Showing papers on "Azadirachta published in 1992"

Constituents of Azadirachta indica: isolation and structure elucidation of a new antibacterial tetranortriterpenoid, mahmoodin, and a new protolimonoid, naheedin.

Abstract: Mahmoodin [1], a new limonoid, has been isolated from Azadirachta indica (neem) oil, along with seven known tetranortriterpenoids, azadirone, epoxyazadiradione, nimbin, gedunin, azadiradione, deacetylnimbin, and 17-hydroxyazadiradione. A new protolimonoid, naheedin [3], has been obtained from the neem fruits along with azadirachtol. Their structures have been elucidated through chemical and spectral analyses including 2D nmr studies. The absolute configuration of 1 was established by comparison of its cd spectrum with those of the known tetranortriterpenoids. Mahmoodin showed significant antibacterial activity against various Gram-positive and Gram-negative organisms. Four hydrocarbons, icosane, docosane, 2-methyltricosane, and docosene, have also been identified by gc-ms of the EtOH extract of the fruit coats. Only docosane has earlier been reported from neem, while the remaining three are unreported from this plant.

The potential for controlling post‐flowering pests of cowpea, Vigna unguiculata Walp. using neem, Azadirachta indica A. Juss

Abstract: The insecticidal activity of neem, Azadirachta indica A. Juss., was tested on two major cowpea pests using different concentrations of aqueous extracts, and powders of both neem seed and kernel. The pests were larvae of Maruca testulalis Geyer (Lepidoptera: Pyralidae), the legume pod borer and Clavigralla tomentosicollis Stal (Hemiptera: Coreidae), the cowpea coreid bug. Ife Brown, an improved local cowpea variety, and IT84S‐2246, a breeding line from IITA grain legume programme, were used in the study. Neem proved effective in acting as an insecticide and affected the rates of development of both pests at concentration as low as ca. 9% solution (wt/vol.). Imaginal survival was found to decrease with increasing neem concentration, but a point was reached where further increase in the amount of neem produced no significant changes in survival rates. Most bug nymphs died within 9 days of infestation but those which survived to adult in the 5% solution (wt/vol.) of the seed extract took almost twice...

Monograph on neem (Azadirachta indica A. Juss.).

Abstract: Found on the Indian subcontinent, neem ( Azadirachta indica A. juss) is an evergreen valued for its medicinal and pesticidal uses. Neem is an effective preservative, as the seed extract repels insects by taste or smell and modifies their growth by inducing hormonal changes in the larval stage of various insects.

The use and efficacy of Azadirachta indica ADR ('Neem') and Curcuma longa ('Turmeric') in scabies. A pilot study.

Abstract: In the Ayurvedha and Sidha system of medicine (Indian system of medicine) Azadirachta indica ADR ('Neem') and Curcuma longa ('Turmeric') has been used for healing chronic ulcers and scabies. The 'Neem' and 'Turmeric' was used as a paste for the treatment of scabies in 814 people. In 97% of cases cure was obtained within 3 to 15 days of treatment. We find that this is a very cheap, easily available, effective and acceptable mode of treatment for the villagers in the developing countries. We have noticed no toxic or adverse reaction so far. However, further research is needed.

Evaluation of neem, Azadirachta indica, with and without water management, for the control of culicine mosquito larvae in rice‐fields

Abstract: Applications of neem, Azadirachta indica (Meliaceae), to rice-fields were evaluated with the dual objective of controlling the culicine mosquito vectors of Japanese encephalitis virus (JEV) and enhancing the grain yield. Since crude neem products deteriorate under improper storage conditions, a laboratory bioassay was developed to screen neem cake powder against mosquito larvae, Culex quinquefasciatus. Only samples of neem giving over 90% bioassay mortality were used in field trials. When good quality neem cake powder was applied at the dose of 500 kg/ha, either alone or coated over urea, there was a striking reduction in the abundance of late instar culicine larvae and pupae. Only fourteen pupae were obtained over a period of 13 weeks in neem cake powder treated plots, and four in those treated with neem coated urea, compared with 101 in control plots. Both treatments were significantly less than the control, but on par with one another. In another field trial, neem cake coated urea was tested at 500 and 250 kg neem/ha in combination with water management practices. No reduction in efficacy was noted at the lower dose. Larval abundance in plots under water management alone did not differ significantly from the controls, but was significantly reduced when water management was combined with neem products. Two stable formulations, 'Neemrich-I' (lipid rich) and 'Neemrich-II' (azadirachtin rich), also gave good suppression of immature culicines. All the treatments with neem also gave higher grain yield than the control.(ABSTRACT TRUNCATED AT 250 WORDS)

