salannin and nimbin

One new compound, 2H, 3H-cyclopent[b] furo [2',3':4,5] naphtho [2,4-d] heptlactone-[3,7] furan-6aceticacid, 3-(acetyloxy)-8-(3-furyl)-2a, 4a, 4b, 4c,5,5a, 6, 6a, 8, 9,9a, 10a,10b-13 hydrogen-2a,5a,6a,5-tetramethyl-3-[[(2E)-2-methyl-1-oxo-2-butenyl]oxy]-methyl ester, named azadirachta R (1), along with 10 known ones, Azadirachta A, AZ-B, AZ-D, AZ-H, AZ-I, nimbin, deacetylnimbin, salannin, deacetylsalannin and azadiradione were isolated from the crude extracts of neem (Azadirachta indica A. Juss) seeds, which were determined by UV, IR, HR-ESI-MS and NMR data analyses. According to the in vitro antibacterial activity experimental results, this compound showed good antibacterial activity to two bacteria, the minimum inhibitory concentration and the minimum bactericidal concentration of compound 1 to two kinds of bacteria are 50 and 25 mg/L, respectively, which were determined by resazurin colour-micro-dilution method. The experimental results provide a theoretical basis for the comprehensive utilisation of azadirachtin compounds in the future.

Topics: Anti-Bacterial Agents; Azadirachta; Drug Evaluation, Preclinical; Limonene; Limonins; Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests; Molecular Structure; Plant Extracts; Seeds; Triterpenes

The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. These experiments were carried out at 1 and 5x the concentration recommended by the manufacturer. In all experiments the deposition of azadirachtin A (AZA-A) was below the maximum residue level (MRL). Even if at the highest dose, AZA-A half-life time calculated as pseudo first order kinetic was 1.2 days in agreement with the recommended preharvest interval (PHI) of 3 days. Experiments with a model system showed that sunlight photodegradation is the main factor influencing the rate of disappearance of AZA-A after greenhouse treatment while tomato epicuticular waxes doubled the photodegradation rate of AZA-A in a commercial formulation.

Topics: Chromatography, High Pressure Liquid; Food Technology; Half-Life; Insecticides; Kinetics; Limonene; Limonins; Photolysis; Solanum lycopersicum; Spectrometry, Mass, Electrospray Ionization; Sunlight; Triterpenes

Azadirachtoids were determined by liquid chromatography/mass spectrometry (LC/MS) in five methanolic seed extracts of the neem tree and in a commercial formulation. On average, seed extracts contain azadirachtin A (10.9%), azadirachtin B (3.5%), nimbin (10.4%), and large quantities of salannin (19.0%). The composition of the commercial formulations may present different azadirachtoids contents depending on the natural extracts used in the preparation. Because these compounds may also show insecticide activity, the efficacy on field of these formulations may be very different. Photodegradation of pure azadirachtoids was also studied. Azadirachtins and related compounds are very sensitive to sunlight, degrading rapidly, with half-lives of the order of 11.3 h for azadirachtin A and 5.5 h for azadirachtin B and few minutes for the other limonoids compounds studied. The residues of azadirachtins and the main constituents, e.g., salannin, nimbin, deacetylnimbin, and deacetylsalannin, of the neem seed extract were determined on strawberries after field treatment using two different formulations. This residue study on strawberry was carried out to assess not only the azadirachtin content but also the main azadirachtoids contents. Three days after field application at five times the dose recommended by the manufacturer, residues of azadirachtin A and B were 0.03 and 0.01 mg/kg, respectively, while residues of salannin (LOQ 0.01 mg/kg) and nimbin (LOQ 0.5 mg/kg) were not detectable.

