nematicidal carboxylic acids and aldehydes from Melia azedarach fruits.

Melia azedarach is a species gaining scientific interest mostly concerning its range of biological activities against agricultural target pests. The nematicidal melia methanol extract (MME) obtained from the fruits, acting against the phytonematode Meloidogyne incognita , is herein reported to contain hexadecanoic, acetic, and hexanoic acids as well as furfural, 5-hydroxymethylfurfural, 5-methylfurfural, and furfurol. All compounds were tested individually for nematicidal activity against the nematode second-stage juveniles, in paralysis experiments. The nematicidal activity was studied both after nematodes' immersion in treatment solutions and after exposure to test substance vapors. Clear dose and time response relationships were established at the dose ranges of 31.2-500 and 1-100 µg/mL, concerning the aldehydes and carboxylic acids, respectively, implementing analogous predominance of nematicidal activity. Nevertheless, no synergistic effects were observed in respective mixture interaction bioassays among furfural, 5-hydroxymethylfurfural, 5-methylfurfural, and furfurol. Furfural was the most active bionematicidal compound reported herein for the first time as a natural constituent of M. azedarach.

Cytotoxic tirucallane triterpenoids from Melia azedarach fruits.

The phytochemical investigation of the dichloromethane-soluble part of the methanol extract obtained from the fruits of Melia azedarach afforded one new tirucallane-type triterpene, 3-alpha-tigloylmelianol and three known tirucallanes, melianone, 21-beta-acetoxy-melianone, and methyl kulonate. The structure of the isolated compounds was mainly determined by 1D and 2D NMR experiments as well as HPLC-Q-TOF mass spectrometry. The cytotoxicity of the isolated compounds toward the human lung adenocarcinoma epithelial cell line A549 was determined, while no activity was observed against the phytonematode Meloidogyne incognita.

Liquid chromatography electrospray ionization tandem mass spectrometric determination of quassin and neoquassin in fruits and vegetables.

Quassia amara wood chips are used by organic farmers as a valid alternative to synthetic insecticides. The powder of Q. amara contains high levels of quassin, neoquassin and picrasinoside B. In this study we developed a liquid chromatography mass spectrometry method for the rapid and accurate quantification of the insecticide quassinoids on fruits and vegetables. Quassinoids were extracted from fruits and vegetables with acetonitrile and separated on a Zorbax Column Eclipse XDB C8 by isocratic elution with a mobile phase consisting of water and methanol with 0.1% of formic acid. Using a high-performance liquid chromatograph coupled with an electrospray ionization tandem mass spectrometer (HPLC/ESI-MS/MS), quassinoids were selectively and simultaneously detected monitoring the multiple reaction (MRM) transitions of proton adduct precursor ions: m/z 389.5 --> 222.9 for quassin, 391.5 --> 372.9 for neoquassin and 576.1 --> 394.5 for picrasinoside B. For all quassinoids calibration was linear over a working range of 1 and 100 microg/kg with r > 0.991. Limit of determination (LOD) and limit of quantification (LOQ) for both quassinoids were 0.5 and 1 microg/kg respectively while for picrasinoside B they were 5 and 10 microg/kg. Quassinoid recoveries ranged from 85.3% to 105.3% with coefficients of variation between 2.5% and 12.8% for fruit and vegetables. The presence of interfering compounds in the fruit and vegetable extract was evaluated and found to be minimal. Due to the linear behavior it was concluded that the multiple reaction transitions of precursor ions can be used for analytical purposes, i.e. for identification and quantification of quassin, neoquassin, and picrasinoside B in fruit and vegetable extracts at trace levels.

Liquid chromatography-tandem mass spectrometric ion-switching determination of chlorantraniliprole and flubendiamide in fruits and vegetables.

The anthranilic and phthalic diamides, chlorantraniliprole (CAP) and flubendiamide (FLU), respectively, represent a new class of very effective insecticides that activate the ryanodine-sensitive intracellular calcium release channel (ryanodine receptor). This paper reports an analytical method for the simultaneous determination of the two insecticides on fruits and vegetables by liquid chromatography-electrospray tandem mass spectrometry operated in the positive and negative ionization switching mode. The two diamides were extracted with acetonitrile and separated on a Zorbax Column Eclipse XDB C8 (4.6 mm x 150 mm i.d., 3 microm) by isocratic elution with a mobile phase consisting of acetonitrile and water with 0.1% formic acid pumped at a flow rate of 0.4 mL/min. The diamides were selectively detected by multiple reaction monitoring for transitions of proton adduct precursor ions simultaneously: positive m/z 484.3-->285 for CAP, m/z 445.5-->169 for internal standard, and negative m/z 681.4-->253 for FLU. For CAP calibration in the positive mode was linear over a working range of 2 to 1000 microg/L with r > 0.992. The limit of detection (LOD) and limit of quantification (LOQ) for CAP were 0.8 and 1.6 microg/kg, respectively. For FLU in the negative mode the corresponding values were 1-1000 microg/L for linear working range, with r > 0.996 and 0.4 and 0.8 microg/L for LOD and LOQ, respectively. Moreover, the presence of interfering compounds in the fruit and vegetable extracts was found to be minimal. Due to the linear behavior of the MS detector response for the two analytes, it was concluded that the multiple reaction transitions of molecular ions in the ion-switching mode can be used for analytical purposes, that is, for identification and quantification of diamides in fruit and vegetable extracts at trace levels.