Behavioural effects of a neem insecticide on Coptotermes formosanus (Isoptera: Rhinotermitidae).

Abstract: The neem tree, Azadirachta indica is the source of azadirachtin and other compounds with potent insecticidal, feeding deterrent, and insect growth regulator activity. This study investigated the effects of a commercial insecticide formulation (Margosan‐O) containing 0.3% azadirachtin and 14% neem oil on orientation, tunnelling, and feeding behaviour of the Formosan subterranean termite, Coptotermes formosanus. In short‐term orientation assays, termite workers did not avoid papers treated with a 1000 ppm solution of azadirachtin. Termite workers also readily penetrated sand containing 20, 100, or 500 ppm azadirachtin, although significant mortality occurred in the 100 ppm treatment. However, subsequent observations indicated that termites avoided long‐term contact with the treated sand. In two multiple‐choice feeding assays, C. formosanus workers fed significantly less on papers containing azadirachtin concentrations >100 ppm. Azadirachtin, and possibly other neem oil components, thus show some to...

Azadirachtins H and I: Two New Tetranortriterpenoids from Azadirachta indica

Abstract: Two new tetranortriterpenoids, azadirachtin H {3} and azadirachtin I {4} have been isolated from neem kernels. Their structures were determined by spectral analyses and comparison to known compounds

Toxicity of plant extracts to three storage beetles (Coleoptera)

Abstract: Eleven indigenous Ghanaian plant species were tested for their toxicity to 3 storage pest species: Acanthoscelides obtectus, Prostephanus truncatus and Sitophilus oryzae under laboratory conditions. P. truncatus was reared on loose maize grains, S. oryzae on wheat grains and A. obtectus on cowpeas. All rearings were done in an incubator at 25–26°C and 65–75% R.H. The plant extracts evaluated were obtained from the neem Azadirachta indica leaf and seed, Chromolaena odorata leaf, Cissampelos owariensis leaf and root, Datura metel seed, Datura stramonium seed, Erythrophleum suaveolens leaf, Grewia carpinifolia leaf, Ricinus communis seed, Sida acuta leaf, Solanum nigrum leaf, and Strophanthus hispidus leaf. Crude ethanol extracts at concentrations of 10% (wt/vol) were used as topical applications. The effect of the plant extracts was compared with that of the neem. R. communis and S. nigrum were the crude materials most toxic to the three pest species. Extracts of C. owariensis and E. suaveolens were also very effective, and more promising than the neem extracts. Least effective were S. acuta, C. odorata, G. carpinifolia and S. hispidus. A. obtectus was usually most and P. truncatus least sensitive to the plant extracts. Zusammenfassung Zur toxischen Wirkung von Pflanzenextrakten auf drei vorratsschadliche Kafer (Coleoptera) Elf einheimische ghanaische Pflanzenarten wurden unter Laborbedingungen auf ihre Wirkung auf die 3 vorratsschadlichen Kaferarten Acanthoscelides obtectus, Prostephanus truncatus sowie Sitophilus oryzae untersucht. P. truncatus wurde an Maiskornern, S. oryzae an Weizenkornern und A. obtectus an Kuhbohnen aufgezogen. Verwendet wurde ein Inkubator mit 25-26°C und 65-75% rel. Luftfeuchte. Die Extrakte wurden aus folgenden Pflanzenarten gewonnen: Azadirachta indica-Blatter und -Samen, Chromolaena odorata-Blatter, Cissampelos owariensis-Blatter und -Wurzeln, Datura metel-Samen, Datura stramonium-Samen, Erythrophloeum suaveolens-Blatter, Grewia carpinifolia-Blatter, Ricinus communis-Samen, Sida acuta-Blatter, Solanum nigrum-Blatter und Strophantus hispidus-Blatter. Ihre Athanolextrakte wurden in 10%iger Konzentration topikal angewendet. Die Wirkung wurde mit jener von Neemextrakt verglichen. R. communis und S. nigrum erwiesen sich gegenuber den 3 Schadlingen als am wirkungsvollsten. Extrakte aus C. owariensis und E. suaveolens waren ebenfalls sehr wirkungsvoll und mehrversprechender als Neemextrakte. Die geringsten Wirkungen zeigten S. acuta, C. odorata, G. carpinifolia und S. hispidus. A. obtectus war am empfindlichsten und P. truncatus am wenigsten empfindlich gegenuber den Pflanzenextrakten.

