging 42 days post-harvest. For the early harvest (15 weeks after planting (WAP)), the mean number of S. zeamais recorded from a maize monoculture (7.39) was significantly (P < 0.05) higher than the mean numbers of weevils emerging from a maize–soybean intercrop (2.31), but not significantly higher than the number recorded in maize–groundnut (3.87) intercrop. For the late harvest (18 WAP), the mean number of emerged adult observed in the maize–soybean intercrop (6.13) was significantly lower than the mean number of adult emerging from the monocrop maize (13.24). Maize–groundnut intercrop did not significantly reduce field infestation of S. zeamais compared with monocrop maize. Percentage weight loss observed in early harvested maize was significantly (P < 0.0001) lower than what was observed in late-harvested maize. Percentage weight loss was highest in stored maize harvested from monocrop maize plots for the early harvest, whereas intercropping maize with soybean reduced percentage weight loss when harvest was delayed.  相似文献   

5.
Pressurized liquid extraction (PLE), an environmentally friendly technique, was used to obtain antiviral compounds from the edible seaweed Himanthalia elongata. The antiviral properties of PLE extracts (hexane, ethanol, and water) were evaluated against herpes simplex virus type 1 (HSV-1) at different stages during viral infection. Pre-treatment of Vero cells with 75 μg mL−1 of ethanol extract inhibited virus infection by approximately 90%, whereas the same concentration of water and hexane extracts reduced the virus infectivity to 78% and 70%, respectively. Moreover, ethanol extract was also more effective against HSV-1 intracellular replication than water and hexane extracts. The antiviral activity of water PLE extract was found to correlate with polysaccharides, since the polysaccharide-rich fraction isolated from this extract showed higher antiviral activity than the original water extract. A GC–MS characterization of the hexane and ethanol extracts showed that the antiviral activity of the hexane extract seemed to be related with the presence of fucosterol; meanwhile, in the case of the ethanol extract, other compounds, besides fucosterol, could be involved in this activity. Results demonstrated that PLE was an appropriate technique to obtain antiviral agents from H. elongata. These antiviral compounds were in addition to polysaccharides, which are the antiviral agents usually proposed when studying seaweeds.  相似文献   

6.
The present study was aimed to evaluate six indigenous plant extracts for their ability to protect maize from infestation by maize weevil Sitophilus zeamais (M). The plant extracts were tested for its toxicity by fumigation and grain surface coating methods. Further, the effects of botanical treatments on F1 progeny, seed emergence and antifungal activities were studied. The results indicated that the extracts of Eicchornia crassipes controlled the test insect in grain surface coating method (100%, P = 0.05). Further, the same plant extract had significantly reduced the development of F1 progeny (97 ± 0.7%). In germination experiments, T + UEx samples showed normal seed germination of maize. However, in T + Ex samples, the seed germination depended on the grain protectant efficacy of the tested botanical extracts. Always higher percantage seed germination was recorded in those treatments where there was less infestation. Extracts of Carica papaya had significantly reduced the incidence of seed-borne fungus Aspergillus flavus (4 ± 2.4%) and did not affect the seed germination when compared to other treatments and untreated control.  相似文献   

7.
The bark of the Fagara heitzii tree in the west‐central African Republic of Congo (Congo–Brazzaville) is known anecdotally to provide protection for human residents against fleas and to be of use as a narcotic in fishing (similar to rotenone). We found that powder and hexane extracts from the bark of the Fagara heitzii tree contain insecticidal compounds. Dried powder (14.5 mg) on the bottom of a Petri dish is the residue at 14.494 mg per dish (LD50) for 20 adult maize weevils Sitophilus zeamays after four days. The LD50 of the same material to 20 adult cowpea weevils Callosobruchus maculatus was slightly higher at 16.144 mg/dish (after 48 h). These weevils cause significant economic damage to cowpea and maize in Congo–Brazzaville. Hexane extracts of the bark of Fagara heitzii were also toxic to these weevils. Symptoms of toxicity suggested the extracts were slow‐acting nerve poisons or respiratory inhibitors or both. The time needed to develop full toxicity suggested a respiratory poison. The hexane extract was also toxic to the American cockroach Periplaneta americana. The symptoms in the cockroach were similar, but cockroaches also exhibited apparent escape attempts suggesting they could detect the compounds. Signs of apparent irritation or exaggerated locomotion in all three insects also suggested irritation or nerve effects.  相似文献   