Topics: Azadirachta; Fragaria; Fruit; Half-Life; Limonene; Limonins; Plant Extracts; Sunlight; Triterpenes

Photo-oxidation of the neem limonoids nimbin and salannin with UV light in the presence of oxygen gives two isomeric lactone products per limonoid, nimbinolide and isonimbinolide, and salanninolide and isosalanninolide, respectively. When compared in insect tests with the important limonoids of neem seeds, azadirachtin, nimbin and salannin, isonimbinolide and isosalanninolide show activity greater than that of nimbin or salannin and in some respects show activity approaching that of azadirachtin. The photo-oxidation products were tested for anti-feedant activity and toxicity against larvae of three species of Lepidoptera, Spodoptera littoralis (Boisd), Spodoptera frugiperda (FE Smith) and Helicoverpa armigera (Hübner) and nymphs of the locusts Schistocerca gregaria (Forskål) and Locusta migratoria (L).

Topics: Animals; Azadirachta; Feeding Behavior; Insecticides; Larva; Lepidoptera; Limonene; Limonins; Molecular Structure; Triterpenes

A range of cultured cells of invertebrate and vertebrate origin was grown in the presence of a number of phytochemical pesticides to test the effect of the latter on cell proliferation. The main observation was that azadirachtin was a potent inhibitor of insect cell replication, with an EC50 of 1.5 x 10(10) M against Spodoptera cells and of 6.3 x 10(9) M against Aedes albopictus cells, whilst affecting mammalian cells only at high concentrations (> 10(-4) M). As expected, the other phytochemical pesticides, except for rotenone, had little effect on the growth of the cultured cells. Rotenone was highly effective in inhibiting the growth of insect cells (EC50:10(-8) M) but slightly less toxic towards mammalian cells (EC50:2 x 10(-7) M). Neem terpenoids other than azadirachtin and those very similar in structure significantly inhibited growth of the cell cultures, but to a lesser degree. The major neem seed terpenoids, nimbin and salannin, for example, inhibited insect cell growth by 23% and 15%, respectively.

Topics: Animals; Cell Division; Cell Line; Cells, Cultured; Chrysanthemum cinerariifolium; Diterpenes; Dose-Response Relationship, Drug; Humans; Insecta; Insecticides; Invertebrates; Limonene; Limonins; Molecular Structure; Rotenone; Terpenes; Triterpenes; Tumor Cells, Cultured

A simple and rapid method involving solid phase extraction and liquid chromatography for the determination of azadirachtin-A and -B, nimbin and salannin at nanogram levels in neem oil samples is presented. The neem oil samples are defatted and the compounds of interest extracted by mixing the sample with hexane and passing the hexane solution through a graphitised carbon black column. After washing the column with 2 ml of hexane, azadirachtin-A and -B, nimbin and salannin are eluted with 5 ml of acetonitrile and quantified using HPLC with UV detection. The recoveries of azadirachtin-A and -B, nimbin and salannin in fortified oil samples were 97.4-104.7%. The upper limit of quantification is up to 100 micrograms ml-1 without any additional clean-up and with little interference from lipids during the analysis by HPLC. The method was successfully applied to various neem oil samples collected from different locations in India.

Topics: Antiviral Agents; Diterpenes; Enzyme Inhibitors; Glycerides; Humans; Insect Repellents; Insecticides; Limonene; Limonins; Terpenes; Triterpenes

The effects of azadirachtin, salannin, nimbin, and 6-desacetylnimbin on ecdysone 20-monooxygenase (E-20-M) activity were examined in three insect species. Homogenates of wandering stage third instar larvae of Drosophila melanogaster, or abdomens from adult female Aedes aegypti, or fat body or midgut from fifth instar larvae of Manduca sexta were incubated with radiolabeled ecdysone and increasing concentrations (from 1 x 10(-8) to 1 x 10(-3) M) of the four compounds isolated from seed kernels of the neem tree, Azadirachta indica. All four neem tree compounds were found to inhibit, in a dose-dependent fashion, the E-20-M activity in three insect species. The concentration of these compounds required to elicit a 50% inhibition of this steroid hydroxylase activity in the three insect species examined ranged from approximately 2 x 10(-5) to 1 x 10(-3).

Topics: Aedes; Animals; Aryl Hydrocarbon Hydroxylases; Diterpenes; Drosophila melanogaster; Enzyme Inhibitors; Female; Insecticides; Limonene; Limonins; Manduca; Steroid Hydroxylases; Triterpenes