Effects of neem, Azadirachta indica on six species of maize insect pests

Abstract: Laboratory studies were conducted to evaluate the efficacy of neem, Azadirachta indica against corn earworm (CEW), Heliocoverpa zea fall armyworm (FAW), Spodoptera frugiperda sugarcane borer (SCB), Diatraea saccharalis southwestern corn borer (SWCB), Diatraea grandiosella maize weevil (MW), Sitophilus zeamais and larger grain borer (LGB), Prostephanus truncatus. Neem seed powder at the rate of 5 g and 10 g, and neem seed oil at the rate of 1 ml per kg of meridic diets, were incorporated into the diet of CEW, FAW, SCB and SWCB. Maize grain was treated with 5 and 10 ml neem seed oil per kg of grain and infested with adult MW and LGB. The presence of neem seed powder and neem seed oil in the diets significantly reduced the survival and growth of CEW, FAW, SCB and SWCB. Neem oil also had significant effects on the survival of MW. In the case of LGB the effects of neem oil, however, were not profound. Results indicate that neem has good potential to be used as a control agent for the CEW, FAW, SCB, SW...

Several antifeedants from neem oil, azadirachta indica a. juss., against reticulitermes speratus kolbe (isoptera: rhinotermitidae)

Abstract: A methanol extract of neem oil indicated antifeedant activity at 200 μg/disc by a no-choice bioassay against Reticulitermes speratus Kolbe. The extract was purified by recycling HPLC to isolate 11 compounds of variable termite antifeedant potency. Deacetylgedunin was the most active compound (95% protective concentration or PC95 = 113.7 μg/disc). This was followed by salannin, gedunin, 17-hydroxyazadiradione, nimbandiol, azadiradione, deacetylsalannin, and deacetylnimbin, with PC95 estimates of 203.3, 218.4, 235.6, 245.4, 827.5, 1373.1, and 1581.2 μg/disc, respectively. Epoxyazadiradione, 17-epiazadiradione, and nimbin were not active (PC95 estimates were beyond the bioassay limits). It could be presumed, by comparing their structures and activities, that the furan ring, αβ-unsaturated ketone and hydroxyl group each played an important role in determining the antifeedant activity.

Growth of Tilapia zilli exposed to sublethal concentrations of crude extracts of Azadirachta indica

Abstract: A b s t r act - The effects on growth of Tilapia zilli exposed for 12 weeks to sublethal crude extracts of Azadirachta indica was investigated in static bioassays and a constant aeration system. Weight increased with the decline of nominal concentrations of the extracts. Long-term exposure of T. zilli to sublethal concentration of the extract caused growth retardation. The exposed fish showed abnormal behavioural responses at 1.56 and 0.78 mg dm", these responses being minimal at lower concentrations. The use by local fishermen of extracts of A. indica to kill fish is therefore ill-advised.