8.
Females of the almond seed wasp,Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae), responded in an olfactometer positively to odours from almond flowers and unripe fruits, but not to almond leaf odours and odours from flowers and unripe fruits of certain other nonhostPrunus species. Males responded to none of these odours. Extracts of undamaged unripe almond fruits (using ethanol, methanol, acetone, hexane, dichloromethane, or petroleum ether) stimulated female aggregation on glass surfaces treated with these extracts; in addition, certain fruit extracts (ethanol, methanol, or acetone) stimulated oviposition. Extracts of undamaged almond leaves (ethanol, methanol, or acetone) and flowers (ethanol or methanol) also stimulated female aggregation and oviposition. Aggregation and oviposition in response to an ethanol extract of almond fruits was intense in females aged 5 to 14 days and from 12∶00 to 18∶00h (photophase between 06∶00 and 20∶00). Certain almond fruit (ethanol, methanol, acetone or hexane) and flower extracts (ethanol or methanol) also provoked female response in the olfactometer. The results strongly suggest that certain chemical stimuli emanating from parts of the almond tree play a major role in host selection and oviposition. Some of the extracts tested may be a good source for the isolation, identification and synthesis of compounds stimulating attraction, aggregation and oviposition in nature. *** DIRECT SUPPORT *** A3414024 00003  相似文献   

9.
The dynamics of infestation and losses of stored maize due to the larger grain borer (Prostephanus truncatus Horn) and maize weevils (Sitophilus zeamais Motschulsky) were investigated in Tanzania. In single species populations, significantly higher maize damage (P ≤ 0.05) was caused by P. truncatus (23.3%) compared to S. zeamais (6.4%). Weight losses caused by P. truncatus were higher (12.7%) than for S. zeamais (6.7%) under similar conditions. A higher proportion of P. truncatus in the initial infestation population led to significantly higher (≤0.05) maize damage compared to equal or higher proportions of S. zeamais. Irrespective of the initial number of S. zeamais, population size increased to levels higher than for P. truncatus. Maize losses in unimproved storage structures were >80% compared to <2.5% in improved structures under natural infestation. Inter-specific competition appeared to influence the dynamics of infestation, damage levels and weight losses. The first two months of storage were critical for damaging insect populations to build up.  相似文献   

10.
In the study, water, ethanol, methanol, dichloromethane, and acetone extracts of Asparagus officinalis L. were obtained by maceration. DPPH⋅, ABTS⋅+, FRAP, and CUPRAC methods determined the antioxidant capacities of all extracts. Moreover, the in vitro effects of extracts on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase (CA)-I, CA-II and α-Glycosidase were investigated. At a 10 μg/ml concentration, the extract with the highest Fe3+ reduction capacity was ethanol (AE), and the extract with the highest Cu2+ reduction capacity was acetone (AA). AE for AChE (IC50=21.19 μg/ml) and α-Glycosidase (IC50: 70.00 μg/ml), methanol (AM) for BChE (IC50=17.33 μg/ml), CA−I and II (IC50=79.65 and 36.09 μg/ml, respectively) showed the most potent inhibition effect. The content analysis of acetone extract was performed with LC/MS-MS, the first three phytochemicals found most were p-Coumaric acid, rutin, and 4-hydroxybenzoic acid (284.29±3.97, 135.39±8.19, and 102.06±5.51 μg analyte/g extract, respectively).  相似文献   

