Acute inhalation toxicity study of n-heneicosane and its combination with diflubenzuron: An attracticide of Aedes aegypti.

OBJECTIVE: Combination of an oviposition pheromone and an insect growth regulator for the control of vectors is an effective approach. There is a need for toxicological evaluation before its introduction. The present study evaluates the acute inhalation toxicity of n-heneicosane and its combination with diflubenzuron in a head-only inhalation exposure chamber made of glass. MATERIALS AND METHODS: A head-only inhalation exposure chamber made of glass (volume: 3.5 l) was used for exposing four rats at a time. A glass nebulizer was used for aerosolization of n-heneicosane and its combination with diflubenzuron (1:10 w/w). Nebulization pressure was 10 and 15 psi and the air flow of exposure the chamber was adjusted to 30 lpm. Male Wistar rats were acclimatized in whole body plethysmographs that were connected to volumetric flow pressure transducers by silicon tubes. The transducers were connected to an amplifier and a digitized response was recorded through an oscillograph and personal computers. Respiratory variables were recorded online. After inhalation exposure, various other parameters like survival, body weight, organ body weight index and biochemical changes were recorded for analysis. RESULTS AND DISCUSSION: Particle size determination proved that the aerosol particles were within the respirable range. LC50 of n-heneicosane and its combination with diflubenzuron was found to be more than 5 g/m3. There were minimal changes observed during exposure to n-heneicosane and also its combination with diflubenzuron on the respiratory variables. The changes were not consistent with the dose. CONCLUSION: n-Heneicosane and its combination with diflubenzuron showed low mammalian toxicity.

Chemical composition and seasonal variation of the volatile oils from Trembleya phlogiformis leaves

ABSTRACT Trembleya phlogiformis DC., Melastomataceae, is a shrub whose leaves are used as a dye for dyeing wool and cotton. The present article aimed to carry out the morphological description of the species, to study the chemical composition of volatile oils from the leaves and flowers and the seasonal variability from the leaves during a year. Macroscopic characterization was carried out with the naked eye and with a stereoscopic microscope. Volatile oils were isolated by hydrodistillation in Clevenger apparatus and analyzed by gas chromatography/mass spectrometry. The major components of the volatile oil of T. phlogiformis flowers were: n-heneicosane (33.5%), phytol (12.3%), n-tricosane (8.4%) and linoleic acid (6.1%). It was verified the existence of a large chemical variability of the volatile oils from the leaves of T. phlogiformis over the months, with the majority compound (oleic alcohol, ranging from 5.7 to 26.8%) present in all samples. A combination of Cluster Analysis and Principal Component Analysis showed the existence of three main clusters, probably related to the seasons. The results suggested that the volatile oils of T. phlogiformis leaves possess high chemical variability, probably related to variation associated with rainfall and the variation in the behavior of specimens throughout the year. This research provides insights for future studies on the volatile oils obtained from the T. phlogiformis leaves and flowers, mainly related to biological markers of applications monitored in the leaves and flowers of this species.

Prenatal developmental toxicity study of n-heneicosane in Wistar rats.

n-Heneicosane (C21) is one of the vital pheromone for attracting mosquitoes of Aedes spp to lay their eggs in areas of stagnant fresh water, for their subsequent destruction, thus controlling spread of dangerous disease transmission by the vectors. As part of a safety evaluation, we have investigated embryo toxic and teratogenic potential, if any, of C21 following OECD Test Guideline 414. C21 was offered at a dose of 1 g/kg body weight mixed in the standard rat pellet diet to treated rats, whereas the control group received only standard rat pellet diet. There were no mortalities and animals did not show any clinical signs of toxicity. A similar pattern of body weight gain, feed and water intake was observed in treated and control groups. Analysis of maternal toxic response, maternal end points of development of the foetus and developmental end points for litters did not show any gross structural abnormality in dams or foetus of treated group compared to that of the control group. Thus, it was concluded that C21 at a dose of 1 g/kg was neither embryo toxic nor teratogenic in Wister rats. Furthermore, the no observed adverse effect level for teratogenicity for C21 in rats may be considered as 1 g/kg body weight under the present experimental conditions.