Fitness reduction and mortality effects of neem-based pesticides on the Colorado potato beetle Leptinotarsa decemlineata Say (Col., Chrysomelidae)

Abstract: Colorado potato beetle (CPB) adults and larvae were treated in the laboratory with extracts and oil from seed kernels of the neem tree (Azadirachta indica A. Juss.). Beetles exhibited a decreased feeding rate and reduction of fecundity and vitality. Morphogenetic defects were observed in the F1 progeny of treated females. The number of egg masses produced by females which fed on neem-treated potato leaves were smaller. Partly the eggs showed chorion defects and dried up or were affected by fungi. Trials in small scale field plots confirmed the reduction of fecundity in treated beetles. The number of adults in the F1 progeny was reduced to 1 percent of the control group. Larvae showed a highly increased mortality when treated directly with neem oil in the laboratory or fed on oil treated foliage. This result was confirmed in small plot field trials especially when AZT-extract and AZT-extract + neem oil were used. These neem products were highly efficient against all instars of CPB. Zusammenfassung Zum Einflus von Niemprodukten auf Fitnes und Mortalitat des Kartoffelkafers, Leptinotarsa decemlineata Say (Col., Chrysomelidae) Imagines und Larven des Kartoffelkafers Leptinotarsa decemlineata wurden in Labor- und Freilandversuchen mit Extrakten und Ol aus Samen des Niembaumes (Azadirachta indica A. Juss.) behandelt. In Laborversuchen wurden bei den Adulten eine verminderte Futteraufnahme, Verlust der Flugfahigkeit und speziell bei den Weibchen eine reduzierte Fekunditat festgestellt. Die behandelten Versuchstiere legten weniger und kleinere Eigelege ab. Teilweise war das Chorion der Eier geschadigt, die dann vertrockneten oder Pilzbefall aufwiesen. In der F1-Generation behandelter Weibchen wurden morphogenetische Schaden beobachtet. Parzellenversuche bestatigten eine stark verminderte Fekunditat. Die Anzahl adulter Nachkommen in der F1-Generation wurde auf 1% der Kontrollgruppe reduziert. Larven, die im Labor mit Niemol behandelt wurden, zeigten eine stark erhohte Mortalitat. Diese Wirkung konnte in Parzellenversuchen vor allem bei der Verwendung von AZT-Extrakt und AZT-Extrakt + Niemol bestatigt werden, die gegen alle Larvenstadien hochwirksam waren.

Effects of azadirachtin on Rhodnius prolixus: immunity and trypanosoma interaction

Abstract: The effects of azadirachtin, a tetranortriterpenoid from the neem tree Azadirachta indica J., on both immunity and Trypanosoma cruzi interaction within Rhodnius prolixus and other triatomines, were presented. Given through a blood meal, azadirachtin affected the immune reactivity as shown by a significant reduction in numbers of hemocytes and consequently nodule formation following challenge with Enterobacter cloacae beta 12, reduction in ability to produce antibacterial activities in the hemolymph when injected with bacteria, and decreased ability to destroy the infection caused by inoculation of E. cloacae cells. A single dose of azadirachtin was able to block the development of T. cruzi in R. prolixus if given through the meal at different intervals, together with, before or after parasite infection. Similarly, these results were observed with different triatomine species and different strains of T. cruzi. Azadirachtin induced a permanent resistance of the vector against reinfection with T. cruzi. The significance of these data is discussed in relation to the general mode of azadirachtin action in insects.

Chemistry of insect antifeedants from Azadirachta indica, Part 14: absolute configuration of azadirachtin

Abstract: The absolute configuration of the insect antifeedant azadirachtin is determined by high field NMR application of the Mosher method and confirmed by X-ray crystallographic analysis.

Experimental Azadirachta indica toxicosis in chicks.

Abstract: Brown Hisex chicks were fed Azadirachta indica ripe fruit at 2, 5 or 10% of basic diet from their 7th to 35th d of age. Decreased body weight gain and efficiency of feed utilization and hepatonephropathy were most severe in chicks fed the 10% A indica diet. These changes were accompanied by anemia and increases in LDH, GOT and ALP activities and uric acid concentration and by decreased serum total protein. Hepatocytes and renal tubular cells did not completely revert to normal 2 w after removal from the test diets.

Plants with insecticidal activities against four major insect pests in Pakistan.