11.
Cheese wood, Alstonia boonei De Wild stem bark was extracted with five different solvents namely: methanol, ethanol, acetone, petroleum ether and n-hexane. The extracts were tested for insecticidal activity on cowpea bruchid, Callosobruchus maculatus (Fab.). Adult mortality and adult emergence of the insects were investigated. Oviposition deterrences using dual-choice and multiple-choice tests were also investigated as well as percentage damage and weight loss at temperature of 28?±?2?°C and 75?±?5% relative humidity. Results showed that at the rate of 2% extract per 20?g of cowpea seeds, methanol, petroleum ether and n-hexane extracts caused 100% mortality of adult cowpea bruchid after four?days of post treatment. When the bruchid had choice of oviposition substrate, they laid significantly (p?<?0.05) fewer eggs on cowpea seeds treated with extracts compared to untreated seeds. There was no adult emergence in seeds treated with methanol, ethanol, petroleum ether and n-hexane extracts and 100% reduction in F1 progeny was recorded compared with untreated that had 81.86% adults emergence and 0% reduction in F1 progeny. The results obtained from this study revealed that methanol, ethanol, acetone, petroleum ether and n-hexane extracts of A. boonei stem bark were effective in controlling C. maculatus and could serve as an alternative to synthetic insecticides for the protection of stored cowpeas against bruchids.  相似文献   

12.
The triphenyl tetrazolium chloride (TTC) reduction assay was evaluated and improved with maize seed (Zea mays cv. Zhengdan958). The reduced TTC in embryo was extracted with three kinds of organic solvents: trichloroacetic acid (TCA)/acetone, ethanol, and acetone. The absorbance spectra of the three extracts were similar, with a maximum at 485 nm. The efficiency of TCA/acetone in extracting the reduced TTC was higher than that of acetone and ethanol. A negative correlation between TTC reduction and malondialdehyde content in embryo was demonstrated. The TCA/acetone extraction may be used as a routine protocol for TTC reduction assay of seed vigor in cereal (e.g. maize, rice, wheat and barley) seeds.  相似文献   

13.
This paper describes a series of experiments conducted to determine why Sitophilus zeamaisMots . and Sitotroga cerealella (Oliv. ) could not survive together in maize cultures in the laboratory. The effect of S. zeamais on different developmental stages of S. cerealella was investigated. The presence of adult S. zeamais slightly affected moth copulation, egg laying and moth eggs in a mixed culture, but large numbers of developing moths inside maize grains were killed by the adult weevil through feeding on the grains. The major cause of elimination of S. cerealella by S. zeamais from mixed cultures was therefore found to be damage to the immature moths in grain and such moth mortality increased as the developing moths became bigger in the grains. A weevil: grain ratio of approximately 1.4∶1 was found to be the critical weevil density at which the moth disappeared from the mixed cultures.  相似文献   

14.
Two lichen metabolites, rhizonaldehyde ( 1 ) and rhizonyl alcohol ( 2 ), were isolated from the acetone extract of Lobaria pulmonaria by chromatographic methods, and their chemical structures were determined by UV/VIS, IR, and 1D‐ and 2D‐NMR spectroscopic methods. The gastroprotective and in vivo antioxidant activities of extracts of L. pulmonaria and its metabolites, 1 and 2 , were investigated in indomethacin‐induced ulcer models in rats. The gastric lesions were significantly reduced by acetone, hexane, and CHCl3 extracts, with 75.3–41.5% inhibition. Rhizonyl alcohol ( 2 ) significantly reduced the gastric lesions with an inhibition rate of 84.6–42.8%, whereas rhizonaldehyde ( 1 ) significantly increased the gastric lesions. Antioxidant parameters and myeloperoxidase activities were also evaluated in the gastric tissues of the rats. Indomethacin caused oxidative stress, which resulted in lipid peroxidation in gastric tissues by decreasing the levels of the antioxidants as compared to healthy rat tissues. In contrast to indomethacin, all extracts and rhizonyl alcohol ( 2 ) caused a significant decrease in lipid peroxidation levels and an increase in antioxidant parameters, superoxide dismutase, glutathione peroxidase, and glutathione‐S‐transferase, and reduced glutathione in gastric tissues. The administration of rhizonyl alcohol ( 2 ) also resulted in a decrease in gastric myeloperoxidase activity increased by indomethacin. The gastroprotective effect of rhizonyl alcohol ( 2 ) can be attributed to its antioxidant properties and its suppressing effect on neutrophil infiltration into gastric tissues.  相似文献   

