Plant secondary metabolites as potential bioinsecticides? Study of the effects of plant-derived volatile organic compounds on the reproduction and behaviour of the pest beetle Tenebrio molitor.

Modern agriculture has many environmental consequences, such as soil contamination, accumulation of toxic compounds in the environment or risk of adverse effects on nontarget organisms and for these reasons, scientists are seeking a more environmentally friendly alternative to synthetic insecticides. This study investigated the effects of four plant secondary metabolites classified as volatile organic compounds (VOCs), which have potential as bioinsecticides, (E)-2-decenal, furfural, 2-undecanone and (E,E)-2-4-decadienal, in concentrations 10-5 and 10-7 M, on female reproductive processes and larval hatchability of the Tenebrio molitor beetle. Our study indicates proper development of ovaries after application of compounds however the volume of terminal oocytes was significantly reduced, with the strongest effect of (E)- 2-decenal which reduced the volume approximately three times. The relative vitellogenin expression level was reduced, with the strongest effect observed after application of furfural, (E,E)- 2-4-decadienal and (E)- 2-decenal in concentration 10-7 M, at the same time patency index was significantly reduced up to 2-times after application of furfural at 10-7 M. What is more important morphological changes translated into physiological ones. The number of laid eggs was affected, with the strongest inhibition after application of furfural (∼43% reduction), (E,E)- 2-4-decadienal (∼33%) and (E)- 2-decenal at concentration 10-7 M (∼33%). Moreover, we observed up to 13% (in case of 2-undecanone) decrease in larval hatchability. Tested compounds exhibited a repellent effect and caused 60% reduction of insect survivability after (E)- 2-decenal at concentration 10-5 M. Altogether, VOCs seems like potential bioactive compounds in plant protection.

Synthesis of 3-phenyl-3-phenylthiopropionic acids, amides, amines and studies on their pharmacological properties.

The addition of mercaptobenzene to cinnamic acids yielded 3-phenyl-3-phenylthiopropionic acids which were then converted to the amides. The latter compounds were reduced to the amines with lithium aluminum hydride. Some of the obtained amides displayed significant biological activity.

Synthesis and pharmacological properties of some 7H-[1] benzothiopyrano-[3,2-c] quinolin-7-ones.

The title compounds 3a-d were prepared by intramolecular cyclization of 2-[S-(quinolyl-4)]-thiobenzoic acids 2a-d. The effects of 3a-d on the central nervous system were tested. Among the investigated benzothiopyranoquinolinones, the 2-chloro-6-methyl-derivative (3c) showed analgesic activity in the hot-plate and the writhing tests in doses over 100 mg/kg. Among known, biologically active polycyclic heterocyclic systems [1], benzothiopyranoquinolinones with variously condensed heterocyclic rings, have received little attention. 7H-[1] Benzothiopyrano [3,2-c] quinolin-7-one (3a) is an example of one of the four possible isomers in such systems. In continuation of our search for new centrally active compounds [12], we report here the synthesis and characterization of the parent system 3a and its three derivatives 3b-d. Since some thioxanthene derivatives [9] are known to be neuroleptic drugs, and few known in literature compounds [2, 13, 20] derived from the 3a system have not been tested pharmacologically for the central nervous system activity, we decided to investigate the influence of [1]-benzothiopyranoquinolinones 3a-d on the central nervous system of mice. The results of pharmacological screening are presented in this paper.

Synthesis and pharmacological screening of some N-carboxymethylbarbituric acid derivatives. I.

Reaction of haloacetate with barbital and methylphenobarbital in polar aprotic solvents in the presence of anhydrous K2CO3 gave N-carboalkoxymethyl derivatives in good yields. Acidic hydrolysis of the latter compounds affords N-carboxymethyl derivatives of barbital 8 or methylphenobarbital 7. From acid 7 and 8 via acid chlorides, amides 11--20 were prepared. These amides lack anticonvulsant activity and show only slight sedative and analgesic action.