Clinical safety of lauric acid for cattle and its in vitro and in vivo efficacy against Rhipicephalus microplus

The aim of the present study was to test the in vitro acaricidal activity of saturated fatty acids (hexanoic, octanoic, decanoic, lauric, myristic, palmitic, octadecanoic, eicosanoic, docosanoic and tetracosanoic) against Rhipicephalus microplus and select a candidate compound for the subsequent determination of its clinical safety for mice and bovines as well as its in vivo efficacy (ethical clearance number 507/2013). None of the compounds exhibited in vitro larvicidal effectiveness, but acaricidal effectiveness was greater than 95 % in the adult immersion test at 40 mg/ml (hexanoic, octanoic, decanoic, lauric, myristic, palmitic and eicosanoic acids). After a second AIT evaluation of serial concentrations of the fatty acids, lauric and myristic acids were selected for the safety and in vivo efficacy assays. No adverse effect was found in the local lymph node assay in mice treated with lauric or myristic acid. Moreover, no clinical signs of systemic poisoning or dermatological, hematological or biochemical abnormalities were found in cattle after the topical application of 1 % lauric acid. In the dose determination test, the 1% solution of this compound exhibited 86% efficacy in cattle naturally infested by a field population of Rhipicephalus microplus susceptible to all chemical groups, except synthetic pyrethroids. The efficacy of 1 % lauric acid was 53.4 % in the dose confirmation test performed on another herd with a field R. microplus population resistant to all chemical groups of acaricides. In conclusion, fatty acids are potential bioactive compounds for the control of R. microplus. Topically applied lauric acid (C12) exhibits in vivo acaricide activity against adults, nymphs and larvae of R. (B) microplus and is safe for cattle.

Protective effects and potential mechanism of salvianolic acid B on sodium laurate-induced thromboangiitis obliterans in rats

BACKGROUND

The root of Salvia miltiorrhiza f. alba (RSMA) (Lamiaceae) is used for the treatment of patients with thromboangiitis obliterans (TAO) in traditional Chinese medicine. Previously, a mixture of phenolic acids extracted from RSMA has shown significant protective effects on TAO rats.

PURPOSE

This study investigates the inhibitory effects of salvianolic acid B on TAO induced by sodium laurate injection in rats to explore the effective constituents of RSMA in TAO treatment.

METHODS

TAO rats were developed using injected sodium laurate. After treatment with ligustrazine hydrochloride (15 mg/kg) and various doses of salvianolic acid B (10, 20, 40 mg/kg) by tail intravenous injection, levels of thromboxane B₂ (TXB₂), 6-keto-prostaglandin F_1α (6-keto-PGF_1α) and endothelin-1 (ET-1) in plasma were determined using enzyme-linked immunosorbent assay. The right femoral arteries were studied by hematoxylin and eosin staining and immunohistochemical analysis to determine pathological changes and overexpression of tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) in the femoral artery walls of TAO rats.

RESULTS

Salvianolic acid B significantly decreased the expressions of TXB₂ and ET-1 and increased the expression of 6-keto-PGF_1α in plasma, and significantly inhibited the overexpression of TNF-α and iNOS in the femoral artery walls of TAO rats at medium and high doses.

CONCLUSION

Salvianolic acid B has a protective effect on TAO rats. The mechanism may involve inhibition of thrombosis and TAO-associated inflammatory responses, which may explain the success of RSMA treatment of TAO in humans in traditional Chinese medical practice. Hence, it may be a potential drug for TAO treatment in conventional medicine.

Good Fats versus Bad Fats: A Comparison of Fatty Acids in the Promotion of Insulin Resistance, Inflammation, and Obesity

Recently, debate has erupted in both the scientific community and throughout the lay public around whether a low-fat or low-carbohydrate diet is better for weight loss. In other words, is it better to cut fat or cut carbohydrate for weight loss. However, going beyond this debate (fat versus carbohydrate), are questions around whether certain fatty acids are worse for promoting insulin resistance, inflammation, and obesity. The overall evidence in the literature suggests that medium-chain saturated fats (such as lauric acid, found in coconut oil) and monounsaturated fat (oleic acid, found in olive oil) are less likely to promote insulin resistance, inflammation, and fat storage compared to long-chain saturated fatty acids (such as stearic acid found in large quantities in butter, but particularly palmitic acid found in palm oil) especially when consumed on top of a diet moderate in refined carbohydrates. Compared to long-chain saturated fats, lauric acid and oleic acid have an increased fatty acid oxidation rate, are more likely to be burned for energy and less likely to be stored in adipose tissue, and thus promote increased energy expenditure. Omega-6 polyunsaturated fatty acids (PUFAs), such as linoleic acid, as found in vegetable oils may contribute to obesity, whereas omega-3 PUFA may be protective. Importantly, both olive oil as part of a Mediterranean diet, and omega-3 from fish and fish oil have been proven to reduce risk of cardiovascular (CV) events.