15.
The toxicity of organic plant extracts to Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) was assessed for three tropical plant species: branches, leaves, and seeds of Annona montana (Annonaceae), branches of Aristolochia paulistana (Aristolochiaceae), and leaves and branches of Casearia sylvestris (Salicaceae). The screening assay resulted that the extracts of A. montana seeds obtained with hexane (LC50?=?534.75 mg kg?1 and LT50?=?6.10 days) and with dichloromethane (LC50?=?424.67 mg kg?1 and LT50?=?5.03 days) were the most promising treatments, followed by the extract prepared from A. montana leaves with hexane (LC50?=?837.70 mg kg?1 and LT50?=?4.90 days). Moreover, extracts (at 1,500 mg kg?1) prepared from C. sylvestris branches with dichloromethane and A. paulistana with hexane caused significant mortality (37% and 41.5%, respectively) beyond sublethal effects on S. zeamais. Therefore, based on the biological assays, extraction yield, and evaluation of the chromatographic profile of the crude extracts by TLC, the hexane extract of A. montana seeds was selected and fractioned using liquid-liquid partitioning. The hydroalcoholic fraction caused mortality of 55.5%, significantly superior to dichloromethane fraction, which caused 35.5% of mortality. Chemical analyses (1H NMR, HPLC, and TLC) were performed, and the results showed the presence of alkaloids and acetogenins in both active fractions, which have been associated with bioactivity. Therefore, extracts prepared from A. montana seeds (especially) is an interesting source of new compounds with promising grain-protectant properties.  相似文献   

16.
Wood is mainly made up of cellulose, hemicelluloses, lignin polymers and other organic and inorganic substances, making it susceptible to deteriorate by various biological agents. Tectona grandis L.f. (Teak) is a timber species with high resistance to biological deterioration, valued for its durability, beauty, and mechanical resistance. The purpose of this work was to evaluate the antifungal activity of crude extracts from teak on various fungi that cause wood deterioration. For this, Teak heartwood was obtained, then fragmented and pulverized until obtaining a flour which was used for compounds extraction using the Soxhlet technique coupled to a rotary evaporator through solvents of increasing polarity (hexane, dichloromethane, tetrahydrofuran, and acetone). The extracts obtained were tested against fungal organisms collected in the field, and the LC50 was determined using teak crude extracts on Artemia salina as a biological model. The results obtained showed that a high flour yield was obtained with hexane (0.951 g), followed by tetrahydrofuran (0.446 g), dichloromethane (0.348 g), and acetone (0.152 g). By using nine fungal organisms that predominantly correspond to the genus Aspergillus, the extractable compounds were tested, inhibiting 25% of mycelial growth with tetrahydrofuran (T. versicolor), and 40.9% with dichloromethane (G. trabeum). Likewise, the biological model of A. salina showed an LC50 of 84.9 μg/mL with hexane, 43.3 μg/mL with dichloromethane, 59.6 μg/mL with tetrahydrofuran, and 54.7 μg/mL with acetone. For this reason, it is concluded that Teak wood contains many extractable compounds in relation to its weight, besides having antimicrobial activity when extracted through polar compounds such as dichloromethane and tetrahydrofuran.  相似文献   

