Effects of diethylene glycol butyl ether and butoxyethoxyacetic acid on rat and human erythrocytes

Investigation of the Adulteration of Essential Oils by GC-MS

Background:

A lack of regulation about the chemical composition of essential oils and the growing popularity of these oils among consumers presents an urgent need for the accurate characterization of various oil types from a variety of manufacturers. The aim of this paper was to characterize the composition of essential oils bought from a popular retail location, with the goal of understanding the chemical composition and presence of adulterants with potential toxicity.

Methods:

Reported herein is an investigation into the components of a variety of essential oils using gas chromatography-mass spectrometry (GC-MS). The investigation initially focused on two popular oils, tea tree and lavender oil, and then moved to investigate four additional essential oils from the same brand (sandalwood, rose, eucalyptus, and lemongrass).

Results:

Results of this analysis indicated that all six store brand essential oils contained Carbitol (in concentrations from 23% to 35%), and four of the six oils had diethyl phthalate (in concentrations ranging from 0.33% to 16%). These toxicants are particularly concerning because they are known inhalation hazards, and the intended usage of these oils is for aromatherapy (i.e. inhalation).

Conclusion:

These results highlight a potentially significant and under-reported health concern from inhalation of toxic contaminants in the store brand oils, and showcase the need for more regulation and transparency about the composition of these commercial products.

Fertility and developmental toxicity studies of diethylene glycol monobutyl ether (DGBE) in rats

OBJECTIVES

The solvent, dimethylene glycol monobutyl ether (DGBE), is a component of latex paints, inks; it is used as a degreasing agent, industrial detergent. The aim of the study was evaluating the effects of DGBE administered by gavage on the estrous cycle and given with drinking water on fertility in rats and early development of their progeny.

MATERIALS AND METHODS

Female rats were exposed to DGBE by gavage during 8 weeks at 250, 500 or 1000 mg/kg/day. Vaginal smears were collected during the exposure and 4 weeks after its cessation. Fertility studies were performed in male and female animals exposed to in drinking water. Males were exposed for 10 weeks and then mated with females exposed before mating, during pregnancy and lactation. Young animals were observed during 3 weeks after birth.

RESULTS

DGBE does not cause disturbances of the menstrual cycle in females. Parameters used to assess the general toxicity indicate that males receiving DGBE in drinking water are more sensitive to this compound than females: significantly greater, dose-dependent relative spleen weight, significant decrease in hematological parameters from 8% to 15% depending on the dose, were observed. Clinical chemistry parameters (HDL-cholesterol, BUN) and some markers of oxidative stress differ between the exposed groups and the control one, but without adverse health effect. The microscopic examination of internal organs did not reveal morphological changes in male and female rats.

CONCLUSION

The results of our study on the impact of exposure to DGBE on fertility in rats indicate that the substance administered for 9-10 weeks to females and males at a limit dose of 1000 mg/kg did not impair fertility or viability of their offspring during the first three weeks of life.

Phospholipid bilayer-perturbing properties underlying lysis induced by pH-sensitive cationic lysine-based surfactants in biomembranes

Amino acid-based surfactants constitute an important class of natural surface-active biomolecules with an unpredictable number of industrial applications. To gain a better mechanistic understanding of surfactant-induced membrane destabilization, we assessed the phospholipid bilayer-perturbing properties of new cationic lysine-based surfactants. We used erythrocytes as biomembrane models to study the hemolytic activity of surfactants and their effects on cells' osmotic resistance and morphology, as well as on membrane fluidity and membrane protein profile with varying pH. The antihemolytic capacity of amphiphiles correlated negatively with the length of the alkyl chain. Anisotropy measurements showed that the pH-sensitive surfactants, with the positive charge on the α-amino group of lysine, significantly increased membrane fluidity at acidic conditions. SDS-PAGE analysis revealed that surfactants induced significant degradation of membrane proteins in hypo-osmotic medium and at pH 5.4. By scanning electron microscopy examinations, we corroborated the interaction of surfactants with lipid bilayer. We found that varying the surfactant chemical structure is a way to modulate the positioning of the molecule inside bilayer and, thus, the overall effect on the membrane. Our work showed that pH-sensitive lysine-based surfactants significantly disturb the lipid bilayer of biomembranes especially at acidic conditions, which suggests that these compounds are promising as a new class of multifunctional bioactive excipients for active intracellular drug delivery.