Abstract: Local flora was screened for pesticidal activity against insect pests of field crops, Aesculus indica (flower and leaf) extract was found effective (up to 75% mortality) against sugarcane mealybug (Saccharicoccus sacchari). Schinus molli (leaf), and Aesculus Indica (leaf and flower) extract caused significant (60–70%) mortality in yellow rice stem borer (Schirpophaga incertulas) larvae. Azadirachta indica leaf powder fed to chickpea pod borer (Heliothis armigera) caused failure in pupation and adult emergence. Addition of Azadirachta Indica and Broussentia papyrifera to artificial diet restricted the adult emergence in Heliothis armigera. Similarly, prolonged larval period (21 days compared to 14 in control), delayed pupation and deformed adult formation resulted after treatment with Azadirachta indica (leaf) and Melia azedarech (fruit) powder. Significant mortality (60–90%) was observed in sugarcane pyrilla (Pyrilla perpusilla) adults treated with Azadirachta indica, Dryopteris ramosa and Schinu...

Utilization of Water Washed Neem (Azadirachta indica) Seed Kernel Cake as a Protein Source for Growing Pigs

Abstract: Sixteen 80 days old indigenous pigs, divided in two groups, were fed diets containing either 35, 10, 47, 6, 1.5 and 0.5 parts maize, groundnut cake (GNC), wheat bran, fish meal, mineral mixture and salt (Control) or the same diet with GNC replaced by water washed neem (Azadirachta indica) seed kernel cake (experimental). The pigs on experimental diet, during 180 days of feeding, grew significantly (P<0.05) faster and efficiently (P<0.05) utilised the feed with comparable nutrient digestibility and higher (P<0.01) nitrogen retention. The blood enzyme profile (serum aspartic transaminase, alanine transaminase, alkaline and acid phosphatase) was similar in the two groups. Feed cost per kg pork production was reduced by 11% on experimental diet. Thus incorporation of water washed neem seed kernel cake is recommended for feeding growing pigs.

Nematicidal Principles from Neem (Azadirachta indica A. Juss) Part III Isolation and Bioassay of Some Neem Meliacins

Abstract: Eight pure C-secomeliacirts including azadirachtin, a mixture of isomeric azadirachtins and two fractions of diametrically opposite polarity were derived from neem (Azadirachta indica A. Juss) seed kernels both by isolation and partial synthesis. Different concerttratipns of the C-seco meliacins between 50 and 250 ppm along with carbofuran at 20 ppm as the reference nematicide were evaluated in vitro against root- knot nematode (Meloidogyne incogntta Kofoid and White) Chitwood. The bioassay results expressed as per cent mortality and LC50 values, respectively after 24 and 48 h treatments revealed that all the 8 meliacins were highly nematicidal with LC50 values ranging between 55 and 157 ppm. The non-polar fraction which was tentatively identified as a long chain ketone was inactive and the other two fractions were moderately active. A highly significant positive correlation was obtained between LC50 and Rf of test meliacins, thereby implicating the influence of hydrophilicity of the molecule on nematotoxicity. Another salient observation was the delayed nematicidal action of some meliacins such as nimbin and salannin, which has a striking parallelism to the typical slow mode of action in arthropods.

Antifeeding Potency of Neem ( Azadirachta indica ) Extractives and Limonoids against Termite ( Reticulitermes speratus )

Abstract: ニームオイル (HN) は, 非選択条件下でヤマトシロアリの摂食を阻害した. HNのメタノール抽出物 (HN-01) はHNの4倍の活性を有した. 次いで, 他の12種類のメタノール抽出物を評価したところ, 6種類は強い (PC95<1.0%w/w), 3種類は中程度の (PC95=1～3%w/w) 活性を示し, 残りの3種類は無活性 (PC95検定域外) であった. HN-01の活性画分より精製された11種類の主要なリモノイドによって, HN-01の活性の81.5%が明らかとなった. PC95より高い供試量のとき, 無供餌のものよりも若干はやく死亡する傾向がみられたが, 急性毒性効果は認められなかった. 本研究によりニーム抽出物のシロアリ防除への有用性が示唆された.