17.
Artemisia annua L. (Asteraceae Family) is an important plant in Asia that has been used for treating different diseases, including fever due to malaria, wounds, tubercolisis, scabues, pain, convulsions, diabetes, and inflammation. In this study we aimed to evaluate the effects of different polarity extracts (hexane, dichloromethane, ethyl acetate, ethanol, ethanol/water (70 %) and water) from A. annua against the burden of inflammation and oxidative stress occurring in colon tissue exposed to LPS. In parallel, chemical composition, antiradical, and enzyme inhibition effects against α-amylase, α-glucosidase, tyrosinase, and cholinesterases were evaluated. The water extract contained the highest content of the total phenolic with 34.59 mg gallic acid equivalent (GAE)/g extract, while the hexane had the highest content of the total flavonoid (20.06 mg rutin equivalent (RE)/g extract). In antioxidant assays, the polar extracts (ethanol, ethanol/water and water) exhibited stronger radical scavenging and reducing power abilities when compared to non-polar extracts. The hexane extract showed the best AChE, tyrosinase and glucosidase inhibitory effects. All extracts revealed effective anti-inflammatory agents, as demonstrated by the blunting effects on COX-2 and TNFα gene expression. These effects seemed to be not related to the only phenolic content. However, it is worthy of interest to highlight how the higher potency against LPS-induced gene expression was shown by the water extract ; thus suggesting a potential phytotherapy application in the management of clinical symptoms related to inflammatory colon diseases, although future in vivo studies are needed to confirm such in vitro and ex vivo observations.  相似文献   

18.
Raphanus sativus, a common cruciferous vegetable has been attributed to possess a number of pharmacological and therapeutic properties. This present study evaluated the protective effect of different parts of R. sativus such as root, stem and leaf obtained with a variety of extraction solvents against cell death and oxidative DNA damage induced by hydrogen peroxide (H2O2) in normal human lymphocytes. R. sativus extracts as such showed no cytotoxicity and genotoxicity to the lymphocytes at the tested concentrations. Of the different extracts, hexane extract of root and methanolic extract of stem and leaf showed significant protective effect against oxidative damage induced by 200 μM H2O2 in a dose dependent manner, as compared to cells exposed only to H2O2. Our results suggest that the protective effect afforded by R. sativus extract could be related to the presence of isothiocyanates and polyphenolics, as they possess significant capacity to remove reactive species by virtue of their ability to scavenge free radicals and induce antioxidant enzyme system in the cells.  相似文献   

19.
Different organic solvent crude extracts from the leaves of Alangium salviifolium (L.F.) Wangerin, were tested for their feeding deterrence, larvicidal activity and protein concentrations on the fourth instar larvae of Spodoptera litura L. under laboratory conditions. Treatments were given through two different host plant leaves such as brinjal and castor. The bioassay was carried out at different concentrations viz., 0.625, 1.25, 2.5 and 5%. The maximum antifeedant activity in brinjal (52.0%) and castor (29.97%) leaf discs was recorded in ethyl acetate extract as compared with hexane and chloroform extracts at 5% concentration. The result of larvicidal activity revealed that the maximum larval mortality was registered in brinjal leaves (65.81%) and castor with (57.48%) in ethyl acetate extract as compared to hexane and chloroform extracts at 5% concentration. The ethyl acetate extract of A. salviifolium contained alkaloids, diterpenoids, and saponins. The treatment also reduced haemolymph protein concentration after 48 h.  相似文献   

20.
Sclerotium rolfsii Sacc. is an important fungal pathogen affecting the production of tomato (Lycopersicon esculentum Mill.). Conventional control methods using chemicals are expensive, which constitute environmental hazards. This has necessitated the search for alternatives in botanicals. Ethanol and supernatant solution of fermented maize slurry extracts from Ocimum gratissimum, Cymbopogon citratus, Xylopia aethiopica, Aframomum melegueta and Allium sativum were evaluated. In vitro test was carried out at 1, 2, 3, 4 and 5% concentrations against the pathogen. Mycelial growth was significantly reduced in the following descending order: O. gratissimum?>?A. melegueta?>?A. sativum?>?X. aethiopica?>?C. citratus. Supernatant solution extracts of O. gratissimum and A. melegueta at 5% concentration gave highest mycelial reduction (0.00?mm), respectively, while O. gratissimum ethanol extract recorded highest mycelial reduction (0.23?mm) among the ethanol extracts. Supernatant solution of fermented maize slurry extracts of O. gratissimum and A. melegueta at 5% concentration was more effective in reducing mycelial growth of S. rolfsii.  相似文献   

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