Toxic effects of Litsea elliptica Blume essential oil on red blood cells of Sprague-Dawley rats

Litsea elliptica Blume leaves have been traditionally used as medicinal herbs because of its antimutagenicity, chemopreventative and insecticidal properties. In this study, the toxic effects of L. elliptica essential oil against Sprague-Dawley rat's red blood cells (RBCs) were evaluated. L. elliptica essential oil was given by oral gavage 5 times per week for 3 treated groups in the doses of 125, 250, and 500 mg/(kg body weight), respectively, and the control group received distilled water. Full blood count, RBC osmotic fragility, RBC morphological changes, and RBC membrane lipid were analyzed 28 d after the treatment. Although L. elliptica essential oil administration had significantly different effects on hemoglobin (Hb), mean cell hemoglobin concentration (MCHC), mean cell volume (MCV), and mean cell hemoglobin (MCH) in the experimental groups as compared to the control group (P<0.05), the values were still within the normal range. L. elliptica induced morphological changes of RBC into the form of echinocyte. The percentage of echinocyte increased significantly among the treated groups in a dose-response manner (P<0.001). The concentrations of RBC membrane phospholipids and cholesterol of all treated groups were significantly lower than those of control group (P<0.001). However, the RBC membrane osmotic fragility and total proteins of RBC membrane findings did not differ significantly between control and treated groups (P>0.05). It is concluded that structural changes in the RBC membrane due to L. elliptica essential oil administration did not cause severe membrane damage.

Diethylene glycol monobutyl ether (DGBE): two- and thirteen-week oral toxicity studies in Fischer 344 rats

Standard toxicologic endpoints, supplemented by additional examinations, were studied for groups of 10 Fischer 344 rats/sex given drinking water formulated to supply 0, 50, 250, or 1000 mg diethylene glycol monobutyl ether (DGBE)/kg/day for 13 weeks. These dose levels were based upon initial investigations using drinking water formulated to supply 0, 1000, 1500 or 2000 mg DGBE/kg/day for two weeks. All rats survived the respective treatment intervals with no adverse treatment-related in-life effects, including no alterations in a functional observational battery. In both studies, rats given > or = 1000 mg/kg/day consumed less water and feed and weighed slightly less than controls. For rats given > or = 1000 mg DGBE/kg/day, the liver and red blood cells (RBC) were the primary target organs although the effects were slight. In the 13-week study, rats given 1000 mg/kg/day had statistically significant increased relative liver weight (7-10%) and hepatic cytochrome P450s (24-39%) and UGT (approximately 16%) levels along with slight, statistically significant, decreases in serum total protein, cholesterol and aspartate aminotransferase. Histopathologically, very slight hepatocyte hypertrophy and increased individual hepatocyte degeneration were found in females only. At 1000 mg/kg/day, the RBC count, hemoglobin (Hgb) and hematocrit (Hct) were minimally, but statistically significantly, decreased (5.1-8.7%) but RBC morphology, RBC indices, reticuloctye count and bone marrow and spleen histopathology were unaffected. Absolute and relative kidney weights statistically significantly increased (6-13%) with an equivocal increase in minor histopathologic changes typical of early spontaneous nephropathy. There were no adverse effects on urinalysis, clinical chemistry, sperm parameters or testis histopathology. At 250 mg/kg/day, there were equivocal decreases (approximately 2-3%) in RBC count, Hgb and Hct that were statistically significant for the RBC count and Hgb, but these changes were within the historical control range. This dose level was considered the no adverse effect level (NOAEL).