Saturated hydrocarbons in human femoral arterial tissues and plaques

Mineral oil in food, cosmetic products, and in products regulated by other legislations

For a few years, mineral oils and their potential adverse health effects have been a constant issue of concern in many regulatory areas such as food, cosmetics, other consumer products, and industrial chemicals. Analytically, two fractions can be distinguished: mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). This paper aims at assessing the bioaccumulative potential and associated histopathological effects of MOSH as well as the carcinogenic potential of MOAH for consumer-relevant mineral oils. It also covers the absorption, distribution, metabolism, and excretion of MOSH and MOAH upon oral and dermal exposures. The use and occurrence of consumer-relevant, highly refined mineral oils in food, cosmetics and medicinal products are summarized, and estimates for the exposure of consumers are provided. Also addressed are the challenges in characterizing the substance identity of mineral oil products under REACH. Evidence from more recent autopsy and biopsy studies, along with information on decreasing food contamination levels, indicates a low risk for adverse hepatic lesions that may arise from the retention of MOSH in the liver. With respect to MOAH, at present there is no indication of any carcinogenic effects in animals dermally or orally exposed to highly refined mineral oils and waxes. Such products are used not only in cosmetics but also in medicinal products and as additives in food contact materials. The safety of these mineral oil-containing products is thus indirectly documented by their prevalent and long-term use, with a simultaneous lack of clinical and epidemiological evidence for adverse health effects.

Distribution of hydrocarbons in bovine tissues

Liver, heart, kidneys, muscle and adipose (perirenal and subcutaneous) tissues were collected from six animals for analysis of their hydrocarbon composition. Qualitative and quantitative determinations were carried out by gas chromatography and combined gas chromatography-mass spectrometry. Although differing in the proportions, a homologous series of n-alkanes ranging from n-C12 to n-C31 was found in all the samples examined. The isoprenoid hydrocarbons phytane and phytene (phy-1-ene and phyt-2-ene) were also identified.

Tissue variation in hydrocarbon composition in the rabbit

This study, which deals with the distribution of hydrocarbons in seven types of rabbit tissues, was done for the purpose of providing information that might help shed light on the biological relevance of the hydrocarbons in mammalian metabolism. Liver, kidneys, brain, spleen, skeletal muscle, perinephric adipose, and a sample of blood serum were collected from a single animal for analysis of their hydrocarbon composition. The analytical methodology consisted of solvent extraction, saponification (adipose), elution chromatography on hydrated alumina, and combined gas chromatography-mass spectrometry. Hydrocarbons were detected in all of the tissues examined at concentrations estimated to range from 0.1 to 0.01% of the total lipid extracted Three quite distinct distribution modes were recognized. The bulk of the identified components consisted of normal, saturated, nonterpenoid hydrocarbons in the C16 to C33 range. Squalene, phytene, phytadiene, and pristane were the only terpenoids detected. Nonterpenoid branched (iso and anteiso) hydrocarbons were identified unequivocally and in significant amounts in the muscle only. The adipose was the only tissue which was relatively rich in monoalkenes, and its overall hydrocarbon composition closely resembled that of the feed. The results of the study are not consistent with metabolic inertness. The observed qualitative and quantitative differences might reflect function and metabolic activities of the individual organs in a way yet to be elucidated.

Nature of alkanes in beef heart lipids

n-Alkanes have been found to be the major saturated hydrocarbon components in the fatty tissues on beef heart. These alkanes consist of a homologous series C14-C35, with the C29 and C31 n-alkanes being most abundant. C16, C19, and C20 isoprenoid alkanes also were identified. A C17 isoprenoid alkane tentatively was identified. The fatty tissues on beef heart contained 32 mug/g saturated hydrocarbons. The distribution pattern of these saturated hydrocarbons is in marked contrast to the alkane distribution in beef liver where branched and cyclic alkanes are predominant. The enrichment and the similarity of the n-alkane distribution in the fatty tissues on heart and in pasture plants may have implications for the physiological aspects of hydrocarbons in the diet.

Saturated hydrocarbons in bovine liver

A homologous series of n-alkanes (C(14)-C(33)) and two isoprenoid hydrocarbons, 2,6,10,14-tetramethylhexadecane (phytane) and 2,6,10,14-tetramethylpentadecane (pristane) have been identified in bovine liver. Another branched but non-isoprenoid alkane and three isomers of molecular formula C(20)H(40) were partially identified. Phytane and the C(18)-C(22) and C(29)-C(33)n-alkanes were found to be the major components in liver, suggesting that at least the main hydrocarbon components were derived from various plants in the diet. The hydrocarbons were separated and identified by a series of steps involving solvent extraction, saponification, elution chromatography on alumina and silica gel columns, molecular sieving and by infrared and ultraviolet spectroscopy, followed by combined capillary gas chromatography-mass spectrometry.

Lipid composition of human serum lipoproteins

1. The lipid compositions of the low-density lipoproteins, the high-density lipoproteins and the ultracentrifugal residue of human serum are presented, with emphasis on certain lipoprotein classes and lipid components not previously described. 2. Except for the lipoproteins with the lowest and highest densities, there is a trend for stepwise successive increase or, respectively, decrease in the relative amounts of the main constituents of lipoproteins. 3. High-density lipoprotein-2 and high-density lipoprotein-3 have different amounts of certain lipids; high-density lipoprotein-2 has relatively more free cholesterol and sphingomyelin; high-density lipoprotein-3 has more free fatty acids, diglycerides and ceramide monohexosides. 4. All the lipoproteins contain hydrocarbons of the alkane series. The greatest amount, which averages 4.4% of total lipid extracted, is in the ultracentrifugal residue; n-alkanes comprise 18-50% of the hydrocarbons. 5. All the lipoproteins contain ceramide monohexosides. The highest relative contents of these glycolipids are in high-density lipoprotein-3 and in the ultracentrifugal residue. 6. The ultracentrifugal residue contains 55% of the total quantity of free fatty acids present in serum. The remaining free fatty acids are distributed among the other lipoprotein classes. 7. The choline-containing phospholipids (phosphatidylcholine, lysophosphatidylcholine and sphingomyelin) comprise about 90% of the phospholipids in all the lipoprotein classes except the low-density lipoprotein-2, which contains about 80% of these phospholipids. 8. The presence of a large amount of lysophosphatidylcholine in the ultracentrifugal residue and the successive decrease of sphingomyelin from the low-density lipoprotein-1 to the ultracentrifugal residue was confirmed. 9. The low-density lipoprotein-2 and the ultracentrifugal residue are characterized by relatively high contents of the lower glycerides.