The effects of azadirachtin on feeding by Myzus persicae

Abstract: Azadirachtin, a tetranortriterpenoid isolated from the seeds of the neem tree (Azadirachta indica A. Juss), has strong antifeedant effects on a wide range of insects, but there is confusing evidence for its efficacy against aphids. In initial tests, azadirachtin applied systemically, (20 ppm + 0.02% Tween 80) did not deter settling and feeding by Aphis fabae (Scop.), but was strongly antifeedant against locusts (Schistocerca gregaria Forskal) (A.J. Nisbet, unpubl. results).

Triterpene derivatives of azadirachtin having insect antifeedant and growth inhibitory activity and a process for extracting such compounds from the neem plant

Abstract: The invention discloses novel triterpene derivatives of azadirachtin of the formulae 2 to 11 of the drawings and a process for isolating new triterpene derivatives of azadirachtin from the various parts of the neem plant(Azadirachta indica A-Juss), which process comprises grinding the parts of the neem plant to get a powder, extracting the powder with a binary immiscible solvent consisting of one polar and another non-polar solvent in a ratio of 1:2 to obtain an extract, filtering the extract to get a filtrate having two layers, one layer containing lipids and the other layer containing the new triterpene derivatives of azadirachtin and water soluble constituents including sugars, separating the layers by known methods, concentrating the layer containing the new triterpenes of the formulae 2-11 including derivatives of azadirachtin and water soluble salts, treating the resultant concentrate with a polar solvent and if necessary, warm the concentrate having the solvent, and filtering/decanting the resultant solution to produce a filtrate containing the mixture of the new triterpene derivatives of azadirachtin. The lipid layer is concentrated in any known manner, the lipid concentrate is treated with a polar solvent, chilled to a temperature of 0° to -10° C. and filtered to produce a filtrate containing lipids. The new triterpene derivatives of azadirachtin are useful in suppressing the insect pest population below the economic threshold level by their antifeedant and growth inhibitory activities.

Effect of Margosan-O on the development of the leafhopperasymmetrasca decedens

Abstract: The effect of Margosan-O, a formulation of a natural insecticide obtained from the neem (Azadirachta indica A. Juss) tree, on the development of the leafhopperAsymmetrasca decedens (Paoli), was investigated by testing insect performance (i) on cotyledons ofGossypium hirsutum cotton seedlings treated with different concentrations; (ii) on cotton seedlings stood with their petioles in different aqueous dilutions of Margosan-O and recording mortality until the adult stage; and (iii) determining the repellent effect on adults by recording their location on treatedvs untreated cotyledons in choice and no-choice situations. In foliar and in systemic treatments with 2% Margosan-O, practically none of the leafhoppers reached the adult stage. As the concentrations were lowered there was a gradual rise in the percentage of adults emerging; on untreated cotyledons 60-80% of the adults emerged. Feeding was zero or very low at high Margosan-O concentrations. Adult leafhoppers settled in significantly higher numbers on untreated than on treated cotyledons in both choice and no-choice experiments.

Neem (Azadirachta indica A Juss) A Natural Insecticide: Status and Need for Bioassay Standards

Abstract: Neem (Azadirachta indica A Juss) has been closely associated with the socio-cultural and religious aspects of Indian life since ancient times. It is used for various purposes in India and elsewhere. The use of neem for the protection of stored grains and woollen clothes is an age-old practice in India. India has 14 million neem trees, the largest in the world; producing annually 4,13,000 tons of dry fruits which in turn yield 83,000 tons of neem oil and 3,30,000 tons of neem cake. Presently, neem oil is mostly used for soap making while neem cake is used in manures and cattlefeeds. In view of Indian potential and infrastructural facilities, and scientifically proven medicinal, pesticidal and other uses of neem, it has become necessary to exploit it in an integrated manner for its most economical utilization. The availability of technology for neem insecticide and the registration for insect control use have placed neem at a take-off stage for its use on a large scale in India and elsewhere to alternate and/or replace synthetic insecticides to the extent possible in integrated pest management. This paper discusses latest developments in neem science, and suggests greater need of standardization of neem formulations by using biological standards for their successful utilization in insect pest management.