Combinatorial use of sodium laurate with taurine or L-glutamine enhances colonic absorption of rebamipide, poorly absorbable antiulcer drug, without any serious histopathological mucosal damages

We previously reported that the combinatorial use of sodium laurate (C12) with several amino acids such as taurine (Tau) and L-glutamine (L-Gln) enhanced the colonic absorption of phenol red with attenuating the local toxicity caused by C12. However, even these amino acids could not protect epithelial cells from being damaged if the mucosal damage got worse to the coagulation necrosis by an excessive dose of C12. Comparing C12 with sodium caprate (C10), used in drug products marketed, 100 micromol C10 was needed to exert the similar absorption-enhancement of rebamipide, a poorly absorbable antiulcer drug, to that by 10 micromol C12, and 100 micromol C10 was obviously more toxic to the mucosa than 10 micromol C12. The combinatorial use of C12 with Tau or L-Gln enhanced the colonic absorption of rebamipide four to nine times larger in AUC than the control. Histopathologic studies clearly showed that Tau and L-Gln exerted the cytoprotective action on epithelial cells suffering from slight damages such as shrinkage and exfoliation, more articulately at 6 h than at 1.5 h after dosing. In conclusion, the combinatorial use of C12 with Tau or L-Gln could lead to a novel formulation improving the bioavailability of poorly absorbable drugs without any serious local damages.

Amino acids protect epithelial cells from local toxicity by absorption enhancer, sodium laurate

To develop the safe absorption-enhancing formulation attenuating the local toxicity caused by an absorption enhancer, sodium laurate (C12), the effects of amino acids on the local toxicity by C12 were examined in rats. The absorption of phenol red, an unabsorbable marker drug, was significantly enhanced by 10 mM C12 in an in situ colon loop study and the addition of L-glutamine (L-Gln), L-arginine, or L-methionine at 10 mM did not change the promoting effect of C12. However, C12 significantly increased the elution of phospholipids, total protein, and lactate dehydrogenase, which are markers for local toxicity, from colon, but these amino acids attenuated the local toxicity caused by C12 significantly. Transport study using an Ussing-type chamber showed that the permeability of colonic membrane to phenol red was significantly enhanced by C12 and that L-Gln did not decrease the permeability enhanced by C12. Transmucosal electrical resistance was extensively decreased by C12, indicating that C12 could enhance the drug absorption at least partly by expanding the paracellular route. L-Gln significantly, but not completely, recovered resistance lowered by C12. Electrical potential difference was markedly reduced by C12, suggesting that C12 lowered the viability of mucosal cells, but 10 mM L-Gln significantly recovered potential difference almost to the control level. These results suggested the possibility that absorption-enhancing formulation with low local toxicity, which is low enough to be used practically, could be developed by using an amino acid like L-Gln as an ingredient attenuating the local toxicity caused by C12.

A two-center study of the development of acute irritation responses to fatty acids

BACKGROUND

A human 4-hour patch test has been developed for evaluating the acute irritation potential of chemicals. This method was developed for comparative irritation assessments. Although skin irritation responses in human subjects can be quite variable, this test method has proven robust in both intra- and interlaboratory tests. However, the previous interlaboratory studies were not optimal in that slightly differing protocols were used and the studies were not controlled for time of year or source of test chemicals. As a result, some variation in acute irritation responses were seen that might have been reduced somewhat had these variables been controlled to a greater extent.

OBJECTIVE

The purpose of the current study was to examine interlaboratory reproducibility of the 4-hour patch test when conducted under as identical as set of test conditions as possible.

METHODS

Two laboratories conducted a direct comparison study of the acute irritation potential of three structurally related, undiluted fatty acids (octanoic acid, decanoic acid, and dodecanoic acid) in comparison to a benchmark positive control chemical (20% sodium dodecyl sulfate [SDS]). The studies were run within a 4-month period using the same commercial source of test chemicals. Test subjects were treated with each chemical under occluded patch conditions for gradually increasing exposure duration up to 4 hours. The results were then evaluated in terms of total cumulative incidence of positive responses and time response patterns.

RESULTS

Using statistical comparisons of the proportion of the subjects with a positive irritant reaction to each substance, the rank order of irritation potential was decanoic acid >/= octanoic acid > SDS >> and dodecanoic acid. The statistical comparisons and the time-response patterns for each chemical were nearly identical at the two laboratories. There were also very similar, and intriguing, variations in the interchemical response patterns seen in the two studies.

CONCLUSION

When conducted under as controlled a set of test conditions as was reasonably possible, this acute irritation protocol shows remarkably high consistency across independent test laboratories, further supporting its continued development and acceptance as a valid and more predictive tool for assessing skin irritation potential.

Dietary saturated and trans fatty acids and lipoprotein metabolism

Earlier studies have shown that not all saturated fatty acids are equally hypercholesterolaemic: stearic acid (C18:0) and saturated fatty acids with less than 12 carbon atoms are thought not to raise serum cholesterol levels. This suggests that the cholesterol-raising effects of saturated fatty acids can be attributed to lauric acid (C12:0), myristic acid (C14:0) and palmitic acid (C16:0). These three saturated fatty acids also have different effects on serum total cholesterol levels. Results from recent controlled dietary experiments suggest that lauric acid raises serum total and low-density lipoprotein (LDL) cholesterol levels slightly less, and myristic acid more, as compared with palmitic acid. Myristic acid, however, also causes higher levels of high-density lipoprotein (HDL) cholesterol. Stearic acid has only a slight effect on serum LDL and HDL cholesterol levels as compared with oleic acid. Trans monounsaturated fatty acids, however, increase LDL and decrease HDL cholesterol levels. Precise effects on lipoproteins of short and medium chain triglycerides (C4:0-C10:0) have never been examined.

Lauryl ether sulphate dermatitis in Denmark

Lauryl ether sulphate (LES), a synthetic detergent, may sometimes contain an allergenic impurity, which has given rise to several outbreaks of contact dermatitis. Such an outbreak occurred in Denmark in 1971. All cases diagnosed were confined to one household, while other cases may have passed unnoticed.