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The purpose of this work was to stud the biodegradation of citronellol, citronellal and citronellyl acetate by a soil Pseudomonas mendocina strain (IBPse 105) isolated from a Cymbopogon windelandi field. This strain efficiently used citronellol, citronellal, citronellyl acetate and myrcene as sole source of carbon, but was not able to grow on other 15 monoterpenoids evaluated.Gas chromatography-mass spectrometry (GC-MS) analysis of metabolites accumulation during P. medocina IBPse 105 growth on citronellol showed that this strain uses the citronellol catabolic pathway described for other species of the genus. IBPse 105 degradation of citronellyl acetate initiates by its hydrolysis to citronellol. The mini-Tn5 insertion in mutant IBPse 105-303, impaired in citronellol degradation, but able to grow on citronellal, was located in a homologous of the P. aeruginosa atuB gene, that codifies citronellol deshydrogenase. [ABSTRACT FROM AUTHOR]

Nematicidal activity of 22 monoterpenoids were evaluated in vitro and in pot experiments. Twenty of the twenty-two monoterpenoids significantly reduced hatching, and 11 reduced J2 mobility of the root-knot nematode Meloidogyne incognita at a concentration of 250 mg/liter. In general, compounds with hydroxyl and carbonyl groups exhibited higher nematicidal activity than other terpenoids. Borneol, carveol, citral, geraniol, and ct-terpineol showed the highest nematicidal activity among the in vitro tested monoterpenoids. These compounds exhibited a dose dependent effect, and drastically reduced eggs hatching and J2 viability at low concentrations. These monoterpenoids, at 100 and 250 mg/kg concentration, diminished root galling of tomato plants in pot experiments. The results suggest that the selected monoterpenoids, and essential oils with high concentration of these compounds, are potential nematicides against Meloidogyne. [ABSTRACT FROM AUTHOR]

Volatile oils from aerial parts of 10 Brazilian accessions of Cunila spicata were characterized by analytical gas chromatography and gas chromatography/mass spectroscopy. Twenty-three constituents accounting fir 89.04-98.00% of the total essential oil were identified. Four new chemotypes of this species with high concentrations of linalool/1,8- cineole, 1 ,8-cineole, carvone/carveol, and 1 ,8-cineole/limonene were identified. Geographically, all the accessions from the Southeast range of Rio Grande do Sul State belonged to the linalool/1,8-cineole chemotype, where those from the Northeast mountains of the State were distributed in the four chemical groups. [ABSTRACT FROM AUTHOR]

Urinary tract infection by Proteus mirabilis depends on several virulence properties that are coordinately regulated with swarming differentiation. Here we report the antibacterial and anti-swarming effect of seventeen terpenoids, and the effect of subinhibitory concentrations of five selected terpenoids on swarming, biofilm formation and haemolysin activity. The results showed that all the terpenes evaluated, particularly oxygenated terpenoids, inhibited P. mirabilis with MIC values ranging between 3 and 10 mg/L. Moreover, citral, citronellol and geraniol effectively inhibit P. mirabilis swarming in a dose dependent manner, reducing swimming/swarming cell differentiation and haemolysin activity at 1/10 MIC concentration. The inhibition of P. mirabilis swarming and virulence factor expression by selected oxygenated terpenoids suggest that essential oils with high concentration of these compounds have the potential to be developed as products for preventing P. mirabilis infections.